Venus.
Our (at times) closest planetary neighbour and our “sister” world.
Similar in size to the Earth but about 40 million kilometres closer in orbit to the Sun,
the second planet of our Solar System has long been the source of stories, myths and legends.
In more recent times, however, we have gone beyond seeing just that bright circle close to the Sun
at the start and end of the day.
Beginning at the height of the Cold War, numerous robotic missions have been sent to Venus
to observe, orbit, and in some cases, even land.
And, using technology that sees in not only the visible light but also in the infrared,
ultraviolet and radio spectra,
what we have found is a world that is different to Earth in almost every way imaginable.
I’m Alex McColgan, and you’re watching Astrum.
Join us today on this supercut as we take a
journey to the star of the morning and the evening,
using technology both old and new to uncover the secrets of Venus,
and descending through its thick atmosphere to arrive at the surface of our closest companion.
Venus is the 2nd planet from the Sun and it's our closest neighbour.
Its average orbital radius around the Sun is 0.72AU or roughly 108 million km.
It doesn’t vary much at all from this mean orbital radius,
as it’s the planet with the least eccentric orbit, orbiting in a nearly perfect circle.
At Venus’ closest approach to us, it is the closest of any other planet,
being only 41 million kms away.
Interestingly though, this is not when it’s brightest in our sky, as when it's closest to us,
we only see the night side as it’s between us and the Sun. It is still visible though as the
sunlight refracts through the atmosphere. It’s actually brightest when it’s a thinner crescent
shape in the sky, and when this happens, it is the brightest object we see at night after the moon.
As such, Venus is commonly misreported as an "unidentified flying object". U.S. President
Jimmy Carter reported having seen a UFO in 1969, which later analysis suggested was
probably Venus. Countless other people have mistaken Venus for something more
exotic due to its startling brightness. I recently had the pleasure of looking
at Venus through a telescope and remarkably the crescent shape of it was very visible.
With Venus orbiting between us and the Sun, it may make you wonder if Venus ever eclipses the
Sun from our viewpoint on Earth, and the answer is yes, but surprisingly, very rarely. Transits
happen in pairs, the pairs being 8 years apart, but every pair only happens once every 100 or
so years. The last transit we had was in 2012, but if you didn’t see that I’m afraid the next
one won’t be until 2117. The reason for this rarity is because the orbiting plane of Venus
is not exactly the same as Earth’s. Also, Venus only catches up with Earth every 584 or so days.
These two things combined ensure that, although a spectacular and predictable sight,
it also means we’ll probably only ever have the chance to see it once or twice in our lifetimes.
All the planets orbit anticlockwise around the Sun and with this, Venus is no different. But unlike
all the other planets, it rotates clockwise, or in other words in a retrograde rotation. Not
only that, but it has an extremely slow rotation, rotating once every 243 Earth days – slower than
any other planet. This makes a sidereal day longer than a Venusian year, a Venusian year lasting 224
Earth days. A sidereal day, if you remember from my Mercury episode (which you can check out here,
if you missed it), is one rotation of the planet. Because of this retrograde rotation however,
a solar day (which is sunrise to sunrise) is considerably shorter, at 117 Earth days.
This means you’d experience just less than 2 days on Venus in one year. To give you some
perspective as to how slowly it rotates; at the equator the planet is only rotating at 6.5km/h!
This slow rotation makes it the second most spherical object in the solar system,
after the Sun. It is unclear why Venus rotates backwards compared to the rest of the planets,
but it could be due to a big impact with another object billions of years ago,
or tidal locking with the Sun, or tidal effects on the Venusian atmosphere.
So far, these are all things we can learn through long range observations,
taken from right here on Earth. But for many years that was all we had to go on. Much like
a coy and flirtatious lover, the planet Venus cloaks itself in a literal air of mystery;
a thick enshrouding fog that hides its secrets.
And convincing Venus to relinquish those mysteries would prove to be no easy task,
as the first scientists who tried to woo her found to their dismay. I do find it
ironic that for a planet named after the Goddess of Love, Venus is one of the most
treacherous and hostile worlds imaginable. That either feels very wrong, or very right.
Let’s take a look at those early efforts to explore Venus’s hidden
surface. What did they learn? And what can we find on the true face of Venus?
As the second-brightest object in the night sky and also the closest barring the Moon
in terms of distance (sometimes), Venus has always attracted attention
from those who would gaze up at the heavens. But even today, interplanetary travel is hard, and
at the height of the Cold War, it was even harder. Of the first fifteen missions launched to explore
Venus between 1961 and 1967, only three were classified as “successes” in terms of fulfilling
their specific objectives – Mariners 2 and 5 from NASA, and Venera 4 from the Soviet NPO Lavochkin.
Successful atmospheric entries with Venera 4, 5 and 6 soon followed and, in late 1970,
the USSR finally passed a massive milestone with Venera 7 – the first space probe to
land on the surface of another world and last long enough to send back information about it.
Come with me as we follow Venera down into those treacherous,
obscuring clouds, to see what lies beneath. Still drifting through space, Venera turns towards
Venus. As it begins its descent onto the planet, Venus’ upper atmosphere lies before it, extending
from the fringes of space at around 250km above the surface, and down to around 60 kilometres
above it. Here, it sees nothing but a thin haze - 99% of Venus’ atmosphere by mass lies below this
point. This makes Venera’s descent through this layer easy enough; in very much the same way as
our own atmosphere would be at similar altitudes. But Venus’ upper atmosphere’s chemical composition
could not be more different – a sign of things to come as we and Venera descend further. Instead of
a majority of nitrogen and oxygen as on Earth, we begin to pick up traces of carbon dioxide – it’s
not enough to cause significant effects on the temperature at this altitude, but it’s significant
as a marker of what lies beneath. Other than the difference in chemistry, however, at this altitude
the atmosphere behaves roughly the same as that of our home planet at similar altitudes – with vast
temperature differences between day and night; highs of -37°C to lows of -143°C. For Venera,
this is the easy part. An interesting sideshow to the noticeable presence of carbon dioxide
is the presence of some oxygen atoms, which emit infrared radiation that can be seen by telescopes
and spacecraft. In this picture taken by the Venus Express orbiter in the infrared wavelength,
the blue is the “airglow” caused by the oxygen high in the Venusian atmosphere.
As Venera moves downward through the layers, it comes to the main visible cloud deck of Venus
at around 60km from the surface - the thick, dull yellow that we associate with pictures in
visible light is almost entirely because of this cloud deck, terminating approximately 40km from
the ground. In this part of the atmosphere, ultraviolet radiation from the Sun breaks up
carbon dioxide into carbon monoxide and single oxygen atoms. These atoms then easily react with
sulphur dioxide and water vapour, two other trace compounds in the Venusian atmosphere,
to produce the clouds of sulphuric acid that we see. Sulphuric acid, just as a side note,
is highly corrosive and the resulting acid rain just adds to the hellish nature of Venus, although
it does evaporate before it hits the surface. But that is still to come. For now, this is the calm
before the storm - the relatively temperate region before the real hell that Venera must soon enter.
As Venera enters that chaotic churn of violent, acidic cloud, it likely would appreciate
if it could take a little of that earlier tranquillity with it.
Sometimes I feel that way too, when I’ve got a chaotic day ahead.
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Now back to Venera.
As you can immediately tell, the surface of Venus cannot be seen through the planet’s thick cloud
cover, so Venera will have to go in blind. That same cover reflects around three-quarters of the
sunlight that hits Venus, sometimes letting as little as 10% of the sunlight through,
as the ice crystals formed from the sulphuric acid that floats in the atmosphere are extremely
reflective. This reflectivity goes a long way towards explaining how bright Venus looks,
both to satellites going by, and to observers on Earth – remember, it’s the second brightest
object in the night sky! These clouds are also capable of producing lightning
much like on Earth, although it’s not as common. When we look at those mustard yellow clouds in the
visible spectrum, they appear thick and obscuring, revealing little of what lies beneath. However,
we have an advantage that Venera did not possess. Infra-red sensor technology.
In the infrared spectrum, things look a lot different! This image taken by the
JAXA spacecraft Akatsuki throws things into much sharper relief, showing clear “light and dark”
spots and bands wrapping around Venus’ atmosphere. And here is where we see the thick carbon dioxide
composition of the atmosphere very clearly indeed. Carbon dioxide is an effective “greenhouse gas”,
trapping the heat that arrives from the Sun, resulting in an incredibly high surface and
atmospheric temperature. Under the scope of infrared observation, this becomes very apparent
as the entire surface glows under the heat generated by the thick layer of carbon dioxide.
The dark patches and stripes are the previously mentioned clouds of sulphuric acid, and we can
see them high above the much brighter thick and hot carbon dioxide layer near the surface.
Can you imagine what Venera would experience as it travels through this hell?
Sulphuric acid assaults its outer casing. Winds blow at 100 metres per second, 60 times
the rotation speed of the planet; fast enough to circumnavigate the planet in just 4 days, which
makes the planet look like it’s rotating a lot faster than it actually is. The temperature, which
at an altitude of 50-55km is anywhere between 25 to 75°C, sharply rises; reaching blistering
levels. Surface air pressure on Venus is 75 to 100 times what you’d find on Earth - comparably,
it’s like having an entire car sitting on your thumbnail. As Venera descends further,
however, even weirder conditions can be found. Once Venera passes through the bottom of the
sulphuric acid cloud deck, it arrives in “clean” air once again. But things here are strange. The
pressure here is now so great, it’s starting to have an effect on the Carbon Dioxide in the
atmosphere. The density of carbon dioxide at this level is so high that it no longer acts as a gas,
but more as a kind of supercritical fluid – a state of matter somewhere between liquid
and gas where a substance takes on some of the characteristics of both. The wind has slowed
down here after the baffling fast speeds of the upper clouds - the atmosphere below is so thick,
that winds “blow” at little more than 5 km/h. It would feel like wading through water with
a slow but inexorable current - albeit in a river that is 464°C; hot enough to melt lead.
For point of comparison, that makes it 34°C hotter than Mercury’s peak temperature,
even though Mercury is closer to the Sun, and Venus only gets 25% of the solar radiation that
Mercury does. The difference is that Mercury doesn’t have an atmosphere to retain the heat,
whereas Venus certainly does. This means at night time and even at the poles,
the temperature remains fairly constant. While much of this surface might feel alien
to us back on Earth, there’s one similarity - the level of gravity. Venus’ size and mass are
very similar to our Earth, hence why it’s often referred to as our sister or twin planet. Venus
is one of the four inner terrestrial planets and it is a rocky planet. Its diameter is slightly
smaller than Earth’s at 12,100km compared to Earth’s 12,740km, and its density is
5.3 g/cm3 compared to our 5.5 g/cm3. This means the gravity on Venus is only a tenth weaker than
that on Earth; surface gravity being 8.9 m/s2. But what can modern technology tell us of Venus
and its layers? To further illustrate the vast heat at this altitude level on Venus, let’s look
at a picture of the lower atmosphere of Venus taken in the near-infrared range – a wavelength
of 2.3 micrometres - by the Galileo satellite. The red, hot areas of the lower atmosphere are clearly
visible, as are the darker patches caused by the clouds of sulphuric acid higher in the atmosphere.
The lower reaches of the Venusian atmosphere are incredibly hot, and there are distinct
layers of that atmosphere, different in both temperature and composition.
To further demonstrate the differences between the atmospheric layers of Venus,
let’s now have a look at the layers we’ve seen so far under ultraviolet light.
While the images (again, from the JAXA spacecraft) taken in the 283 and 365 nanometre wavelengths do
not show much contrast in colour and brightness as the infrared images, they do show more
variance than ones viewed in visible light. The areas of darkness and blotchiness of the cloud
layers indicate the ultraviolet light is being absorbed rather than reflected,
but exactly what chemical – or combination of chemicals – causes this absorption is still a
matter of debate among the astronomy community. Clearly, there are elements (and compounds) of
the Venusian atmosphere that still evade our attempts to discover and categorise them.
And on the subject of Venus’ atmosphere defying explanation, here’s a look at Venus’ poles in
the infrared. Notice anything strange about them? Present at both Venus’ North and South
poles are large polar vortexes, about the size of Europe, whipped up by those 100 m/s winds.
What’s really weird though is that they have not just one central eye, but two, and scientists are
still not quite sure why. Venus’ complex, highly variable polar vortexes are extremely hard to
model as they can change on timescales of less than 24 hours, making them quite the mystery.
But once it was past the enigmatic atmosphere, what did Venera see down there?
Let’s conclude Venera’s journey through the thick, acidic clouds, and arrive
at the surface of our closest companion. Earlier, we saw the very first image ever
sent from the surface of Venus. Due to the massive clouds of sulphuric acid obscuring
any kind of view from space, the only images of Venus that show the surface in visible light are
those that have been taken from a lander on the surface. And of those, we only have six,
taken from four of the Soviet Venera probes that landed, such as our Venera 7. The air
is surprisingly clear - scientists had wondered whether everything would be obscured by a thick
haze, but this doesn’t appear to be the case. Everything is a dull yellow - the colour of the
acidic composition of the atmosphere – and while we might be surprised to find solid,
rocky ground under the thick crushing air of Venus, that ground is also utterly desolate. It
hints at ancient lava flows now hardened into flat plains, and eroded under Venus’ intense
atmosphere. Everything seems very dry, which is unsurprising given the baking heat. Perhaps,
a billion years into the future when the Sun has increased luminosity enough, we might see similar
runaway greenhouse effects and results on Earth... But here we must leave Venera. The Venera series
of probes, including the one whose journey we have been following, never lasted more than a
couple of hours on Venus’ surface, due to the combination of heat and crushing pressure.
Their images give us a brief but vital glimpse into conditions down there on the rocky ground.
But while fascinating, these insights into the surface conditions on Venus fell far
short of what scientists wanted to know. After all, Venera’s photographs only covered a tiny
fraction of the planet’s surface area. But if landing probes on the planet’s surface was
proving almost impossible, was there another way to peer through Venus’ cloying clouds?
It turned out there was. It’s not infrared or ultraviolet; neither infrared nor ultraviolet
imaging can break through the thick cloudy atmosphere, to see and map the surface with
any kind of clarity. You need something different. Step forward...radar imaging.
In the 1970s, the Pioneer Venus Orbiter, also known as Pioneer Venus 1 or Pioneer 12,
provided some radar mapping data, but its resolution was low and its images incomplete.
Imagine trying to map the Earth but Google Maps didn’t let you zoom in further than 75 km. New
York City would just be one pixel. So, pretty hard to make an accurate map. Additionally,
Pioneer 12 didn’t map the northern and southernmost parts of Venus.
That’s like a map of Earth with most of the Arctic and Antarctic circles missing.
The USSR began the process of using radar to map the surface of Venus with their later Venera
models – 15 and 16 – in 1983, producing images with a resolution of 1-2 kilometres on the ground.
NASA decided they could do better. They wanted to see it all — landforms, tectonics,
impact and chemical processes, erosion, and even get to know Venus’s interior. So they mounted an
ambitious mission to capture the entire surface of the planet in ultra-high detail, along with a
gravitational map that would give insights into what lies beneath. That mission was Magellan.
Now, before I show you Magellan’s photos, you need to understand three key engineering innovations
that made Magellan's mission so groundbreaking. First, to penetrate Venus's dense atmosphere,
Magellan improved on Pioneer’s basic radar altimetry. Engineers used a 3.7m high-gain Voyager
antenna, and components from other past missions, to create a Synthetic Aperture Radar (SAR) that
collected multiple readings of each area from different orbital positions. These combined
readings simulated observations from a much larger antenna, revealing unprecedented surface details.
Second, Magellan followed a polar orbital path, scanning Venus in north-south strips
during each of its 3 hour 15 minute orbits. In total, it completed six 243-day mapping
cycles — cycles 1-3 mapped the planet’s surface and cycles 4-6 captured gravitational field data.
By the end of its first cycle on May 15th, 1991, Magellan exceeded its 70% mapping goal,
covering 83.7%. By the end of cycle 3, it had mapped 98% of Venus at 100-250 meter resolution.
The probe ended up sending home more data than all of NASA’s previous planetary missions combined,
a total of 150 gigabytes. By today’s standards, it admittedly isn’t that impressive — your phone
probably has more storage capacity. But for the early-90s, it was quite something.
Finally, after its third mapping cycle in September 1992, Magellan transmitted a continuous
radio signal to NASA's Deep Space Network. Based on how the probe’s acceleration changed as it
orbited the planet, this would produce a change to the radio signal via the Doppler effect, allowing
scientists to decipher Venus’s gravity field. This revealed information about the planet's
interior structure and density distribution. The images I’m about to show you are 10 times
sharper than any previous radar images taken from Earth or orbiting spacecraft at the time,
and 250 times sharper than Pioneer 12’s data. For the first time, we actually got to see what
was lurking under those thick, noxious clouds. Let’s take a look. Where previous missions had
shown only vague outlines, Magellan revealed a world in exquisite detail, revealing for
the first time the surface characteristics of our next-door neighbour. This mosaic took a
decade to put together, with the bulk of the radar data coming from Magellan's readings.
. When you approach Venus, you immediately notice the lack of craters.
Compared with the Moon or Mars, it’s pretty untouched, with Magellan only identifying 940
impact craters across the entire planet. Many small impact craters are missing because their
meteors burn-up in Venus’s atmosphere. And the other craters we did find didn’t look as expected.
Take these three craters for example — Howe, Danilova, and Aglaonice. On impact,
debris from the surface is ejected and forms the pale yellow blanket-like formations around each
crater. Crater ejecta leave behind distinctive marks and shapes that help scientists determine
the angle and energy of impact and how long ago it happened, the composition of surface
and subsurface materials, and much more. What’s interesting about these crater ejecta is they all
show sinuous flows in a flower-shaped pattern, not unlike lava flows. They’re made of molten
rock and remain this way for way longer than expected due to Venus’s high surface temperatures.
The Adivar crater is another great example of Venus’s unique ejecta patterns. On
airless worlds like the Moon, ejected material from the impact follows an arced,
ballistic path. But on Venus, the ejected debris interacts with the planet’s dense atmosphere,
creating powerful winds that sweep the material outward in ground-hugging flows. This creates
unusual streaks like the horseshoe-shaped one we see here — which are only found on Venus.
Finally, the 90 km-wide Addams crater has a 600 km outflow tail, likely made of impact melt or magma,
which can remain in its liquid form for much longer due to the high temperature and pressure
on Venus. The scarcity of these craters suggests Venus’s surface is actually quite young. Indeed,
gravity data collected by Magellan supports the hypothesis that Venus underwent a global
resurfacing event approximately 300 to 500 million years ago. So what
could have caused such a dramatic event? Volcanoes — lots and lots of volcanoes!
We knew Venus had volcanic features before Magellan, but we had no idea that a staggering 85%
of the planet is covered in volcanic flows. Like these “pancake domes” — 65 kilometers wide — with
broad, flat tops less than one kilometer tall. They likely formed from highly viscous lava,
which later cooled and withdrew, leading to the cracks and pits you can see in the image.
Or these sprawling lava flows, stretching for hundreds of kilometers over the fractured plains
beneath two large shield volcanoes — Sapas Mons and Maat Mons. By studying the varying shapes and
patterns of these volcanic plains, scientists can identify different volcanic formation processes,
from localized shield volcano eruptions to massive regional lava flooding events.
Speaking of Maat Mons, let’s take a closer look. Towering at a dizzying 8,000m tall,
it’s almost as large as Mt Everest. It’s also a shield volcano — characterised by its broad,
gently sloping sides. They’re typically formed by fluid lava flows — like the Mauna Loa in Hawaii.
Shield volcanoes are not the only kind of volcano you’ll see on Venus. Small volcanic domes like
these are also very common features on the planet’s surface. Unlike shield volcanoes,
volcanic domes are formed by small, bulbous masses of lava too thick to flow very far. As
it slowly exits the vent the lava piles up and cools on the sides. This cluster of volcanoes
sits between rough lava flows in the east, and smooth lava flows in the west, indicating
two different types of lava overlapping, though the exact process remains unknown.
The abundance of lava flows and volcanic features on Venus confirmed that volcanism
played a dominant role in shaping Venus’s surface, and gave rise to the theory that
the planet might still be volcanically active to this day. In 2024, researchers who were
revisiting Magellan’s archival data found that two volcanoes actually erupted during
the probe’s watch in the early 1990s. This supported a historic finding from the previous
year that Maat Mons had also erupted in 1991. So what’s going on beneath the surface? What
is Venus’s mantle like? A hint to those answers lies in the surface coronae, like this 500-km-wide
Yavine Corona. When hot, upwelling magma from the depths of a planet’s mantle reaches the
surface — or the lithosphere, it leaves its mark. On Earth, our tectonic plates shift over
this magma hotspot, creating volcanic chains like Hawaii, or flood basalts. But Venus only has one
single tectonic plate, so mantle plume activity pushes the surface upward before collapsing as the
magma cools. The result? These coronae. Despite being hundreds of millions of years old, many
coronae appear well-preserved. There are around 500 of them, widely distributed across the planet
in patterns inconsistent with plate boundaries, and their characteristics suggest a lithosphere
that is too thick or strong to break into mobile plates like Earth's. All this evidence suggests
a unique style of lithospheric deformation where the crust stays largely in place but is pushed,
pulled, and deformed by forces below. This “stagnant lid” planet model might
also play a role in Venus’s runaway greenhouse effect. On Earth, our tectonic plates carry out
vital processes like burying oceanic carbon. When it rains, atmospheric carbon interacts
with mountain rocks to create new minerals which slowly make their way to the oceans,
and eventually find themselves stored in seabed sediment. This sediment is then subducted when an
oceanic plate sinks the seabed back into Earth’s magma layer — a process that regulates Earth’s
temperatures and the concentration of carbon dioxide in our atmosphere. Since Venus’s crust
is stagnant and devoid of tectonic activity, this regulatory process can’t take place.
Instead, heat builds up beneath the surface and greenhouse gases are not effectively removed from
the atmosphere. The hotter the interior becomes, the more unstable the system,
until the whole lithosphere overturns in a global resurfacing event, and the cycle begins again.
We aren’t exactly sure when the last resurfacing event occurred on Venus, but NASA’s technical
report following Magellan suggests that it happened around 300 million years ago.
Another curious symptom of Venus’s unique tectonics and mantle activity are the tesserae
that we can see in the highland regions of the planet. They are distinctive geological
features characterized by highly deformed terrain with a tile-like appearance. They
cover about 8% of Venus's surface and are primarily found in the highland regions. As
some of the oldest visible surface features on Venus they date back about 750 million years.
The USSR’s Venera 15 and 16 missions first identified these formations in the 80s,
but Magellan brought them to life in spectacular detail, like this photo of Alpha Regio, one of the
most prominent tesserae on Venus. Scientists still aren’t sure exactly how tesserae form, but the two
leading theories indicate they are likely made of volcanic rocks, or they are part of Venus’s
continental crust — deformed through compression or expansion. If so, they’d be gateways into
Venus’s geological past, and possibly even show us what the climate was like billions of years ago.
Fascinatingly, Magellan actually managed to capture the first evidence of active tectonics
occurring on another planet in the solar system — in Venus’s Aphrodite Terra, a continental area
roughly the size of Africa. The image on the left was taken in late November of 1990 during
Magellan's first trip around Venus. The image on the right was taken eight months later,
as the spacecraft flew over the region for the second time. See the bright, flow-like area that
appeared? It’s likely the result of a landslide, which was possibly triggered by a “Venusquake”.
On the 13th of October, 1994, after completing one of the most successful deep space missions ever,
the probe made its final descent into the atmosphere of the planet it had studied so
devoutly over the last 4 years. As it plunged toward the surface, it continued to transmit
data about Venus's upper atmosphere until it was consumed by the intense heat and pressure.
So...with all we now know about our nearest planetary neighbour,
what remains to be discovered from Venus in the future? The answer is...a lot!
In recent times, by far the biggest news regarding Venus has been the discovery (or perhaps not) of
the gas phosphine high in the Venusian atmosphere. In 2020, measurements from the James Clerk Maxwell
Telescope indicated the presence of trace amounts of the gas. Phosphine is produced through a
variety of different processes, but one of those – and the one that got everyone very excited – is
through microbes in a low-oxygen environment. Life in one of the most unlikely, hellish places
imaginable? What an outcome that would be! However, subsequent studies found no such
phosphine again, and by 2022 the idea of it being present in the Venusian atmosphere had
been dismissed by NASA. It would have appeared that the findings of the initial study were in
error...but then Professor Jane Greaves of the University of Cardiff went on record at
a prestigious meeting in 2023 that the JCMT had found phosphine once again, this time deeper
within the atmosphere of Venus. Hopefully, future missions will give us a definitive
answer to this truly tantalising question. Many other questions await answers, too.
Why, for instance, did two planets – Venus and Earth – so similar in size,
evolve so differently? Was there in fact liquid water on the surface once upon a time? What is a
more accurate picture of the chemical composition of both the Venusian atmosphere and the surface
that might help answer these conundrums? After decades of being relatively overlooked
in favour of Earth orbit assignments and outer planetary probes, Venus has suddenly garnered
interest again. Several missions are scheduled to be launched for Venus within the next ten years.
NASA’s upcoming VERITAS and DAVINCI missions will hopefully set out to answer questions like
“Was there ever water on Venus?
If there was, would Venus have been habitable?
How has the planet evolved through time?
Is Venus still volcanically active today?” and many more questions.
Currently scheduled to launch in 2028-2030, if they proceed,
they will revolutionize our understanding of Venus once again.
DAVINCI+ will study Venus’ clouds during two gravity assist flybys, and also send a descent
probe deep into Venus’ atmosphere to get a better understanding of its gases, chemistry, and water
history. Even though it isn't expected to survive the landing, the probe will collect valuable
data and images on its hour-long descent to the planet’s scorched surface Meanwhile, the VERITAS
spacecraft will be a Venus orbiter, similar to MAVEN currently orbiting Mars. Over the three
Earth years it spends circling our neighbour, its job will be to search for evidence of ongoing
volcanism and tectonic activity by measuring heat coming from the surface, and analysing the
composition of Venus's tesserae. These findings will hopefully help us understand just how
different (or similar) Venus and Earth are. Regrettably, I can’t discuss these missions
without that caveat – if they proceed – as VERITAS and DAVINCI are both missions that
will be cancelled if NASA’s proposed budget cuts go through. MAVEN is already around Mars,
and yet it too could be turned off to save money. You can learn all about those budget cuts here,
along with my opinion on it; but for now, let’s just cross our fingers that these illuminating
missions are allowed to go ahead as planned. But even if they do not, the other nations
of the world are stepping up. ESA, Russia, China, India and even one private American venture – the
Venus Life Finder – are all planning missions with ambitions that lie Venus-ward. With any luck, one,
more, or all of them will lead us on a voyage of great discovery about our beloved star of
the morning and evening, divulging a wealth of information and answering
some of our burning questions about Venus. So there we have it. Looking at Venus through
a variety of differing wavelengths has given us far more knowledge than visible light alone could
give. We have been able to discern volcano and crater formations through kilometres of opaque
clouds, determine some of the chemical composition of both atmosphere and surface, and use infrared
imaging to make the invisible visible to us. All of these have granted us precious hints as to
why the conditions on it are so extreme...and just maybe that there is the possibility, however slim,
of simple microbial life on our closest neighbour. What would you like to learn about Venus? What is
your favourite aspect of it that stands out the most to you? Let me know in the comments
below. But for now, I’m Alex McColgan, and this has been Astrum. I’ll see you again next time.