Exoplanet K2-18b

Cypress said:
Good then, I didn't see an estimate of it's density.

Definitely higher gravity than Earth either way. I don't know if 5g or 8g neccessarily excluded the possibility of life.
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Can you calculate out the number of Gs by knowing what the pounds per square inch is? I'm thinking of creatures who evolved to live in our seas that exist under tremendous pressure. IOW are Gs and pounds-per-square-inch pressure at all equivalent?
 
ThatOwlWoman said:
Can you calculate out the number of Gs by knowing what the pounds per square inch is? I'm thinking of creatures who evolved to live in our seas that exist under tremendous pressure. IOW are Gs and pounds-per-square-inch pressure at all equivalent?
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g is the acceleration due to gravity (usually in m/s^2). Not the same thing as pressure.

The gravity on the planet is a function of the mass of a thing on the surface * the mass of the planet /square of the distance between the two masses (Further multiplied by a constant). It is a function of MASS and wouldn't have a term related to area (eg "square inch")


(EDITTED: TO CORRECT ERROR.)
 
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NiftyNiblick said:
Excuse me for changing the subject, Oom,
but you seem to know the mods and administrators much better than I do.

Have CFM [Banjo Fuck],
Frank Apisa,
and Asshat Zombie [or whatever Fredo last called himself]
all passed away?

I miss at least one of those three,
but it appears that they've all died.
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CFM is permabanned
Frank's taking a forum break
Asshat changed his name to something else.
 
ThatOwlWoman said:
Maybe this way keeps the less-mature astronomers from jumping up and down and screaming about naming them after gods, or sci-fi planets, or the like.
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Naming them after famous drag queens would produce an interesting reaction from the Trumpers. Throw in J. Edger Hoover just for fun. :thup:

Hoover-JEdgar-Cartoon-Crossdressing-01.jpg
 
ThatOwlWoman said:
Can you calculate out the number of Gs by knowing what the pounds per square inch is? I'm thinking of creatures who evolved to live in our seas that exist under tremendous pressure. IOW are Gs and pounds-per-square-inch pressure at all equivalent?
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Gravity is a force of acceleration, not a type of pressure per se.

The acceleration due to gravity should be roughly uniform across the entire surface of a planet and affect all animals the same, leaving aside considerations such as air friction and buoyancy.

You make a good point that certain animals in the ocean are adapted to extreme hydrostatic pressures.



I don't know enough to say whether or not 8 Gs would render a planet inhospitable to life. My first gut reaction was there wouldn't be any reason life could not evolve under an 8G gravitational field.
 
Cypress said:
Gravity is a force of acceleration, not a type of pressure per se.

The acceleration due to gravity should be roughly uniform across the entire surface of a planet and affect all animals the same, leaving aside considerations such as air friction and buoyancy.

You make a good point that certain animals in the ocean are adapted to extreme hydrostatic pressures.



I don't know enough to say whether or not 8 Gs would render a planet inhospitable to life. My first gut reaction was there wouldn't be any reason life could not evolve under an 8G gravitational field.
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Thanks for learning me something. ;)

I suspect that it could indeed evolve to cope with its environment. That is what our experience with life on this planet has shown.

It would make a great sci-fi story to speculate on just what those lifeforms would be like.
 
ThatOwlWoman said:
Thanks for learning me something. ;)

I suspect that it could indeed evolve to cope with its environment. That is what our experience with life on this planet has shown.

It would make a great sci-fi story to speculate on just what those lifeforms would be like.
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I think you're right.

A giraffe couldn't live in an 8g gravitational field.

But who says microbes, or exotic forms of multicellular life can't?
 
ThatOwlWoman said:
Thanks for learning me something. ;)

I suspect that it could indeed evolve to cope with its environment. That is what our experience with life on this planet has shown.

It would make a great sci-fi story to speculate on just what those lifeforms would be like.
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Something low to the ground; snakes and turtles.
 
Doc Dutch said:
Naming them after famous drag queens would produce an interesting reaction from the Trumpers. Throw in J. Edger Hoover just for fun. :thup:

Hoover-JEdgar-Cartoon-Crossdressing-01.jpg
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Legend has it that there are 300 million dieties in the Hindu pantheon, so we would never run out of names for planets.
 
Cypress said:
It looks to me like the Earth is rotating the wrong direction.

I think silicon based life is wishful thinking. It just isn't nearly as versatile as carbon.
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Correct. The Sun is rising in the West.

As for alternative life form chemistry, even this Wiki link quickly goes over my head: https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry
The element silicon has been much discussed as a hypothetical alternative to carbon. Silicon is in the same group as carbon on the periodic table and, like carbon, it is tetravalent. Hypothetical alternatives to water include ammonia, which, like water, is a polar molecule, and cosmically abundant; and non-polar hydrocarbon solvents such as methane and ethane, which are known to exist in liquid form on the surface of Titan.
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What I do garner from it is that such lifeforms could exist in environments where carbon lifeforms would be severely hampered. High gravity might be one, although I doubt 8Gs is high enough to stop carbon lifeforms.
 
Doc Dutch said:
Correct. The Sun is rising in the West.

As for alternative life form chemistry, even this Wiki link quickly goes over my head: https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry

What I do garner from it is that such lifeforms could exist in environments where carbon lifeforms would be severely hampered. High gravity might be one, although I doubt 8Gs is high enough to stop carbon lifeforms.
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It's fun to speculate about alien life!

Silicon being tetravalent (four electrons in it's valence shell, allowing for up to four chemical bonds) isn't in itself sufficient to say Si is an adequate analog for C in biochemistry. Si is a much larger atom than C, and that means, in part , C tends to make stronger bonds with it's outer valence shell electrons. Carbon is vastly more versatile than silicon in the types of bonds and amount of different molecules it forms

I never thought liquid ammonia was a feasible substitute as a solvent for water. NH[SUB]3[/SUB] is only liquid at temperatures somewhere below negative 270 F, and at those temperatures I can't see chemical kinetics being sufficient for biological chemical reactions.
 
Doc Dutch said:
Theoretically, silicon-based lifeforms could exist. They'd be like the Horta on Star Trek and well suited to a high gravity environment. I don't know if they'd be throwing off oxygen or DMS.

R.e228a0e6c54c21271cd6fa0b7b1ab772
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Thanks, couldn't for the life of me recall what those aliens were called in that episodes.
 
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