First Exo-Planet with water!

EARTH TO WATERWORLD:

"Prepare to be squished under the almighty heel of Earth's jack fins!!"
 
Almost everyday now a wild ass fantasy science fiction story of my youth hits the headlines as something brand new in the sight of Man.

You want to know about this world? Read Mission of Gravity the science fiction novel by American writer Hal Clement. The novel was serialized in Astounding Science Fiction magazine in April–July 1953. (per our friends at Wiki -- https://en.wikipedia.org/wiki/Mission_of_Gravity )

:th:
 
BillC said:
If it's twice the diameter, 8 times the mass, and (big if) the same average density of earth, then the surface gravity would be twice that of earth. If gravitational compression has reduced its radius and increased its density, then the surface gravity would be higher.
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I looked at the paper, and the density they derived was ~ 3.3 g/cm3. Earth's is ~ 5.5 g/cm3. My quick calcs showed a surface gravity of ~ 1.5 x Earth's. Not so bad if you evolved there.
 
Cheetah said:
I wonder what life would look like if it evolved there.
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Maybe like an entire world of Amazon Warrior Mermaids wearing svelte form fitting Neoprene™ ready to enslave all Earth men for the purpose of copulating with them!
 
Cheetah said:
I think if there is complex life there is a lot you
Certain things just work better and it's likely evolution and chemistry will solve similar problems in similar ways.
I think it's quite likely alien 'fish' in similar niches to earth fish might look superficially very similar. Having a streamlined body with a flat tail on one end, to propel itself forward, and a mouth on the other end is just the best design.
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Covergent evolution, I agree. Life finds a way, and that way seems to be whatever is the easiest solution.

When I was a child I was absolutely fascinated (and still am) by how strikingly similar in form and function many species of ichthyosaurs and modern cetaceans are despite how far removed they are from one another genetically.
 
They detected water vapour in the atmosphere. And the planet is in the habitable zone in which liquid water can exist. But water is a greenhouse gas, and there could be other greenhouse gases in it's atmosphere. Venus has water vapour in it's atmosphere (0.002%) and is in the habitable zone, but there's certainly no liquid water on Venus' surface.

I'm not suggesting that there isn't liquid water on this planet, only that because we don't know the full composition and density of it's atmosphere it's premature to conclude that it has liquid water. Still, this is an exciting finding!
 
Cheetah said:
I think if there is complex life there is a lot you could speculate about, for example.

Carbon based.
Probably uses the same 20 amino acids as here if not all of them.
Something very similar to DNA & RNA if not exactly.
Made of cells.

If there are free swimming animals:
Bodyplan basically a tube with a mouth on one end and a pooper on the other.
Bilaterally symmetrical.
There is a lot more stuff like this.


Certain things just work better and it's likely evolution and chemistry will solve similar problems in similar ways.
I think it's quite likely alien 'fish' in similar niches to earth fish might look superficially very similar. Having a streamlined body with a flat tail on one end, to propel itself forward, and a mouth on the other end is just the best design.
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Basically, I agree with your thinking here.

Life is fundamentally just chemistry; complex chemistry for sure but chemistry nonetheless. Also, evolution and environment are inter-relational - if the environment of this planet was similar to that of the Earth at the equivalent time after its formation, then it seems logical to me that the chemical reaction known as abiogenesis might result in similar chemical reactions. Life on such a planet, at least at the microscopic level could be very similar to that on the Earth.
 
If it has oceans and temperatures comparable to earth, the higher mass might not be a problem for fish-like creatures in the oceans. If there is also land, there could be land-based creatures adapted to the higher G.

Still hoping we find something closer to earth, but 111 light years is relatively close, on the galactic scale. The radius of the Milky Way is about 50,000 light years, so it's in our neighborhood, but not next door.
 
Gord_in_Toronto said:
Almost everyday now a wild ass fantasy science fiction story of my youth hits the headlines as something brand new in the sight of Man.

You want to know about this world? Read Mission of Gravity the science fiction novel by American writer Hal Clement. The novel was serialized in Astounding Science Fiction magazine in April–July 1953. (per our friends at Wiki -- https://en.wikipedia.org/wiki/Mission_of_Gravity )

:th:
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The story is set on a highly oblate planet named Mesklin, which has surface gravity that varies between 700 g at the poles and 3 g at the equator.
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That doesn't seem possible to me. There's a reason why the larger the planet, the closer to a sphere it becomes.
 
sphenisc said:
Saturn is more oblate than Earth.
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Saturn is like that because it spins rapidly. Once an object gets big enough (and that size is smaller than the moon) it is round and the main deformity would be due to spin. A planet going around the sun as close as this one would probably be tidally locked. If there was life on the planet it would be confined to a ring where the sun was low on the horizon.
 
rjh01 said:
Saturn is like that because it spins rapidly. Once an object gets big enough (and that size is smaller than the moon) it is round and the main deformity would be due to spin. A planet going around the sun as close as this one would probably be tidally locked. If there was life on the planet it would be confined to a ring where the sun was low on the horizon.
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I agree with you, though there was this in the article linked in the OP:

The alien planet may therefore be "tidally locked" to its star, always showing the red dwarf the same face, just as Earth's moon only ever shows its near side to us. But this would not be a dealbreaker for the existence of life.

"A tidally locked planet can also be habitable," said Ingo Waldmann of CSED, a member of Tsiaras' team. Modeling studies suggest that "the energy from the dayside can be quite equally distributed to the nightside," Waldmann added.
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Roboramma said:
I agree with you, though there was this in the article linked in the OP:
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I wonder if plants could grow without sunlight in the dark side? Come to think of it plant life would be a struggle if the sun is low in the sky and emits mainly in the infrared. Not much energy would get to the ground.
 
Craig B said:
What does the life that evolved on earth "look like"? It varies a bit. There are petunias and there are kangaroos. The life on the other planet may look something like these.

But I would love to see alien living organisms. To my mind, whether or not life exists elsewhere is by far the most interesting outstanding mystery.
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Oh no, not again.
 
PhantomWolf said:
They looked at the star light as the planet passed in front of the star and noted what absorption was occurring, because water and other chemicals absorb certain parts of the spectrum. Water has a very distinctive absorption in the IR part of the spectrum, so by looking at the light before and comparing it to that as the planet passes, if you see the absorption of those frequencies in the IR part of the spectrum, then you can say that the starlight had to pass through water, and the only source of that water is the planet.
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The fact that they can do this is simply amazing.

Suppose that the planet is marginally Earth-like. Earth is a big rock, surrounded by a little envelope of gas, a small portion of which is water. You can't take a picture of the planet, but as the planet passes in front of the star, the light from the star gets a little bit dimmer. How much dimmer depends on the size of the rock. So, they can measure that change in brightness, and figure that if the star is getting dimmer at periodic intervals, there must be a planet passing in front of it. Now, to detect the water, they have to say that specific components of the starlight are dimmed by a small fraction of the size of the gas envelope surrounding the rock, which is partially transparent to some light, but less transparent to other light.

And from that they can figure out that there's an atmosphere with water.

It's pretty amazing stuff, really.

I must admit that as I see reports of really strange configurations of planets being discovered, especially if there are really huge planets with very short orbits, I have to wonder if there might be some other explanations for the periodicity of light shifts, and I wonder just how clear the light shifts really are. If you were to plot out successive light measurements on a graph, would it really be obvious that there were periodic changes in intensity, or is this the sort of thing that can only be sorted out by taking Fourier transforms and picking out the relevant frequencies, which are too faint to be noticed by humans looking at a chart?

I'm not expecting answers to that, by the way. I assume that these guys check each others' math and that regardless of how they are doing it, it's pretty clear that there are planets. I'm just marveling that it's possible.
 
Meadmaker said:
I must admit that as I see reports of really strange configurations of planets being discovered, especially if there are really huge planets with very short orbits, I have to wonder if there might be some other explanations for the periodicity of light shifts, and I wonder just how clear the light shifts really are. If you were to plot out successive light measurements on a graph, would it really be obvious that there were periodic changes in intensity, or is this the sort of thing that can only be sorted out by taking Fourier transforms and picking out the relevant frequencies, which are too faint to be noticed by humans looking at a chart?

I'm not expecting answers to that, by the way. I assume that these guys check each others' math and that regardless of how they are doing it, it's pretty clear that there are planets. I'm just marveling that it's possible.
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Here is some information about Kepler 37, which has at least four planets orbiting it. Light curves for three are shown.

https://www.researchgate.net/figure...7-The-transit-model-fit-to-the_fig1_235681889

Kepler 37b is not very obvious without the resultant curve shown, but 37c and 37d are very obvious.


NOTE: Don't be confused by the notations - the chart marked "a" is 37b, "b" is 37c, and "c" is 37d.
 
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