Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

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

smithsonianmag.com

Post reply on HN
Print view View original

141–150 of 236 posts

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

#141

Post by btach »

cookiengineer wrote: post #88
cambalache wrote: post #79

Earlier quoted context omitted.

I suspected so. But all those objects are in this solar system.Brown dwarfs are sub-stellar bodies.

Touche, you are technically correct. Though some might argue that in the changing nature of fusion reactions and body mass, this sorting of sub-stellar bodies is only true for as long as our star is a red dwarf. Once that's over (thinking in the larger timescale of things) and it becomes a brown dwarf, what then? Wasn't it a solar system at one point in time?

(I'm not an astronomer, my understanding is not absolute, please correct if I'm wrong) I believe our Sun is a type G, yellow dwarf. A red dwarf is usually much smaller, if considering "red dwarf" being a type M, then usually no more than 0.6 solar masses, usually much smaller, and a tiiiiny fraction of the luminosity of Sol. Brown dwarfs are not massive enough to fuse hydrogen, where red dwarfs generally are. According to https://en.wikipedia.org/wiki/Red_dwarf, above 0.25 solar masses, they should evolve into red giants, otherwise will shrink into a white dwarf once hydrogen fusion is ceased. The universe isn't old enough to have any red dwarf of 0.25 solar masses to do so, however as their lifespans are so long.

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

#142

Post by mech422 »

jakelazaroff wrote: post #84
mech422 wrote: post #81

Why is everyone so caught up on the atmospheric pressure of Venus being 90 atmospheres? That's only 3K feet of water, and plenty of stuff lives deeper then that in the oceans - so obviously things can survive the pressure ?

I think the issue is that we can't.

Fair enough. I just see the pressure mentioned often in a context that makes it seem its a problem for 'life'.

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

#143

Post by erispoe »

dimitrios1 wrote: post #131
galaxyLogic wrote: post #99

Earlier quoted context omitted.

> And it could be again... It could. On the other hand Earth could become the next Venus, if climate change runs out of control. No?

No. For one, Earth is much further away. But most importantly, we have no clue if our current carbon levels are any sort of maxima in regards to what the planet can handle. We just have our own little recent industrialized history, and some charts about the past that are, at best, educated guesses. As George Carlin would say, "The planet will shake us off like a bad cold" Climate change is more important for our spec…

The planet might be ok after us, but still might not be able to birth another potentially space faring civilization, dooming earth life to extinction.

Look at how:

- no other earth based space faring civilization has evolved before us.

- other intelligent species do not seem well equipped to do so, as it's hard to evolve tools without hands / prehensile organs (cetaceans), or when your lifespan is short or you're not social (octopuses & squids).

- we used up pretty much all easily accessible fossil fuels for our industrial revolution and they may take hundreds of millions of years to reconstitute, and it's unclear if anyone could evolve an industrial civilization without that kickstart of easy energy.

It's far from certain that if we disappear earth will get another good shot at evolving a space faring civilization before it's too late.

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

#144

Post by f6v »

tsimionescu wrote: post #104
01100011 wrote: post #55

And it could be again... I wish we would plan ahead and try a solar shield at L1. If we cooled the planet sufficiently, the CO2 would solidify and we could get to work processing it. Venus is far more interesting than the dusty little rock we keep probing. Sure, it may take a millenium, but the sooner we start, the sooner we finish.

> Sure, it may take a millenium, but the sooner we start, the sooner we finish. For technology with uncertain results and uncertain resource requirements, this does not follow. It may well be that any effort we spend today is entirely wasted 100 years from now.

But you won’t learn anything unless we try. And having some shared goal for the humanity could be life changing.

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

#145

Post by thaumasiotes »

brnt wrote: post #136
thaumasiotes wrote: post #125

Earlier quoted context omitted.

> So when it says Venus was hospitable for billions of years, let’s say 2 billion years, that amounts already to 14% of all there was and will ever be. Huh? You're saying the universe is about to end?

I guess he meant that Venus' habitable days will never return.

That would be 14% of all there ever has been.

In order for it to also be 14% of all there ever will be, the future would need to have zero duration.

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

#146

Post by f6v »

chii wrote: post #65
rtx wrote: post #58

Earlier quoted context omitted.

Or send some microbes which convert it into oxygen. You are right Mars doesn't have enough resources to support anything.

that's an interesting proposition. If terraforming is really about engineering the right microbes to slowly (over several millenia even?) the atmosphere to habitable for humans, do we currently have the technology to actually accomplish it? Or is it still too advanced form of engineering?

I think biology-wise it’s a question of money. We might not be able to engineer such microbes just right now, but we could if we had more resources dedicated to it.

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

#147

Post by jonmc12 »

ramraj07 wrote: post #74
whoisthemachine wrote: post #19

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...

My working hypothesis is that the galaxy (if not at least the solar system) is teeming with rocks containing Protozoa that are ready to colonise any planet with the right conditions (in a matter of thousands of years after the conditions are right) the moment they are ready. Perfectly explains everything we see and honestly would not be surprising at all. We need to start developing meaningful working hypotheses and…

"The Hot Spring Hypothesis for an Origin of Life" - https://www.liebertpub.com/doi/10.1089/ast.2019.2045

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

#148

Post by junippor »

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.

Venus is almost guaranteed to be currently uninhabited because that planet has almost no hydrogen in it.

Almost all "complex chemistry" that we know of involves hydrogen.

So to those people who say "but but but that's just life as we know it". No, it's also chemistry as we know it.

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

#149

Post by fogihujy »

brnt wrote: post #135
protoman3000 wrote: post #117

I recently learned about the estimated age of the universe. It’s only 13.8 billion years. So when it says Venus was hospitable for billions of years, let’s say 2 billion years, that amounts already to 14% of all there was and will ever be. What marvel did happen in this time?

We've had life for about 500 million years on earth. Maybe a billion as single celled life forms. I used to worry that in 5 billion years it'll all be over on account of the sun entering a new phase and engulfing Earth. But it appears in about 800 million years photosynthesis will no longer be possible [1], which puts an even closer limit on our time here. There's a good chance some will get off this rock, but many w…

> We've had life for about 500 million years on earth.

Somewhere from 3.5 to up to 4.5 billion years: https://en.wikipedia.org/wiki/Earliest_known_life_forms

You're right though; our time here is very short and if we want to ensure survival of Earth-based life then we need to start considering panspermia, first to other planets in our own planetary system (assuming they don't have native life already -- we're not entirely sure about that yet), and then to other systems.

If we can colonize a world around a red dwarf, preferably a young one, then Earth-based life should be set for billions of years into the future.

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

#150

Post by tsimionescu »

flawi wrote: post #119
tsimionescu wrote: post #106

Earlier quoted context omitted.

Terraforming refers to 'turning another planet into a second terra'. Marsforming would be 'turning the planet into a second Mars', which wouldn't be particularly useful, since we can't live on Mars anyway.

The joke they're making is that since we are in the process of turning the Earth into a second Mars, we should be calling what we are doing now marsforming.

Whoosh... Sorry
Post reply on HN