The Earth's atmosphere may look empty,
but it's really a complex and dynamic
place swirling with gaseous matter and
thermal energy. Some of its most
spectacular activity is best viewed at
night. If you've ever watched a
lightning storm or a meteor shower, the
breathtaking Aurora Borealis in the
north or the shimmering Aurora Orales in
the south, then you know what an
incredible light show the sky can put
on.
But in recent years, with the help of
highly sensitive cameras, researchers
have been able to document a number of
unusual, previously unrecorded light
producing phenomena.
These occurrences which happen high in
the Earth's atmosphere are known as
transient luminous events.
What are these strange phenomena? Why
are they so elusive? And what can they
teach us about the hidden workings of
our atmosphere?
I'm Alex Mccoan and you're watching
Astramm. Join me today as we look at
incredible images of transient luminous
events as we explore and unravel some of
the most mysterious and elusive
phenomenon in the night sky.
Let's begin with a remarkable image. It
looks like a cross between a lightning
storm and a jellyfish, doesn't it? This
is a red sprite, and the formation
you're looking at is fittingly called a
jellyfish. It's incredibly big, spanning
up to 50 km and originates at an
altitude of 70 to 80 km above the Earth.
Sprites are short-lived events lasting 3
to 5 milliseconds and they travel
downwards at blazing speeds, reaching
10% the speed of light.
For years, sprites were only rumored to
exist. Reports can be found as far back
as the 18th century, but a theoretical
basis wasn't published until 1925 when
physicist CTR Wilson speculated that the
electrical breakdown could occur in the
upper atmosphere. However, despite years
of unverified sightings, it would take
more than six decades for their
existence to be confirmed.
So, what are sprites?
Unlike lightning, which is extremely
hot, sprites are cold plasma events,
much like the reaction inside a
fluorescent tube. Let's think about that
fluorescent light for a moment. It
requires a power source to ionize the
gases trapped inside in order to emit
light. As it happens, sprites also
require an electrical discharge to
trigger their fluorescent reaction. You
see, inside a storm cloud, there is
friction between rising ice crystals
which become positively charged and
sinking soft hail particles which become
negative. These positively charged
crystals in turn cause a negative shield
layer to form in the air above them.
When a positive discharge happens in the
form of a lightning strike, the cloud
becomes neutralized, but the negative
shield layer remains. We now believe it
is this unstable, negatively charged
shield layer that causes electrical
breakdown in the upper atmosphere,
producing sprites.
It is even possible that sprites aren't
especially rare. What makes them
incredibly difficult to observe is that
they occur high in the ionosphere where
they are often hidden by the storm
systems that produce them. So, to see a
sprite, you need a clear sight line over
a thunderstorm
or perhaps a camera positioned above it.
As you can see here, the International
Space Station was lucky enough to get
one in action.
Sprites glow red because under the low
pressure conditions where they
originate, nitrogen emits low frequency
red light where its molecules get
excited. Compare this to auroras, which
are usually green. That's because at the
higher elevation where auroras occur,
Earth's atmosphere has greater levels of
oxygen whose molecules fluores green
when they get excited.
But sprites don't always produce red
light. Sometimes a sprite will set off a
secondary event at a lower elevation.
These secondary events, or tendrils,
often appear blue. While their light is
also produced by nitrogen, the higher
pressure causes them to glow blue and
near ultraviolet. As a result, some
larger sprites, like the jellyfish we
saw earlier, have a remarkable
appearance, glowing red at the top and
blue at the tentacles.
Sprite tendrils aren't the only tle's
with a bluish tint. This event is known
as a blue jet. Discovered only recently,
blue jets are a distinct phenomenon also
initiated by storm systems. In these
events, the positive charge at the top
of a storm cloud forms a leader with a
negative shield layer above the cloud,
producing a discharge that propagates
upwards. This excites the nitrogen,
making a spectacular cone-shaped jet
that glows blue. Why blue? Well,
remember what we said about how
atmospheric pressure affects excited
nitrogen gases? Blue jets occur much
lower in the atmosphere than sprites,
which is why they flues a different
color. There are also smaller TLEs
called blue starters, but scientists
believe they are simply failed blue
jets.
These dimminitive cousins only reach 20
km above the Earth.
At the other end of the family is a
separate phenomenon known as the
gigantic jet and it occurs much higher
in the atmosphere which is why the upper
portion changes color from blue to red.
We'll leave today with one of the rarest
and least understood tle. These green or
red phenomena are known as elves. A
quaint acronym that stands for a
mouthful. Its full name is emission of
light and very low frequency
perturbations due to electromagnetic
pulse sources. Try saying that five
times fast. Unlike sprites and jets,
elves are diffuse ring-shaped phenomena
that occur even higher in the
atmosphere. And unlike what the name
suggests, they are huge. Elves can grow
up to 400 km in diameter and occur 100
km above the Earth.
But despite their size, they are
extremely short-lived events. They only
last a millisecond, so brief that they
can't be seen by the naked eye. While
little is known about elves, we believe
they are caused by an electromagnetic
pulse produced by the discharge of an
underlying thunderstorm.
So, there we have it. An introduction to
some of the most spectacular transient
luminous events that have been confirmed
in recent years.
What other luminous phenomena may be
lurking in the Earth's atmosphere? It's
tantalizing to think about, and because
this is still a fairly new field of
research, we can only imagine what new
surprises may be in store for us.
Want more videos about weird atmospheric
phenomena on Earth? Let me know in the
comments.
Picture
the ocean on a dark and windy day.
Rather than smooth rolling waves, the
surface is rough and choppy with deep
troughs and frothy crests.
Now, imagine that stormy ocean flipped
upside down and blanketing an entire
sky. It may sound crazy, but that image
is a pretty close approximation of
aspiritus clouds, an extremely rare
cloud type that was only recognized by
the World Meteorological Organization in
2017.
Aspiritas, which translates to rough and
uneven, is one of the rarest cloud forms
on record and the only one to have been
formally added to the WMO's cloud atlas
in almost 70 years. Given how recently
they were discovered, not much is known
about how or when aspiritus clouds form,
although we have some theories. So, what
makes Aspiritus clouds different? Why
haven't we noticed them before? And
could their discovery provide a
blueprint for identifying extremely rare
weather events in the future?
I'm Alex Mccoen and you're watching
Astramm. Join me today as we look at
spectacular highdefinition images of
aspiritus clouds. Learn what scientists
think could be giving them their
dramatic appearance and explore the
exciting implications of this unusual
convergence of citizen science and
trailblazing research.
In 2006, Jane Wiggins, an amateur
photographer located in Cedar Rapids,
Iowa, took a photo from her office
window that she described as looking
like Armageddon.
She sent the image to the Cloud
Appreciation Society, which posted it on
their website. The photo immediately set
off shock waves among cloud watchers,
who suspected that it could be evidence
of a previously unknown cloud formation.
Other amateur hobbyists using the Cloud
Spotter mobile app started sharing their
images with each other, sharing weather
conditions to look out for to help
others see it for themselves. This
caught the eye of the Royal
Meteorological Society, which used
dozens of photos collected by the Cloud
Appreciation Society to prepare a case
that they sent to the World
Meteorological Organization.
After several years of debate, the WM
made an announcement. For the first time
since 1951,
they were adding a totally new type of
cloud to the cloud atlas, giving
aspiritus clouds the unique distinction
of being the only cloud type to have
been discovered as a result of digital
crowdsourcing.
But why was this rare? And who decides
what makes a cloud form unique?
Let's start with a primer. Clouds
essentially are liquid droplets or solid
particles suspended in the atmosphere of
a planetary body. While on other
planets, clouds can be made of methane,
ammonia, or even sulfuric acid. Here on
Earth, the vast majority contain liquid
or frozen water. And personally, I'm
glad we don't have many of the sulfuric
acid variety.
Clouds form when saturated air reaches
its due point. The temperature at which
under a given set of barometric
conditions, water vapor condenses into
liquid due to cooling air or increased
saturation from an adjacent water
source. There are five primary cloud
types. Stratus, cumulus, stratouulus,
cumuloneimbus, and cirrus. Each of which
are subdivided into different genre
based on altitude.
However, in addition to these primary
categories, there is a range of
accessory clouds which are clouds that
become detached from the original genus
clouds as well as supplementary
features. All of these are formally
classified in the W cloud atlas, the
international manual for cloud
identification, which uses a linear
nmanllete that has been in place since
the 19th century. The WMO is responsible
for updating the cloud atlas, but
revisions are extremely rare. The last
new formation was Sirrus in added back
in 1951.
Now, aspiritus clouds are thought to be
mostly a supplementary feature of
stratapform clouds, which are low
elevation layered clouds without
vertical development. Although,
aspiritus have also been observed to be
stratouulus or altocumulus.
Interestingly, while the bases of the
stratapform clouds are generally flat,
they tend to develop significant
features at the top due to wind and
temperature changes. This is extremely
common and something you will no doubt
be familiar with if you've looked out of
the window of a plane. What makes
aspiritus clouds unusual is their highly
developed structures at the bottom.
In 2017, researchers from the Cloud
Appreciation Society, University of
Reading, and McGill University published
a paper attempting to describe the
features and causes of aspirus cloud
formation.
According to the authors, aspirus clouds
are defined by their rough, somewhat
wavelike cloud base that lacks the
smooth undulating shape of the possibly
related unulitus cloud type. Given these
semi-wavelike characteristics, the
authors hypothesize that aspiritus
clouds are likely created by weak
ocilitary activity.
There are a few potential causes of
this. One is orography, which is the
wavelike movement caused by the flow of
air over mountainous terrain. However,
there could be other reasons such as
horizontal wind shear, convection, which
is the exchange of matter or temperature
between fluid bodies, or atmospheric
gravity waves. By the way, in case
you're wondering, a gravity wave isn't
the same as a gravitational wave. As
much as I love space-time physics, we're
not talking about massive ripples in the
space-time fabric here.
A gravity wave occurs at the border
between one fluid and another when a
force upsets the equilibrium and gravity
tries to restore it which produces a
back and forth movement or wave orbit.
Some familiar examples of gravity waves
include tsunamis and the changing tides.
You have probably seen the result of
gravity waves affecting clouds too and
julitus clouds. I'm sure you've noticed
cloud formations like this before from a
ground view. The view from space is
equally spectacular.
But aspiritus clouds have an appearance
of roughness that indicates unusual
instability at the cloud base. These
aren't smooth and wavelike like the
unjulitous cloud type we've just looked
at, but have a formation that is chaotic
like the stormy ocean we talked about
earlier. While stratapform clouds often
have what is known as Kevin Helmhalt
instability at the top, an instability
that comes from velocity shear within
fluids,
this instability is more unusual at the
base of clouds. So what might be the
cause? We don't know yet. But the
authors of the 2017 paper from earlier
suggest that this instability may
propagate downward from the top of the
cloud, which could happen if the cloud
is thin enough. Perhaps there are
different reasons each time. The
scientist who captured this time lapse
said that here gravity waves were moving
through an inversion underneath an
elevated region of instability.
You've probably seen an inversion before
where clouds or even smog is trapped
under a layer of hotter air.
Thunderstorms were in the forecast, but
the thunderstorms could not pull their
inflow air from near the surface due to
the inversion. So instead they pulled
from above the inversion. The gravity
waves moving through the inversion
created enough lift that a strong
updraft was formed and it moved in phase
with the peak of the gravity wave. This
enhanced lift from the updraft increased
the amplitude of the wave and made the
aspiritus cloud here very visually
impressive.
Regardless of how it happens, this
internal instability appears to disrupt
the weak ocilitary activity at the base,
resulting in the rough, choppy
appearance. So, when you think about it,
the winds and currents causing the
choppiness of the ocean on a stormy day
aren't that unlike the chaotic forces
scientists think are producing
instability in an aspiritus cloud. In
both cases, complex fluid dynamics are
in play, giving rise to eerily similar
characteristics. Nature may not repeat
itself, but it often rhymes.
So, there you have it. A primer on one
of the newest and least understood cloud
types on record. If this interests you,
you might want to keep watching the sky
and taking photos of anything
interesting you see. Who knew we'd still
be discovering new cloud types? What
else out there don't we know about? And
who knows, you could be part of the next
scientific breakthrough.
When it comes to talking about the
universe, I'm not usually at a loss for
words. But every so often, I see
something so awe inspiring and unusual
that words don't do it justice. And it
seems that when I posted an image of
this last year, it looks like I'm not
alone here. Such is the case with
noctalucent clouds, a strange and
beautiful phenomenon that occurs high in
the Earth's messosphere and requires a
unique set of conditions to form. In
fact, these cloud formations are so
captivating that they've inspired
communities of watchers who share
atmospheric data online in the hope of
seeing one for themselves.
So, what are Noctalucent clouds? What
gives them their ghostly luminescence?
And what surprising insights can they
offer? Not just about Earth's
atmosphere, but perhaps the future of
our planet.
I'm Alex Mcolen and you're watching
Astramm. Join me today as we view
spectacular images of these eerily
beautiful cloud formations. Learn how
they form and understand why they are
giving scientists a surprising window
into Earth's changing atmosphere.
Imagine
a clear summer night. The sun has dipped
below the horizon and Capella is shining
brightly to the north. Suddenly, a
bright streak erupts low in the northern
sky. It might look like a shining silver
thread or perhaps an icy blue whirl.
Slowly, the streaks get brighter and
clearer until finally the whole sky
glistens with a patchwork of eerily
shining clouds.
Night shining clouds such as this
formation photographed over the Baltic
Sea are truly spectacular.
And no, they don't actually emit light.
They get their glowing appearance by
reflecting solar radiation during
astronomical twilight when the sun is
between 6 and 16° below Earth's horizon
and remnant light is scattered in the
upper atmosphere.
Because noctalucent clouds form at very
high altitudes around 76 to 85 km above
the terrestrial surface, they can
reflect the sun long after an observer
has fallen into Earth's shadow. So while
noctalucent clouds also form during
daylight hours, they are only visible to
the unaded eye at night.
To make a noctal cloud, you need water,
dust particles, and incredibly low
temperatures.
Unlike normal clouds which form in the
Earth's troposphere where 75% of the
atmosphere's mass and 99% of its water
vapor occurs, Noctalucent clouds form
high in the upper meosphere which is the
atmosphere's third layer above the
stratosphere.
Just a reminder, the lowest layer of
atmosphere on the Earth is the
troposphere. the boundary of which is
the tropopores. Then the stratosphere,
stratopes, meosphere, meopor,
thermosphere, thermopor, and then
finally the exosphere.
For more about all these layers, check
out this video. The mesosphere is a
tricky region to study since it's too
high for spacecraft to fly and too low
for orbital spacecraft due to
atmospheric drag. Noctalucent clouds
form slightly below the mesopor which is
the upper boundary between the
mesosphere and the thermosphere.
The meopor is also the coldest region of
earth with temperatures that can plummet
below 100°.
By comparison, the coldest temperature
ever recorded in Antarctica was - 89.6°.
These frigid conditions produce tiny ice
crystals less than 100 nanome in
diameter which then gather on dust
particles. Researchers have learned that
the meosphere must reach -20°
C for these ice crystals to form. That's
pretty cold. But if noctalucent clouds
require such cold conditions, why do
they occur during summer?
Well, one unusual property of the meopor
is that it is colder in summer than in
winter. Known as the meoporal,
this happens because hot air in the
lower troposphere expands resulting in
upswelling gases that decompress in the
meosphere causing adiabatic cooling.
Because noctalucent clouds require very
low temperatures, they only appear for
60 to 80 days out of the year, peaking
around 20 days after the solstice. If
you want to see a night shining cloud
formation, you'll need a lookout spot
between plus or minus 50 and 70°
latitude.
Although satellites have spotted many
meospheric clouds north of the 70th
parallel, here on Earth, the polar
regions have too much ambient light
during the summer for optimal viewing.
So, if you happen to live in northern
Norway or Alaska, you'll have to travel
south for your noctal cloud watching.
That's a pretty good survey of what we
know. So, let's talk about what we
don't.
Saying the meosphere is a very dry place
would be a bit of an understatement. In
fact, it is 1 million times drier than
air from the Sahara Desert. Not exactly
a place you'd expect to find clouds. We
currently think upswelling air from the
troposphere is the likely cause of this
moisture. More puzzling, however, is the
question of where the dust is coming
from. One theory is that it comes from
space in the form of debris.
The Earth gets bombarded daily with
thousands of meteorites and other space
debris. Could they leave enough dust to
create such massive cloud formations? Or
could there be other causes?
Interestingly, Noctalucent clouds were
first cited in 1895,
2 years after Crackatoa's massive
volcanic eruption in Indonesia, which
spew debris into the upper atmosphere.
It has to be something big like this
because otherwise the atmospheric layers
don't mix very much and so dust wouldn't
usually make it to the meosphere.
We also know that man-made sources such
as exhaust from space shuttles can
sometimes trigger no clouds such as a
2014 incident when the Space X Falcon 9
caused no clouds over Orlando, Florida.
In 2009, the United States Naval
Research Laboratory successfully created
an artificial noctalucent cloud using
exhaust particles from a suborbital
sounding rocket. And in 2018, the
University of Alaska created a noctal
cloud by releasing water from a
suborbital rocket. But without such
proximate causes, the source isn't easy
to pinpoint.
Luckily, NASA has launched a satellite
known as the Aeronomy of Ice in the
Meosphere or AIM to answer these and
other pressing questions. It was first
launched in 2007, but as of 2022 is
still operational.
AIM is powered by two solar panels and
is equipped with three payload
instruments. The cosmic dust experiment,
which emits pulses to measure speeding
dust particles. The cloud imaging and
particle size has four cameras that
image meospheric clouds from variable
angles to create a detailed 2D panoramic
view. And the solar occultation for ice
experiment, which measures particles,
temperature, and atmospheric gases in
order to identify chemicals and
conditions for noctalucent cloud
formation. There have also been several
experiments to synchronize Ames
observations with those of low-flying
aircraft. The first of which was
conducted in July 2009.
By synchronizing data between satellites
and aircraft, scientists can construct
far more detailed models of meospheric
cloud formation and their features than
they could from aim alone.
For NASA and other atmospheric
researchers, answering these questions
is no idle matter. The messosphere is a
remarkably sensitive indicator of
changes that are happening elsewhere in
the atmosphere. The same features that
make it so unusual, its rarified gases
and sensitivity to changes far down in
the troposphere, make it a useful canary
in the coal mine, so to speak. Decades
of noctalucent cloud study have made it
clear that they are becoming more
frequent, and climate researchers are
now beginning to link changes in
noctalucent cloud distribution to global
climate change.
As the troposphere gets hotter, the
messosphere visav the mesopor's anomaly
may well be getting cooler and improving
our understanding of the mesosphere has
other farreaching implications as well.
It is a vital part of the atmosphere for
re-entering spacecraft. And because the
meosphere is so dry and low density,
studying it could help us learn about
atmospheres on other planets such as
Mars. By deepening our knowledge of the
mesosphere, researchers hope not only to
understand the properties of noctalucent
clouds, but also Earth's atmosphere as a
whole and how it is changing over time.
They are watching you.
Ever feel that prickle across your neck?
That ominous sensation of eyes on you,
but you can't detect anyone around?
Well, although they can't spot the
culprit directly, your senses might be
onto something. The Earth is surrounded
by eyes studying you, tracking you,
trying to understand every aspect of
your dayto-day life. They are our own
satellites, and there are hundreds of
them, and I don't think we have quite
realized how good they've gotten.
There are satellites with mirrors the
size of Hubbles, not pointed at distant
galaxies to unravel their mysteries, but
staring down at you. There are
satellites that can see through clouds
and don't care if it's day or night.
They see just as clearly either way. In
this age of information where companies
are pushing for more and more data and
governments strive to keep track of
criminals and threats, the thing that
might be harder and harder to find is
privacy.
Are the benefits worth the cost?
I'm Alex Mccoan and you're watching
Astramm. And it is time to look out the
nearest window and smile for the camera
there. Now, do you want to see how your
picture turned out?
In 1957, the number of artificial
satellites in space first ticked up from
zero to one. Sputnik 1 was launched by
the Soviet Union officially to practice
their satellite deployment methods and
to send test radio signals through the
atmosphere, but also to show the world
that they were winning the space race.
The world, however, did not take long to
catch up. In 2007, 50 years later, there
were 912 active satellites orbiting the
Earth.
As a testament to how quickly the
industry is growing, it took only 10
years for that number to reach 1,778.
In 2022,
the number hit 6,95
and this number is set to grow. The
company SpaceX alone wants to eventually
raise the number of active Starling
satellites to a whopping 42,000.
In the next 10 years, there could be
hundreds of thousands of satellites from
various different countries and private
organizations orbiting our planet.
Of course, not all of these satellites
are there for observation. around half
of the ones active right now are
communication satellites. But still,
according to data collected by the UCS,
the aptly named Union of Concerned
Scientists, at the start of 2022, there
were 1,052
eyes looking down on us. That's a lot of
eyes, and they're getting sharper.
Let's discuss spatial resolution. This
is a measurement of how many meters on
the ground are represented by a single
pixel in a satellite taken image. The
early cameras on satellites like LANCAT
1 had a resolution of 80 m, which is to
say a single pixel represented an 80x 80
m square, meaning you could almost fit
an entire football field in it. This
made them good for taking sweeping
images of our planet at large and
perhaps for keeping track of massive
objects like clouds and weather fronts.
But there was hardly the sense that our
privacy was at risk. Now, well, see for
yourself.
These full color videos were taken by
Carbonite 2, a commercially available
satellite that captures an entire 5 km
swath as it passes by at 500 km in low
Earth orbit.
The resolution for this video is 1 m,
which is good enough that you can pick
out details like the motion of waves on
the sea or cars driving along the road
in real time. Although you might not be
able to distinguish their car make and
most likely not their drivers, the
advantages of such a video are obvious.
Transport officials can keep an eye on
traffic congestion and it becomes easy
to track the speed of urbanization.
There are also numerous scientific
benefits which we'll get into later. But
there's one undeniable feature of such
improved resolution that made it very
interesting for governments around the
world. And the main reason you might be
worried, it becomes easier for spy
satellites to keep track of you.
Spy satellites have also come a long
way. Originally, when the CIA began
their secretive corona project,
disguised as an innocent space
exploration program called Discoverer,
satellite cameras were recording their
images onto actual film, which then had
to be jettisoned and parachuted back
down to Earth, where the capsules
carrying the sensitive data could later
be recovered. One of these capsules was
actually the first ever man-made object
to be recovered from space. It wasn't
the most efficient system and spy
satellites tended not to last longer
than a year before they ran out of film
and capsules. Now everything is digital,
significantly improving the lifespan of
such satellites.
As for what they can see, well, for
obvious reasons, governments tend not to
reveal how good the resolution is on
their spy satellites. However, it's
interesting to note that the video I
showed you earlier of the 1 m resolution
satellite camera is not the best the
market has to offer. Other satellites
boast 50 cm and even 25 cm resolutions
and some such as Umbra SAR satellite
claim to have reached 16 cm. And this is
only about as good as they are legally
allowed to get. The United States has
laws in place that make it illegal to
have satellites with better resolutions
than that. Although companies are
pushing for this restriction to be
lowered so that they can keep up with a
competitive global market that doesn't
always have such restrictions.
Take a note of that though. This is not
about capability.
True, the laws of physics put some
constraints on us that make better
resolutions difficult to impossible
without having a satellite fly close
enough to the planet that atmospheric
drag will start to cause it to fall or
without making a light gathering mirror
so large that it becomes difficult to
launch them on a rocket. However, it's
not accurate to say that spy satellites
can't get better resolution. There are
rumors of resolutions hitting at least
10 cm resolution, perhaps even 1 cm.
Rumors that were at least partially
confirmed by the previous US President
Donald Trump by accident in a tweet he
posted. In 2019, Iran attempted a rocket
launch that ended in failure. Trump felt
it was necessary to tell the world that
the US government had not been involved
in sabotaging the rocket launch. To
prove his point, he included a photo of
the damaged launch site, hoping to show
that there were no signs of foul play.
This may well have been true, but
intelligence experts around the world
were stunned at the crisp detail
included in the image. After analysis,
it was revealed that the image had to
have been at least 10 cm resolution,
perhaps even better. Let's get a feel
for what an image better than 10 cm
resolution might look like on a regular
high street.
This is the bit where you might need to
wave to the camera. This image is not a
satellite image, but was taken by a
plane flying over the town of Zurich.
However, it does reveal what a better
than 10 cm resolution image can show. We
are no longer on the resolution of
making out cars. Here you can see the
branches on trees, even the color of
clothes on people. You can see a lot of
detail. Can you imagine what a 1 cm
image might look like?
This represents technology that exists
today. In fact, better technology is now
out there. The satellite that took this
is a keyhole 11 spy satellite. A keyhole
12 already exists, which amateur
astronomers have managed to image in
spite of official pictures naturally not
being released to the public. We don't
know the resolution on this one, but it
has dimensions similar to the Hubble
telescope. And one of the reasons Hubble
used the mirror size that they did was
because they realized they could use the
same supplier as the US Department of
Defense.
So there are potentially 11 additional
Hubbles out there. Imagine how much
further we would be if they were used
for science instead of spying.
We are also no longer in an era where
cloud cover or nighttime can ensure
privacy. Synthetic aperture radar
imaging is capable of piercing through
clouds as the technology doesn't collect
visible light, but instead sends down a
radar pulse and then times how long it
takes to bounce back. Done enough times
over a wide area with some sensitive
equipment to discern the different times
taken of different parts of the wave to
return. SAR satellites can form detailed
physical models of the ground and can
even simulate having a much larger
mirror than they can actually carry.
Because they are not reliant on natural
light but are sending their own pulses.
These types of satellites can work
during the night as well as the day.
So with all of this, you likely are
starting to feel a little worried for
your privacy. It's unsettling to think
that at any time you step out the house,
eyes could be on you, watching you walk
or drive to your destination, seeing who
you meet, where you go. They are
probably not able to read your phone
screen, but that's not far off. The cost
of privacy feels huge. If you live in a
city like London, you may have been
thinking this anyway with the number of
cameras around, but even where there are
no cameras, you aren't safe.
However, it should be pointed out that
satellites with decent resolution,
although probably not at the 10 cm mark,
can be extremely beneficial for studying
our planet. It's hard to list the
benefits in full, but they include
weather monitoring, studies of our
climate, including sea level rises, CO2
levels in our atmosphere, tracking
aerosol emissions, and seeing the
current dimensions of the ice sheets,
tracking surface temperatures, crop
health, irrigation use, water quality.
You can even use precise satellites with
cloud penetration to see the hot spots
on wildfires, giving firefighters a
better chance at tackling blazes. or we
can better understand hurricanes,
atmospheric dust clouds, and other
disasters.
In one incredible application, a NASA
satellite intended to study cyclones was
used to track locust swarms across
eastern Africa, mapping out the most
fertile, water- richch areas that locust
like to lay their eggs in or feed in
during their juvenile forms. In so
doing, they helped reduce swarms in
Kenya in 2019, which was incredibly
beneficial to farmers and the people
whose food they supply.
Perhaps the bit that feels uncomfortable
is if it seems like the people watching
us do not have our immediate benefits at
heart. Studying the planet feels like a
positive and worthy goal, and accurate
data is helpful in that. However, it's
also undeniable that businesses across
the world would love to keep track of
where people are shopping, population
trends, and other metrics that allow
them to better sell to customers, which
is a goal you're less likely to want to
sacrifice your own privacy for.
Monitoring might help city planners to
keep track of the flow of traffic on
roads and get a better sense of where to
build relief roads or other helpful
interventions. Spy and law enforcement
agencies also, in fairness, do a lot of
good. They stop terrorism and catch
criminals. But it's scary to think that
once the technology is here, if ever the
government in possession of it decides
to use it for more invasive goals,
there's not much that can be done to
stop them.
At the end of the day, perhaps this is
something inevitable that we will all
simply have to get used to. it's
difficult to stop the flow of progress.
As long as there are advantages to
better resolutions on satellites, people
will want to pursue developing them. In
any case, it's at least good to know
just how effective it's all becoming
because then your decisions on the
matter can be informed, too. You can
decide whether this is becoming
something that makes you nervous or
something you aren't really bothered
about. Whether this needs tighter
regulation through lawgivers or whether
it is a necessary cost to be paid for
the ease and security of modern life.
Wherever you stand on this matter, best
put a brave face on. Smile. After all,
you never know who is watching.
Imagine 100 nuclear bombs going off at
the same time. This was the equivalent
force of hunger tonga hunga haipe which
produced the most atmospheric
disturbance ever recorded by modern
instruments and the most powerful
eruption since the 1883 Krakatoa
eruption. The shock wave from it created
a pressure wave that traveled around the
globe at least four times. And although
it wasn't audible for all of that time,
it was heard as far away as New Zealand,
Australia, and Alaska. Just one of the
aftershocks sounded like this.
It caused the tsunami and devastated the
volcanic island it was situated on. The
ash and dust blanketed Tonga and was
carried through the stratosphere across
vast distances. Fortunately, eruptions
like this are rare, but it just goes to
show nature's fury should not be
underestimated. Imagine you're at home
or at the office when the walls of the
room you're in start shaking violently.
Books fall off the shelves. Cabinets
threaten to topple over. You quickly
realize this is an earthquake. And then
you look up and it occurs to you that
there is another entire story of
building above you. As the walls
continue to wobble, you know that should
they fall, that roof above you is coming
down and you stand a good chance of
dying. So you look up as the quake goes
on and on and you wonder, will it hold?
Will it hold? When you see the footage
from the Japan 2024 Noto Peninsula
earthquake that struck in the afternoon
on New Year's Day when families were
gathered in their homes, it's easy to
envision the fear that must have been
felt by those who experienced it. This
was a deadly tragedy with 241 people
killed and 1,296
injured. In spite of its relatively
small size, Japan is the country with
the fourth largest number of major
earthquakes in the world over the last
few decades. Our planet Earth is
frequently shaken by earthquakes.
But there are things about Norto that
make it different from any other
earthquake that we've seen before.
I'm Alex Mccoan and you're watching
Astramm. And today we'll be entering a
world of earthquake swarms and changes
to the Earth's rotation.
Of earthquake shake tables carrying
buildings 10 stories high and a
geological mystery that remains unsolved
to this day.
It's no wonder that Japan is regularly
impacted by earthquakes. Japan sits on
the western edge of the Ring of Fire,
one of the most tectonically active
places on Earth. These vast plates of
rock and soil constantly and inexorably
shift over the course of millions of
years, sometimes pulling apart and
sometimes moving together. To further
complicate matters, Japan sits along the
edge of multiple smaller plates at once.
The Pacific plate pushes west and
subducts or slides underneath the
Philippine Sea plate and the Okhatosk
plate. But the Amuran plate also pushes
up against the Okhatosk plate while the
Philippine plate subducts underneath the
Amuran plate and the smaller Okinawa
plate at the same time.
It's a complex geological wrestling
match, one which led to the formation of
the islands of Japan in the first place,
but one that also causes a lot of
friction and tension beneath the
surface. What happens when the forces of
play become too much for the friction
that holds it back and things slip?
That's when you get earthquakes.
However, in the case of the Japan
January 2024 earthquake that struck in
the Nto Peninsula, it caught locals by
surprise. Why? Because Noto is not
actually on one of the major fault
lines, and scientists are not yet quite
sure why earthquakes are even happening
there. If you map out the location of
earthquakes by depth and location over
the last 25 years, you can see that they
congregate mostly on the eastern side of
Japan where the Pacific plate subducts
under the Ohatosk plate. You can even
see how earthquakes that are further
west are also triggered deeper beneath
the ground representing the fact that
the subducting plate has moved further
underground with the additional
distance. But rather than striking on
the eastern side of the island, the
January 2024 earthquake hit NTO to the
west.
There are other peculiarities.
Strange things have been happening
beneath Notto over the last 3 years.
Since 2020, Nto has been experiencing
tens of thousands of small earthquakes
in a geological event known as an
earthquake swarm. But
counterintuitively,
this consistent rumbling is normally not
something to worry about, as several
small shakes are better than one big
one, and earthquake swarms generally die
out quietly rather than producing large
earthquakes.
Noto's earthquake swarm bucked the
scientific models, lasting too long and
producing the exceptionally powerful
January 2024 earthquake, and scientists
do not really know why.
The consequences were serious. The
January 2024 earthquake was a magnitude
7.5 and struck at 10 400 p.m. Japanese
time on New Year's Day when people were
gathered in their homes.
It was not just one event, but hit with
a number of force shocks and
aftershocks.
1,200
of them that ranged across an area over
150 km across.
At least seven were magnitude 5 or
higher.
40,000 homes immediately lost power.
Roads cracked. Buildings collapsed. The
Japanese government quickly issued a
tsunami warning across the west coast of
Japan. The first waves of which arrived
just 1 minute later in Suzu. A wave as
high as 5 m was expected. Although most
of the footage captured is a wave of
only 1 to 2 m high. Certainly the force
was enough that buildings along the
coast were swept away.
All told, there were hundreds of deaths
and over a thousand injuries across six
prefixures and over 18 billion US
dollars in property damage. The train
itself bucked and rose.
One strange feature of notto is that
there has been an unexplained upswell
that has been taking place there beneath
the crust since the earthquake swarm
started in 2020. The edge of the
peninsula has risen by about 3 cm since
then, indicating something was gathering
down there. Perhaps water, perhaps
magma. Scientists aren't really sure.
When the earthquake itself hit, however,
that's when the peninsula really started
to rise. Some sections of the land rose
as much as 4 m. And you can see the
effects in these satellite images. The
change in the land's elevation altered
where the sea met the shore, pushing the
coastline back 250 m, leaving some ports
completely cut off from the water.
And when this much land moves, it can
influence the rotation of the planet
itself.
Changing the distribution of mass on the
planet's surface changes how quickly it
spins. In the same way, a ballerina
pulling her arms in will rotate faster.
In 2011, the magnitude 9 To<unk>hoku
earthquake in Japan shortened Earth's
day by 1.8 micros secondsonds or 1.8
millionth of a second. It's not much.
And other effects such as differing sea
levels also change the Earth's rotation
speed. But it's amazing to see how
interconnected the planet is. An
earthquake in Japan can affect the
entire world. No matter where you are,
your life was imperceptibly altered by
the Notto earthquake.
With all of this, it is no wonder that
scientists across the globe are working
hard to understand the causes of
earthquakes. But for those who live
under their constant threat, such as for
the people in Japan, or other countries
like Indonesia, China, or Iran, it's
also important to defend against their
consequences.
So in an effort to improve their
architectural design to make them more
earthquake resistant, Japan's National
Research Institute for Earth Science and
Disaster Resilience has taken steps such
as developing the world's largest
earthquake simulator, effort
supports buildings as tall as 10 stories
and can use real life data to simulate
the most devastating earthquakes Japan
has ever experienced. By testing
different designs in the different types
of earthquake scenarios, architects have
been able to design braces, beams, and
metal joints that reinforce traditional
Japanese houses, making them more
earthquake resistant. It can be the
difference between a building staying
upright or collapsing entirely.
Interestingly, NASA's space program
indirectly helped with creating
earthquake resistant buildings in Japan.
Consider the Tokyo Skytree, the world's
tallest tower at 634 m. A place I saw
with my own eyes once when I was
visiting Japan. Given the risk of
earthquakes in Tokyo, it was vital that
engineers designed a building that could
withstand large shakes. They did so
using a central 360 m tall concrete
column that sits on four massive rubber
bearings which attaches to the building
around it using fluid dampeners
developed during the NASA Apollo
program. When an earthquake strikes,
these fluid dampeners cause the central
column to sway at a different rate to
the exoskeleton of the building around
it. The different rhythms of motion
counteract each other, reducing the
motion in the building overall.
Incredibly, these effects can reduce the
force of earthquakes by up to 50%.
Earthquakes can carry a terrible cost in
lives and destroyed homes and
livelihoods. For the Noto Peninsula, the
people there have slowly begun the task
of rebuilding their lives. Although the
broken roads initially made it difficult
for emergency services and repair
workers to get around, power has been
restored to the majority of the 40,000
homes that were affected. Although as of
March 2024, 790 still were without
electricity. 18,880
were without water and 11,400 people
were still in evacuation shelters in
Ishikawa Prefecture.
Earthquakes are overwhelming examples of
the natural force that exists beneath us
at all times. They can shatter cities
and recovering from them is a slow task,
but it speaks to the hardiness and
determination of the people who make
places like Japan their home. They seek
to find solutions to powerful
earthquakes to predict them and to
mitigate their damage with clever
engineering.
This can help us all. Through studying
the processes that take place beneath
our feet, we can better navigate this
world that we live on in a way that
helps us thrive. The world is dangerous,
but also beautiful. And like life, its
face is ever changing. It's up to us to
face that change until we can overcome
any disaster that befalls us.
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