NASA doubles down on Venus missions, asking what made the planet uninhabitable

NASA announced yesterday that it will fund two new missions to Venus to study its atmosphere and topography, both chosen from the Discovery Program. The two missions will seek to understand how Venus made the transition from a theoretically Earth-like climate to becoming the solar system’s hottest planet. Venus is often …

[Pete 2]

Told you so!

> The two missions will seek to understand how Venus made the transition from a theoretically Earth-like climate to becoming the solar system’s hottest planet

Because the Venusians didn't listen to all the warnings about climate change

[Pascal Monett]

Earth's far distant future

If I'm not mistaken, Earth's far distant future is to have its atmosphere stripped away by the Sun in its Red Giant phase, with all the oceans boiled away.

The only question is weather the expansion of our star's diameter will mean that Earth will orbit from farther away or not, which would mean that our charcoaled planet will not be engulfed by our star's outer atmosphere and melt away.

Earth's far distant future is not to become Venus. That may, however, be a rather close future, geologically speaking.

[Martin J Hooper]

Is the reason Venus is so hot is that it's closest to the Sun? or am I getting my planets mixed up?

[Throatwarbler Mangrove]

You are thinking of Mercury.

[Filippo]

Venus is substantially closer to the Sun than Earth. That probably accounts for a good bit of its temperature. However, Venus is a lot hotter than Earth - more than what can be attributed to its position alone. That's because its atmosphere is full of greenhouse gases that trap heat, or at least that's what we figure based on the data we have.

The point of the missions is to get more information about that. If there's some currently unknown planetary mechanism that can have a big effect on heat retention (in either direction), it would be really, really nice to know about it, given the current issues on Earth.

Fun fact: there's an altitude on Venus, high up in the sky, where both the temperature and pressure of the atmosphere are nice for humans (alas, the composition is still deadly, so no cloud cities).

[Anonymous Coward]

Mercury is the closest planet to the Sun. But the surface temperature of Venus is higher than that of Mercury even though it receives only about 1/4 the energy from the Sun per unit area. (Mercury's surface temperature is much more variable, but even at its highest is lower than that of Venus.) This is caused by an enormous greenhouse effect as Venus has an insane amount of atmosphere and it's almost all CO2: what's not clear I think is how Venus got from something sane to where it is now (or, perhaps, whether it ever was sane).

[Throatwarbler Mangrove]

Why bother?

There's naff all there. It's just a bunch of hot rocks and stormclouds. You know, until the protomolecule gets ahold of it.

[DJV]

what made the planet uninhabitable?

Rowdy neighbours...

[Anonymous Coward]

Background music for the boffins

While they have their obligatory pints. Bon voyage.

Space Truckin

[Umbracorn]

Terraforming Venus Quickly

I'm sure this will restart the debate on terraforming Venus.

Aside from a few "minor details", like what to do with all that sulfuric acid, the main problem seems to be reining in the greenhouse effect.

I'd like to see a model where the sunlight/insolation is reduced and the temperature falls just enough that the carbon dioxide starts falling as snow, at the poles.

https://www.universetoday.com/113412/how-do-we-terraform-venus/

[Anonymous Coward]

Re: Terraforming Venus Quickly

The wild-eyed naïvety of the 'let's just go to (Mars|Venus|other) and terraform it' people is kind of charming. I mean there's a little tiny problem with the atmosphere on the Earth that we've caused which we are managing to do approximately nothing about, and which, despite being rather small, is likely to be civilisation-ending if we continue to do nothing. So, hey, let's go to Venus, which has an atmosphere with a hundred times the mass of Earth's, which is essentially all CO2, with clouds of sulphuric acid, and solve that problem. Well, they're charming until they make a lot of money from a bubble and start thinking that, as they are now gods, they can do it for real.

[Timbo]

Davinci+ mission might not last long...

According to the Press Release: "The mission consists of a DESCENT (my caps !!) sphere that will plunge through the planet’s thick atmosphere, making precise measurements of noble gases and other elements to understand why Venus’ atmosphere is a runaway hothouse compared the Earth’s."

https://www.nasa.gov/press-release/nasa-selects-2-missions-to-study-lost-habitable-world-of-venus

And, apparently "Venus today is a hellish world. It has a crushing carbon dioxide atmosphere 90 times as thick as Earth’s. There is almost no water vapor. Temperatures reach 864 degrees Fahrenheit (462 degrees Celsius) at its surface."

and:

"Above the dense CO2 layer are thick clouds, consisting mainly of sulfuric acid, which is formed by sulfur dioxide and water through a chemical reaction resulting in sulfuric acid hydrate. Additionally, the atmosphere consists of approximately 1% ferric chloride. Other possible constituents of the cloud particles are ferric sulfate, aluminium chloride and phosphoric anhydride. "

and

"Strong 300 km/h (185 mph) winds at the cloud tops go around Venus about every four to five Earth days. Winds on Venus move at up to 60 times the speed of its rotation, whereas Earth's fastest winds are only 10–20% rotation speed."

So, very strong winds, sulfuric acid atmosphere and extremly high temps at the surface.

One wonders how NASA can build something that will last long enough to survive and take useful readings and photo's...still, they have between 7 and 9 years until the launch date, so something will turn up no doubt...unless someone makes the $500m budget vanish quickly !

[Anonymous Coward]

Re: Davinci+ mission might not last long...

Perhaps that's why they mention taking pictures on the way down...just in case it gets crushed by the pressure on the surface....

[Anonymous Coward]

Re: Davinci+ mission might not last long...

The surface winds are not too bad I think. What is really horrible is keeping electronics cool: unless you can invent things that will run at 460 centigrade ambient (so actually hotter since they will be generating heat) then you need to devote lots of power to cooling, and finding that power is hard I think: you need an RTG but the hot side of that needs to run much hotter than the surface temperature which starts to get seriously frightening, and I don't think thermocouples are anywhere near up to the kind of power output required, so you need, really, to run some kind of steam engine: I think there are schemes involving a Stirling engine.

There have been fairly mad plans involving valve electronics, which will run at that kind of temperature, but I suspect the answer is either very-high-temperature solid-state electronics or a mission with a very short life on the surface which just fries when its coolant runs out.

Venus is horrible.

[IT Poser]

Re: unless you can invent things that will run at 460 centigrade ambient

Luckily brilliant boffins already invented silcon carbide (SiC) semiconductors:

https://www.universetoday.com/137803/building-electronics-can-work-venus/#:~:text=These%20circuits%2C%20which%20would%20be,like%20conditions%20for%20prolonged%20periods.

And for those who claim money spent on space exploration is money wasted instead of doing something to make things better here on Earth:

https://www.eetimes.com/how-sic-devices-have-changed-the-face-of-semiconductor-sector/

[Anonymous Coward]

Re: unless you can invent things that will run at 460 centigrade ambient

That's interesting! How far are they from being able to make processors with these things? I guess the other question is whether you can use them for photovoltaics: my guess is 'no' because of the whole wide bandgap thing. Also I'm not sure how bright the surface is, so photovoltaics might anyway not be useful.

[IT Poser]

Re: unless you can invent things that will run at 460 centigrade ambient

Sorry for the delayed response. Life happened.

SiC MOSFETS and diodes are being manufactured. Connect these components properly and we get a processor. Granted this will be primitive compared to an 8086 but developing new technology takes time. Then again Apollo Lunar Module computers were primitive compared to early PCs.

Venus' thick atmosphere pairs well with wind turbines.