WEBVTT 00:00.640 --> 00:04.670 align:start position:0% Our<00:00:00.920> moon<00:00:01.280> surface<00:00:02.000> is<00:00:02.480> covered<00:00:03.160> with<00:00:03.360> scars 00:04.670 --> 00:04.680 align:start position:0% Our moon surface is covered with scars 00:04.680 --> 00:06.870 align:start position:0% Our moon surface is covered with scars left<00:00:04.920> behind<00:00:05.440> from<00:00:05.640> the<00:00:05.760> countless<00:00:06.320> impacts 00:06.870 --> 00:06.880 align:start position:0% left behind from the countless impacts 00:06.880 --> 00:08.510 align:start position:0% left behind from the countless impacts throughout<00:00:07.280> its<00:00:07.480> life. 00:08.510 --> 00:08.520 align:start position:0% throughout its life. 00:08.520 --> 00:10.590 align:start position:0% throughout its life. Reminders<00:00:09.200> that<00:00:09.400> the<00:00:09.560> early<00:00:09.840> solar<00:00:10.160> system 00:10.590 --> 00:10.600 align:start position:0% Reminders that the early solar system 00:10.600 --> 00:14.230 align:start position:0% Reminders that the early solar system was<00:00:10.840> a<00:00:10.960> very<00:00:11.640> violent<00:00:12.160> place. 00:14.230 --> 00:14.240 align:start position:0% was a very violent place. 00:14.240 --> 00:16.990 align:start position:0% was a very violent place. But<00:00:14.360> amongst<00:00:14.760> this<00:00:15.040> pockmarked<00:00:16.000> backdrop, 00:16.990 --> 00:17.000 align:start position:0% But amongst this pockmarked backdrop, 00:17.000 --> 00:19.430 align:start position:0% But amongst this pockmarked backdrop, one<00:00:17.200> crater<00:00:17.680> stands<00:00:18.160> out. 00:19.430 --> 00:19.440 align:start position:0% one crater stands out. 00:19.440 --> 00:20.990 align:start position:0% one crater stands out. If<00:00:19.600> you've<00:00:19.800> ever<00:00:20.000> looked<00:00:20.200> closely<00:00:20.800> at<00:00:20.920> the 00:20.990 --> 00:21.000 align:start position:0% If you've ever looked closely at the 00:21.000 --> 00:24.190 align:start position:0% If you've ever looked closely at the full<00:00:21.200> moon,<00:00:21.920> you<00:00:22.120> might<00:00:22.400> recognize<00:00:23.240> this, 00:24.190 --> 00:24.200 align:start position:0% full moon, you might recognize this, 00:24.200 --> 00:26.390 align:start position:0% full moon, you might recognize this, Tycho<00:00:24.840> crater. 00:26.390 --> 00:26.400 align:start position:0% Tycho crater. 00:26.400 --> 00:28.550 align:start position:0% Tycho crater. Its<00:00:26.560> long<00:00:27.120> white<00:00:27.440> rays<00:00:27.840> stretch<00:00:28.200> out<00:00:28.320> like 00:28.550 --> 00:28.560 align:start position:0% Its long white rays stretch out like 00:28.560 --> 00:31.630 align:start position:0% Its long white rays stretch out like fingers<00:00:29.240> over<00:00:29.520> the<00:00:29.640> lunar<00:00:29.960> surface. 00:31.630 --> 00:31.640 align:start position:0% fingers over the lunar surface. 00:31.640 --> 00:34.950 align:start position:0% fingers over the lunar surface. This<00:00:31.840> crater<00:00:32.400> is<00:00:32.840> 85<00:00:33.560> km<00:00:34.040> across<00:00:34.800> with<00:00:34.920> a 00:34.950 --> 00:34.960 align:start position:0% This crater is 85 km across with a 00:34.960 --> 00:38.470 align:start position:0% This crater is 85 km across with a central<00:00:35.400> mountain<00:00:35.920> 2.5<00:00:36.920> km<00:00:37.440> high,<00:00:38.160> and<00:00:38.240> it<00:00:38.320> was 00:38.470 --> 00:38.480 align:start position:0% central mountain 2.5 km high, and it was 00:38.480 --> 00:42.150 align:start position:0% central mountain 2.5 km high, and it was created<00:00:38.920> by<00:00:39.360> a<00:00:39.720> cataclysmic<00:00:40.680> event,<00:00:41.600> one<00:00:41.920> of 00:42.150 --> 00:42.160 align:start position:0% created by a cataclysmic event, one of 00:42.160 --> 00:44.750 align:start position:0% created by a cataclysmic event, one of such<00:00:42.600> scale<00:00:43.480> that<00:00:43.600> not<00:00:43.840> only<00:00:44.080> was<00:00:44.240> ejecta 00:44.750 --> 00:44.760 align:start position:0% such scale that not only was ejecta 00:44.760 --> 00:46.830 align:start position:0% such scale that not only was ejecta catapulted<00:00:45.480> to<00:00:45.560> the<00:00:45.800> opposite<00:00:46.320> side<00:00:46.600> of<00:00:46.680> the 00:46.830 --> 00:46.840 align:start position:0% catapulted to the opposite side of the 00:46.840 --> 00:48.110 align:start position:0% catapulted to the opposite side of the moon, 00:48.110 --> 00:48.120 align:start position:0% moon, 00:48.120 --> 00:50.030 align:start position:0% moon, but<00:00:48.240> its<00:00:48.360> effects<00:00:48.840> were<00:00:48.960> felt<00:00:49.560> all<00:00:49.760> the<00:00:49.880> way 00:50.030 --> 00:50.040 align:start position:0% but its effects were felt all the way 00:50.040 --> 00:52.430 align:start position:0% but its effects were felt all the way back<00:00:50.320> here<00:00:50.640> on<00:00:50.960> Earth. 00:52.430 --> 00:52.440 align:start position:0% back here on Earth. 00:52.440 --> 00:53.750 align:start position:0% back here on Earth. But<00:00:52.560> what<00:00:52.720> collided<00:00:53.200> with<00:00:53.320> the<00:00:53.400> moon<00:00:53.640> to 00:53.750 --> 00:53.760 align:start position:0% But what collided with the moon to 00:53.760 --> 00:56.070 align:start position:0% But what collided with the moon to create<00:00:54.080> this<00:00:54.280> huge<00:00:54.720> scar? 00:56.070 --> 00:56.080 align:start position:0% create this huge scar? 00:56.080 --> 00:57.950 align:start position:0% create this huge scar? When<00:00:56.360> did<00:00:56.520> it<00:00:56.680> happen? 00:57.950 --> 00:57.960 align:start position:0% When did it happen? 00:57.960 --> 01:00.230 align:start position:0% When did it happen? And<00:00:58.200> how<00:00:58.760> did<00:00:58.920> it<00:00:59.040> impact<00:00:59.480> life<00:00:59.760> here<00:01:00.040> on 01:00.230 --> 01:00.240 align:start position:0% And how did it impact life here on 01:00.240 --> 01:01.990 align:start position:0% And how did it impact life here on Earth? 01:01.990 --> 01:02.000 align:start position:0% Earth? 01:02.000 --> 01:03.670 align:start position:0% Earth? I'm<00:01:02.200> Alex<00:01:02.440> Mcalgon,<00:01:03.040> and<00:01:03.200> you're<00:01:03.360> watching 01:03.670 --> 01:03.680 align:start position:0% I'm Alex Mcalgon, and you're watching 01:03.680 --> 01:06.390 align:start position:0% I'm Alex Mcalgon, and you're watching Astrum.<00:01:04.720> Join<00:01:05.040> me<00:01:05.360> as<00:01:05.519> we<00:01:05.640> head<00:01:05.960> up<00:01:06.160> to<00:01:06.280> the 01:06.390 --> 01:06.400 align:start position:0% Astrum. Join me as we head up to the 01:06.400 --> 01:08.710 align:start position:0% Astrum. Join me as we head up to the lunar<00:01:06.720> surface<00:01:07.360> to<00:01:07.480> learn<00:01:07.880> all<00:01:08.200> there<00:01:08.400> is<00:01:08.600> to 01:08.710 --> 01:08.720 align:start position:0% lunar surface to learn all there is to 01:08.720 --> 01:11.230 align:start position:0% lunar surface to learn all there is to know<00:01:09.000> about<00:01:09.440> our<00:01:09.640> moon's<00:01:10.000> incredible<00:01:10.840> Tycho 01:11.230 --> 01:11.240 align:start position:0% know about our moon's incredible Tycho 01:11.240 --> 01:12.350 align:start position:0% know about our moon's incredible Tycho crater, 01:12.350 --> 01:12.360 align:start position:0% crater, 01:12.360 --> 01:15.030 align:start position:0% crater, and<00:01:12.480> to<00:01:12.560> explore<00:01:13.080> its<00:01:13.440> greatest<00:01:14.080> mysteries, 01:15.030 --> 01:15.040 align:start position:0% and to explore its greatest mysteries, 01:15.040 --> 01:17.230 align:start position:0% and to explore its greatest mysteries, many<00:01:15.400> of<00:01:15.480> which<00:01:16.000> are<00:01:16.160> still<00:01:16.720> baffling 01:17.230 --> 01:17.240 align:start position:0% many of which are still baffling 01:17.240 --> 01:20.670 align:start position:0% many of which are still baffling scientists<00:01:17.840> to<00:01:17.960> this<00:01:18.160> day. 01:20.670 --> 01:20.680 align:start position:0% scientists to this day. 01:20.680 --> 01:22.750 align:start position:0% scientists to this day. There<00:01:20.960> are<00:01:21.200> thousands<00:01:21.840> of<00:01:21.960> impact<00:01:22.280> craters<00:01:22.640> on 01:22.750 --> 01:22.760 align:start position:0% There are thousands of impact craters on 01:22.760 --> 01:23.790 align:start position:0% There are thousands of impact craters on the<00:01:22.840> moon. 01:23.790 --> 01:23.800 align:start position:0% the moon. 01:23.800 --> 01:26.750 align:start position:0% the moon. 5,000<00:01:24.360> of<00:01:24.440> which<00:01:24.960> are<00:01:25.080> more<00:01:25.280> than<00:01:25.440> 20<00:01:26.000> km<00:01:26.600> in 01:26.750 --> 01:26.760 align:start position:0% 5,000 of which are more than 20 km in 01:26.760 --> 01:28.030 align:start position:0% 5,000 of which are more than 20 km in width. 01:28.030 --> 01:28.040 align:start position:0% width. 01:28.040 --> 01:31.030 align:start position:0% width. But<00:01:28.120> Tycho,<00:01:28.880> named<00:01:29.240> for<00:01:29.360> the<00:01:29.800> infamous<00:01:30.520> 16th 01:31.030 --> 01:31.040 align:start position:0% But Tycho, named for the infamous 16th 01:31.040 --> 01:34.270 align:start position:0% But Tycho, named for the infamous 16th century<00:01:31.680> Danish<00:01:32.120> astronomer<00:01:32.760> Tycho<00:01:33.280> Brahe, 01:34.270 --> 01:34.280 align:start position:0% century Danish astronomer Tycho Brahe, 01:34.280 --> 01:36.830 align:start position:0% century Danish astronomer Tycho Brahe, is<00:01:34.720> one<00:01:34.920> of<00:01:35.000> the<00:01:35.080> most<00:01:35.320> prominent. 01:36.830 --> 01:36.840 align:start position:0% is one of the most prominent. 01:36.840 --> 01:39.430 align:start position:0% is one of the most prominent. Formed<00:01:37.160> by<00:01:37.520> an<00:01:37.680> enormous<00:01:38.440> collision,<00:01:39.160> more<00:01:39.360> on 01:39.430 --> 01:39.440 align:start position:0% Formed by an enormous collision, more on 01:39.440 --> 01:42.750 align:start position:0% Formed by an enormous collision, more on that<00:01:39.640> later,<00:01:40.480> and<00:01:40.640> stretching<00:01:41.240> 85<00:01:42.080> km<00:01:42.640> in 01:42.750 --> 01:42.760 align:start position:0% that later, and stretching 85 km in 01:42.760 --> 01:45.390 align:start position:0% that later, and stretching 85 km in diameter,<00:01:43.760> Tycho<00:01:44.120> crater<00:01:44.520> is<00:01:44.760> large<00:01:45.160> enough 01:45.390 --> 01:45.400 align:start position:0% diameter, Tycho crater is large enough 01:45.400 --> 01:47.110 align:start position:0% diameter, Tycho crater is large enough to<00:01:45.520> be<00:01:45.680> visible<00:01:46.160> from<00:01:46.440> Earth<00:01:46.760> with<00:01:46.880> the 01:47.110 --> 01:47.120 align:start position:0% to be visible from Earth with the 01:47.120 --> 01:50.070 align:start position:0% to be visible from Earth with the unaided<00:01:47.920> eye,<00:01:48.600> particularly<00:01:49.480> when<00:01:49.680> the<00:01:49.760> moon 01:50.070 --> 01:50.080 align:start position:0% unaided eye, particularly when the moon 01:50.080 --> 01:51.830 align:start position:0% unaided eye, particularly when the moon is<00:01:50.320> full. 01:51.830 --> 01:51.840 align:start position:0% is full. 01:51.840 --> 01:56.430 align:start position:0% is full. From<00:01:52.000> its<00:01:52.160> rim<00:01:52.640> to<00:01:52.760> its<00:01:53.000> floor,<00:01:53.840> it<00:01:53.960> is<00:01:54.360> 4.8<00:01:55.600> km 01:56.430 --> 01:56.440 align:start position:0% From its rim to its floor, it is 4.8 km 01:56.440 --> 01:57.550 align:start position:0% From its rim to its floor, it is 4.8 km deep. 01:57.550 --> 01:57.560 align:start position:0% deep. 01:57.560 --> 01:59.390 align:start position:0% deep. To<00:01:57.640> give<00:01:57.840> you<00:01:58.000> a<00:01:58.040> sense<00:01:58.360> of<00:01:58.480> scale,<00:01:59.120> that's 01:59.390 --> 01:59.400 align:start position:0% To give you a sense of scale, that's 01:59.400 --> 02:01.630 align:start position:0% To give you a sense of scale, that's more<00:01:59.640> than<00:01:59.800> twice<00:02:00.440> as<00:02:00.680> deep<00:02:01.120> as<00:02:01.240> the<00:02:01.360> Grand 02:01.630 --> 02:01.640 align:start position:0% more than twice as deep as the Grand 02:01.640 --> 02:03.950 align:start position:0% more than twice as deep as the Grand Canyon<00:02:02.080> here<00:02:02.320> on<00:02:02.520> Earth. 02:03.950 --> 02:03.960 align:start position:0% Canyon here on Earth. 02:03.960 --> 02:06.790 align:start position:0% Canyon here on Earth. Bright<00:02:04.479> rays<00:02:05.000> emanate<00:02:05.479> from<00:02:05.640> its<00:02:05.760> epicenter, 02:06.790 --> 02:06.800 align:start position:0% Bright rays emanate from its epicenter, 02:06.800 --> 02:10.029 align:start position:0% Bright rays emanate from its epicenter, reaching<00:02:07.240> out<00:02:07.800> thousands<00:02:08.640> of<00:02:08.759> kilometers. 02:10.029 --> 02:10.039 align:start position:0% reaching out thousands of kilometers. 02:10.039 --> 02:12.150 align:start position:0% reaching out thousands of kilometers. This<00:02:10.360> curious<00:02:11.040> splash<00:02:11.360> pattern<00:02:11.760> is<00:02:11.959> what 02:12.150 --> 02:12.160 align:start position:0% This curious splash pattern is what 02:12.160 --> 02:14.550 align:start position:0% This curious splash pattern is what happens<00:02:12.600> when<00:02:12.800> a<00:02:12.920> massive<00:02:13.480> object<00:02:13.959> impacts 02:14.550 --> 02:14.560 align:start position:0% happens when a massive object impacts 02:14.560 --> 02:17.550 align:start position:0% happens when a massive object impacts lunar<00:02:14.840> soil,<00:02:15.640> sending<00:02:16.000> debris<00:02:16.440> flying<00:02:17.400> with 02:17.550 --> 02:17.560 align:start position:0% lunar soil, sending debris flying with 02:17.560 --> 02:20.470 align:start position:0% lunar soil, sending debris flying with enough<00:02:17.840> force<00:02:18.160> to<00:02:18.440> wrap<00:02:18.840> around<00:02:19.240> the<00:02:19.320> moon 02:20.470 --> 02:20.480 align:start position:0% enough force to wrap around the moon 02:20.480 --> 02:24.350 align:start position:0% enough force to wrap around the moon all<00:02:20.640> the<00:02:20.760> way<00:02:21.240> to<00:02:21.400> its<00:02:21.760> opposite<00:02:22.400> side. 02:24.350 --> 02:24.360 align:start position:0% all the way to its opposite side. 02:24.360 --> 02:25.670 align:start position:0% all the way to its opposite side. Let's<00:02:24.480> take<00:02:24.640> a<00:02:24.720> closer<00:02:25.080> look<00:02:25.320> at<00:02:25.400> some<00:02:25.520> of<00:02:25.600> the 02:25.670 --> 02:25.680 align:start position:0% Let's take a closer look at some of the 02:25.680 --> 02:27.990 align:start position:0% Let's take a closer look at some of the features<00:02:26.000> of<00:02:26.080> Tycho<00:02:26.440> crater<00:02:27.200> and<00:02:27.400> see<00:02:27.760> what 02:27.990 --> 02:28.000 align:start position:0% features of Tycho crater and see what 02:28.000 --> 02:30.390 align:start position:0% features of Tycho crater and see what they<00:02:28.160> can<00:02:28.360> teach<00:02:28.680> us<00:02:28.880> about<00:02:29.200> its<00:02:29.360> origins. 02:30.390 --> 02:30.400 align:start position:0% they can teach us about its origins. 02:30.400 --> 02:33.390 align:start position:0% they can teach us about its origins. After<00:02:30.760> all,<00:02:31.280> a<00:02:31.360> crater<00:02:31.920> of<00:02:32.040> this<00:02:32.280> size<00:02:32.760> must 02:33.390 --> 02:33.400 align:start position:0% After all, a crater of this size must 02:33.400 --> 02:37.350 align:start position:0% After all, a crater of this size must have<00:02:33.600> come<00:02:34.120> from<00:02:34.360> a<00:02:34.520> pretty<00:02:35.160> violent<00:02:35.640> event. 02:37.350 --> 02:37.360 align:start position:0% have come from a pretty violent event. 02:37.360 --> 02:39.070 align:start position:0% have come from a pretty violent event. Perhaps<00:02:37.760> the<00:02:38.120> first<00:02:38.440> thing<00:02:38.640> you'll<00:02:38.800> notice 02:39.070 --> 02:39.080 align:start position:0% Perhaps the first thing you'll notice 02:39.080 --> 02:41.230 align:start position:0% Perhaps the first thing you'll notice about<00:02:39.360> Tycho<00:02:39.720> crater<00:02:40.280> is<00:02:40.520> its<00:02:40.760> central 02:41.230 --> 02:41.240 align:start position:0% about Tycho crater is its central 02:41.240 --> 02:42.470 align:start position:0% about Tycho crater is its central mountain. 02:42.470 --> 02:42.480 align:start position:0% mountain. 02:42.480 --> 02:45.750 align:start position:0% mountain. Its<00:02:42.680> peak<00:02:43.160> reaches<00:02:43.520> up<00:02:43.840> 2.5<00:02:44.800> km<00:02:45.520> from<00:02:45.640> the 02:45.750 --> 02:45.760 align:start position:0% Its peak reaches up 2.5 km from the 02:45.760 --> 02:49.270 align:start position:0% Its peak reaches up 2.5 km from the crater<00:02:46.080> floor<00:02:46.760> and<00:02:46.880> stretches<00:02:47.640> 15<00:02:48.320> km<00:02:48.840> across 02:49.270 --> 02:49.280 align:start position:0% crater floor and stretches 15 km across 02:49.280 --> 02:50.910 align:start position:0% crater floor and stretches 15 km across at<00:02:49.400> its<00:02:49.520> widest<00:02:49.880> point. 02:50.910 --> 02:50.920 align:start position:0% at its widest point. 02:50.920 --> 02:52.630 align:start position:0% at its widest point. While<00:02:51.240> much<00:02:51.480> of<00:02:51.560> the<00:02:51.680> regolith<00:02:52.160> that<00:02:52.280> makes<00:02:52.520> up 02:52.630 --> 02:52.640 align:start position:0% While much of the regolith that makes up 02:52.640 --> 02:54.270 align:start position:0% While much of the regolith that makes up the<00:02:52.720> moon's<00:02:53.000> surface<00:02:53.440> looks<00:02:53.720> similar<00:02:54.080> to<00:02:54.200> the 02:54.270 --> 02:54.280 align:start position:0% the moon's surface looks similar to the 02:54.280 --> 02:56.430 align:start position:0% the moon's surface looks similar to the untrained<00:02:54.760> eye,<00:02:55.440> NASA's<00:02:56.000> Lunar 02:56.430 --> 02:56.440 align:start position:0% untrained eye, NASA's Lunar 02:56.440 --> 02:58.350 align:start position:0% untrained eye, NASA's Lunar Reconnaissance<00:02:57.120> Orbiter<00:02:57.800> discovered<00:02:58.240> that 02:58.350 --> 02:58.360 align:start position:0% Reconnaissance Orbiter discovered that 02:58.360 --> 03:00.830 align:start position:0% Reconnaissance Orbiter discovered that the<00:02:58.480> peak<00:02:58.840> surface<00:02:59.320> is<00:02:59.720> actually<00:03:00.320> a<00:03:00.440> treasure 03:00.830 --> 03:00.840 align:start position:0% the peak surface is actually a treasure 03:00.840 --> 03:03.190 align:start position:0% the peak surface is actually a treasure trove<00:03:01.280> of<00:03:01.600> interesting<00:03:02.280> and<00:03:02.560> distinctive 03:03.190 --> 03:03.200 align:start position:0% trove of interesting and distinctive 03:03.200 --> 03:06.630 align:start position:0% trove of interesting and distinctive textures.<00:03:04.320> Some<00:03:04.519> parts<00:03:05.000> are<00:03:05.080> smooth,<00:03:06.200> others 03:06.630 --> 03:06.640 align:start position:0% textures. Some parts are smooth, others 03:06.640 --> 03:09.270 align:start position:0% textures. Some parts are smooth, others are<00:03:06.760> blocky.<00:03:07.800> The<00:03:07.920> base<00:03:08.239> is<00:03:08.440> streaked<00:03:08.920> with 03:09.270 --> 03:09.280 align:start position:0% are blocky. The base is streaked with 03:09.280 --> 03:12.350 align:start position:0% are blocky. The base is streaked with fine<00:03:09.560> deposits<00:03:10.640> and<00:03:10.840> there<00:03:11.080> are<00:03:11.600> enormous 03:12.350 --> 03:12.360 align:start position:0% fine deposits and there are enormous 03:12.360 --> 03:13.790 align:start position:0% fine deposits and there are enormous gullies. 03:13.790 --> 03:13.800 align:start position:0% gullies. 03:13.800 --> 03:16.310 align:start position:0% gullies. All<00:03:14.040> these<00:03:14.320> features<00:03:14.800> paint<00:03:15.160> a<00:03:15.239> picture<00:03:16.120> and 03:16.310 --> 03:16.320 align:start position:0% All these features paint a picture and 03:16.320 --> 03:18.550 align:start position:0% All these features paint a picture and through<00:03:16.600> this<00:03:16.920> and<00:03:17.400> other<00:03:17.680> images, 03:18.550 --> 03:18.560 align:start position:0% through this and other images, 03:18.560 --> 03:20.229 align:start position:0% through this and other images, scientists<00:03:19.080> have<00:03:19.200> discovered<00:03:19.680> that<00:03:19.800> the<00:03:19.920> rock 03:20.229 --> 03:20.239 align:start position:0% scientists have discovered that the rock 03:20.239 --> 03:22.670 align:start position:0% scientists have discovered that the rock that<00:03:20.440> makes<00:03:20.800> up<00:03:20.959> Tycho's<00:03:21.519> mountain<00:03:22.400> is 03:22.670 --> 03:22.680 align:start position:0% that makes up Tycho's mountain is 03:22.680 --> 03:24.949 align:start position:0% that makes up Tycho's mountain is actually<00:03:23.120> not<00:03:23.720> the<00:03:23.840> same<00:03:24.160> kind<00:03:24.400> of<00:03:24.519> rock<00:03:24.800> that 03:24.949 --> 03:24.959 align:start position:0% actually not the same kind of rock that 03:24.959 --> 03:27.830 align:start position:0% actually not the same kind of rock that forms<00:03:25.400> the<00:03:25.480> crater's<00:03:25.920> basin<00:03:26.480> or<00:03:26.680> its<00:03:26.880> rim. 03:27.830 --> 03:27.840 align:start position:0% forms the crater's basin or its rim. 03:27.840 --> 03:30.350 align:start position:0% forms the crater's basin or its rim. So,<00:03:28.320> what's<00:03:28.560> this<00:03:29.040> out<00:03:29.280> of<00:03:29.360> place<00:03:29.680> rock<00:03:30.000> doing 03:30.350 --> 03:30.360 align:start position:0% So, what's this out of place rock doing 03:30.360 --> 03:31.509 align:start position:0% So, what's this out of place rock doing here? 03:31.509 --> 03:31.519 align:start position:0% here? 03:31.519 --> 03:33.229 align:start position:0% here? It's<00:03:31.680> actually<00:03:32.040> because<00:03:32.480> Tycho<00:03:32.880> is<00:03:33.040> what's 03:33.229 --> 03:33.239 align:start position:0% It's actually because Tycho is what's 03:33.239 --> 03:36.030 align:start position:0% It's actually because Tycho is what's known<00:03:33.600> as<00:03:33.760> a<00:03:33.880> complex<00:03:34.640> crater. 03:36.030 --> 03:36.040 align:start position:0% known as a complex crater. 03:36.040 --> 03:38.509 align:start position:0% known as a complex crater. Unlike<00:03:36.600> simple<00:03:37.040> craters<00:03:37.560> whose<00:03:38.120> impact 03:38.509 --> 03:38.519 align:start position:0% Unlike simple craters whose impact 03:38.519 --> 03:40.509 align:start position:0% Unlike simple craters whose impact basins<00:03:38.959> are<00:03:39.040> smaller<00:03:39.680> and<00:03:39.840> look<00:03:40.080> like<00:03:40.280> some 03:40.509 --> 03:40.519 align:start position:0% basins are smaller and look like some 03:40.519 --> 03:42.710 align:start position:0% basins are smaller and look like some giant<00:03:41.000> has<00:03:41.160> simply<00:03:41.519> scooped<00:03:42.120> out<00:03:42.280> a<00:03:42.320> chunk<00:03:42.640> of 03:42.710 --> 03:42.720 align:start position:0% giant has simply scooped out a chunk of 03:42.720 --> 03:45.190 align:start position:0% giant has simply scooped out a chunk of the<00:03:42.800> ground<00:03:43.200> with<00:03:43.320> an<00:03:43.519> extra<00:03:43.840> large<00:03:44.120> spoon, 03:45.190 --> 03:45.200 align:start position:0% the ground with an extra large spoon, 03:45.200 --> 03:47.949 align:start position:0% the ground with an extra large spoon, complex<00:03:45.600> craters<00:03:46.080> are<00:03:46.280> formed<00:03:46.720> by<00:03:46.959> impacts<00:03:47.640> so 03:47.949 --> 03:47.959 align:start position:0% complex craters are formed by impacts so 03:47.959 --> 03:51.070 align:start position:0% complex craters are formed by impacts so large<00:03:48.880> their<00:03:49.080> collision<00:03:49.800> creates<00:03:50.320> recoil<00:03:51.000> in 03:51.070 --> 03:51.080 align:start position:0% large their collision creates recoil in 03:51.080 --> 03:53.310 align:start position:0% large their collision creates recoil in the<00:03:51.200> bedrock<00:03:51.680> beneath<00:03:52.000> the<00:03:52.120> surface. 03:53.310 --> 03:53.320 align:start position:0% the bedrock beneath the surface. 03:53.320 --> 03:55.350 align:start position:0% the bedrock beneath the surface. Rock<00:03:53.520> that<00:03:53.640> was<00:03:53.760> once<00:03:54.000> buried<00:03:54.480> deep<00:03:54.840> gets 03:55.350 --> 03:55.360 align:start position:0% Rock that was once buried deep gets 03:55.360 --> 03:57.430 align:start position:0% Rock that was once buried deep gets propelled<00:03:55.880> up<00:03:56.080> in<00:03:56.200> the<00:03:56.280> center,<00:03:57.080> forming 03:57.430 --> 03:57.440 align:start position:0% propelled up in the center, forming 03:57.440 --> 03:59.310 align:start position:0% propelled up in the center, forming peaks<00:03:57.880> that<00:03:58.040> are<00:03:58.120> composed<00:03:58.640> of<00:03:58.760> a<00:03:58.840> very 03:59.310 --> 03:59.320 align:start position:0% peaks that are composed of a very 03:59.320 --> 04:01.190 align:start position:0% peaks that are composed of a very different<00:03:59.720> sort<00:03:59.960> of<00:04:00.080> rock<00:04:00.520> to<00:04:00.640> the<00:04:00.760> rest<00:04:01.120> of 04:01.190 --> 04:01.200 align:start position:0% different sort of rock to the rest of 04:01.200 --> 04:02.630 align:start position:0% different sort of rock to the rest of the<00:04:01.280> crater. 04:02.630 --> 04:02.640 align:start position:0% the crater. 04:02.640 --> 04:04.950 align:start position:0% the crater. This<00:04:02.800> process<00:04:03.200> is<00:04:03.360> a<00:04:03.440> bit<00:04:04.040> like<00:04:04.400> what<00:04:04.560> happens 04:04.950 --> 04:04.960 align:start position:0% This process is a bit like what happens 04:04.960 --> 04:07.350 align:start position:0% This process is a bit like what happens when<00:04:05.080> a<00:04:05.120> droplet<00:04:05.520> of<00:04:05.680> water<00:04:06.000> lands<00:04:06.280> in<00:04:06.400> a<00:04:06.440> pond. 04:07.350 --> 04:07.360 align:start position:0% when a droplet of water lands in a pond. 04:07.360 --> 04:09.590 align:start position:0% when a droplet of water lands in a pond. The<00:04:07.440> surface<00:04:07.840> is<00:04:08.000> disturbed,<00:04:09.000> water<00:04:09.360> gets 04:09.590 --> 04:09.600 align:start position:0% The surface is disturbed, water gets 04:09.600 --> 04:12.590 align:start position:0% The surface is disturbed, water gets displaced,<00:04:10.880> but<00:04:11.120> then<00:04:11.520> gravity<00:04:12.080> reasserts 04:12.590 --> 04:12.600 align:start position:0% displaced, but then gravity reasserts 04:12.600 --> 04:14.630 align:start position:0% displaced, but then gravity reasserts itself,<00:04:13.360> and<00:04:13.480> the<00:04:13.640> edges<00:04:14.040> of<00:04:14.160> the<00:04:14.280> newly 04:14.630 --> 04:14.640 align:start position:0% itself, and the edges of the newly 04:14.640 --> 04:17.150 align:start position:0% itself, and the edges of the newly formed<00:04:14.920> basin<00:04:15.520> rush<00:04:15.920> in<00:04:16.359> to<00:04:16.480> restore<00:04:17.000> the 04:17.150 --> 04:17.160 align:start position:0% formed basin rush in to restore the 04:17.160 --> 04:18.830 align:start position:0% formed basin rush in to restore the equilibrium. 04:18.830 --> 04:18.840 align:start position:0% equilibrium. 04:18.840 --> 04:21.270 align:start position:0% equilibrium. All<00:04:19.000> that<00:04:19.359> inward-rushing<00:04:20.280> water<00:04:20.720> meets<00:04:21.160> in 04:21.270 --> 04:21.280 align:start position:0% All that inward-rushing water meets in 04:21.280 --> 04:23.790 align:start position:0% All that inward-rushing water meets in the<00:04:21.359> middle,<00:04:22.160> and<00:04:22.520> with<00:04:22.680> nowhere<00:04:22.960> else<00:04:23.120> to<00:04:23.240> go, 04:23.790 --> 04:23.800 align:start position:0% the middle, and with nowhere else to go, 04:23.800 --> 04:26.190 align:start position:0% the middle, and with nowhere else to go, some<00:04:24.280> is<00:04:24.520> forced<00:04:24.960> upwards. 04:26.190 --> 04:26.200 align:start position:0% some is forced upwards. 04:26.200 --> 04:28.030 align:start position:0% some is forced upwards. And<00:04:26.280> when<00:04:26.400> this<00:04:26.520> happens<00:04:26.880> to<00:04:27.040> rock<00:04:27.320> that<00:04:27.520> has 04:28.030 --> 04:28.040 align:start position:0% And when this happens to rock that has 04:28.040 --> 04:31.190 align:start position:0% And when this happens to rock that has suddenly,<00:04:29.040> violently<00:04:29.760> melted,<00:04:30.880> what<00:04:31.000> was 04:31.190 --> 04:31.200 align:start position:0% suddenly, violently melted, what was 04:31.200 --> 04:33.950 align:start position:0% suddenly, violently melted, what was formerly<00:04:31.720> bedrock<00:04:32.440> is<00:04:32.640> pulled<00:04:33.040> up<00:04:33.360> along<00:04:33.840> for 04:33.950 --> 04:33.960 align:start position:0% formerly bedrock is pulled up along for 04:33.960 --> 04:35.630 align:start position:0% formerly bedrock is pulled up along for the<00:04:34.080> ride. 04:35.630 --> 04:35.640 align:start position:0% the ride. 04:35.640 --> 04:37.270 align:start position:0% the ride. This<00:04:35.760> is<00:04:35.960> one<00:04:36.120> of<00:04:36.200> the<00:04:36.320> reasons<00:04:36.800> scientists 04:37.270 --> 04:37.280 align:start position:0% This is one of the reasons scientists 04:37.280 --> 04:40.070 align:start position:0% This is one of the reasons scientists want<00:04:37.480> to<00:04:37.600> study<00:04:38.120> Tycho's<00:04:38.640> peak<00:04:38.960> further.<00:04:39.919> It 04:40.070 --> 04:40.080 align:start position:0% want to study Tycho's peak further. It 04:40.080 --> 04:42.270 align:start position:0% want to study Tycho's peak further. It offers<00:04:40.360> an<00:04:40.600> excellent<00:04:41.160> opportunity<00:04:41.760> to<00:04:41.919> learn 04:42.270 --> 04:42.280 align:start position:0% offers an excellent opportunity to learn 04:42.280 --> 04:44.390 align:start position:0% offers an excellent opportunity to learn what<00:04:42.520> the<00:04:42.640> deep<00:04:43.040> interior<00:04:43.800> of<00:04:43.919> the<00:04:44.040> moon<00:04:44.240> is 04:44.390 --> 04:44.400 align:start position:0% what the deep interior of the moon is 04:44.400 --> 04:45.950 align:start position:0% what the deep interior of the moon is like. 04:45.950 --> 04:45.960 align:start position:0% like. 04:45.960 --> 04:49.430 align:start position:0% like. Surveyor<00:04:46.360> 7,<00:04:47.160> in<00:04:47.400> 1968,<00:04:48.680> discovered<00:04:49.200> that<00:04:49.320> the 04:49.430 --> 04:49.440 align:start position:0% Surveyor 7, in 1968, discovered that the 04:49.440 --> 04:51.430 align:start position:0% Surveyor 7, in 1968, discovered that the surface<00:04:49.919> regolith<00:04:50.320> in<00:04:50.400> the<00:04:50.520> area<00:04:50.840> surrounding 04:51.430 --> 04:51.440 align:start position:0% surface regolith in the area surrounding 04:51.440 --> 04:54.350 align:start position:0% surface regolith in the area surrounding Tycho<00:04:52.160> comprised<00:04:52.919> basalt<00:04:53.360> rock<00:04:53.919> with<00:04:54.120> high 04:54.350 --> 04:54.360 align:start position:0% Tycho comprised basalt rock with high 04:54.360 --> 04:56.390 align:start position:0% Tycho comprised basalt rock with high levels<00:04:54.680> of<00:04:54.800> calcium<00:04:55.680> and<00:04:55.840> low<00:04:55.960> levels<00:04:56.280> of 04:56.390 --> 04:56.400 align:start position:0% levels of calcium and low levels of 04:56.400 --> 04:57.510 align:start position:0% levels of calcium and low levels of sodium. 04:57.510 --> 04:57.520 align:start position:0% sodium. 04:57.520 --> 04:59.590 align:start position:0% sodium. But<00:04:57.840> what<00:04:58.000> lies<00:04:58.280> deeper<00:04:58.600> down? 04:59.590 --> 04:59.600 align:start position:0% But what lies deeper down? 04:59.600 --> 05:02.150 align:start position:0% But what lies deeper down? Until<00:04:59.840> we<00:04:59.960> sample<00:05:00.400> the<00:05:00.560> mountain<00:05:01.080> itself, 05:02.150 --> 05:02.160 align:start position:0% Until we sample the mountain itself, 05:02.160 --> 05:04.270 align:start position:0% Until we sample the mountain itself, scientists<00:05:02.600> can<00:05:02.880> only<00:05:03.200> guess<00:05:03.640> how<00:05:03.840> Tycho's 05:04.270 --> 05:04.280 align:start position:0% scientists can only guess how Tycho's 05:04.280 --> 05:06.710 align:start position:0% scientists can only guess how Tycho's bedrock<00:05:04.880> fits<00:05:05.320> into<00:05:05.560> the<00:05:05.680> broader<00:05:06.160> geological 05:06.710 --> 05:06.720 align:start position:0% bedrock fits into the broader geological 05:06.720 --> 05:08.830 align:start position:0% bedrock fits into the broader geological narrative. 05:08.830 --> 05:08.840 align:start position:0% narrative. 05:08.840 --> 05:10.870 align:start position:0% narrative. Tycho<00:05:09.120> crater<00:05:09.520> is<00:05:09.800> visible<00:05:10.320> from<00:05:10.480> the<00:05:10.640> Earth 05:10.870 --> 05:10.880 align:start position:0% Tycho crater is visible from the Earth 05:10.880 --> 05:12.670 align:start position:0% Tycho crater is visible from the Earth with<00:05:11.000> the<00:05:11.080> naked<00:05:11.440> eye,<00:05:12.040> but<00:05:12.160> to<00:05:12.280> truly 05:12.670 --> 05:12.680 align:start position:0% with the naked eye, but to truly 05:12.680 --> 05:14.470 align:start position:0% with the naked eye, but to truly appreciate<00:05:13.240> its<00:05:13.400> features,<00:05:13.840> you<00:05:14.120> need<00:05:14.360> the 05:14.470 --> 05:14.480 align:start position:0% appreciate its features, you need the 05:14.480 --> 05:16.990 align:start position:0% appreciate its features, you need the right<00:05:14.720> gear.<00:05:15.640> This<00:05:15.840> is<00:05:16.080> true<00:05:16.440> of<00:05:16.720> other 05:16.990 --> 05:17.000 align:start position:0% right gear. This is true of other 05:17.000 --> 05:18.990 align:start position:0% right gear. This is true of other aspects<00:05:17.440> of<00:05:17.520> the<00:05:17.640> moon,<00:05:17.840> too.<00:05:18.480> For<00:05:18.600> instance, 05:18.990 --> 05:19.000 align:start position:0% aspects of the moon, too. For instance, 05:19.000 --> 05:21.990 align:start position:0% aspects of the moon, too. For instance, on<00:05:19.120> the<00:05:19.200> 12th<00:05:19.520> of<00:05:19.680> August<00:05:20.080> 2026,<00:05:21.320> the<00:05:21.440> moon<00:05:21.800> as 05:21.990 --> 05:22.000 align:start position:0% on the 12th of August 2026, the moon as 05:22.000 --> 05:24.550 align:start position:0% on the 12th of August 2026, the moon as a<00:05:22.080> whole<00:05:22.480> will<00:05:22.760> be<00:05:23.000> part<00:05:23.400> of<00:05:23.520> a<00:05:23.600> jaw-dropping 05:24.550 --> 05:24.560 align:start position:0% a whole will be part of a jaw-dropping 05:24.560 --> 05:26.350 align:start position:0% a whole will be part of a jaw-dropping solar<00:05:25.000> celestial<00:05:25.560> convergence<00:05:26.080> with<00:05:26.240> our 05:26.350 --> 05:26.360 align:start position:0% solar celestial convergence with our 05:26.360 --> 05:29.310 align:start position:0% solar celestial convergence with our sun,<00:05:27.080> a<00:05:27.160> solar<00:05:27.680> eclipse.<00:05:28.680> And<00:05:28.840> if<00:05:29.000> you're<00:05:29.200> in 05:29.310 --> 05:29.320 align:start position:0% sun, a solar eclipse. And if you're in 05:29.320 --> 05:32.150 align:start position:0% sun, a solar eclipse. And if you're in the<00:05:29.440> path<00:05:29.919> for<00:05:30.040> that<00:05:30.720> and<00:05:30.919> want<00:05:31.120> to<00:05:31.240> see<00:05:31.520> it, 05:32.150 --> 05:32.160 align:start position:0% the path for that and want to see it, 05:32.160 --> 05:33.750 align:start position:0% the path for that and want to see it, your<00:05:32.440> eyes<00:05:32.680> will<00:05:32.800> thank<00:05:33.080> you<00:05:33.200> for<00:05:33.320> choosing 05:33.750 --> 05:33.760 align:start position:0% your eyes will thank you for choosing 05:33.760 --> 05:35.870 align:start position:0% your eyes will thank you for choosing the<00:05:33.880> right<00:05:34.120> solar<00:05:34.440> glasses,<00:05:35.360> like<00:05:35.480> the<00:05:35.600> ones 05:33.760 --> 05:37.150 align:start position:0% off their purchase. Now,<00:06:29.040> back<00:06:29.240> to<00:06:29.320> Tycho<00:06:29.680> crater. 05:36.526 --> 05:36.536 align:start position:0% Now, back to Tycho crater. 05:36.536 --> 05:38.405 align:start position:0% Now, back to Tycho crater. There<00:06:32.200> is<00:06:32.400> another<00:06:32.720> feature<00:06:33.080> of<00:06:33.160> Tycho's<00:06:33.600> peak 05:38.405 --> 05:38.415 align:start position:0% There is another feature of Tycho's peak 05:38.415 --> 05:41.405 align:start position:0% There is another feature of Tycho's peak that<00:06:34.240> tells<00:06:34.600> us<00:06:34.760> much<00:06:35.160> about<00:06:35.480> its<00:06:35.640> history. 05:41.405 --> 05:41.415 align:start position:0% that tells us much about its history. 05:41.415 --> 05:43.126 align:start position:0% that tells us much about its history. Do<00:06:36.960> you<00:06:37.040> see<00:06:37.200> this<00:06:37.440> line<00:06:37.800> running<00:06:38.160> across<00:06:38.520> the 05:43.126 --> 05:43.136 align:start position:0% Do you see this line running across the 05:43.136 --> 05:44.646 align:start position:0% Do you see this line running across the mountain<00:06:39.080> here? 05:44.646 --> 05:44.656 align:start position:0% mountain here? 05:44.656 --> 05:48.246 align:start position:0% mountain here? This<00:06:40.440> is<00:06:40.880> a<00:06:41.080> high<00:06:41.520> watermark<00:06:42.440> of<00:06:42.600> a<00:06:42.680> sword. 05:48.246 --> 05:48.256 align:start position:0% This is a high watermark of a sword. 05:48.256 --> 05:50.366 align:start position:0% This is a high watermark of a sword. But<00:06:43.840> before<00:06:44.120> you<00:06:44.280> ask,<00:06:44.800> no,<00:06:45.280> this<00:06:45.480> was<00:06:45.640> not 05:50.366 --> 05:50.376 align:start position:0% But before you ask, no, this was not 05:50.376 --> 05:52.566 align:start position:0% But before you ask, no, this was not caused<00:06:46.240> by<00:06:46.400> an<00:06:46.560> ancient<00:06:47.080> lunar<00:06:47.400> water<00:06:47.720> lake 05:52.566 --> 05:52.576 align:start position:0% caused by an ancient lunar water lake 05:52.576 --> 05:54.686 align:start position:0% caused by an ancient lunar water lake lapping<00:06:48.480> against<00:06:48.840> the<00:06:48.919> mountain,<00:06:49.560> as<00:06:49.800> cool<00:06:50.080> as 05:54.686 --> 05:54.696 align:start position:0% lapping against the mountain, as cool as 05:54.696 --> 05:55.966 align:start position:0% lapping against the mountain, as cool as that<00:06:50.400> would<00:06:50.520> be. 05:55.966 --> 05:55.976 align:start position:0% that would be. 05:55.976 --> 05:57.886 align:start position:0% that would be. When<00:06:51.600> the<00:06:51.720> asteroid<00:06:52.120> that<00:06:52.400> impacted<00:06:52.919> the<00:06:53.000> moon 05:57.886 --> 05:57.896 align:start position:0% When the asteroid that impacted the moon 05:57.896 --> 06:00.126 align:start position:0% When the asteroid that impacted the moon created<00:06:53.880> Tycho<00:06:54.200> crater<00:06:54.720> and<00:06:55.080> pulled<00:06:55.440> that 06:00.126 --> 06:00.136 align:start position:0% created Tycho crater and pulled that 06:00.136 --> 06:02.486 align:start position:0% created Tycho crater and pulled that peak<00:06:55.880> to<00:06:55.960> the<00:06:56.080> surface,<00:06:57.120> the<00:06:57.200> entire<00:06:57.680> crater 06:02.486 --> 06:02.496 align:start position:0% peak to the surface, the entire crater 06:02.496 --> 06:04.486 align:start position:0% peak to the surface, the entire crater floor<00:06:58.320> would<00:06:58.440> have<00:06:58.560> been<00:06:58.840> superheated<00:06:59.840> in<00:06:59.919> the 06:04.486 --> 06:04.496 align:start position:0% floor would have been superheated in the 06:04.496 --> 06:05.606 align:start position:0% floor would have been superheated in the collision 06:05.606 --> 06:05.616 align:start position:0% collision 06:05.616 --> 06:09.086 align:start position:0% collision into<00:07:01.360> a<00:07:01.440> boiling<00:07:02.120> hot<00:07:02.400> pond<00:07:02.840> of<00:07:03.040> impact<00:07:03.520> melt. 06:09.086 --> 06:09.096 align:start position:0% into a boiling hot pond of impact melt. 06:09.096 --> 06:10.886 align:start position:0% into a boiling hot pond of impact melt. Under<00:07:04.840> the<00:07:05.040> softening<00:07:05.600> influence<00:07:06.080> of<00:07:06.160> that 06:10.886 --> 06:10.896 align:start position:0% Under the softening influence of that 06:10.896 --> 06:14.126 align:start position:0% Under the softening influence of that heat<00:07:07.000> and<00:07:07.200> the<00:07:07.560> insidious<00:07:08.320> pull<00:07:08.600> of<00:07:08.720> gravity, 06:14.126 --> 06:14.136 align:start position:0% heat and the insidious pull of gravity, 06:14.136 --> 06:15.446 align:start position:0% heat and the insidious pull of gravity, parts<00:07:09.880> of<00:07:09.960> the<00:07:10.040> surrounding<00:07:10.480> rim<00:07:10.720> would<00:07:10.840> have 06:15.446 --> 06:15.456 align:start position:0% parts of the surrounding rim would have 06:15.456 --> 06:17.606 align:start position:0% parts of the surrounding rim would have later<00:07:11.280> broken<00:07:11.760> off<00:07:12.080> and<00:07:12.400> fallen<00:07:12.800> into<00:07:13.000> the 06:17.606 --> 06:17.616 align:start position:0% later broken off and fallen into the 06:17.616 --> 06:20.646 align:start position:0% later broken off and fallen into the pool,<00:07:13.880> sending<00:07:14.280> tsunami<00:07:14.919> waves<00:07:15.320> propagating 06:20.646 --> 06:20.656 align:start position:0% pool, sending tsunami waves propagating 06:20.656 --> 06:22.846 align:start position:0% pool, sending tsunami waves propagating out<00:07:16.440> through<00:07:16.720> the<00:07:16.800> melt. 06:22.846 --> 06:22.856 align:start position:0% out through the melt. 06:22.856 --> 06:25.246 align:start position:0% out through the melt. This<00:07:18.600> mark<00:07:18.960> was<00:07:19.160> formed<00:07:19.640> when<00:07:19.800> a<00:07:19.840> tsunami<00:07:20.560> of 06:25.246 --> 06:25.256 align:start position:0% This mark was formed when a tsunami of 06:25.256 --> 06:27.886 align:start position:0% This mark was formed when a tsunami of molten<00:07:21.320> rock<00:07:22.000> splashed<00:07:22.480> against<00:07:22.880> the<00:07:22.960> peak's 06:27.886 --> 06:27.896 align:start position:0% molten rock splashed against the peak's 06:27.896 --> 06:29.046 align:start position:0% molten rock splashed against the peak's edges. 06:29.046 --> 06:29.056 align:start position:0% edges. 06:29.056 --> 06:31.405 align:start position:0% edges. Eventually,<00:07:25.080> the<00:07:25.240> melt<00:07:25.640> cooled<00:07:26.440> and<00:07:26.640> formed 06:31.405 --> 06:31.415 align:start position:0% Eventually, the melt cooled and formed 06:31.415 --> 06:33.766 align:start position:0% Eventually, the melt cooled and formed the<00:07:27.000> surface<00:07:27.400> we<00:07:27.520> see<00:07:27.680> today,<00:07:28.520> though<00:07:28.960> not 06:33.766 --> 06:33.776 align:start position:0% the surface we see today, though not 06:33.776 --> 06:36.086 align:start position:0% the surface we see today, though not without<00:07:29.800> leaving<00:07:30.120> these<00:07:30.440> fascinating<00:07:31.160> clues 06:36.086 --> 06:36.096 align:start position:0% without leaving these fascinating clues 06:36.096 --> 06:38.846 align:start position:0% without leaving these fascinating clues as<00:07:31.800> to<00:07:31.919> their<00:07:32.160> past<00:07:32.610> [music]<00:07:32.640> existence. 06:38.846 --> 06:38.856 align:start position:0% as to their past [music] existence. 06:38.856 --> 06:41.126 align:start position:0% as to their past [music] existence. Impact<00:07:34.720> melt<00:07:35.040> pooling<00:07:35.600> also<00:07:35.919> explains<00:07:36.520> the 06:41.126 --> 06:41.136 align:start position:0% Impact melt pooling also explains the 06:41.136 --> 06:42.966 align:start position:0% Impact melt pooling also explains the smoother<00:07:37.280> parts<00:07:37.640> of<00:07:37.720> the<00:07:37.840> peak<00:07:38.280> and<00:07:38.400> the 06:42.966 --> 06:42.976 align:start position:0% smoother parts of the peak and the 06:42.976 --> 06:44.806 align:start position:0% smoother parts of the peak and the surrounding<00:07:38.919> crater<00:07:39.280> floor. 06:44.806 --> 06:44.816 align:start position:0% surrounding crater floor. 06:44.816 --> 06:48.206 align:start position:0% surrounding crater floor. But<00:07:40.400> that<00:07:40.600> melt<00:07:40.960> can<00:07:41.280> be<00:07:41.440> found<00:07:41.960> elsewhere. 06:48.206 --> 06:48.216 align:start position:0% But that melt can be found elsewhere. 06:48.216 --> 06:50.686 align:start position:0% But that melt can be found elsewhere. Let's<00:07:44.120> widen<00:07:44.640> our<00:07:44.760> view<00:07:45.080> to<00:07:45.200> the<00:07:45.320> surrounding 06:50.686 --> 06:50.696 align:start position:0% Let's widen our view to the surrounding 06:50.696 --> 06:52.886 align:start position:0% Let's widen our view to the surrounding landscape<00:07:46.720> of<00:07:46.800> the<00:07:46.920> lunar<00:07:47.160> surface. 06:52.886 --> 06:52.896 align:start position:0% landscape of the lunar surface. 06:52.896 --> 06:54.886 align:start position:0% landscape of the lunar surface. These<00:07:48.800> breathtaking<00:07:49.680> Hubble<00:07:49.920> images<00:07:50.320> of 06:54.886 --> 06:54.896 align:start position:0% These breathtaking Hubble images of 06:54.896 --> 06:57.166 align:start position:0% These breathtaking Hubble images of Tycho<00:07:51.040> really<00:07:51.440> showcase<00:07:51.960> the<00:07:52.080> violence<00:07:52.560> that 06:57.166 --> 06:57.176 align:start position:0% Tycho really showcase the violence that 06:57.176 --> 07:00.406 align:start position:0% Tycho really showcase the violence that extended<00:07:53.200> out<00:07:53.440> beyond<00:07:53.720> the<00:07:53.800> crater<00:07:54.160> itself. 07:00.406 --> 07:00.416 align:start position:0% extended out beyond the crater itself. 07:00.416 --> 07:03.246 align:start position:0% extended out beyond the crater itself. In<00:07:56.000> 2013,<00:07:57.080> Tim<00:07:57.360> Krüger<00:07:57.840> and<00:07:58.040> his<00:07:58.280> team<00:07:58.600> of 07:03.246 --> 07:03.256 align:start position:0% In 2013, Tim Krüger and his team of 07:03.256 --> 07:04.686 align:start position:0% In 2013, Tim Krüger and his team of researchers<00:07:59.360> at<00:07:59.480> the<00:07:59.560> Institute<00:08:00.120> of 07:04.686 --> 07:04.696 align:start position:0% researchers at the Institute of 07:04.696 --> 07:07.526 align:start position:0% researchers at the Institute of Planetology<00:08:01.120> presented<00:08:01.760> a<00:08:01.880> map<00:08:02.480> of<00:08:02.640> more<00:08:02.840> than 07:07.526 --> 07:07.536 align:start position:0% Planetology presented a map of more than 07:07.536 --> 07:10.086 align:start position:0% Planetology presented a map of more than 3,000<00:08:04.200> melt<00:08:04.480> pools<00:08:04.880> in<00:08:05.000> the<00:08:05.120> surrounding 07:10.086 --> 07:10.096 align:start position:0% 3,000 melt pools in the surrounding 07:10.096 --> 07:12.326 align:start position:0% 3,000 melt pools in the surrounding area,<00:08:06.480> highlighting<00:08:07.120> where<00:08:07.480> burning 07:12.326 --> 07:12.336 align:start position:0% area, highlighting where burning 07:12.336 --> 07:14.206 align:start position:0% area, highlighting where burning fragments<00:08:08.320> of<00:08:08.400> regolith<00:08:09.240> would<00:08:09.400> have<00:08:09.480> been 07:14.206 --> 07:14.216 align:start position:0% fragments of regolith would have been 07:14.216 --> 07:15.606 align:start position:0% fragments of regolith would have been flung<00:08:10.160> out<00:08:10.280> of<00:08:10.360> the<00:08:10.440> crust<00:08:10.720> of<00:08:10.760> the<00:08:10.880> moon's 07:15.606 --> 07:15.616 align:start position:0% flung out of the crust of the moon's 07:15.616 --> 07:17.886 align:start position:0% flung out of the crust of the moon's surface<00:08:11.560> by<00:08:11.680> the<00:08:11.800> impact. 07:17.886 --> 07:17.896 align:start position:0% surface by the impact. 07:17.896 --> 07:20.206 align:start position:0% surface by the impact. By<00:08:13.560> noting<00:08:14.000> that<00:08:14.160> there<00:08:14.480> is<00:08:14.800> one<00:08:15.040> direction 07:20.206 --> 07:20.216 align:start position:0% By noting that there is one direction 07:20.216 --> 07:22.006 align:start position:0% By noting that there is one direction that<00:08:15.960> had<00:08:16.200> fewer<00:08:16.560> melt<00:08:16.840> points<00:08:17.200> than<00:08:17.360> the 07:22.006 --> 07:22.016 align:start position:0% that had fewer melt points than the 07:22.016 --> 07:24.566 align:start position:0% that had fewer melt points than the others,<00:08:18.160> Krüger<00:08:18.720> and<00:08:18.840> his<00:08:19.000> team<00:08:19.600> were<00:08:19.720> able<00:08:19.960> to 07:24.566 --> 07:24.576 align:start position:0% others, Krüger and his team were able to 07:24.576 --> 07:27.046 align:start position:0% others, Krüger and his team were able to confirm<00:08:20.520> that<00:08:20.760> this<00:08:21.080> hadn't<00:08:21.480> been<00:08:21.840> a<00:08:21.880> direct 07:27.046 --> 07:27.056 align:start position:0% confirm that this hadn't been a direct 07:27.056 --> 07:29.686 align:start position:0% confirm that this hadn't been a direct blow,<00:08:23.360> but<00:08:23.480> the<00:08:23.600> asteroid<00:08:24.120> had<00:08:24.480> likely<00:08:24.919> come 07:29.686 --> 07:29.696 align:start position:0% blow, but the asteroid had likely come 07:29.696 --> 07:33.566 align:start position:0% blow, but the asteroid had likely come in<00:08:25.400> at<00:08:25.600> an<00:08:25.720> oblique<00:08:26.280> 35°<00:08:27.200> to<00:08:27.480> 45°<00:08:28.400> angle, 07:33.566 --> 07:33.576 align:start position:0% in at an oblique 35° to 45° angle, 07:33.576 --> 07:35.966 align:start position:0% in at an oblique 35° to 45° angle, arriving<00:08:29.680> from<00:08:29.840> the<00:08:29.919> southwest. 07:35.966 --> 07:35.976 align:start position:0% arriving from the southwest. 07:35.976 --> 07:38.726 align:start position:0% arriving from the southwest. But,<00:08:31.800> as<00:08:32.000> I<00:08:32.039> mentioned<00:08:32.520> earlier,<00:08:33.400> those<00:08:33.719> balls 07:38.726 --> 07:38.736 align:start position:0% But, as I mentioned earlier, those balls 07:38.736 --> 07:41.085 align:start position:0% But, as I mentioned earlier, those balls of<00:08:34.360> molten<00:08:34.760> rock<00:08:35.280> weren't<00:08:35.640> limited<00:08:36.159> to<00:08:36.280> just 07:41.085 --> 07:41.095 align:start position:0% of molten rock weren't limited to just 07:41.095 --> 07:44.166 align:start position:0% of molten rock weren't limited to just the<00:08:36.719> immediate<00:08:37.240> area. 07:44.166 --> 07:44.176 align:start position:0% the immediate area. 07:44.176 --> 07:46.606 align:start position:0% the immediate area. The<00:08:39.800> Apollo<00:08:40.159> 17<00:08:41.240> mission<00:08:41.599> landed<00:08:41.960> at<00:08:42.039> the 07:46.606 --> 07:46.616 align:start position:0% The Apollo 17 mission landed at the 07:46.616 --> 07:49.366 align:start position:0% The Apollo 17 mission landed at the Taurus-Littrow<00:08:43.039> Valley<00:08:43.560> in<00:08:43.680> the<00:08:43.800> Mons<00:08:44.360> Taurus 07:49.366 --> 07:49.376 align:start position:0% Taurus-Littrow Valley in the Mons Taurus 07:49.376 --> 07:53.686 align:start position:0% Taurus-Littrow Valley in the Mons Taurus Mountains,<00:08:45.839> a<00:08:45.920> location<00:08:46.960> 2,250 07:53.686 --> 07:53.696 align:start position:0% Mountains, a location 2,250 07:53.696 --> 07:56.246 align:start position:0% Mountains, a location 2,250 km<00:08:49.800> away<00:08:50.080> from<00:08:50.240> Tycho. 07:56.246 --> 07:56.256 align:start position:0% km away from Tycho. 07:56.256 --> 07:58.446 align:start position:0% km away from Tycho. One<00:08:52.080> of<00:08:52.280> the<00:08:52.440> primary<00:08:53.000> goals<00:08:53.360> for<00:08:53.480> the<00:08:53.520> mission 07:58.446 --> 07:58.456 align:start position:0% One of the primary goals for the mission 07:58.456 --> 08:00.566 align:start position:0% One of the primary goals for the mission was<00:08:54.240> to<00:08:54.400> sample<00:08:54.839> material<00:08:55.360> taken<00:08:55.720> from<00:08:56.000> a 08:00.566 --> 08:00.576 align:start position:0% was to sample material taken from a 08:00.576 --> 08:02.766 align:start position:0% was to sample material taken from a landslide<00:08:56.800> along<00:08:57.160> one<00:08:57.320> of<00:08:57.400> the<00:08:57.520> nearby<00:08:57.920> crater 08:02.766 --> 08:02.776 align:start position:0% landslide along one of the nearby crater 08:02.776 --> 08:05.406 align:start position:0% landslide along one of the nearby crater walls.<00:08:59.160> Specifically,<00:08:59.839> they<00:09:00.080> were<00:09:00.240> targeting 08:05.406 --> 08:05.416 align:start position:0% walls. Specifically, they were targeting 08:05.416 --> 08:08.126 align:start position:0% walls. Specifically, they were targeting the<00:09:01.240> light<00:09:01.680> mantle,<00:09:02.480> a<00:09:02.560> prominent<00:09:03.240> bright 08:08.126 --> 08:08.136 align:start position:0% the light mantle, a prominent bright 08:08.136 --> 08:10.766 align:start position:0% the light mantle, a prominent bright streak<00:09:04.080> stretching<00:09:04.640> 5<00:09:05.000> km<00:09:05.480> across<00:09:05.880> the<00:09:06.000> valley 08:10.766 --> 08:10.776 align:start position:0% streak stretching 5 km across the valley 08:10.776 --> 08:13.046 align:start position:0% streak stretching 5 km across the valley floor<00:09:06.839> from<00:09:07.040> the<00:09:07.120> base<00:09:07.440> of<00:09:07.560> a<00:09:07.640> 2-km<00:09:08.320> tall 08:13.046 --> 08:13.056 align:start position:0% floor from the base of a 2-km tall 08:13.056 --> 08:16.046 align:start position:0% floor from the base of a 2-km tall mountain<00:09:09.400> known<00:09:09.760> as<00:09:10.000> South<00:09:10.440> Massif. 08:16.046 --> 08:16.056 align:start position:0% mountain known as South Massif. 08:16.056 --> 08:18.726 align:start position:0% mountain known as South Massif. This<00:09:11.760> site<00:09:12.160> is<00:09:12.400> the<00:09:12.760> only<00:09:13.200> known<00:09:13.520> landslide<00:09:14.120> of 08:18.726 --> 08:18.736 align:start position:0% This site is the only known landslide of 08:18.736 --> 08:21.246 align:start position:0% This site is the only known landslide of its<00:09:14.400> kind<00:09:14.760> on<00:09:14.839> the<00:09:14.920> moon<00:09:15.720> and<00:09:16.200> is<00:09:16.400> highly 08:21.246 --> 08:21.256 align:start position:0% its kind on the moon and is highly 08:21.256 --> 08:24.566 align:start position:0% its kind on the moon and is highly unusual<00:09:17.520> even<00:09:17.800> by<00:09:18.040> lunar<00:09:18.400> standards.<00:09:19.440> It<00:09:19.560> is<00:09:19.720> a 08:24.566 --> 08:24.576 align:start position:0% unusual even by lunar standards. It is a 08:24.576 --> 08:27.366 align:start position:0% unusual even by lunar standards. It is a long<00:09:20.760> runout<00:09:21.400> landslide,<00:09:22.400> meaning<00:09:22.760> the 08:27.366 --> 08:27.376 align:start position:0% long runout landslide, meaning the 08:27.376 --> 08:29.726 align:start position:0% long runout landslide, meaning the debris<00:09:23.360> traveled<00:09:24.000> an<00:09:24.040> incredibly<00:09:24.960> long 08:29.726 --> 08:29.736 align:start position:0% debris traveled an incredibly long 08:29.736 --> 08:32.366 align:start position:0% debris traveled an incredibly long distance<00:09:25.760> across<00:09:26.200> the<00:09:26.320> moon<00:09:26.600> to<00:09:26.720> get<00:09:26.960> there. 08:32.366 --> 08:32.376 align:start position:0% distance across the moon to get there. 08:32.376 --> 08:34.726 align:start position:0% distance across the moon to get there. And<00:09:28.160> the<00:09:28.240> exact<00:09:28.600> mechanisms<00:09:29.200> of<00:09:29.320> this<00:09:29.480> travel 08:34.726 --> 08:34.736 align:start position:0% And the exact mechanisms of this travel 08:34.736 --> 08:37.646 align:start position:0% And the exact mechanisms of this travel remained<00:09:30.680> a<00:09:30.760> mystery<00:09:31.120> for<00:09:31.240> decades. 08:37.646 --> 08:37.656 align:start position:0% remained a mystery for decades. 08:37.656 --> 08:39.886 align:start position:0% remained a mystery for decades. To<00:09:33.280> solve<00:09:33.560> this<00:09:33.720> mystery,<00:09:34.360> astronauts<00:09:34.960> Gene 08:39.886 --> 08:39.896 align:start position:0% To solve this mystery, astronauts Gene 08:39.896 --> 08:42.766 align:start position:0% To solve this mystery, astronauts Gene Cernan<00:09:36.040> and<00:09:36.360> Harrison<00:09:36.920> Schmitt,<00:09:37.800> a<00:09:37.920> trained 08:42.766 --> 08:42.776 align:start position:0% Cernan and Harrison Schmitt, a trained 08:42.776 --> 08:45.246 align:start position:0% Cernan and Harrison Schmitt, a trained geologist,<00:09:39.240> successfully<00:09:39.960> gathered<00:09:40.320> samples 08:45.246 --> 08:45.256 align:start position:0% geologist, successfully gathered samples 08:45.256 --> 08:48.086 align:start position:0% geologist, successfully gathered samples from<00:09:40.920> the<00:09:41.000> site<00:09:41.320> in<00:09:41.440> 1972,<00:09:42.880> bringing<00:09:43.200> back<00:09:43.520> a 08:48.086 --> 08:48.096 align:start position:0% from the site in 1972, bringing back a 08:48.096 --> 08:52.966 align:start position:0% from the site in 1972, bringing back a total<00:09:44.280> of<00:09:44.480> 110<00:09:45.640> kg<00:09:46.520> of<00:09:46.680> lunar<00:09:46.880> material.<00:09:48.120> Among 08:52.966 --> 08:52.976 align:start position:0% total of 110 kg of lunar material. Among 08:52.976 --> 08:55.886 align:start position:0% total of 110 kg of lunar material. Among these<00:09:48.920> were<00:09:49.120> two<00:09:49.640> pristine<00:09:50.320> core<00:09:50.600> samples 08:55.886 --> 08:55.896 align:start position:0% these were two pristine core samples 08:55.896 --> 08:57.526 align:start position:0% these were two pristine core samples drilled<00:09:51.760> straight<00:09:52.280> out<00:09:52.520> of<00:09:52.640> the<00:09:52.760> light 08:57.526 --> 08:57.536 align:start position:0% drilled straight out of the light 08:57.536 --> 08:58.606 align:start position:0% drilled straight out of the light mantle. 08:58.606 --> 08:58.616 align:start position:0% mantle. 08:58.616 --> 09:00.606 align:start position:0% mantle. At<00:09:54.240> the<00:09:54.360> time,<00:09:54.720> officials<00:09:55.080> at<00:09:55.200> NASA<00:09:55.520> knew<00:09:55.880> that 09:00.606 --> 09:00.616 align:start position:0% At the time, officials at NASA knew that 09:00.616 --> 09:02.526 align:start position:0% At the time, officials at NASA knew that future<00:09:56.440> technology<00:09:57.000> would<00:09:57.200> far<00:09:57.480> surpass 09:02.526 --> 09:02.536 align:start position:0% future technology would far surpass 09:02.536 --> 09:04.766 align:start position:0% future technology would far surpass their<00:09:58.240> own<00:09:58.480> research<00:09:58.800> capabilities,<00:10:00.000> so<00:10:00.120> they 09:04.766 --> 09:04.776 align:start position:0% their own research capabilities, so they 09:04.776 --> 09:07.206 align:start position:0% their own research capabilities, so they stored<00:10:00.800> a<00:10:00.880> portion<00:10:01.360> of<00:10:01.440> these<00:10:01.600> samples<00:10:01.960> away, 09:07.206 --> 09:07.216 align:start position:0% stored a portion of these samples away, 09:07.216 --> 09:10.086 align:start position:0% stored a portion of these samples away, completely<00:10:03.320> untouched<00:10:04.040> and<00:10:04.360> sealed<00:10:05.120> for<00:10:05.280> over 09:10.086 --> 09:10.096 align:start position:0% completely untouched and sealed for over 09:10.096 --> 09:12.446 align:start position:0% completely untouched and sealed for over five<00:10:06.160> decades. 09:12.446 --> 09:12.456 align:start position:0% five decades. 09:12.456 --> 09:15.166 align:start position:0% five decades. The<00:10:08.080> time<00:10:08.320> to<00:10:08.400> unseal<00:10:08.840> them<00:10:09.040> came<00:10:09.400> in<00:10:09.560> 2025, 09:15.166 --> 09:15.176 align:start position:0% The time to unseal them came in 2025, 09:15.176 --> 09:17.566 align:start position:0% The time to unseal them came in 2025, when<00:10:10.840> a<00:10:10.880> team<00:10:11.200> led<00:10:11.400> by<00:10:11.600> geologist<00:10:12.360> Julia 09:17.566 --> 09:17.576 align:start position:0% when a team led by geologist Julia 09:17.576 --> 09:20.206 align:start position:0% when a team led by geologist Julia Magnarini<00:10:14.120> from<00:10:14.320> London's<00:10:14.800> Natural<00:10:15.360> History 09:20.206 --> 09:20.216 align:start position:0% Magnarini from London's Natural History 09:20.216 --> 09:23.166 align:start position:0% Magnarini from London's Natural History Museum<00:10:16.440> used<00:10:16.680> medical-grade<00:10:17.440> micro<00:10:17.800> CT<00:10:18.240> scans 09:23.166 --> 09:23.176 align:start position:0% Museum used medical-grade micro CT scans 09:23.176 --> 09:25.246 align:start position:0% Museum used medical-grade micro CT scans to<00:10:18.800> peer<00:10:19.200> inside<00:10:19.760> these<00:10:19.960> cores<00:10:20.440> without 09:25.246 --> 09:25.256 align:start position:0% to peer inside these cores without 09:25.256 --> 09:26.606 align:start position:0% to peer inside these cores without damaging<00:10:21.200> them. 09:26.606 --> 09:26.616 align:start position:0% damaging them. 09:26.616 --> 09:29.526 align:start position:0% damaging them. They<00:10:22.280> analyzed<00:10:23.120> clasts,<00:10:24.240> rocky<00:10:24.560> fragments 09:29.526 --> 09:29.536 align:start position:0% They analyzed clasts, rocky fragments 09:29.536 --> 09:31.406 align:start position:0% They analyzed clasts, rocky fragments that<00:10:25.160> broke<00:10:25.480> off<00:10:25.640> the<00:10:25.760> slope<00:10:26.080> of<00:10:26.200> South<00:10:26.520> Massif 09:31.406 --> 09:31.416 align:start position:0% that broke off the slope of South Massif 09:31.416 --> 09:33.446 align:start position:0% that broke off the slope of South Massif during<00:10:27.200> the<00:10:27.320> landslide,<00:10:28.280> and<00:10:28.400> compared<00:10:28.800> their 09:33.446 --> 09:33.456 align:start position:0% during the landslide, and compared their 09:33.456 --> 09:35.526 align:start position:0% during the landslide, and compared their shape<00:10:29.360> and<00:10:29.520> composition<00:10:30.480> to<00:10:30.600> computer 09:35.526 --> 09:35.536 align:start position:0% shape and composition to computer 09:35.536 --> 09:38.166 align:start position:0% shape and composition to computer simulations<00:10:31.720> of<00:10:31.800> the<00:10:31.920> event.<00:10:32.960> And<00:10:33.240> what<00:10:33.520> they 09:38.166 --> 09:38.176 align:start position:0% simulations of the event. And what they 09:38.176 --> 09:41.126 align:start position:0% simulations of the event. And what they discovered<00:10:34.760> is<00:10:34.960> quite<00:10:35.280> mind-blowing. 09:41.126 --> 09:41.136 align:start position:0% discovered is quite mind-blowing. 09:41.136 --> 09:43.086 align:start position:0% discovered is quite mind-blowing. As<00:10:36.920> the<00:10:37.000> mountainside<00:10:37.520> began<00:10:37.800> to<00:10:37.880> collapse, 09:43.086 --> 09:43.096 align:start position:0% As the mountainside began to collapse, 09:43.096 --> 09:45.086 align:start position:0% As the mountainside began to collapse, the<00:10:38.720> falling<00:10:39.080> rocks<00:10:39.360> started<00:10:39.920> grinding 09:45.086 --> 09:45.096 align:start position:0% the falling rocks started grinding 09:45.096 --> 09:47.446 align:start position:0% the falling rocks started grinding against<00:10:41.000> each<00:10:41.160> other<00:10:41.360> with<00:10:41.520> intense<00:10:42.120> force, 09:47.446 --> 09:47.456 align:start position:0% against each other with intense force, 09:47.456 --> 09:49.366 align:start position:0% against each other with intense force, eventually<00:10:43.560> coating<00:10:43.960> themselves<00:10:44.480> in<00:10:44.600> their 09:49.366 --> 09:49.376 align:start position:0% eventually coating themselves in their 09:49.376 --> 09:51.046 align:start position:0% eventually coating themselves in their own<00:10:45.320> dust. 09:51.046 --> 09:51.056 align:start position:0% own dust. 09:51.056 --> 09:53.406 align:start position:0% own dust. This<00:10:46.800> layer<00:10:47.200> of<00:10:47.360> fine<00:10:47.600> powder<00:10:48.040> lubricated<00:10:48.839> the 09:53.406 --> 09:53.416 align:start position:0% This layer of fine powder lubricated the 09:53.416 --> 09:55.926 align:start position:0% This layer of fine powder lubricated the giant<00:10:49.280> rocks,<00:10:50.000> allowing<00:10:50.480> huge<00:10:50.960> masses<00:10:51.320> of 09:55.926 --> 09:55.936 align:start position:0% giant rocks, allowing huge masses of 09:55.936 --> 09:58.126 align:start position:0% giant rocks, allowing huge masses of debris<00:10:51.839> to<00:10:52.000> collide<00:10:52.520> across<00:10:52.920> the<00:10:53.040> lunar<00:10:53.320> floor 09:58.126 --> 09:58.136 align:start position:0% debris to collide across the lunar floor 09:58.136 --> 10:01.006 align:start position:0% debris to collide across the lunar floor like<00:10:53.880> fluids.<00:10:54.880> This<00:10:55.080> might<00:10:55.360> finally<00:10:55.920> explain 10:01.006 --> 10:01.016 align:start position:0% like fluids. This might finally explain 10:01.016 --> 10:04.166 align:start position:0% like fluids. This might finally explain how<00:10:56.760> lunar<00:10:57.040> landslides<00:10:57.680> traveled<00:10:58.120> so<00:10:58.320> far. 10:04.166 --> 10:04.176 align:start position:0% how lunar landslides traveled so far. 10:04.176 --> 10:05.726 align:start position:0% how lunar landslides traveled so far. But<00:10:59.800> another<00:11:00.080> question<00:11:00.480> still<00:11:00.720> remained 10:05.726 --> 10:05.736 align:start position:0% But another question still remained 10:05.736 --> 10:08.606 align:start position:0% But another question still remained unanswered.<00:11:02.440> What<00:11:02.760> actually<00:11:03.160> triggered<00:11:03.920> this 10:08.606 --> 10:08.616 align:start position:0% unanswered. What actually triggered this 10:08.616 --> 10:11.486 align:start position:0% unanswered. What actually triggered this massive<00:11:04.480> collapse<00:11:04.800> in<00:11:04.880> the<00:11:04.960> first<00:11:05.240> place? 10:11.486 --> 10:11.496 align:start position:0% massive collapse in the first place? 10:11.496 --> 10:13.886 align:start position:0% massive collapse in the first place? In<00:11:07.280> more<00:11:07.600> analyses<00:11:08.280> of<00:11:08.520> the<00:11:08.640> Apollo<00:11:08.960> 17 10:13.886 --> 10:13.896 align:start position:0% In more analyses of the Apollo 17 10:13.896 --> 10:16.406 align:start position:0% In more analyses of the Apollo 17 samples,<00:11:10.280> scientists<00:11:10.880> found<00:11:11.160> traces<00:11:11.600> of 10:16.406 --> 10:16.416 align:start position:0% samples, scientists found traces of 10:16.416 --> 10:19.766 align:start position:0% samples, scientists found traces of impact<00:11:12.480> melt<00:11:12.800> glass<00:11:13.480> at<00:11:13.600> the<00:11:13.720> location. 10:19.766 --> 10:19.776 align:start position:0% impact melt glass at the location. 10:19.776 --> 10:21.806 align:start position:0% impact melt glass at the location. It<00:11:15.400> is<00:11:15.520> believed<00:11:15.880> that<00:11:16.040> these<00:11:16.320> pieces<00:11:16.680> of<00:11:16.839> then 10:21.806 --> 10:21.816 align:start position:0% It is believed that these pieces of then 10:21.816 --> 10:24.446 align:start position:0% It is believed that these pieces of then superheated<00:11:18.000> glass<00:11:18.800> were<00:11:18.920> thrown<00:11:19.560> all<00:11:19.800> the 10:24.446 --> 10:24.456 align:start position:0% superheated glass were thrown all the 10:24.456 --> 10:26.886 align:start position:0% superheated glass were thrown all the way<00:11:20.280> from<00:11:20.480> Tycho.<00:11:21.440> And<00:11:21.560> remember,<00:11:21.920> that's 10:26.886 --> 10:26.896 align:start position:0% way from Tycho. And remember, that's 10:26.896 --> 10:29.766 align:start position:0% way from Tycho. And remember, that's more<00:11:22.680> than<00:11:22.880> 2,000<00:11:23.760> km,<00:11:24.720> causing<00:11:25.160> the 10:29.766 --> 10:29.776 align:start position:0% more than 2,000 km, causing the 10:29.776 --> 10:31.806 align:start position:0% more than 2,000 km, causing the landslide<00:11:26.080> when<00:11:26.240> they<00:11:26.400> crashed<00:11:26.960> into<00:11:27.200> the 10:31.806 --> 10:31.816 align:start position:0% landslide when they crashed into the 10:31.816 --> 10:34.086 align:start position:0% landslide when they crashed into the slopes<00:11:27.800> of<00:11:28.000> South<00:11:28.360> Massif. 10:34.086 --> 10:34.096 align:start position:0% slopes of South Massif. 10:34.096 --> 10:37.246 align:start position:0% slopes of South Massif. This<00:11:30.000> really<00:11:30.520> gives<00:11:30.839> you<00:11:31.040> a<00:11:31.120> sense<00:11:31.520> of<00:11:31.760> how<00:11:32.160> far 10:37.246 --> 10:37.256 align:start position:0% This really gives you a sense of how far 10:37.256 --> 10:39.206 align:start position:0% This really gives you a sense of how far this<00:11:32.960> glass<00:11:33.360> flew. 10:39.206 --> 10:39.216 align:start position:0% this glass flew. 10:39.216 --> 10:41.486 align:start position:0% this glass flew. And<00:11:35.000> no<00:11:35.160> wonder,<00:11:35.960> based<00:11:36.280> on<00:11:36.400> the<00:11:36.480> size<00:11:36.880> of 10:41.486 --> 10:41.496 align:start position:0% And no wonder, based on the size of 10:41.496 --> 10:42.886 align:start position:0% And no wonder, based on the size of Tycho<00:11:37.320> crater, 10:42.886 --> 10:42.896 align:start position:0% Tycho crater, 10:42.896 --> 10:44.646 align:start position:0% Tycho crater, the<00:11:38.560> energy<00:11:38.920> released<00:11:39.360> from<00:11:39.520> the<00:11:39.680> impact<00:11:40.080> that 10:44.646 --> 10:44.656 align:start position:0% the energy released from the impact that 10:44.656 --> 10:47.206 align:start position:0% the energy released from the impact that created<00:11:40.760> it<00:11:41.080> would<00:11:41.200> have<00:11:41.320> been<00:11:41.480> comparable<00:11:42.360> to 10:47.206 --> 10:47.216 align:start position:0% created it would have been comparable to 10:47.216 --> 10:52.126 align:start position:0% created it would have been comparable to 30<00:11:43.600> trillion<00:11:44.600> tons<00:11:45.000> of<00:11:45.120> TNT<00:11:46.120> or<00:11:46.680> 2<00:11:47.040> billion 10:52.126 --> 10:52.136 align:start position:0% 30 trillion tons of TNT or 2 billion 10:52.136 --> 10:54.446 align:start position:0% 30 trillion tons of TNT or 2 billion nuclear<00:11:48.160> bombs<00:11:48.800> on<00:11:48.920> the<00:11:49.040> scale<00:11:49.480> of<00:11:49.560> the<00:11:49.680> one 10:54.446 --> 10:54.456 align:start position:0% nuclear bombs on the scale of the one 10:54.456 --> 10:57.526 align:start position:0% nuclear bombs on the scale of the one used<00:11:50.280> on<00:11:50.440> Hiroshima,<00:11:51.520> all<00:11:52.040> going<00:11:52.360> off<00:11:52.760> at<00:11:52.920> the 10:57.526 --> 10:57.536 align:start position:0% used on Hiroshima, all going off at the 10:57.536 --> 10:59.766 align:start position:0% used on Hiroshima, all going off at the same<00:11:53.640> time. 10:59.766 --> 10:59.776 align:start position:0% same time. 10:59.776 --> 11:02.086 align:start position:0% same time. This<00:11:55.480> would<00:11:55.640> create<00:11:56.000> something<00:11:56.840> far<00:11:57.160> brighter 11:02.086 --> 11:02.096 align:start position:0% This would create something far brighter 11:02.096 --> 11:04.086 align:start position:0% This would create something far brighter than<00:11:57.760> the<00:11:57.840> small<00:11:58.280> impact<00:11:58.720> flash<00:11:59.080> witnessed<00:11:59.400> by 11:04.086 --> 11:04.096 align:start position:0% than the small impact flash witnessed by 11:04.096 --> 11:05.966 align:start position:0% than the small impact flash witnessed by Artemis<00:12:00.080> two<00:12:00.440> astronauts<00:12:01.000> during<00:12:01.280> their 11:05.966 --> 11:05.976 align:start position:0% Artemis two astronauts during their 11:05.976 --> 11:07.966 align:start position:0% Artemis two astronauts during their recent<00:12:01.840> lunar<00:12:02.080> trip. 11:07.966 --> 11:07.976 align:start position:0% recent lunar trip. 11:07.976 --> 11:10.646 align:start position:0% recent lunar trip. With<00:12:03.640> a<00:12:03.680> blast<00:12:04.320> that<00:12:04.680> size,<00:12:05.480> some<00:12:05.680> of<00:12:05.760> Tycho's 11:10.646 --> 11:10.656 align:start position:0% With a blast that size, some of Tycho's 11:10.656 --> 11:12.126 align:start position:0% With a blast that size, some of Tycho's material<00:12:06.800> would<00:12:06.920> have<00:12:07.000> not<00:12:07.200> just<00:12:07.400> flown 11:12.126 --> 11:12.136 align:start position:0% material would have not just flown 11:12.136 --> 11:14.726 align:start position:0% material would have not just flown around<00:12:07.920> the<00:12:08.000> moon,<00:12:08.800> but<00:12:09.040> escaped<00:12:09.680> its<00:12:09.920> weak 11:14.726 --> 11:14.736 align:start position:0% around the moon, but escaped its weak 11:14.736 --> 11:17.446 align:start position:0% around the moon, but escaped its weak gravity<00:12:10.920> entirely. 11:17.446 --> 11:17.456 align:start position:0% gravity entirely. 11:17.456 --> 11:18.966 align:start position:0% gravity entirely. And<00:12:13.320> where<00:12:13.600> would<00:12:13.760> they<00:12:13.840> have<00:12:14.000> gone<00:12:14.240> after 11:18.966 --> 11:18.976 align:start position:0% And where would they have gone after 11:18.976 --> 11:19.886 align:start position:0% And where would they have gone after that? 11:19.886 --> 11:19.896 align:start position:0% that? 11:19.896 --> 11:22.766 align:start position:0% that? Well,<00:12:16.040> towards<00:12:16.640> the<00:12:16.880> other<00:12:17.280> large<00:12:17.720> source<00:12:18.120> of 11:22.766 --> 11:22.776 align:start position:0% Well, towards the other large source of 11:22.776 --> 11:25.326 align:start position:0% Well, towards the other large source of gravity<00:12:18.920> in<00:12:19.120> the<00:12:19.240> immediate<00:12:19.760> area, 11:25.326 --> 11:25.336 align:start position:0% gravity in the immediate area, 11:25.336 --> 11:26.766 align:start position:0% gravity in the immediate area, Earth. 11:26.766 --> 11:26.776 align:start position:0% Earth. 11:26.776 --> 11:28.966 align:start position:0% Earth. Imagine<00:12:22.880> what<00:12:23.160> this<00:12:23.520> would<00:12:23.760> have<00:12:23.960> looked<00:12:24.200> like 11:28.966 --> 11:28.976 align:start position:0% Imagine what this would have looked like 11:28.976 --> 11:31.686 align:start position:0% Imagine what this would have looked like for<00:12:24.600> the<00:12:24.720> dinosaurs<00:12:25.360> alive<00:12:25.720> back<00:12:25.960> then. 11:31.686 --> 11:31.696 align:start position:0% for the dinosaurs alive back then. 11:31.696 --> 11:34.406 align:start position:0% for the dinosaurs alive back then. One<00:12:27.360> night,<00:12:27.840> the<00:12:27.960> moon<00:12:28.320> would<00:12:28.680> suddenly<00:12:29.120> flash 11:34.406 --> 11:34.416 align:start position:0% One night, the moon would suddenly flash 11:34.416 --> 11:36.846 align:start position:0% One night, the moon would suddenly flash with<00:12:30.080> a<00:12:30.120> brilliant<00:12:30.800> light<00:12:31.480> as<00:12:31.600> the<00:12:31.760> impact<00:12:32.240> had 11:36.846 --> 11:36.856 align:start position:0% with a brilliant light as the impact had 11:36.856 --> 11:39.806 align:start position:0% with a brilliant light as the impact had crashed<00:12:33.000> headlong<00:12:33.720> into<00:12:34.040> its<00:12:34.200> surface. 11:39.806 --> 11:39.816 align:start position:0% crashed headlong into its surface. 11:39.816 --> 11:41.286 align:start position:0% crashed headlong into its surface. And<00:12:35.440> for<00:12:35.520> those<00:12:35.760> ancient<00:12:36.040> dinosaurs<00:12:36.600> that 11:41.286 --> 11:41.296 align:start position:0% And for those ancient dinosaurs that 11:41.296 --> 11:43.446 align:start position:0% And for those ancient dinosaurs that missed<00:12:37.040> the<00:12:37.200> main<00:12:37.520> event,<00:12:38.440> there<00:12:38.520> was<00:12:38.680> still<00:12:38.880> a 11:43.446 --> 11:43.456 align:start position:0% missed the main event, there was still a 11:43.456 --> 11:44.726 align:start position:0% missed the main event, there was still a show. 11:44.726 --> 11:44.736 align:start position:0% show. 11:44.736 --> 11:47.486 align:start position:0% show. The<00:12:40.360> moon<00:12:40.839> would<00:12:41.000> have<00:12:41.160> borne<00:12:41.640> a<00:12:41.800> strange, 11:47.486 --> 11:47.496 align:start position:0% The moon would have borne a strange, 11:47.496 --> 11:50.766 align:start position:0% The moon would have borne a strange, glowing,<00:12:43.800> orange<00:12:44.200> scar<00:12:44.800> for<00:12:45.240> many<00:12:45.720> nights<00:12:46.160> to 11:50.766 --> 11:50.776 align:start position:0% glowing, orange scar for many nights to 11:50.776 --> 11:53.526 align:start position:0% glowing, orange scar for many nights to come,<00:12:47.080> the<00:12:47.160> signature<00:12:47.839> of<00:12:48.000> the<00:12:48.200> red-hot 11:53.526 --> 11:53.536 align:start position:0% come, the signature of the red-hot 11:53.536 --> 11:55.526 align:start position:0% come, the signature of the red-hot impact<00:12:49.480> melt<00:12:49.839> still<00:12:50.160> cooling<00:12:50.760> on<00:12:50.880> its 11:55.526 --> 11:55.536 align:start position:0% impact melt still cooling on its 11:55.536 --> 11:57.366 align:start position:0% impact melt still cooling on its surface. 11:57.366 --> 11:57.376 align:start position:0% surface. 11:57.376 --> 11:59.686 align:start position:0% surface. But<00:12:53.280> as<00:12:53.560> spectacular<00:12:54.400> as<00:12:54.560> that<00:12:54.800> show<00:12:55.080> would 11:59.686 --> 11:59.696 align:start position:0% But as spectacular as that show would 11:59.696 --> 12:02.806 align:start position:0% But as spectacular as that show would have<00:12:55.360> been,<00:12:56.080> it<00:12:56.200> wasn't<00:12:56.480> until<00:12:56.880> hours<00:12:57.360> or<00:12:57.839> days 12:02.806 --> 12:02.816 align:start position:0% have been, it wasn't until hours or days 12:02.816 --> 12:05.406 align:start position:0% have been, it wasn't until hours or days later,<00:12:59.080> once<00:12:59.320> the<00:12:59.440> debris<00:13:00.000> had<00:13:00.240> cleared<00:13:00.800> the 12:05.406 --> 12:05.416 align:start position:0% later, once the debris had cleared the 12:05.416 --> 12:07.325 align:start position:0% later, once the debris had cleared the 380,000 12:07.325 --> 12:07.335 align:start position:0% 380,000 12:07.335 --> 12:09.886 align:start position:0% 380,000 km<00:13:03.440> between<00:13:03.800> the<00:13:03.880> moon<00:13:04.160> and<00:13:04.240> the<00:13:04.440> Earth,<00:13:05.280> that 12:09.886 --> 12:09.896 align:start position:0% km between the moon and the Earth, that 12:09.896 --> 12:11.126 align:start position:0% km between the moon and the Earth, that the<00:13:05.560> real<00:13:05.880> fireworks<00:13:06.009> [music] 12:11.126 --> 12:11.136 align:start position:0% the real fireworks [music] 12:11.136 --> 12:13.246 align:start position:0% the real fireworks [music] would<00:13:06.880> have<00:13:07.000> begun. 12:13.246 --> 12:13.256 align:start position:0% would have begun. 12:13.256 --> 12:15.566 align:start position:0% would have begun. Within<00:13:09.200> hours<00:13:09.839> of<00:13:09.960> being<00:13:10.240> jettisoned<00:13:10.839> into 12:15.566 --> 12:15.576 align:start position:0% Within hours of being jettisoned into 12:15.576 --> 12:17.846 align:start position:0% Within hours of being jettisoned into space,<00:13:11.839> most<00:13:12.160> of<00:13:12.240> the<00:13:12.360> molten<00:13:12.800> moon<00:13:13.040> rock 12:17.846 --> 12:17.856 align:start position:0% space, most of the molten moon rock 12:17.856 --> 12:19.966 align:start position:0% space, most of the molten moon rock would<00:13:13.600> have<00:13:13.880> resolidified<00:13:14.760> into<00:13:15.040> hard 12:19.966 --> 12:19.976 align:start position:0% would have resolidified into hard 12:19.976 --> 12:21.246 align:start position:0% would have resolidified into hard meteorites. 12:21.246 --> 12:21.256 align:start position:0% meteorites. 12:21.256 --> 12:24.286 align:start position:0% meteorites. Upon<00:13:17.240> entry<00:13:17.720> into<00:13:18.080> Earth's<00:13:18.440> atmosphere,<00:13:19.480> that 12:24.286 --> 12:24.296 align:start position:0% Upon entry into Earth's atmosphere, that 12:24.296 --> 12:26.806 align:start position:0% Upon entry into Earth's atmosphere, that rock<00:13:20.080> would<00:13:20.280> start<00:13:20.680> heating<00:13:21.040> up<00:13:21.160> again. 12:26.806 --> 12:26.816 align:start position:0% rock would start heating up again. 12:26.816 --> 12:29.166 align:start position:0% rock would start heating up again. 30%<00:13:23.200> would<00:13:23.400> have<00:13:23.640> burned<00:13:23.920> up<00:13:24.040> entirely, 12:29.166 --> 12:29.176 align:start position:0% 30% would have burned up entirely, 12:29.176 --> 12:31.486 align:start position:0% 30% would have burned up entirely, lighting<00:13:25.040> up<00:13:25.160> the<00:13:25.240> sky.<00:13:26.280> But<00:13:26.360> the<00:13:26.480> remaining 12:31.486 --> 12:31.496 align:start position:0% lighting up the sky. But the remaining 12:31.496 --> 12:34.526 align:start position:0% lighting up the sky. But the remaining 70%<00:13:28.360> would<00:13:28.560> have<00:13:28.720> hit<00:13:29.000> the<00:13:29.120> ground, 12:34.526 --> 12:34.536 align:start position:0% 70% would have hit the ground, 12:34.536 --> 12:37.326 align:start position:0% 70% would have hit the ground, bombarding<00:13:30.720> the<00:13:30.840> planet<00:13:31.320> with<00:13:31.640> tiny<00:13:32.280> or 12:37.326 --> 12:37.336 align:start position:0% bombarding the planet with tiny or 12:37.336 --> 12:40.446 align:start position:0% bombarding the planet with tiny or larger<00:13:33.320> fragments<00:13:34.120> over<00:13:34.320> the<00:13:34.440> course<00:13:34.920> of<00:13:35.200> days 12:40.446 --> 12:40.456 align:start position:0% larger fragments over the course of days 12:40.456 --> 12:42.086 align:start position:0% larger fragments over the course of days to<00:13:36.280> weeks. 12:42.086 --> 12:42.096 align:start position:0% to weeks. 12:42.096 --> 12:44.126 align:start position:0% to weeks. Enough<00:13:37.880> material<00:13:38.400> would<00:13:38.560> fall<00:13:38.800> that,<00:13:39.360> if<00:13:39.480> it 12:44.126 --> 12:44.136 align:start position:0% Enough material would fall that, if it 12:44.136 --> 12:47.006 align:start position:0% Enough material would fall that, if it were<00:13:39.920> spread<00:13:40.520> out,<00:13:41.240> estimates<00:13:41.680> from<00:13:42.000> a<00:13:42.080> lunar 12:47.006 --> 12:47.016 align:start position:0% were spread out, estimates from a lunar 12:47.016 --> 12:49.166 align:start position:0% were spread out, estimates from a lunar and<00:13:42.760> planetary<00:13:43.200> science<00:13:43.600> conference<00:13:44.200> predict 12:49.166 --> 12:49.176 align:start position:0% and planetary science conference predict 12:49.176 --> 12:51.486 align:start position:0% and planetary science conference predict it<00:13:44.840> would<00:13:45.000> have<00:13:45.200> covered<00:13:45.560> the<00:13:45.720> entire<00:13:46.560> Earth 12:51.486 --> 12:51.496 align:start position:0% it would have covered the entire Earth 12:51.496 --> 12:56.806 align:start position:0% it would have covered the entire Earth in<00:13:47.160> a<00:13:47.240> layer<00:13:47.880> 0.1<00:13:49.080> to<00:13:49.200> 0.3<00:13:50.560> mm<00:13:51.160> thick.<00:13:52.120> And<00:13:52.200> of 12:56.806 --> 12:56.816 align:start position:0% in a layer 0.1 to 0.3 mm thick. And of 12:56.816 --> 12:58.766 align:start position:0% in a layer 0.1 to 0.3 mm thick. And of course,<00:13:52.920> in<00:13:53.040> reality,<00:13:53.880> there<00:13:54.040> would<00:13:54.160> have 12:58.766 --> 12:58.776 align:start position:0% course, in reality, there would have 12:58.776 --> 13:02.686 align:start position:0% course, in reality, there would have been<00:13:54.720> larger<00:13:55.240> fragments<00:13:55.840> here<00:13:56.160> and<00:13:56.280> there. 13:02.686 --> 13:02.696 align:start position:0% been larger fragments here and there. 13:02.696 --> 13:04.766 align:start position:0% been larger fragments here and there. But,<00:13:58.480> there<00:13:58.720> is<00:13:58.960> one<00:13:59.240> mystery<00:13:59.720> when<00:13:59.880> it<00:13:59.960> comes 13:04.766 --> 13:04.776 align:start position:0% But, there is one mystery when it comes 13:04.776 --> 13:07.686 align:start position:0% But, there is one mystery when it comes to<00:14:00.400> this<00:14:00.600> day<00:14:00.880> of<00:14:01.160> raining<00:14:01.640> rock<00:14:01.960> and<00:14:02.080> glass. 13:07.686 --> 13:07.696 align:start position:0% to this day of raining rock and glass. 13:07.696 --> 13:10.566 align:start position:0% to this day of raining rock and glass. When<00:14:03.640> exactly<00:14:04.400> did<00:14:04.600> it<00:14:04.760> happen? 13:10.566 --> 13:10.576 align:start position:0% When exactly did it happen? 13:10.576 --> 13:13.566 align:start position:0% When exactly did it happen? And<00:14:06.200> unfortunately,<00:14:07.200> the<00:14:07.360> answer<00:14:07.800> is<00:14:08.560> we're 13:13.566 --> 13:13.576 align:start position:0% And unfortunately, the answer is we're 13:13.576 --> 13:16.846 align:start position:0% And unfortunately, the answer is we're actually<00:14:09.760> not<00:14:10.000> quite<00:14:10.280> sure. 13:16.846 --> 13:16.856 align:start position:0% actually not quite sure. 13:16.856 --> 13:18.486 align:start position:0% actually not quite sure. When<00:14:12.520> the<00:14:12.640> Apollo<00:14:13.000> astronauts<00:14:13.520> brought<00:14:13.840> their 13:18.486 --> 13:18.496 align:start position:0% When the Apollo astronauts brought their 13:18.496 --> 13:20.886 align:start position:0% When the Apollo astronauts brought their sample<00:14:14.360> of<00:14:14.480> glass<00:14:14.880> back<00:14:15.200> to<00:14:15.400> Earth,<00:14:16.000> cosmic 13:20.886 --> 13:20.896 align:start position:0% sample of glass back to Earth, cosmic 13:20.896 --> 13:23.126 align:start position:0% sample of glass back to Earth, cosmic ray<00:14:16.560> exposure<00:14:17.120> dating<00:14:17.840> placed<00:14:18.120> the<00:14:18.200> Tycho 13:23.126 --> 13:23.136 align:start position:0% ray exposure dating placed the Tycho 13:23.136 --> 13:26.286 align:start position:0% ray exposure dating placed the Tycho crater<00:14:19.040> event<00:14:19.440> at<00:14:19.560> around<00:14:20.080> 108<00:14:21.200> million<00:14:21.600> years 13:26.286 --> 13:26.296 align:start position:0% crater event at around 108 million years 13:26.296 --> 13:28.686 align:start position:0% crater event at around 108 million years ago,<00:14:22.520> right<00:14:23.000> at<00:14:23.120> the<00:14:23.280> end<00:14:23.600> of<00:14:23.720> the<00:14:23.920> early 13:28.686 --> 13:28.696 align:start position:0% ago, right at the end of the early 13:28.696 --> 13:30.566 align:start position:0% ago, right at the end of the early Cretaceous<00:14:24.800> period. 13:30.566 --> 13:30.576 align:start position:0% Cretaceous period. 13:30.576 --> 13:32.806 align:start position:0% Cretaceous period. This<00:14:26.240> makes<00:14:26.520> Tycho<00:14:26.920> crater<00:14:27.400> relatively<00:14:27.960> young 13:32.806 --> 13:32.816 align:start position:0% This makes Tycho crater relatively young 13:32.816 --> 13:35.726 align:start position:0% This makes Tycho crater relatively young by<00:14:28.840> lunar<00:14:29.160> crater<00:14:29.520> standards,<00:14:30.480> and<00:14:30.600> explains 13:35.726 --> 13:35.736 align:start position:0% by lunar crater standards, and explains 13:35.736 --> 13:38.366 align:start position:0% by lunar crater standards, and explains why<00:14:31.440> the<00:14:31.560> crater<00:14:31.960> is<00:14:32.120> still<00:14:32.440> so<00:14:32.800> pristine,<00:14:33.760> and 13:38.366 --> 13:38.376 align:start position:0% why the crater is still so pristine, and 13:38.376 --> 13:41.206 align:start position:0% why the crater is still so pristine, and its<00:14:34.040> rays<00:14:34.440> are<00:14:34.800> so<00:14:35.200> bright.<00:14:36.120> There's<00:14:36.320> not<00:14:36.520> been 13:41.206 --> 13:41.216 align:start position:0% its rays are so bright. There's not been 13:41.216 --> 13:43.446 align:start position:0% its rays are so bright. There's not been time<00:14:37.120> for<00:14:37.200> them<00:14:37.360> to<00:14:37.480> get<00:14:37.600> disturbed<00:14:38.120> by<00:14:38.320> later, 13:43.446 --> 13:43.456 align:start position:0% time for them to get disturbed by later, 13:43.456 --> 13:46.206 align:start position:0% time for them to get disturbed by later, smaller<00:14:39.760> meteor<00:14:40.160> impacts. 13:46.206 --> 13:46.216 align:start position:0% smaller meteor impacts. 13:46.216 --> 13:48.166 align:start position:0% smaller meteor impacts. You<00:14:41.839> think<00:14:42.080> that<00:14:42.360> locating<00:14:42.839> small<00:14:43.080> pieces<00:14:43.480> of 13:48.166 --> 13:48.176 align:start position:0% You think that locating small pieces of 13:48.176 --> 13:50.486 align:start position:0% You think that locating small pieces of asteroid<00:14:44.200> impact<00:14:44.560> glass,<00:14:45.320> known<00:14:45.570> [music]<00:14:45.600> as 13:50.486 --> 13:50.496 align:start position:0% asteroid impact glass, known [music] as 13:50.496 --> 13:52.806 align:start position:0% asteroid impact glass, known [music] as tektites,<00:14:47.040> that's<00:14:47.320> a<00:14:47.440> similar<00:14:47.880> point<00:14:48.160> in<00:14:48.240> the 13:52.806 --> 13:52.816 align:start position:0% tektites, that's a similar point in the 13:52.816 --> 13:55.686 align:start position:0% tektites, that's a similar point in the fossil<00:14:48.680> record,<00:14:49.440> would<00:14:49.720> have<00:14:49.880> been<00:14:50.120> easy. 13:55.686 --> 13:55.696 align:start position:0% fossil record, would have been easy. 13:55.696 --> 13:57.966 align:start position:0% fossil record, would have been easy. But,<00:14:51.800> in<00:14:52.040> the<00:14:52.200> whole<00:14:52.480> world,<00:14:53.240> there<00:14:53.360> are 13:57.966 --> 13:57.976 align:start position:0% But, in the whole world, there are 13:57.976 --> 14:00.486 align:start position:0% But, in the whole world, there are actually<00:14:53.960> only<00:14:54.360> five<00:14:55.080> known<00:14:55.480> fields<00:14:55.880> of 14:00.486 --> 14:00.496 align:start position:0% actually only five known fields of 14:00.496 --> 14:02.501 align:start position:0% actually only five known fields of tektites<00:14:56.560> created<00:14:57.040> by<00:14:57.160> meteors, 14:02.501 --> 14:02.511 align:start position:0% tektites created by meteors, 14:02.511 --> 14:02.806 align:start position:0% tektites created by meteors, >> [music] 14:02.806 --> 14:02.816 align:start position:0% >> [music] 14:02.816 --> 14:06.806 align:start position:0% >> [music] >> and<00:14:59.080> none<00:14:59.320> of<00:14:59.440> them<00:14:59.880> are<00:15:00.000> related<00:15:00.520> to<00:15:00.640> Tycho. 14:06.806 --> 14:06.816 align:start position:0% >> and none of them are related to Tycho. 14:06.816 --> 14:09.246 align:start position:0% >> and none of them are related to Tycho. There<00:15:02.520> is<00:15:02.920> other<00:15:03.200> evidence<00:15:03.680> that<00:15:03.880> is<00:15:04.160> equally 14:09.246 --> 14:09.256 align:start position:0% There is other evidence that is equally 14:09.256 --> 14:10.406 align:start position:0% There is other evidence that is equally bizarre. 14:10.406 --> 14:10.416 align:start position:0% bizarre. 14:10.416 --> 14:13.046 align:start position:0% bizarre. In<00:15:06.040> her<00:15:06.160> doctoral<00:15:06.640> thesis,<00:15:07.440> researcher<00:15:08.200> Elena 14:13.046 --> 14:13.056 align:start position:0% In her doctoral thesis, researcher Elena 14:13.056 --> 14:15.166 align:start position:0% In her doctoral thesis, researcher Elena Martin<00:15:09.120> from<00:15:09.320> the<00:15:09.440> Lund<00:15:09.800> University<00:15:10.520> in 14:15.166 --> 14:15.176 align:start position:0% Martin from the Lund University in 14:15.176 --> 14:17.325 align:start position:0% Martin from the Lund University in Sweden<00:15:11.520> demonstrated<00:15:11.770> [music]<00:15:12.160> that<00:15:12.280> Tycho 14:17.325 --> 14:17.335 align:start position:0% Sweden demonstrated [music] that Tycho 14:17.335 --> 14:21.006 align:start position:0% Sweden demonstrated [music] that Tycho could<00:15:13.080> be<00:15:13.360> older<00:15:14.000> than<00:15:14.080> 117<00:15:15.080> million<00:15:15.360> years. 14:21.006 --> 14:21.016 align:start position:0% could be older than 117 million years. 14:21.016 --> 14:24.006 align:start position:0% could be older than 117 million years. She<00:15:16.640> did<00:15:16.839> this<00:15:17.320> by<00:15:17.480> searching<00:15:18.040> for<00:15:18.520> that<00:15:18.880> Tycho 14:24.006 --> 14:24.016 align:start position:0% She did this by searching for that Tycho 14:24.016 --> 14:26.526 align:start position:0% She did this by searching for that Tycho meteor<00:15:19.920> layer<00:15:20.600> in<00:15:20.720> sediment<00:15:21.200> deposited<00:15:21.920> on 14:26.526 --> 14:26.536 align:start position:0% meteor layer in sediment deposited on 14:26.536 --> 14:28.446 align:start position:0% meteor layer in sediment deposited on the<00:15:22.200> floor<00:15:22.520> in<00:15:22.600> the<00:15:22.680> Pacific<00:15:23.120> Ocean, 14:28.446 --> 14:28.456 align:start position:0% the floor in the Pacific Ocean, 14:28.456 --> 14:30.926 align:start position:0% the floor in the Pacific Ocean, examining<00:15:24.480> samples<00:15:25.000> with<00:15:25.280> ages<00:15:25.720> ranging<00:15:26.120> from 14:30.926 --> 14:30.936 align:start position:0% examining samples with ages ranging from 14:30.936 --> 14:35.126 align:start position:0% examining samples with ages ranging from 103<00:15:27.680> to<00:15:27.840> 117<00:15:29.040> million<00:15:29.360> years<00:15:29.600> old. 14:35.126 --> 14:35.136 align:start position:0% 103 to 117 million years old. 14:35.136 --> 14:37.766 align:start position:0% 103 to 117 million years old. And<00:15:30.760> yet,<00:15:31.320> she<00:15:31.520> found<00:15:32.000> Tycho<00:15:32.400> meteorites<00:15:33.160> in 14:37.766 --> 14:37.776 align:start position:0% And yet, she found Tycho meteorites in 14:37.776 --> 14:40.726 align:start position:0% And yet, she found Tycho meteorites in precisely<00:15:34.520> none<00:15:34.760> of<00:15:34.880> them. 14:40.726 --> 14:40.736 align:start position:0% precisely none of them. 14:40.736 --> 14:43.646 align:start position:0% precisely none of them. One<00:15:36.920> grain<00:15:37.440> was<00:15:37.640> found<00:15:38.120> that<00:15:38.480> could<00:15:38.800> have<00:15:38.960> come 14:43.646 --> 14:43.656 align:start position:0% One grain was found that could have come 14:43.656 --> 14:46.166 align:start position:0% One grain was found that could have come from<00:15:39.280> the<00:15:39.360> moon,<00:15:40.200> but<00:15:40.360> it<00:15:40.560> did<00:15:40.880> not<00:15:41.160> match<00:15:41.520> the 14:46.166 --> 14:46.176 align:start position:0% from the moon, but it did not match the 14:46.176 --> 14:48.806 align:start position:0% from the moon, but it did not match the chemical<00:15:42.160> composition<00:15:42.840> expected<00:15:43.680> from<00:15:43.880> Tycho 14:48.806 --> 14:48.816 align:start position:0% chemical composition expected from Tycho 14:48.816 --> 14:50.246 align:start position:0% chemical composition expected from Tycho specifically. 14:50.246 --> 14:50.256 align:start position:0% specifically. 14:50.256 --> 14:52.726 align:start position:0% specifically. So,<00:15:46.120> it<00:15:46.320> is<00:15:46.440> still<00:15:46.840> not<00:15:47.080> clear<00:15:47.400> exactly<00:15:47.960> when 14:52.726 --> 14:52.736 align:start position:0% So, it is still not clear exactly when 14:52.736 --> 14:54.526 align:start position:0% So, it is still not clear exactly when the<00:15:48.400> asteroid<00:15:48.800> that<00:15:49.040> impacted<00:15:49.640> Tycho 14:54.526 --> 14:54.536 align:start position:0% the asteroid that impacted Tycho 14:54.536 --> 14:55.806 align:start position:0% the asteroid that impacted Tycho occurred. 14:55.806 --> 14:55.816 align:start position:0% occurred. 14:55.816 --> 14:57.966 align:start position:0% occurred. That's<00:15:51.560> something<00:15:52.200> only<00:15:52.480> further<00:15:52.880> study<00:15:53.320> will 14:57.966 --> 14:57.976 align:start position:0% That's something only further study will 14:57.976 --> 14:59.926 align:start position:0% That's something only further study will be<00:15:53.640> able<00:15:53.880> to<00:15:53.960> confirm. 14:59.926 --> 14:59.936 align:start position:0% be able to confirm. 14:59.936 --> 15:02.286 align:start position:0% be able to confirm. But<00:15:55.560> while<00:15:55.840> analysis<00:15:56.720> of<00:15:57.040> ancient<00:15:57.440> impacts 15:02.286 --> 15:02.296 align:start position:0% But while analysis of ancient impacts 15:02.296 --> 15:04.526 align:start position:0% But while analysis of ancient impacts like<00:15:58.040> Tycho<00:15:58.440> is<00:15:58.560> limited<00:15:58.960> to<00:15:59.080> samples<00:15:59.720> and 15:04.526 --> 15:04.536 align:start position:0% like Tycho is limited to samples and 15:04.536 --> 15:06.006 align:start position:0% like Tycho is limited to samples and computer<00:16:00.440> models, 15:06.006 --> 15:06.016 align:start position:0% computer models, 15:06.016 --> 15:08.086 align:start position:0% computer models, sometimes<00:16:01.960> we<00:16:02.120> do<00:16:02.600> get<00:16:02.800> to<00:16:02.880> watch<00:16:03.160> the<00:16:03.280> moon 15:08.086 --> 15:08.096 align:start position:0% sometimes we do get to watch the moon 15:08.096 --> 15:11.366 align:start position:0% sometimes we do get to watch the moon get<00:16:03.920> a<00:16:04.000> brand<00:16:04.480> new<00:16:04.680> scar<00:16:05.040> in<00:16:05.160> real<00:16:05.400> time. 15:11.366 --> 15:11.376 align:start position:0% get a brand new scar in real time. 15:11.376 --> 15:14.446 align:start position:0% get a brand new scar in real time. In<00:16:07.080> late<00:16:07.360> spring<00:16:07.840> of<00:16:07.960> 2024,<00:16:09.200> a<00:16:09.280> space<00:16:09.720> rock 15:14.446 --> 15:14.456 align:start position:0% In late spring of 2024, a space rock 15:14.456 --> 15:17.326 align:start position:0% In late spring of 2024, a space rock traveling<00:16:10.520> at<00:16:10.680> extraordinary<00:16:11.600> speed<00:16:12.200> slammed 15:17.326 --> 15:17.336 align:start position:0% traveling at extraordinary speed slammed 15:17.336 --> 15:19.886 align:start position:0% traveling at extraordinary speed slammed into<00:16:13.080> the<00:16:13.160> lunar<00:16:13.440> surface,<00:16:14.360> punching<00:16:14.840> a<00:16:14.960> fresh 15:19.886 --> 15:19.896 align:start position:0% into the lunar surface, punching a fresh 15:19.896 --> 15:24.286 align:start position:0% into the lunar surface, punching a fresh crater<00:16:16.080> 225<00:16:17.560> m<00:16:17.880> across,<00:16:18.960> roughly<00:16:19.280> the<00:16:19.400> width 15:24.286 --> 15:24.296 align:start position:0% crater 225 m across, roughly the width 15:24.296 --> 15:26.966 align:start position:0% crater 225 m across, roughly the width of<00:16:20.080> two<00:16:20.320> football<00:16:20.640> pitches<00:16:21.080> end-to-end. 15:26.966 --> 15:26.976 align:start position:0% of two football pitches end-to-end. 15:26.976 --> 15:28.686 align:start position:0% of two football pitches end-to-end. Thanks<00:16:22.680> to<00:16:22.800> NASA's<00:16:23.360> Lunar<00:16:23.640> Reconnaissance 15:28.686 --> 15:28.696 align:start position:0% Thanks to NASA's Lunar Reconnaissance 15:28.696 --> 15:30.806 align:start position:0% Thanks to NASA's Lunar Reconnaissance Orbiter<00:16:24.520> Camera,<00:16:25.400> scientists<00:16:25.839> were<00:16:25.960> able<00:16:26.160> to 15:30.806 --> 15:30.816 align:start position:0% Orbiter Camera, scientists were able to 15:30.816 --> 15:33.325 align:start position:0% Orbiter Camera, scientists were able to capture<00:16:26.800> the<00:16:26.960> high-resolution<00:16:27.760> before<00:16:28.440> and 15:33.325 --> 15:33.335 align:start position:0% capture the high-resolution before and 15:33.335 --> 15:35.325 align:start position:0% capture the high-resolution before and after<00:16:29.200> images<00:16:29.640> of<00:16:29.720> the<00:16:29.839> site. 15:35.325 --> 15:35.335 align:start position:0% after images of the site. 15:35.335 --> 15:38.086 align:start position:0% after images of the site. It<00:16:30.920> is<00:16:31.080> the<00:16:31.320> largest<00:16:32.040> fresh<00:16:32.440> crater<00:16:33.160> ever 15:38.086 --> 15:38.096 align:start position:0% It is the largest fresh crater ever 15:38.096 --> 15:40.206 align:start position:0% It is the largest fresh crater ever observed<00:16:34.160> during<00:16:34.480> the<00:16:34.600> orbiter's<00:16:35.040> entire 15:40.206 --> 15:40.216 align:start position:0% observed during the orbiter's entire 15:40.216 --> 15:43.126 align:start position:0% observed during the orbiter's entire 17-year<00:16:36.720> mission,<00:16:37.520> more<00:16:37.720> than<00:16:37.880> three<00:16:38.240> times 15:43.126 --> 15:43.136 align:start position:0% 17-year mission, more than three times 15:43.136 --> 15:45.686 align:start position:0% 17-year mission, more than three times the<00:16:38.720> size<00:16:39.120> of<00:16:39.240> the<00:16:39.360> previous<00:16:39.800> record<00:16:40.120> holder. 15:45.686 --> 15:45.696 align:start position:0% the size of the previous record holder. 15:45.696 --> 15:49.046 align:start position:0% the size of the previous record holder. It<00:16:41.280> stretches<00:16:41.880> 43<00:16:42.760> m<00:16:43.080> deep,<00:16:43.800> features<00:16:44.120> steep 15:49.046 --> 15:49.056 align:start position:0% It stretches 43 m deep, features steep 15:49.056 --> 15:51.526 align:start position:0% It stretches 43 m deep, features steep walls,<00:16:45.360> and<00:16:45.480> is<00:16:45.600> surrounded<00:16:46.120> by<00:16:46.360> shattered 15:51.526 --> 15:51.536 align:start position:0% walls, and is surrounded by shattered 15:51.536 --> 15:54.886 align:start position:0% walls, and is surrounded by shattered boulders<00:16:47.520> up<00:16:47.640> to<00:16:47.800> 13<00:16:48.640> m<00:16:49.000> wide. 15:54.886 --> 15:54.896 align:start position:0% boulders up to 13 m wide. 15:54.896 --> 15:56.886 align:start position:0% boulders up to 13 m wide. Deep<00:16:50.680> inside,<00:16:51.440> scientists<00:16:51.986> [music]<00:16:52.080> even 15:56.886 --> 15:56.896 align:start position:0% Deep inside, scientists [music] even 15:56.896 --> 16:00.526 align:start position:0% Deep inside, scientists [music] even detected<00:16:53.040> dark,<00:16:53.880> glassy<00:16:54.440> rock<00:16:55.280> flash<00:16:55.640> melted 16:00.526 --> 16:00.536 align:start position:0% detected dark, glassy rock flash melted 16:00.536 --> 16:02.006 align:start position:0% detected dark, glassy rock flash melted by<00:16:56.200> the<00:16:56.320> intense<00:16:56.571> [music]<00:16:56.880> energy<00:16:57.320> of<00:16:57.440> the 16:02.006 --> 16:02.016 align:start position:0% by the intense [music] energy of the 16:02.016 --> 16:03.126 align:start position:0% by the intense [music] energy of the collision. 16:03.126 --> 16:03.136 align:start position:0% collision. 16:03.136 --> 16:05.206 align:start position:0% collision. According<00:16:59.040> to<00:16:59.120> models,<00:16:59.839> an<00:17:00.040> impact<00:17:00.440> of<00:17:00.520> this 16:05.206 --> 16:05.216 align:start position:0% According to models, an impact of this 16:05.216 --> 16:08.046 align:start position:0% According to models, an impact of this scale<00:17:01.040> on<00:17:01.280> any<00:17:01.640> given<00:17:02.000> patch<00:17:02.360> of<00:17:02.480> lunar<00:17:02.760> ground 16:08.046 --> 16:08.056 align:start position:0% scale on any given patch of lunar ground 16:08.056 --> 16:10.886 align:start position:0% scale on any given patch of lunar ground is<00:17:03.800> a<00:17:03.880> true<00:17:04.520> once-in-a-century<00:17:05.600> event, 16:10.886 --> 16:10.896 align:start position:0% is a true once-in-a-century event, 16:10.896 --> 16:14.805 align:start position:0% is a true once-in-a-century event, expected<00:17:06.959> only<00:17:07.199> once<00:17:07.600> every<00:17:07.920> 139<00:17:09.280> years. 16:14.805 --> 16:14.815 align:start position:0% expected only once every 139 years. 16:14.815 --> 16:16.445 align:start position:0% expected only once every 139 years. So,<00:17:10.439> catching<00:17:10.880> it<00:17:11.120> this<00:17:11.400> soon<00:17:11.720> after 16:16.445 --> 16:16.455 align:start position:0% So, catching it this soon after 16:16.455 --> 16:19.166 align:start position:0% So, catching it this soon after formation<00:17:12.920> is<00:17:13.079> an<00:17:13.160> astounding<00:17:13.959> feat<00:17:14.439> of<00:17:14.560> the 16:19.166 --> 16:19.176 align:start position:0% formation is an astounding feat of the 16:19.176 --> 16:22.046 align:start position:0% formation is an astounding feat of the LRO<00:17:15.160> mission. 16:22.046 --> 16:22.056 align:start position:0% LRO mission. 16:22.056 --> 16:23.565 align:start position:0% LRO mission. While<00:17:17.720> going<00:17:17.920> to<00:17:18.040> the<00:17:18.199> moon<00:17:18.439> seems<00:17:18.720> like<00:17:18.959> a 16:23.565 --> 16:23.575 align:start position:0% While going to the moon seems like a 16:23.575 --> 16:25.966 align:start position:0% While going to the moon seems like a rare<00:17:19.480> and<00:17:19.839> noteworthy<00:17:20.400> thing, 16:25.966 --> 16:25.976 align:start position:0% rare and noteworthy thing, 16:25.976 --> 16:28.406 align:start position:0% rare and noteworthy thing, Tycho<00:17:21.800> crater<00:17:22.160> demonstrates<00:17:22.880> that<00:17:23.280> exchange 16:28.406 --> 16:28.416 align:start position:0% Tycho crater demonstrates that exchange 16:28.416 --> 16:30.406 align:start position:0% Tycho crater demonstrates that exchange between<00:17:24.319> the<00:17:24.439> moon<00:17:24.839> and<00:17:24.959> the<00:17:25.160> Earth<00:17:25.480> happens 16:30.406 --> 16:30.416 align:start position:0% between the moon and the Earth happens 16:30.416 --> 16:32.966 align:start position:0% between the moon and the Earth happens more<00:17:26.240> regularly<00:17:26.880> than<00:17:27.079> you<00:17:27.160> might<00:17:27.400> think. 16:32.966 --> 16:32.976 align:start position:0% more regularly than you might think. 16:32.976 --> 16:35.646 align:start position:0% more regularly than you might think. Across<00:17:29.000> the<00:17:29.240> eons,<00:17:30.080> these<00:17:30.400> two<00:17:30.640> bodies<00:17:31.000> have 16:35.646 --> 16:35.656 align:start position:0% Across the eons, these two bodies have 16:35.656 --> 16:38.046 align:start position:0% Across the eons, these two bodies have proven<00:17:31.520> to<00:17:31.640> be<00:17:31.880> a<00:17:32.000> dynamic<00:17:32.560> system<00:17:33.400> where 16:38.046 --> 16:38.056 align:start position:0% proven to be a dynamic system where 16:38.056 --> 16:40.806 align:start position:0% proven to be a dynamic system where material<00:17:34.120> from<00:17:34.400> the<00:17:34.520> one<00:17:35.120> can<00:17:35.280> sometimes,<00:17:36.040> if 16:40.806 --> 16:40.816 align:start position:0% material from the one can sometimes, if 16:40.816 --> 16:43.166 align:start position:0% material from the one can sometimes, if conditions<00:17:36.800> are<00:17:36.920> right,<00:17:37.640> find<00:17:38.000> their<00:17:38.200> way<00:17:38.560> to 16:43.166 --> 16:43.176 align:start position:0% conditions are right, find their way to 16:43.176 --> 16:44.486 align:start position:0% conditions are right, find their way to the<00:17:38.840> other. 16:44.486 --> 16:44.496 align:start position:0% the other. 16:44.496 --> 16:46.206 align:start position:0% the other. Astronauts<00:17:40.600> are<00:17:40.720> returning<00:17:41.200> to<00:17:41.320> the<00:17:41.400> surface 16:46.206 --> 16:46.216 align:start position:0% Astronauts are returning to the surface 16:46.216 --> 16:48.406 align:start position:0% Astronauts are returning to the surface of<00:17:41.800> the<00:17:41.880> moon<00:17:42.160> in<00:17:42.280> 2028. 16:48.406 --> 16:48.416 align:start position:0% of the moon in 2028. 16:48.416 --> 16:50.838 align:start position:0% of the moon in 2028. Perhaps<00:17:44.280> in<00:17:44.400> time,<00:17:45.320> once<00:17:45.560> NASA<00:17:45.840> has<00:17:46.080> finished 16:50.838 --> 16:50.848 align:start position:0% Perhaps in time, once NASA has finished 16:50.848 --> 16:52.886 align:start position:0% Perhaps in time, once NASA has finished [music]<00:17:46.480> building<00:17:46.880> its<00:17:47.080> moon<00:17:47.360> base, 16:52.886 --> 16:52.896 align:start position:0% [music] building its moon base, 16:52.896 --> 16:55.446 align:start position:0% [music] building its moon base, humanity<00:17:48.960> will<00:17:49.200> make<00:17:49.520> their<00:17:49.720> way<00:17:50.280> to<00:17:50.400> Tycho 16:55.446 --> 16:55.456 align:start position:0% humanity will make their way to Tycho 16:55.456 --> 16:58.366 align:start position:0% humanity will make their way to Tycho crater<00:17:51.400> itself,<00:17:52.440> and<00:17:52.600> through<00:17:53.000> careful<00:17:53.520> study 16:58.366 --> 16:58.376 align:start position:0% crater itself, and through careful study 16:58.376 --> 17:00.606 align:start position:0% crater itself, and through careful study of<00:17:54.000> its<00:17:54.160> slopes<00:17:54.680> or<00:17:54.880> by<00:17:55.360> climbing<00:17:55.522> [music]<00:17:55.880> its 17:00.606 --> 17:00.616 align:start position:0% of its slopes or by climbing [music] its 17:00.616 --> 17:03.846 align:start position:0% of its slopes or by climbing [music] its peak,<00:17:56.880> will<00:17:57.120> answer<00:17:57.600> once<00:17:58.080> and<00:17:58.240> for<00:17:58.440> all<00:17:59.080> all 17:03.846 --> 17:03.856 align:start position:0% peak, will answer once and for all all 17:03.856 --> 17:05.846 align:start position:0% peak, will answer once and for all all the<00:17:59.480> numerous<00:17:59.920> questions<00:18:00.480> about<00:18:00.840> Tycho's 17:05.846 --> 17:05.856 align:start position:0% the numerous questions about Tycho's 17:05.856 --> 17:07.606 align:start position:0% the numerous questions about Tycho's origins. 17:07.606 --> 17:07.616 align:start position:0% origins. 17:07.616 --> 17:09.646 align:start position:0% origins. Until<00:18:03.480> then,<00:18:04.200> if<00:18:04.360> we<00:18:04.480> want<00:18:04.680> to<00:18:04.800> learn<00:18:04.960> more 17:09.646 --> 17:09.656 align:start position:0% Until then, if we want to learn more 17:09.656 --> 17:11.846 align:start position:0% Until then, if we want to learn more about<00:18:05.440> Tycho<00:18:05.760> crater,<00:18:06.600> there<00:18:06.720> is<00:18:06.840> always<00:18:07.120> that 17:11.846 --> 17:11.856 align:start position:0% about Tycho crater, there is always that 17:11.856 --> 17:15.126 align:start position:0% about Tycho crater, there is always that layer<00:18:07.680> of<00:18:07.840> rock<00:18:08.560> and<00:18:08.720> tektites<00:18:09.280> to<00:18:09.400> find. 17:15.126 --> 17:15.136 align:start position:0% layer of rock and tektites to find. 17:15.136 --> 17:17.446 align:start position:0% layer of rock and tektites to find. We<00:18:10.760> don't<00:18:11.000> need<00:18:11.200> to<00:18:11.280> go<00:18:11.480> to<00:18:11.600> the<00:18:11.720> moon.<00:18:12.440> We<00:18:12.560> have 17:17.446 --> 17:17.456 align:start position:0% We don't need to go to the moon. We have 17:17.456 --> 17:23.806 align:start position:0% We don't need to go to the moon. We have Tycho<00:18:13.360> crater<00:18:13.720> at<00:18:13.880> home. 17:23.806 --> 17:23.816 align:start position:0% 17:23.816 --> 17:25.886 align:start position:0% The<00:18:19.440> Astrum<00:18:19.800> newsletter<00:18:20.440> is<00:18:20.680> one<00:18:20.840> of<00:18:20.920> the<00:18:21.040> most 17:25.886 --> 17:25.896 align:start position:0% The Astrum newsletter is one of the most 17:25.896 --> 17:28.766 align:start position:0% The Astrum newsletter is one of the most beautiful<00:18:22.000> reads<00:18:22.440> you'll<00:18:22.800> ever<00:18:23.080> get.<00:18:23.880> Even<00:18:24.160> if 17:28.766 --> 17:28.776 align:start position:0% beautiful reads you'll ever get. Even if 17:28.776 --> 17:31.046 align:start position:0% beautiful reads you'll ever get. Even if you're<00:18:24.440> not<00:18:24.760> in<00:18:24.880> it<00:18:25.000> for<00:18:25.080> the<00:18:25.200> news,<00:18:25.880> our<00:18:26.080> photo 17:31.046 --> 17:31.056 align:start position:0% you're not in it for the news, our photo 17:31.056 --> 17:32.846 align:start position:0% you're not in it for the news, our photo of<00:18:26.720> the<00:18:26.840> week<00:18:27.160> always<00:18:27.640> makes<00:18:27.920> it<00:18:28.040> worth 17:32.846 --> 17:32.856 align:start position:0% of the week always makes it worth 17:32.856 --> 17:35.646 align:start position:0% of the week always makes it worth opening.<00:18:29.400> Sign<00:18:29.720> up<00:18:29.840> with<00:18:30.000> the<00:18:30.080> link<00:18:30.360> below. 17:35.646 --> 17:35.656 align:start position:0% opening. Sign up with the link below. 17:35.656 --> 17:37.446 align:start position:0% opening. Sign up with the link below. It's<00:18:31.440> a<00:18:31.560> quick,<00:18:32.200> inspiring<00:18:32.220> [music] 17:37.446 --> 17:37.456 align:start position:0% It's a quick, inspiring [music] 17:37.456 --> 17:39.406 align:start position:0% It's a quick, inspiring [music] way<00:18:33.360> to<00:18:33.480> stay<00:18:33.720> connected<00:18:34.200> to<00:18:34.400> everything 17:39.406 --> 17:39.416 align:start position:0% way to stay connected to everything 17:39.416 --> 17:41.806 align:start position:0% way to stay connected to everything happening<00:18:35.360> in<00:18:35.440> the<00:18:35.520> cosmos<00:18:36.080> from<00:18:36.440> discoveries 17:41.806 --> 17:41.816 align:start position:0% happening in the cosmos from discoveries 17:41.816 --> 17:44.926 align:start position:0% happening in the cosmos from discoveries to<00:18:37.480> missions<00:18:38.400> and<00:18:38.520> the<00:18:38.560> stories<00:18:39.120> behind<00:18:39.560> them. 17:44.926 --> 17:44.936 align:start position:0% to missions and the stories behind them. 17:44.936 --> 17:47.206 align:start position:0% to missions and the stories behind them. Each<00:18:40.680> issue<00:18:41.080> is<00:18:41.440> carefully<00:18:41.920> designed<00:18:42.560> and 17:47.206 --> 17:47.216 align:start position:0% Each issue is carefully designed and 17:47.216 --> 17:49.806 align:start position:0% Each issue is carefully designed and written<00:18:43.400> to<00:18:43.480> make<00:18:43.680> science<00:18:44.120> feel<00:18:44.520> exciting 17:49.806 --> 17:49.816 align:start position:0% written to make science feel exciting 17:49.816 --> 17:52.606 align:start position:0% written to make science feel exciting and<00:18:45.520> easy<00:18:45.760> to<00:18:45.880> follow.<00:18:46.880> If<00:18:47.000> you<00:18:47.240> already<00:18:47.720> enjoy 17:52.606 --> 17:52.616 align:start position:0% and easy to follow. If you already enjoy 17:52.616 --> 17:54.686 align:start position:0% and easy to follow. If you already enjoy our<00:18:48.280> videos,<00:18:49.080> you'll<00:18:49.320> love<00:18:49.600> having<00:18:49.880> this<00:18:50.080> in 17:54.686 --> 17:54.696 align:start position:0% our videos, you'll love having this in 17:54.696 --> 17:57.286 align:start position:0% our videos, you'll love having this in your<00:18:50.360> inbox<00:18:50.760> every<00:18:51.000> week.<00:18:51.800> Join<00:18:52.120> thousands<00:18:52.680> of 17:57.286 --> 17:57.296 align:start position:0% your inbox every week. Join thousands of 17:57.296 --> 18:01.736 align:start position:0% your inbox every week. Join thousands of readers<00:18:53.240> exploring<00:18:53.920> space<00:18:54.520> with<00:18:54.720> Astrum.