ESA to Send Spacecraft to Venus

teeto writes to tell us The International Herald Tribune is reporting that the European Space Agency is planning to send a spacecraft to peer at Venus." From the article: "If the robot craft pulls off the complex maneuver of slowing down enough to swing into orbit, scientists hope it will help solve the mystery of how the shrouded, churning atmosphere of Venus formed and how it maintains the planet's broiler-like temperatures."

An interesting change from Mars, to be sure...

[Ruff_ilb]

As far as I am aware, we know a lot less about the surface of Venus than we do about the surface of Mars or say, Mercury, or even Pluto. Given that Venus is relatively close to us, it seems to make sense to go about exploring it - especially since our satellites can't peer through the thick atmosphere.

Re:Didn't you hear? It's GLOBAL WARMING

[SetupWeasel]

Venus rotates on it's axis once every 243 Earth days. One Venusian day (sunrise to sunrise) is 117 Earth days. It also gets a hell of a lot more radiation than the Earth.

My guess, if it had oceans, the 59 days of straight sunlight would cause them to boil away. With the oceans gone, the surface would bake and scorch sending more gases into the air.

Re:Terraforming

[SetupWeasel]

Too many people get their science from fiction books. Mars has too little gravity and Venus has too long of a day to create an Earth-like planet out of them.

Re:Terraforming

[Jerf]

Heh, you've attracted a lot of replies and nobody's yet hit the right answer.

Propose your choice of terraforming technique. Convert one chemical into another, physically remove the atmosphere, don't care which you choose, really.

Now, compute the energy requirements of your terraforming action.

Then you shall achieve enlightenment.

In short, terraforming Mars for a geologically brief period of time is on the tantalizing edge of feasibility, because a lot of it would involve slightly nudging comets and such to hit Mars. That's a net gravitational energy reduction, and we might be able to manage that. Even so, it might not work; I think it far more likely you'd have to build enclosed settlements, or perhaps even more likely, modify life forms to live on Mars basically as it is, possibly with some resources augmented by the aforementioned comets. But to get from Venus as it is, to a Venus we could walk on, would take an astronomical amount of energy no matter how you slice it. (A rather small "astronomical" amount of energy as such things go, but "astronomical" nonetheless.) It's one of those things that by the time we can do it, we'll probably have better uses for that sort of energy.

By the way, I'm actually-factually talking about energy states, in the technical thermodynamic sense. It's not a matter of waiting for "science" to wave a magic wand; any 'science' that can re-write the laws of thermodynamics is well beyond anything we can speculate about. Conservation laws are about the strongest physics results we have.

Re:Earth's own past is gloomy enough to warn us

[Guppy06]

"To get Venus straightened out for human habitation, you would have flat out get rid of something like 89 parts out of 90 in the Venutian atmosphere,"

Or live above the clouds. Air is a lifting gas in the current Venusian atmosphere.

what's so special about 9.8 m/s^2?

[Quadraginta]

But...why is having roughly 1g of gravity worth the enormous trouble of coping with pressures comparable to those at the bottom of the ocean? And temperatures so high in a corrosive atmosphere that only special and expensive building materials could stand it?

What's wrong with having only a third of a gee or so of gravity? From the point of view of building structures, it's a boon. You have enough gravity to keep stuff in place, and allow conventional building techniques (unlike in orbit), but you can make your trusses and beams slimmer, 'cause they don't have to carry as much weight. You can build out of polystyrene instead of steel, so to speak.

Furthermore, from the pressure point of view, you only have to keep 1 atm of good stuff (breathable air) in, and a few small leaks just mean you need to replenish your air faster, whereas on Venus you need to keep 90 atom of bad stuff (highly toxic air) out, and small leaks mean corrosive poison gas in your breathing air. Ugh.

Not to mention on Mars you can see what you're doing, communicate to orbit with lasers, do a little astronomy, and enjoy the night-time sky, while on Venus you live at the bottom of the worst possible eternal gray pea-soup fog.

Finally, people think there might be life left on Mars, and there's certainly little doubt if we brought life with us it could survive there, while Venus is just completely intolerable to life due to the extreme temperatures.

That's not to say Mars doesn't have problems. The biggest, I suggest, is actually radiation, since Mars has no ozone layer to shield against UV, and no magnetic field to speak of to shield against cosmic rays. You'd not want to stand under the open sky on Mars for very long without good radiation shielding, I think.

wait a minute...

[Quadraginta]

Uh, if the men are from Mars and the women from Venus, how did they end up here on Earth? Possibly each was sent here by whoever else lives on Mars and Venus, respectively.

Apparently we humans are rejects from two worlds...

Re:Earth's own past is gloomy enough to warn us

[Decaff]

As far as the earth goes, the most spectacular environment catastrophe posited is Snowball Earth. Basically, the entire Earth was frozen over with a sheet of ice two miles thick, everything died and there was no oxygen in the atmosphere, for a period of a few hundred million years. It was a rough time, but, ironically, the Earth was saved by an accumulation of 350 times our present level of CO2.

This is almost certainly mistaken, simply because there is no evidence of any extinction - everything didn't die! And unless there was at least some open water to allow gaseous exchange, everything beyond bacteria would probably have died. So, the idea of a totally frozen Earth is not feasible.