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Venus could have been habitable for billions of years (2019)

smithsonianmag.com

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Re: Venus could have been habitable for billions of years (2019)

#11

Post by elihu »

xwdv wrote: post #2

That’s enough time for a civilization to have been born, lived, and died. Unfortunately there’s probably no way to find evidence of their existence by now it seems? Some day they may say Earth could have been habitable for billions of years.

If there was a civilization on Venus anything like our current civilization on Earth, I expect there would still be evidence of it, even in that hostile environment. If nothing else, there'd probably be unnatural formations of ground from mines or freeway construction or whatever.

Re: Venus could have been habitable for billions of years (2019)

#12

Post by zabzonk »

andrewflnr wrote: post #10
lumost wrote: post #5

Earlier quoted context omitted.

It's a bit extreme to make that leap. Multi-cellular life only emerged on Earth ~600 million years ago, after the supposed habitable period of Venus. It's unclear for how much of the 4.6 billion year history of the earth multicellular life could have emerged and just how improbable the evolution of multicellular life is. There are certainly events such as the symbiosis of mitochondria which appear to have occurred on…

Complex multicellularity and cellular endosymbiosis have both occurred multiple times on earth. Those aren't the hard part. Further, there's no reason to assume that having mitochondria (rather than just having an intrinsically more efficient metabolism) is optimal, much less necessary, rather than a path-dependent accident of Earth eukaryotes.

> both occurred multiple times on earth

Citation?

Re: Venus could have been habitable for billions of years (2019)

#13

Post by elihu »

I wonder if one were to install a solar shade in front of Venus to block all light from the sun, how long would it take to cool to "normal" temperatures?

The Earth cools pretty fast between day/night and seasonally, but Venus has a much thicker atmosphere, almost more like an ocean. And then the ground itself wouldn't cool instantly either. That's a lot of thermal mass.

Re: Venus could have been habitable for billions of years (2019)

#14

Post by DoreenMichele »

duxup wrote: post #7

Growing up I absorbed all the space stuff I could find. But it wasn't until recently that I realized that the solar system didn't just form into some static natural state where it largely didn't change until say the sun was finished with it's lifespan. Rather it evolves, changes, planets are habitable, then not, moons are formed and break up, even frozen planets are geologically active and are changing, Saturn's ring…

Not sure how I didn't pick up on that.

The sheer scale of it makes it hard to perceive, so probably you aren't the only one and probably a lot of the literature has similar blind spots which implicitly signals "this isn't happening" and we pick up on that and it gets implicitly repeated until it's hard to give any kind of push back in our own minds.

Re: Venus could have been habitable for billions of years (2019)

#15

Post by vmception »

zabzonk wrote: post #6

It could have been habitable, but probably wasn't - if it had been, life there would almost certainly have resisted the greenhouse effect, as it probably will on Earth, though almost certainly not soon enough to save us monkeys.

We don't know if it wasn't inhabited and we don't know if it is currently uninhabited.

Re: Venus could have been habitable for billions of years (2019)

#16

Post by vmception »

zabzonk wrote: post #12
andrewflnr wrote: post #10

Earlier quoted context omitted.

Complex multicellularity and cellular endosymbiosis have both occurred multiple times on earth. Those aren't the hard part. Further, there's no reason to assume that having mitochondria (rather than just having an intrinsically more efficient metabolism) is optimal, much less necessary, rather than a path-dependent accident of Earth eukaryotes.

> both occurred multiple times on earth Citation?

Any Biology & Ecology 101 book from the last decade and a half.

Re: Venus could have been habitable for billions of years (2019)

#17

Post by zabzonk »

vmception wrote: post #15
zabzonk wrote: post #6

It could have been habitable, but probably wasn't - if it had been, life there would almost certainly have resisted the greenhouse effect, as it probably will on Earth, though almost certainly not soon enough to save us monkeys.

We don't know if it wasn't inhabited and we don't know if it is currently uninhabited.

Of course, which is why I said "probably".

Re: Venus could have been habitable for billions of years (2019)

#19

Post by whoisthemachine »

It's interesting that multi-cellular life developed on Earth around the same time these scientists hypothesize Venus would have become uninhabitable. Unrelated... still, fun to think about.

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

Re: Venus could have been habitable for billions of years (2019)

#20

Post by mc32 »

duxup wrote: post #7

Growing up I absorbed all the space stuff I could find. But it wasn't until recently that I realized that the solar system didn't just form into some static natural state where it largely didn't change until say the sun was finished with it's lifespan. Rather it evolves, changes, planets are habitable, then not, moons are formed and break up, even frozen planets are geologically active and are changing, Saturn's ring…

Until we started sending probes out there, we didn't know much about those bodies. Tectonic plates on Earth were not confirmed till the '60s or so, so... it's not surprising.
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