Momentum is building to explore Venus | Hacker News Reader

Momentum is building to explore Venus

nature.com

198 points6d6b73173 comments

I'm glad Venus is getting more attention. Mars seems to get the most attention as a place to visit, but we seem to ignore Venus.

Venus has a few things going for it that I think make it a better choice for permanent human habitation than Mars.

* Venus has nearly Earth-like gravity (8.9 m/s² instead of 9.8 m/s²)

* The atmosphere 50 km above the surface is the right temperature for liquid water, and has a similar atmospheric pressure to Earth at sea level. [1]

* Venus has suffered a runaway greenhouse effect. It's a good place to experiment on how to mitigate or reverse that without risking Earth. And what we do learn may be applicable to Earth in the not-too-distant future.

[1] https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/200300...

The Soviet Union always put more attention on Venus, and the US more on Mars. From what I can tell this dates back to before there were actual space programs, so I strongly suspect this has to do with the science fiction in the respective languages.

For example in H.G. Wells 1898 War of the Worlds, the bad guys are from Mars, Edgar Rice Burroghs John Carter series is about Mars, etc. whereas engineer cosmonaut Konstantin Feoktsitov wrote that when he was 10 (~1936) he came to a sad realization. Since going into space was better than everything else, any effort he put into anything other than going into space was wasted effort, BUT by the time he got the Ph.D he would need to contribute to that program men would already be on Venus, so he would never be the first to anything[1]. I don't know Russian language sci-fi well enough to guess what the source for this (or maybe was it Tsiolkovsky? dunno), but that suggests to me that the Soviet interest in Venus wasn't just because the US had a stranglehold on Mars or anything like that, it was because Venus spoke to them in the same way that Mars did to Americans. Any Russian speakers can confirm?

[1]: He ended up as Sergei Korolev's right hand man, and was tasked by the Chief Designer himself with stripping all the safety devices out of the Vostok capsule so that it could hold three men [Vokshod]. When Feoktistov objected, Korolev told him if he did a good job, he'd get to take it into space, and Feoktistov accepted the challenge.

One reason could be that early soviet space probes had big issues with durability, generally caused by their unreliable pressurized & gas cooled (generally pure nitrogen at atmospheric pressure) electronics - US generally used much more reliable vacuum rated electronics).

For this the signifficantly shorter flight time to Venus is a big advantage, not to mention that a lander wont survive for long anyway, further reducing issues with probe longevity.

Russia got the first probe on Venus, so maybe it’s success being celebrated and reinforcing more interest.

I just saw an episode of the new BBC series Planets talking about this. One thing they mentioned was that it was seriously suggested even in the 40’s that there could be rainforests and a fertile surface underneath the cloud cover on Venus. Could see the mystery in particular being an interesting thing to grow up hearing about.

Here is a book from the soviet era, about Venus

https://www.goodreads.com/book/show/23302599

"Тайна утренней зари"/"The Mystery of the Dawn"/"Taina Luceafărului".

As for their space program, I do believe they had almost similar investment for Venus and Mars, just Venus was more approachable and the missions were more fruitful(?). They canceled some Mars and Venus programs in time. Some wikipedia page about USSR space program:

https://en.wikipedia.org/wiki/Soviet_space_program

i think the primary reason for US interest in mars is due to the fact that it is much more likely that mars #1) previously contained life and #2) we will be able to find evidence of #1 on mars, vs venus.

On the other hand, NASA’s (recent!) insistence that everything be justified in terms of the search for life is not shared by everybody.

I for example really don’t care at all about potential microbial life vs. extending the domain of earth’s life through permanent settlement and terraformation of both Mars and Venus.

The cloud cover on Venus is so thick it could contain life right now. The belief that it’s necessarily barren due to extreme conditions predates the widespread knowledge of extremophile earthbound life. If you gave me better than even odds that there is life on Venus I’d take them.

I'm not sure there is consensus that Mars is much more likely to have had life. As the article states, Venus had liquid water for 3 billion years versus 400 million for Mars.

well you said it: we know exactly how to heat up mars (greenhouse gases) but its not so clear how to cool down venus. also mars has water.

We don't need to cool it down. We could float a platform about 49.5 km above the surface of Venus, where the temperature and pressure nearly match the earth at sea level. To launch a probe, we could simply drop it from the platform.

This article about Venus is very enlightening: https://en.wikipedia.org/wiki/Atmosphere_of_Venus

my comment was in response to parent saying venus was a better candidate for colonization than mars.

but i am totally on board with exploring venus, although im not convinced the atmospheric issues are significantly lesser than the surface, just different (hurricane winds, sulfuric acid, etc)

How would we float a platform at that height?

By attaching it to a steel balloon filled with breathing gas, which can provide lift in the Venusian atmosphere.

Inside the baloon you get a really nice habitat with the correct Temperature, pressure and gas composition for humans to live in.

Other than a basically unlimited supply of CO2 however, what would the advantage be compared to a just a space station?

With Mars, you can mine building materials from the surface.

CO2 has carbon in it. Strip off the oxygen to breathe, the rest makes very strong building material.

Attach hydrogen, you get rocket fuel. Or plastic. Bind in some nitrogen, you can have proteins. There is probably silane lower down; send down a balloon to collect it, for silicon. Or all the way to the surface, to collect rocks.

Nuke power is totally practical there; no shielding needed, or worry about leaks; you just hang it a mile below your living-space balloons.

You can live there long term since there is gravity.

Also, there is a lot of protection from radiation, from the mass of atmosphere above you and the mass of the planet below you.

Is Mars' gravity too low for long-term habitation?

I know that we know that zero-G is a negative, but do we have any idea if it's a threshold that needs to be reached, a linear response to G-force that scales from untenable to fine, etc?

I would imagine that it's going to be a gradient. Just like any other form of exercise, the more effort you put in, the more positive effect. Humans would need to put in much less effort on Mars. Once we are spread across the solar system there will probably new exercise systems for 0 and .3 G environments.

I am also unsure about how it would affect the prenatal development as the way "layering" occurs is highly dependent on gravity.

The only way to really find out is to go there and live for a while :)

We can float things in the earth atmosphere at sea level. My completely ignorant prior is that we should be able to do it there too, if the temp and pressure are the same.

Much better: the air at normal pressure is much denser, so ordinary breathing air supports a balloon.

Most methods of flying things through Earth's lower atmosphere should apply well to Venus at 50 km: balloons, planes, helicopters, etc. To gather energy for rotors, maybe we could siphon heat from below to power a generator or other type of converter.

Just playing with ideas. :-)

Send your mining robot below. It cools itself with phase change liquids, but also opens high pressure tanks to the 90 bar atmosphere. When you hoist it back, just plug those pressure tanks in to turbines connected to generators. That wouldn't be a huge amount of power, but maybe wildcat prospectors could operate like that in the early days.

Would it be enough energy to compensate for the work you'd need to do to lift the robot back up? Presumably there's some energy gained from sending it down but not enough to bring it back, especially since it is coming back heavier. I just don't know how to work the math on that.

Lisa, in this house we respect the laws of thermodynamics!

Why not use liquid oxygen as the phase change liquid? Then the gas could be caught in a bladder tethered to the ground. When it comes time to ascend, use it as a balloon?

There must be some way to exploit the temperature difference between the surface and 50km up, without mega-engineering.

Hmm, maybe some variant of a solar updraft tower where hot lower atmosphere gases are siphoned up to generate power and heat lifting balloons?

OK that's just opened my eyes a little. It sounds so obvious - if the atmospheric pressure is the same then yes we should be able to fly aircraft. Maybe not with the engines used on Earth but in principle at least. Slightly terrifying that a loss of power should result in a 50km drop to a crushing hot acid death, but probably not much worse in reality to smashing into rock like you would on earth. Very interesting comment - thanks!

> "Most methods of flying things through Earth's lower atmosphere should apply well to Venus at 50 km: balloons, planes, helicopters, etc."

The kind of flying logistics needed to operate a station like the one proposed is something that hasn't been demonstrated on Earth, so doing it on Venus seems like one hell of a stretch. The closest match is the airship aircraft carrier experiments, which did not go well. If it can't work reliably on earth, how can it work reliably above Venus?

I think it's one of those things that looks great on paper but in reality has a ton of trouble. I think airships are like that on Earth and on Venus.

Have you heard of Murphy's law?

Floating above Venus provides the benefits of a gravity well, but there's the danger of sudden buoyancy loss.

Everything about exploring space and planets is a rebut to Murphy's law.

Very cool NASA video: https://www.youtube.com/watch?v=0az7DEwG68A

We don't need to cool Venus down, but in a few hundred years we might need to cool the earth, so learning how to do that on Venus might be a good idea.

Just because you are at sea level, you can't suddenly float stuff in the air. I like your optimism though. :) I was imaging a floating city like cloud city in star wars [0].

[0] https://www.starwars.com/databank/cloud-city

This is a bit more thought out than perhaps OP applied, several theretical investigations have been done into floating cities on venus and it more or less comes down to building blimps out of gasses like nitrogen and oxygen. Because the venus atmosphere is so dense, this would actually work.

I would love to read about those investigations. Do you have any pointers?

https://m.youtube.com/watch?v=BI-old7YI4I&feature=youtu.be

What if your float thing pops? Everyone sinks and dies??

Mars' atmosphere is 95.3% carbon dioxide, which means that the problem we have to solve is not "how do we inject craptons of greenhouse gas into the atmosphere" but "how do we stop the solar wind from stripping away the atmosphere," which is not a problem we have a clear idea as to how to solve.

Contrary to popular belief, the rate that solar wind strips Mars atmosphere is so ridiculously low that we can comfortably kick the problem of stopping it down the road a few hundred thousand years. If we manage to generate a habitable climate by terraforming with additional heat and atmosphere, adding a magnetic field becomes a very low priority.

Venus has more carbon dioxide in its atmosphere and has the added bonus of the surface being pressurized like you are deep sea diving....

Sure but we got to survive till we could clear carbon dioxide

Carl Sagan once proposed an interesting concept of terraforming Venus by floating some kind of bacteria in its atmosphere. The bacteria would be constantly drifting down to the surface and dying, but with no predators and ample resources, multiplying quickly enough to replace the losses, and small enough to be kept aloft by air currents. Gradually they would transform the carbon back into solid mass, and bring the atmospheric pressures and temperatures down to earth levels.

Later on in his career he decided against that scheme, but with our progress in biotechnology, it might be the only feasible approach.

https://en.m.wikipedia.org/wiki/Terraforming_of_Venus

I wouldn't say we know exactly how to heat up Mars. Without a magnetic field, any atmosphere we conjure out of the polar regions would escape into space. We are far, far closer to completely reversing the effects of climate change on Earth than we are to teraforming Mars.

Yeah, but I believe it takes ~10 million years for a Mars atmosphere to escape.

So it could be entirely feasible to treat the Mars atmosphere as a tire, that you "inflate" every now and then to keep the pressure constant.

That would be a very wasteful use of precious volatiles though.

But we could kick up a magnetic field with superconducting rings around the poles though.

Losing 0.00001% per year is not "very wasteful" to me.

There are ideas for putting up a magnetic field based on putting a contraption in whichever L1/L2... point is between Mars and the Sun.

Convert that into tonnes, and then calculate how much biosphere could be supported with that volatile weight. And once it is gone, it is gone. It’s not a renewable resource. You’d be trading away billions of years of future Martian biosphere.

Oxygen and nitrogen are hardly rare substances in the solar system, and probably not even on Mars. There are near infinite number of "tonnes" on Mars.

Besides, if the alternative is to leave Mars dead forever, I'd rather let it live for a billion years.

But maybe I don't get what your alternative is, if any?

Nitrogen and hydrogen are basically only really available via volatiles. They aren’t components of common minerals in the rocks.

The alternative is to spin up a magnetic field with superconducting magnets to protect that atmosphere from the solar wind.

well obviously we'd need orbiters that generate an artificial magnetic field my man!

http://www.nifs.ac.jp/report/NIFS-886.pdf

We do know how to cool Venus. Build a sun shade. It’s an old idea, and a simple idea, and there’s lots of engineering literature on how it can be reasonably accomplished.

I’m going to go out on a limb and guess that Venus’s high temperatures might be determined by solar radiation and the inverse square law and that its atmosphere is on the consequence side of the expression.

That said I entirely agree we should be exploring it!

That's a pretty tenuous limb to go out on.

If that were the case, why is Venus hotter than Mercury, despite being farther away from the sun and having an albedo of 0.75? (Mercury's is about 0.1).

In fact, with its high albedo Venus reflects so much sunlight that it absorbs even less solar energy than Earth does, but despite that, it's hotter than mercury. I am pretty sure that's all due to its atmosphere, and I think every planetary scientist would agree.

Maybe because Mercury is much smaller and thus absorbs far less solar radiation and has a far greater surface area to volume ratio allowing it to radiate heat more efficiently?

Venus's atmospheric composition is a consequence of its placement relative to the sun, mass, and volume.

Can you explain how volume comes into play?

Solar energy absorption is proportional to surface area, and radiative dissipation is also proportional to surface area.

By the way, Mercury is tidally locked, with a hot side facing the sun all the time. Even that hot side is not as hot as Venus.

There is no question, if you were to strip Venus' atmosphere away, it would cool down tremendously and probably be not much warmer than Earth, or even cooler depending on what albedo it ends up with.

This isn't even an open question or a mystery or an active area of study, by the way. This is very solidly known. I was hoping that by pointing out well-known but surprising facts like that Mercury is colder than Venus, and Earth absorbs more sunlight than Venus, it would encourage you to question your previous standpoint. But if you want to really challenge this point, then please at least do a little more to measure the strength of the limb you are standing on.

Atmospheric composition is not in general a function of mass, volume, and distance to a star, by the way. Due to feedback loops, planets can have multiple stable equilibria, and a history-dependent climate and atmosphere. That is why the concept of terraforming even makes sense. A planet with the size, mass, and location of Venus (or Earth...) can be made into a snowball or a fireball depending on albedo and greenhouse effects, and transitioned from one to the other.

I honestly appreciate the lecture.

How does volume come into play? Well because the higher the surface area to volume ratio of a spheroid body is, the more efficiently it interacts with its surroundings, in this case by radiation.

That said, you haven't said a thing to support the position that Venus's atmosphere is the causal factor, and not a consequence of solar inputs. There's no reason to believe we can learn anything about the Earth's atmosphere from Venus than there is we can from Mercury.

Look this isn't that hard. Venus has the atmosphere it does because it used to absorb far more sunlight than it does now which caused the increased albedo.

Venus is closer to Earth.

Given a choice of death by fire and death by cold, death by cold is easier to mitigate against, and is the default problem in space. To survive Venus, you have to first survive the freezing trip to Venus. So you need heating and air conditioning. A lot. Of both.

On Mars, you only need the heating systems that got you to Mars.

Similar problem for radiation: going to Mars leads to less radiation. Going to Venus increases radiation. So in Venus orbit, you need more shielding than you need at low Earth orbit. On Mars, you need less.

There's another commentor suggesting floating in steel balloons. Um, weather is going to be rough. Really, really rough. The mass of building materials necessary to survive the storms strikes me as likely deal-breaker. Never mind the complete lack of light.

I don't know if everything is harder on Venus, but most of the first-order issues are substantially harder.

> death by cold is [...] the default problem in space

well, actually... you need lower-energy atoms for higher-energy ones to rub against to carry away the excess. there's not many atoms in vacuum, so the default problem in space is overheating. see eg. https://en.wikipedia.org/wiki/External_Active_Thermal_Contro... or https://en.wikipedia.org/wiki/Liquid_cooling_and_ventilation...

> you have to first survive the freezing trip to Venus. So you need heating and air conditioning. A lot. Of both.

the heating part is very, very wrong. the AC would be Atmospheric Control, see https://en.wikipedia.org/wiki/International_Space_Station#Sy....

> you need lower-energy atoms for higher-energy ones to rub against to carry away the excess.

Wat? Conductive and convective heat loss are certainly things, but heat radiates away too, and that is exactly how the systems you describe perform. The fact that the hull doesn't radiate much heat away itself isn't suprising, but all things being equal, the system still dies cold. Put the other way: if heat was truly the problem, is there any outcome where ISS melts, short of re-entry?

> s there any outcome where ISS melts, short of re-entry?

i don't think so. should the cooling system fail, the sources of heat (mechanical work, biological processes) would cease way before that.

Stay tuned for the Venus mechanical maker challenge:

https://www.jpl.nasa.gov/edu/events/2019/3/1/mechanical-make...

>With its sulfuric acid clouds, temperatures over 450°C, and 92 times the surface pressure of Earth, Venus is one of the most hostile planetary environments in the solar system. Prior missions have only survived hours! But an automaton (or clockwork mechanical robot) could solve this problem. By utilizing high-temperature alloys, the clockwork rover would survive for months, allowing it to collect and return valuable long-term science data from the surface of Venus.

>Challenge to be announced on July 8, 2019

Question: does NASA have a Venus environmental chamber? They must, right? How big is it?

Yes. NASA Glenn Research Center in Ohio has one, I believe. They were building it when I was an intern ~6 years ago.

Of course, Glenn also has high temperature electronics. Memory is hard to come by, but simple analog and digital circuits are feasible (enough for data digitization, multiplexing, some forward error correction, and transmission to orbital assets).

Here are a couple papers on the idea of all-high-temperature-electronics designs (which I think are a lot more realistic and effective than a mechanical automaton, as fun as that sounds) for a long duration lander design (can be adapted to a rover, etc, as well) related to the work I did:

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201400...

https://www.sciencedirect.com/science/article/pii/S009457651...

Cool stuff. One of my roomies in collitch got his Ph.D. with Choyke who I think is still the godfather of high-bandgap semiconductor physics.

Looks like NASA wants to make cpus with Gallium Nitride now:

https://phys.org/news/2017-12-gallium-nitride-processornext-...

From the link:

> ... at the Glenn Research Center. > > The team has already tested the circuits in a Venus simulation chamber — a 14-tonne stainless-steel tank that can imitate the temperature, pressure and specific chemistry of the Venusian surface.

Thanks, I missed that! Sounds pretty cool.

I don't think anyone won the last challenge, which was for making a mechanical camera, because they kept extending the deadline. The requirements for the camera they wanted were pretty stringent. If they were willing to accept different resolutions image shapes then a hacked antique IR camera would win. Old IR cameras mechanically raster scanned a single detector over a scene fast enough for 15 fps video.

This is great, I didn't know they were following up on this concept. I had read an article [0] from 2017 before but wasn't aware of any further developments.

[0] https://spectrum.ieee.org/automaton/robotics/space-robots/jp...

It’s called an autoclave...

Ha! If it's roomy, plus 92 atmospheres (plus hot acid clouds!)

The Soviets succeeded in returning surface images from a number of their landers, and the photos are quite tantalizing.

http://mentallandscape.com/C_CatalogVenus.htm

"Venus Revealed" is a pretty good read:

https://www.amazon.com/Venus-Revealed-Clouds-Mysteriious-Pla...

very cool, thanks for sharing

Because of Venus's think atmosphere, landing a probe or rover is really easy. The downside, also because of Venus's thick atmosphere, is that the surface is really, really hot. That limits the lifetime of hardware on the surface.

I think it ought to be possible to design a probe that's more like a submersible than a rover. Technically it would be an airship rather than a submarine, but given Venus's thick atmosphere it could be quite heavy and robust. This vehicle could bounce between the surface (for science) and the upper atmosphere (for recharging). In the upper atmosphere the probe could make more coolant from the atmosphere using solar power, and then it could make another dive to the surface.

An airship seems like the most survivable option for longer missions.

I wonder if it would be possible to use one as a carrier for smaller drone-ships. Wind speeds on Venus are quite low, but the force is probably quite insane considering the atmospheric pressure.

For the record the soviet Vega probes deployed a couple baloons and they worked just fine for quite a while.

The enabling technology we need more of is electronics that can work at 500 C. People have demonstrated small-scale integrated circuits, but nothing like a microprocessor. https://science.nasa.gov/technology/technology-stories/elect...

Not really - we don't have to land on the surface of Venus to explore it. https://www.space.com/29140-venus-airship-cloud-cities-incre...

The atmosphere is opaque, so you can't see much from high up.

The most interesting science (to me) would be to look for fossils or other signs of life, for which you have to land and dig.

Not much evidence would be able to survive those temperatures and acidity levels. If you really want to dig through the molten earth, bring a titanium shovel.

So I had two thoughts while reading it:

Is it possible that in the 3 billion years that it had liquid water, Venus evolved advanced life that managed to trigger runaway greenhouse warming?

Secondly, is Venus’s atmosphere a worst case scenario for global warming here or is there something that would prevent it happening?

According to James Hansen's book Storms of My Grandchildren, Venus-level warming is far beyond anything we could achieve on Earth. Given our greater distance from the sun we don't have enough carbon to pull it off.

(The worst we could do is still enough to destroy us, though.)

Does that imply that an advanced enough Venusian life form could have triggered global warming there more easily?

Seems reasonable. Interesting thought.

Maybe we’ll find ruins.

I see no reason why intelligent life with high technology could not have developed on Venus. Say, several hundred million years ago. And perhaps they triggered runaway greenhouse warming, which vaporized the oceans. And so perhaps it was the loss of the oceans that ended plate tectonics, not the other way around.

I doubt that runaway greenhouse warming could get so extreme for Earth. I recall reading that solar input is enough lower here. Also, at million-year scales, I gather that high CO2 levels increase weathering, and drive carbonate deposition in the oceans.

> I see no reason why intelligent life with high technology could not have developed on Venus. Say, several hundred million years ago. And perhaps they triggered runaway greenhouse warming, which vaporized the oceans. And so perhaps it was the loss of the oceans that ended plate tectonics, not the other way around.

The only way that thought experiment could make sense is if they had the technology to do that, but not the technology to escape Venus and get to Earth.

Think about it; several hundred million years ago, Earth was habitable; maybe not for modern humans (but I bet we could do it - though uncomfortably), but definitely life existed in some form:

https://en.wikipedia.org/wiki/Age_of_the_Earth

So there was liquid water, and the Earth wasn't a Dante-esque hellscape of volcanos and lava, etc. It was probably much warmer and more humid, but overall not crazy to live on.

So if your situation was dire enough, and you had the technology to escape the planet (which you'd almost have to, if you had the energy resources to cause your own global warming and demise scenario) - wouldn't you at least try?

So either they tried and failed in some manner (never reaching Earth), or they succeeded (meaning?) or something in between.

Even if they didn't try, with the level of technology, wouldn't they at least have left something behind in the solar system that we'd recognised as created by intelligent life long ago? Some artifact somewhere?

Maybe they did, and we haven't found it (space is big - the solar system is a big place); but I'd almost expect there'd be something orbiting Venus that was artificial (though maybe again, we can't detect it from here - too small, likely inactive, etc). I guess a good question would be, if you were on Venus (or even in Venusian orbit) - could you detect Earth's satellites currently orbiting Earth? Could you detect a singular one (last of its kind) in a degraded, virtually inert state? Again, I don't know.

It's a bit fascinating to think about; part of me wants to say "we should be able/have found something by now" if such a scenario were real - but at the same time, I can think of reasons why we haven't or can't...

Pure speculation, but agriculture or the the equivalent of the industrial revolution might have been enough to create a runaway greenhouse effect. I find it easy to imagine how our civilization could have gone extinct due to fossil fuel use without ever getting anything close to orbital velocity.

From what I've read, runaway greenhouse was more likely on Venus. Mainly because of greater solar input. So that's plausible.

The only way that thought experiment could make sense is if they had the technology to do that, but not the technology to escape Venus and get to Earth.

If you have the technology to do that, but don't have the civilization infrastructure to support it, then escape/colonization might well cease to be a viable option. A global warming catastrophe could well precipitate a collapse of global civilization, in precisely the initially slow, sneaking way which might catch a global civilization unprepared. The Romans knew things were breaking down, but the generation which was invaded by the Vandals didn't think it was quite that time yet. Global civilization might well kick the can down the road with building their sun-shield, then get caught with its pants down, when civilization starts crumbling, and it loses the industrial know-how to pull it off.

How about a downer Sci-fi story, where the closing scene is of a Flat-Venuser enclave surviving in a subvenusian tunnel, telling half understood mythological stories of the long dead Eloi and their plot to blot out the sun?

> The only way that thought experiment could make sense is if they had the technology to do that, but not the technology to escape Venus and get to Earth.

Maybe they DID get to Earth, and are currently busy transforming our atmosphere to generate cozier conditions for themselves?

Who says they didn't escape to Earth, a billion years ago?

It's not as if they would still be around ... unless they live at the sea bottom; then there is no reason we would know.

"Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn."

"In his house at R'lyeh dead Cthulhu waits dreaming."

But seriously, an invasion from Venus a billion years ago would leave no evidence we could reconstruct today. After they went extinct, less than a million years later, their microbes would remain. And eventually become us.

That's the most interesting possibility, I think. Probably not just "become us", though, because there's evidence for eukaryotic life, well before then. But it's only fuzzy structural and geochemical evidence. So they and/or their microbes could have merged.

However, the Earth wasn't so hospitable, ~1000 Ma BP. There wasn't much free oxygen then. Not until 600-800 Ma BP, I gather. So if they were oxygen breathers, they would have been living in habitats. But maybe they made the move ~600 Ma BP. That would have been ~endgame on Venus.

I don't see how any of this is testable, however. Some have argued that Octopodidae aren't originally from Earth. But it's iffy.[0] Still, who knows? Maybe they did come from Venus ;)

0) https://www.snopes.com/fact-check/octopus-dna-origins/

> if you were on Venus (or even in Venusian orbit) - could you detect Earth's satellites currently orbiting Earth?

Inverting it, we could probably not detect any artificial satellite on Venus here from Earth. But we've had launched satellites there, that should be able to detect other ones if they have a good camera (because satellites shine).

So, the question becomes, does any of the satellites there has a good enough camera?

I've often wondered the same thing!

A little while back two NASA scientists published a paper on how you would detect the existence of a previous advanced society on Earth. Apparently, over a long time scale it's actually fairly difficult.

Not at all my area, but it doesn't seem like we can actually answer that question you posed. It's fascinating. Carl Sagan's COSMOS might be the first time I'd ever heard about Global Warming, and he explained how it was through the study of Venus that we really began to understand it.

Now imagine detecting one, when the entire planet is covered in a 90 bar atmosphere with sulphuric acid clouds.

I'll update my downer Sci-fi novel premise. Humanity makes its first Alcubierre drive warp ship. On its test run, something goes wrong, and the ship is shifted by a vast amount in time-space. The ship arrives at an unfamiliar, abandoned star system, with a different sized Sun, vast amounts of orbital construction, but an eerily similar though slightly different configuration of planets. Over time, the test pilot crew realizes that they were merely in stasis and "arrived" back in the Solar System far in the future, and that the 2nd Venus-like planet is actually the Earth.

That's a little like Planet Of the Apes where they find out that they are actually on Earth.

I'll buy that book when you write it.

> A little while back two NASA scientists published a paper on how you would detect the existence of a previous advanced society on Earth. Apparently, over a long time scale it's actually fairly difficult.

Depends on how you define advanced. Anything in geostationary orbit is basically there for the life of the solar system.

they would have just gone to Earth

How do you know? Can we go to Mars today? What if earth gets destroyed before we can emigrate to Mars? (assume that Mars is a clone of earth i.e. the same conditions we have in Earth)

Also it's possible earth wasn't suitable for Venisian life back then.

Because the level of destruction imposed on Venus implies a degree of power a great deal beyond what we have now. Venus has 93 times the atmosphere of Earth. Wrecking Earth's atmosphere to that extent on a short time frame due to intelligent life's activity isn't just burning a tons of hydrocarbons, it would be going out to the Solar System and pulling in mass in quantity to be dropped in to the atmosphere. By the time they got there they ought to have the capacity to do a lot of other things too.

It isn't particularly plausible that life destroyed Venus. It's especially not particularly plausible that it just so happens that life did it to Venus using exactly what happens to be a fashionable thing to talk about here on Earth at this exact time.

They wouldn't have had to wreck their atmosphere to that extent so quickly. What if they wrecked their atmosphere more slowly, then experienced a slow global collapse of civilization due to the climate change? There could have been a "phase change" event where they retained technology, but quickly lost the ability to engage in the magnitude of project required to save their planet. "We of Souvenusia do not trust the people of Norvenusia to act in good faith in the sun-shield project!" Venusian civilization devolves into global war. Then the climate has warmed up to the point, where their wartime activities trigger a global methane clathrate catastrophe.

It's especially not particularly plausible that it just so happens that life did it to Venus using exactly what happens to be a fashionable thing to talk about here on Earth at this exact time.

But it could make for a timely, marketable, ripping good novel!

Say if we suddenly realize earth is going to be unsuitable for all life forms in a year. What would we do? I would fire as many rockets as possible to Mars, carrying all kind of life forms on earth, and hope a few of them will survive and possibly evolve to Mars' environment.

Even all-out nuclear war would leave the Earth far more habitable than Mars. We'd need to come up with quite the feat to extinguish life here, think steering a Moon-sized asteroid.

We do know at this rate earth will be unsuitable for human life in the future and we do almost nothing about. If it were just next year, maybe we would do more about it. But my point is we can't do much since we don't have the technology to go to Mars. Emigrating to Mars is an unsolved problem and it can remain unsolved before we wreck the planet.

That's easy to say, but how would you actually do it?

To use myself as a counterexample, I don't see the point, and wouldn't be inclined to help.

We're trying.

I think these things are path dependent. There's not a particularly good, short-term, economic reason to go to Mars and build it up enough to be self-sustaining. However long term, it probably does improve our civilization's and species' (and perhaps life's) chance at survival. Unfortunately, we're not terribly good at long-term decision making.

It could very well be that there was a window when the hypothetical Venusian civilization had the capacity to leave en masse to Earth but by the time the matter had become pressing enough, it was too late.

For instance, it could be that advanced geoengineering techniques were able to hold off the effects of warming for thousands or tens of thousands of years which reduced the urgency leaving Venus, but over time the cost to maintain such systems became much too expensive and then some crisis (global war?) destroyed the geoengineering scheme, quickly heating Venus and destroying the advanced technological civilization and/or putting it into terminal decline.

Point is you have to do such things when you have the chance, not necessarily when it seems most pressing.

As Randall Monroe has said, "The universe is probably littered with the one-planet graves of cultures which made the sensible economic decision that there's no good reason to go into space--each discovered, studied, and remembered by the ones who made the irrational decision." https://xkcd.com/893/

We went to the Moon ~50 years ago and soon stopped. It was somewhat of a historical accident that we went at all. It's not obvious that we will return in the future (even those efforts to go to the Moon or Mars face voices calling on even private efforts to be stopped). The future has not been written, and we don't know that it'll end up in the positive direction. But we, today, have the power to try.

Or just denied that it was a problem until it was too late to migrate to Earth before their civilization crashed.

Maybe they did :hmm:

I wonder why there isn't a balloon mission being studied.

The upper atmosphere has temperature and pressure similar to Earth at sea level.

Maybe the wind is a big problem? Or insertion from orbit?

"Soviet Union explored the Venus atmosphere with unmanned balloons in 1985 during the Vega mission". Wiki article: https://en.wikipedia.org/wiki/Vega_program#The_Venus_mission

I think upper atmosphere study would be great. There are some colony designs that suggest an oxygen filled colony would float at earth pressure. And with the sulfuric acid and co2 you have everything you need to make water air and fuel. Not to mention protection from asteroids and deadly rays. It would be a challenge but all of the planets and other bodies present their own challenges.

At the same ambient pressure, an O2 would float, but just barely. It wouldn't float like a hydrogen/helium balloon does on earth. If the pressure is the same on either side of the balloon, lift comes from different atomic weights of the gasses. Helium weights much less than air. But the O2 inside the Venus habitat doesn't weigh all that much less than the CO2 outside. As a practical matter, you would probably need lift balloons filled with something other than breathable air/O2. [1]

Then think about what you want to do in this habitat. A solar/nuke-powered refinery for producing rocket fuel? It would need lift bags the size of cities. Not the Goodyear blimp. Think bags filled with cubic kilometers of lifting gas.

[1] This is why balloons wouldn't work on Jupiter/Saturn etc. No balloon can float in a sea of hydrogen. We would need a 'balloon' filled with vacuum, or at least hydrogen under vacuum pressure in comparison to the hydrogen outside. Soft-sided bags wouldn't work.

Well not everything would need to float at earth pressure. The production of any fuels or materials that required heavier equipment could be done at lower atmosphere. You could engineer bacteria to break down sulfuric acid for the hydrogen based fuels, obviously the CO2 to O2 part would be easy, or bacteria to produce certain materials. Also I wasn't talking about methane fuel which would need nuclear I was thinking more basic hydrogen rockets which chemical reactions could be simple and effective enough to produce. Additionally solar is already getting thinner and lighter so I don't think that would be much of a problem. And remember on Venus it's not just CO2 it's very dense and high pressure as well. So earth atmospheric pressure air could lift quite a bit and you don't need to be at exactly sea level pressure all the time. Only real problem I see other than the constant threat of death that all colonies will face is launching to and from any floating colonies.

As for the large blimp colonies, I see nothing wrong with that. Sure they'll be big but not any more difficult than building reinforced lava tube colonies on the moon or going to Mars with building sized 3d printers or excavators that can be used to make long term shelters. Like I said all of the planets are going to have tough problems, short of an earth like planet you aren't going to find an ideal easy scenario. Personaly giant airships housing 50 or so people doesn't seem too bad. Like I said though it's the landing and taking off that seems a bit trickier.

> No balloon can float in a sea of hydrogen.

You could use a hot hydrogen balloon.

https://en.m.wikipedia.org/wiki/A_Meeting_with_Medusa

I wonder if you could synthesise a carbon based material directly from CO2 in the atmosphere and use that to build the gas/vacuum holders.

I know this isn't what you mean by "studied," but here's a NASA produced video mockup of manned blimps over Venus: https://youtu.be/0az7DEwG68A

50 km from the surface, there are hurricane force winds, with temp and pressure similar to earth, but carbon dioxide atmosphere infused with sulfuric acid. Would be a bumpy ride. I wonder if there are tornadoes within that.

From the link:

> This year, the Venera-D team released a report that covered a number of potential additions, including a balloon that could explore the cloudy atmosphere.

Because then conspiracy theorists will understand a weather ballon can be an alien spacecraft too.

Slightly off-topic, but no argument for colonising Venus could possibly be complete without digging this gem of a comment out of the archives about cooking a turkey there: http://www.transterrestrial.com/2013/12/09/venerian-gas-phas...

I've always wondered why we don't seed it with some biology that can eat the components of the Venusian atmosphere (ie: sulfuric acid, carbon dioxide) to make a more habitable planet over time.

In Kim Stanley Robinson's 2312, Venus is terraformed by inserting a large sunshade in the L1 Lagrange point of the Venus-Sun system. This makes Venus significantly cooler and atmospheric CO2 freezes. The frozen CO2 is then easily removed.

Because we've failed to terraform much closer, less inhospitable environments, and the risks for getting it wrong are very high.

Which environments are you referring to? Venus is the closest planet to Earth. The Moon is the only significant body between the two.

And by 'we've failed to terraform', did you mean 'we haven't tried yet'?

We're currently in the process of terraforming earth to make it slightly less habitable.

Terraforming means making it Earth-like. Did you mean terra-deforming?

As far as I'm aware, nobody's succeeded in turning deserts into farm land on a large scale. Various parties keep trying but the water, fertilizer, and maintenance costs are astronomical.

Israel has turned much of it's desert into farmland and forests. For example, the Yatir forest is one: https://en.wikipedia.org/wiki/Yatir_Forest

All of Los Angeles/most of southern California was a desert, wasn't it? Massive water redistribution is the reason tens of millions of people can live there. Much of California's agriculture comes from the same water redistribution projects.

Plus, there's no life that we know of on Venus. A bacterial population capable of living, evolving, and growing exponentially in that environment would be a huge change.

We definitely have. There's huge environmental impact, but that is to be expected.

California's Central Valley project is an example, and China has some that are even larger.

Wait, what are the risks? It's not like you're going to make Venus _more_ inhospitable than it already is.

Worst case scenario is we'd lose some valuable scientific information about Venus in its natural state.

The risk that Venus is or was once host to some form of life, and humans deliberately contaminating Venus with life would obscure any evidence of it. That is a very serious worse-case scenario because non-earth life would be truly invaluable to biology.

It seems like a remote risk to me, but not something to shrug off. Particularly since the usefulness of introducing life to Venus is itself quite remote.

Life in temperatures that melts lead? Oh... or do you mean in the atmosphere?

For all we know the Soviet Vega missions could have introduced airborne microbial life into the high atmosphere. We may have already seeded Venus.

Either. It does seem unlikely, but the truth is we just don't know.

> Life in temperatures that melts lead?

Why not? It'd have to have different chemistry, sure, but even on Earth life exists in some pretty extreme temperature and environment ranges.

Life really starts to struggle above 100 C. I think the most heat tolerant organisms we know of top out around 130 C.

Life that could operate at 500 C is probably not water based at all, which would be very novel and certainly interesting to science.

Yes, that is a high risk. We're not exactly lush with accessible Earth-ish planets near the habitable zone.

Wait, what are the risks? It's not like you're going to make Venus _more_ inhospitable than it already is.

To some weird soul out there on the Internet, this sounds like a challenge.

Microbes require water, and there isn't enough for them on/in Venus

Earth microbes require water. Who knows what alien life has as its building blocks.

You might already know this, but Carl Sagan proposed exactly that plan.

https://en.m.wikipedia.org/wiki/Terraforming_of_Venus

It would probably require more advanced bioengineering and understanding of ecology and extremophiles than we currently have, but it might still be the only feasible plan.

because we probably don't neither Venus nor the techniques required to make such a change, let alone the money or need. the material requirements alone would be staggering plus we cannot discount the attention span problem, this isn't something likely to be done in a life time

You are probably right, but wouldn't any technology which actually has a chance of working, also have the property that a small seeding might have the chance of "taking hold" and working wether we remember to continue on it or not?

To be clear, I mean if someone drops a bunch of microbes, only once, and not all of them die but slowly start to mix and live in the atmosphere, wouldn't they over millennia, very slowly but also very unstoppably, eat until everything they want to eat is eaten?

There is debate within the scientific community about changing other planets in general. Not everyone is convinced that we should alter or terraform to suit our needs.

Some related links:

https://planetaryprotection.nasa.gov/intpolicy/

https://www.astrobio.net/mars/should-we-terraform/

https://en.wikipedia.org/wiki/Ethics_of_terraforming

This is like nimbyism on steroids. "No one build anything what if there is Rare Science in our backyards".

I mean yes I do kinda see your point, but priorities man. There are ridiculously large advantages to colonizing the universe and destroying a few samples is a low price.

It's not that we can't or won't. It's that we should study and debate it before we do anything to change the environment. Given how humans have run roughshod over so many environments, I think carefulness might be warranted.

Particularly when we don't even know have reason to believe there are samples. If/when we detect life elsewhere we can talk about leaving it alone, but there are plenty of rocks in the universe with no life that we can work with.

We can still explore them. It's the contamination of them that is at question.

Why is contamination a question? there are millions of rocks scattered around that are not contaminated or explored. There is more to learn by contaminating a few and seeing what happens than to leave them all uncontaminated.

Wouldn't this take thousands or millions of years? Doesn't seem like there's much incentive for a project like that.

If it's cheap, why not try it?

Because what if there are Venusians there already and we cannot afford to wage an interplanetary war.

They might be there and we don't know about it. However the ability to wage interplanetary war implies are a lot of technology that we would be able to detect. Even if we assume they have the space ships in "mothballs", they would need to test and maintain them - something we can detect - or risk that they don't work when they need them.

We can’t even fix the climate where we live, with much easier solutions.

large part of it is sociopolitical: major populated and productive countries are locked by their social and economical structure into the need of perpetual growth to inject capital at the base as the top scoop up any floating wealth, stopping the growth without some for. of wealth redistribution would cause massive instability and with the margin of today production the first two to introduce climate control will be eaten (economically speaking) by the third one.

on the other hand we could likely today engineer algae or fungi to fix carbon into cellulose but you're going to need massive space for their growth and some place for their disposal, unless you can make some sort of bioplastic out of it, because burning them would defeat the purpose, and I bet once you put the number in the unbelievable scale needed for the project would scare the bejesus out of the very same ambientalists types that are currently most vocal about saving the world but abhor nuclear

anyway I think the real issue NASA has about bioengineering are ethical, and Venus is in the same protection category as Venus https://en.m.wikipedia.org/wiki/Planetary_protection

you can draw parallels between the development of cities as Rome, London, Chicago and Los Angeles substituting environmental protection with historical buildings protections. it's important to preserve the best and most relevant landmarks of course but too much and it becomes a real drag.

Technically we can. We just can't do it (currently) without ruining the living standards for 90% of the world's population.

Europeans said the same about North America when they landed on it.. we might want to study it a bit before making biosphere decisions like that.. not to mention the feasibility of it being possible.

Why couldn't you vacuum insulate the electronics and place some kind of radiative cooling on top of them? You'd need the cooler to be able to radiate all the radiative energy coming into the chamber from outside it, plus what the electronics generate. You'd want the thermos type chamber to be reflective to radiation from one side only.

It would depend on how low energy you can get the electronics, plus how efficient your black body cooler is. I have no idea if the latter could be done practically.

Might be a lot easier than high temperature electronics or mechanical alternatives.

> Why couldn't you vacuum insulate the electronics and place some kind of radiative cooling on top of them?

Radiative cooling only works if you have a hot source and a relatively cooler sink - on Earth, usually the atmosphere.

On Venus the atmosphere is ~462 °C at the surface, so it's going to be much hotter than your electronics - so your sink will be hotter than your source, so the "raditaive cooling" will run in reverse.

Also, the atmospheric pressure on Venus is very high - 92 atmospheres at the surface - the equivalent of being 1km underwater on Earth. Maintaining a vacuum chamber with this much outside pressure (not to mention temperature) would be an incredible feat of materials engineering - and would probably by extremely heavy.

You would also still need sensors and communications outside your vacuum chamber, otherwise your expensive probe can't actually do anything useful.

Pretty sure a completely passive cooling system able to maintain its inside cooler than its outside would violate thermodynamics somehow. I'm not a physicist though.

Has anyone considered colonizing asteroids? If you can spin the asteroids you can generate enough centripetal force to mimic gravity.

Not sure what the chances of asteroids being solid enough to be spun without flying apart though. Another option would be to build a track around the asteroid and move a colony along that track.

Need about 1 kilometer of radius from center and 1 rotation per minute to generate 1 g force.

Interesting.. gravity train: https://i.imgur.com/Q2D5i1K.png

“But momentum is building to explore Venus, in part because scientists say it could hold the secret to understanding what makes a planet habitable. Once Earth’s twin, today Venus is a hellish abode where surface temperatures reach more than 400 °C, atmospheric pressures slam down with enough force to crush heavy machinery and clouds of sulfuric acid blow through the sky. If researchers could decipher why conditions on Venus turned so deadly, that would help them to assess whether life might exist on some of the thousand-plus rocky worlds that astronomers are discovering throughout the Galaxy.”.

life exists here. let’s stop looking for exit strategies and stop wasting valuable time and money on far away rocks.

we need to put all that time and energy dreaming and solving for a better EARTH.

There’s no reason 7.7 billion people can’t collectively do more than one thing at the same time.

I really wonder if we'd be likely to find fossils underground there. Of course landing long enough without melting to find them would be hard.

Reading about the Soviet Union's systematic process to finally get some decent data from a lander was very impressive.

I think this from 2014 looks really cool https://www.youtube.com/watch?v=bcHkWKp9e4Y

Yachts on the methane oceans of Titan and dirigibles in the skies of Venus.

I hope I live to see all this.

Reply on news.ycombinator.com