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Earth was born dry until a cosmic collision made it a blue planet

sciencedaily.com

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Re: Earth was born dry until a cosmic collision made it a blue planet

#21

Post by addaon »

oceanplexian wrote: post #14
lukan wrote: post #8

Earlier quoted context omitted.

Having some water and having lots of water is a slight difference. The most arid dessert on earth is a jungle compared to Mars. (Also Mars could have been also hit.)

Except Titan likely has more water on it than Earth. Therefore unless we’re a fluke of a solar system planetary bodies with water on them should be extremely common.

Titan is outside the frost line. There’s no question that there’s a huge amount of water in solar systems, the question is if there’s a consistent transport system (comets, in this case) that moves it inside the frost line to where liquid water can, given an atmosphere and gravity, exist in conditions that match our familiar conditions for life.

Re: Earth was born dry until a cosmic collision made it a blue planet

#22

Post by [deleted] »

oceanplexian wrote: post #14
lukan wrote: post #8

Earlier quoted context omitted.

Having some water and having lots of water is a slight difference. The most arid dessert on earth is a jungle compared to Mars. (Also Mars could have been also hit.)

Except Titan likely has more water on it than Earth. Therefore unless we’re a fluke of a solar system planetary bodies with water on them should be extremely common.

[deleted]

Re: Earth was born dry until a cosmic collision made it a blue planet

#23

Post by lukan »

oceanplexian wrote: post #14
lukan wrote: post #8

Earlier quoted context omitted.

Having some water and having lots of water is a slight difference. The most arid dessert on earth is a jungle compared to Mars. (Also Mars could have been also hit.)

Except Titan likely has more water on it than Earth. Therefore unless we’re a fluke of a solar system planetary bodies with water on them should be extremely common.

Titan is interesting, but much further away from the sun, so different conditions. We want earthlike conditions, life that can sustain on anything else, is just hypothesis so far.

(As is the claim from the article)

Re: Earth was born dry until a cosmic collision made it a blue planet

#24

Post by joshuahedlund »

xbmcuser wrote: post #18
shireboy wrote: post #4

This could mean in the Drake equation ne -number of planets capable of life- is very small. A planet has to be hit with a comet big enough to deliver a large amount of water but not so big or fast to destroy it. And be in the Goldilocks zone of the star. Also the mass of the planet would play a part - gravity of more massive ones would be more likely to capture a comet. But again, too massive and I could see that ham…

Your assumption we need water for life to exist is in my opinion wrong. We only know Earth so assume that is what is needed for life to exist.

There is a hard limit on the number of atomic elements, and an even smaller limit on the number of soluble compounds that facilitate chemical reactions, and water is demonstrably both the best and the most common in the universe.

So while it may be possible for life to exist without water, any alternatives should be reasonably expected to be even more rare than water-based life

Re: Earth was born dry until a cosmic collision made it a blue planet

#25

Post by quesera »

greenchair wrote: post #13

[flagged]

> but please trust the science!

If you're going to disparage the best idea humanity has ever had, you are required to commit and explicitly suggest your preferred alternative.

Your attempt at clever irony is a negative contribution to the world.

Re: Earth was born dry until a cosmic collision made it a blue planet

#27

Post by munchler »

oceanplexian wrote: post #14
lukan wrote: post #8

Earlier quoted context omitted.

Having some water and having lots of water is a slight difference. The most arid dessert on earth is a jungle compared to Mars. (Also Mars could have been also hit.)

Except Titan likely has more water on it than Earth. Therefore unless we’re a fluke of a solar system planetary bodies with water on them should be extremely common.

The article mentions that the inner planets were initially too hot to retain water, but presumably Titan didn’t have that problem, being much farther from the sun.

Re: Earth was born dry until a cosmic collision made it a blue planet

#29

Post by WillAdams »

stared wrote: post #6

Imagine this sci-fi plot twist: Aliens make live habitable by hitting proto-Earth with a planet, so life can sprout there. They calibrated it such a way that angular size of Moon is the same as of Sun.

That is pretty much the premise of Hal Clement's short story "Halo", which I read in _Space Lash_ (originally published as _Small Changes_), but now available in:

https://www.goodreads.com/book/show/939760.Music_of_Many_Sph...

I recommend folks read it in reverse chronological order, starting at the back, then working to the front and bailing when things get too quaint/old-school/golden-age.

Re: Earth was born dry until a cosmic collision made it a blue planet

#30

Post by aitchnyu »

stared wrote: post #6

Imagine this sci-fi plot twist: Aliens make live habitable by hitting proto-Earth with a planet, so life can sprout there. They calibrated it such a way that angular size of Moon is the same as of Sun.

What if they miscalculated and intelligence evolved when the moon drifted too far to cover the sun?
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