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

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

#161

Post by benlumen »

dredmorbius wrote: post #82
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…

I'm not sure how old you are, but a lot has changed , recently, in our knowledge of Earth, its evolution, the solar system, and astronomy. One of the books I had growing up was a Patrick Moore juvenile book on astronomy, probably Seeing Stars (1970). That had a ... pretty good ... description of the state of knowledge at the time, but it was published only about five years after the 4.5 billion year figure for the ag…

Very good point. I'm in my 30s and it's even come a long way since I was a kid.

We didn't know until recently that there were planets orbiting other stars. We suspected that there might be, but we didn't know. The idea that there could be other "earth-like planets" was a hopeful guess.

When the headlines started coming in from Kepler, that was huge. Very exciting and huge.

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

#162

Post by benlumen »

airstrike wrote: post #64
duxup wrote: post #9

Earlier quoted context omitted.

Or maybe someone's asked that about Mars before we did? https://en.m.wikipedia.org/wiki/Silurian_hypothesis That one kinda blows my mind.

Color me mind blown too... That's worth a submission on its own

If you're interested in ancient civilisation speculation, you must read some Graham Hancock. Or watch his interviews with Joe Rogan.

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

#163

Post by junippor »

mannerheim wrote: post #47
GekkePrutser wrote: post #42

Earlier quoted context omitted.

Well we know that it's not inhabited by 'life as we know it' right now at the very least. Because that's just not going to survive there. It'd be a pretty far stretch to come up with something that can.

There is a habitable zone on Venus in the upper atmosphere, so it's not completely out of the question.

That's been thoroughly debunked.

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

#164

Post by jcims »

chairmanwow1 wrote: post #70
cookiengineer wrote: post #68

Earlier quoted context omitted.

What's mindblowing is the search for planet 9...once you start to realize that we are surrounded by thousands of dead solar systems (brown dwarfs that very likely were red dwarfs before) in our immediate neighborhood. Imagine what we could accomplish by mining their resources!

What does this mean? Surrounded by thousands of dead solar systems? Like nearby (dark) stars?

Maybe a tangentially related question, what happens if you form a system very much like our solar system, but the central body never actually ignites and it just remains a dark ball of hydrogen. Would the system still be called a solar system?

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

#165

Post by ncmncm »

montychain wrote: post #134
ncmncm wrote: post #91

Earlier quoted context omitted.

Venus is interesting in so many ways. It did not, so far as we can tell, get blasted by a Mars-sized proto-planet like Earth did, which made the Moon and entirely re-melted Earth, so probably got a good head start on breeding life. But maybe Earth's plate tectonics came from that event, too. AIUI, our Moon is also the reason we are not tidally -almost- locked to the sun, with a permanent equatorial 250 mph wind.

If Venus wasn't hit with something massive why the weird backwards and slow rotation that no other planet has? I feel like even if Venus had Earth-like atmosphere it'll still be hard for life to endure the 121-day long "day" and "night" where temperature would go from like 250°C to -250°C (numbers from the top of my head). Maybe only on poles there would be possible for water to stay in liquid form for long enough so…

Tidal locking is the normal condition for solid planets. Literally all large and all close-in moons, and most of the distant ones, are tidally locked to the parent planet. Pluto and Charon orbit a common center, locked.

Mars and Ceres get a pass being far from the sun and close to Jupiter. Earth gets a pass because it has a massive moon keeping things stirred up. Venus, like Mercury, is not quite locked. As your rotation period gets close to your orbital period, tidal forces are much reduced. Venus could be oscillating around a resonant point, not yet settled into it.

Temperature difference between day and night cannot be large with a 250 mph global wind keeping the atmosphere well-stirred. Under an ocean, life would be further protected from temperature extremes, with high wind performing evaporative cooling on the day side, and surface ice insulating on the night side.

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

#166

Post by matthewfelgate »

Do you think there could be more landings on Venus like the Russian one in the 1960s?

How did the Russian probe even land and take a photo if the surface temperature is enough to melt metal?!

Could you build a small rover to withstand the elements for a few hours?

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

#167

Post by matthewfelgate »

saiya-jin wrote: post #160
protoman3000 wrote: post #156

Earlier quoted context omitted.

4.5 billion years until by the laws of physics a state emerged, where macrobodies consisting of billions of cells, fueled by exploitation of energy from chemical reactions, are using movement devices that employ triggered explosions, and are constructing machines which assemble elements on atomic level in such way to make apparatuses which enable the harvest of information by the laws of logic. I don’t know, people.…

On a single other planet? Very close to 0. But multiply this number by say 400 billion for our galaxy, and maybe additional 150-2000 billion for all the galaxies, and the chances are not that bad. Probably. Plus the idea that life needs to look the same as here on Earth has no logical base - it could be from number of other elements, forms etc. Basic premise is just multiplication, where it goes from there is anybody…

What other elements do you think could form life?

Or are you speculating there could just be such different physics out there we struggle to image what different worlds could be out there.

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

#168

Post by fogihujy »

protoman3000 wrote: post #156
fogihujy wrote: post #149

Earlier quoted context omitted.

> 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 ent…

4.5 billion years until by the laws of physics a state emerged, where macrobodies consisting of billions of cells, fueled by exploitation of energy from chemical reactions, are using movement devices that employ triggered explosions, and are constructing machines which assemble elements on atomic level in such way to make apparatuses which enable the harvest of information by the laws of logic. I don’t know, people.…

It took several billion years for the stars to form, blow up, and fuse the elements into heavier and heavier elements that then formed our galactic neighbourhood, our sun and ultimately Earth. Then it took more than 4.5 billion years for Earth to cool, develop life (or get contaminated, if it was panspermia) and evolve that life to a point where it split the atom and built a planetary communications network that allows ordering pizza from any single point on the planet's surface.

I'm certain this process could have been quicker elsewhere, and there's no reason to believe life could not develop under different circumstances, but it's definitely plausible that extra-terrestrial life -- assuming it exists -- is a rare thing and that any alien civilizations may be few and very, very far in-between. On the other hand, the Universe is a rather big place, and even if there's just a single species who reached space in the entire galaxy, that still leaves us with the possibility of life elsewhere.

"A long time ago, in a galaxy far away" is quite fitting. Other technological civilizations could have developed, risen and fallen and crumbled into dust while life on Earth was nothing more than a bunch of proteins chilling in a hot spring.

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

#169

Post by fogihujy »

matthewfelgate wrote: post #167
saiya-jin wrote: post #160

Earlier quoted context omitted.

On a single other planet? Very close to 0. But multiply this number by say 400 billion for our galaxy, and maybe additional 150-2000 billion for all the galaxies, and the chances are not that bad. Probably. Plus the idea that life needs to look the same as here on Earth has no logical base - it could be from number of other elements, forms etc. Basic premise is just multiplication, where it goes from there is anybody…

What other elements do you think could form life? Or are you speculating there could just be such different physics out there we struggle to image what different worlds could be out there.

Silicon has been suggested as an alternative to carbon as basis for biochemistry. Ammonia-based life has also been suggested (and is also a rather common sci-fi trope).

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

#170

Post by bregma »

thaumasiotes wrote: post #123
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.

I find it kind of weird to have a different word for the same object depending on where it is. As I understand it, Jupiter would be a brown dwarf except that the presence of the Sun disqualifies it.

Jupiter is orders of magnitude too small to be a brown dwarf. The "brown" implies IR radiation generated by gravitic collapse. If Jupiter was massive enough to generate its own radiance it's unlikely Earth would be around to observe it.

The simplistic solar systems and textbooks in grade school are not just misleading when it comes to scale, but they're really really misleading. Few people really comprehend the scale of things in the universe.

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