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Will a planet facing its star always support life ?

by vrmuth
Tags: facing, life, planet, star, support
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vrmuth
#1
May23-14, 07:45 AM
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I think this is the right forum to start this thread, if not i am sorry please somebody change it .
suppose a planet is in the right distance from its star and it is rocky , has water and atmosphere but the only thing is it's not rotating itself , i mean it's always facing it's star , then will it support life to evolve ?
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Borek
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May23-14, 07:53 AM
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This is definitely not social sciences, I am moving the thread.

I doubt we know enough about abiogenesis to be able to answer this kind of question.

I recall reading theories postulating tides are an important factor (that is, presence of a shore that is washed twice a day). I don't think you can have serious tides on a tidally locked planet.
adjacent
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May23-14, 07:56 AM
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Quote Quote by vrmuth View Post
atmosphere
What kind of atmosphere?
There have to be the right amount of gases to support life.

Borek
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May23-14, 11:06 AM
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Will a planet facing its star always support life ?

Quote Quote by adjacent View Post
What kind of atmosphere?
There have to be the right amount of gases to support life.
We are not talking about supporting life, but about starting one.
jim mcnamara
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May23-14, 12:02 PM
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Planets like that (Example: mercury) have very different environmental properties on the sun-facing side versus the out-facing side, specifically solar energy input.

Nobody knows definitely, but the possibilities for abiogenesis would be very different than what were on planet Earth 4+ billion years ago. Atmospheric differences would be large from side to side. Water and some atmospheric gases would be liquified or frozen on the dark side.

Here is a paper modeling atmospheres on earthlike planets with synchronous orbits:
http://crack.seismo.unr.edu/ftp/pub/gillett/joshi.pdf

They claim a 'habitable' atmosphere can exist on part of the surface, as I read it.
Bandersnatch
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May23-14, 12:25 PM
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Quote Quote by jim mcnamara View Post
Here is a paper modeling atmospheres on earthlike planets with synchronous orbits:
http://crack.seismo.unr.edu/ftp/pub/gillett/joshi.pdf

They claim a 'habitable' atmosphere can exist on part of the surface, as I read it.
That paper is almost 20 years old. Check out this one from 2013:
Stabilizing Cloud Feedback Dramatically Expands the Habitable Zone of Tidally Locked Planets
Their model shows that tide-locked planets may be even advantageous from the habitability range standpoint.
Higher insolation produces stronger substellar convection and therefore higher albedo, making this phenomenon a stabilizing climate feedback. Substellar clouds also effectively block outgoing radiation from the surface, reducing or even completely reversing the thermal emission contrast between dayside and nightside.
bobze
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May23-14, 12:37 PM
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Quote Quote by vrmuth View Post
I think this is the right forum to start this thread, if not i am sorry please somebody change it .
suppose a planet is in the right distance from its star and it is rocky , has water and atmosphere but the only thing is it's not rotating itself , i mean it's always facing it's star , then will it support life to evolve ?
Since we have no real examples we cannot say for sure. I've thought about this before. I don't see why it would be impossible given the correct conditions. I think it would depend on lots of factors, such as atmosphere composition, distance to star, etc.

Maybe the twilight zones on either pole would be good places for life to exist on such a planet of extremes.
vrmuth
#8
May26-14, 05:25 AM
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Quote Quote by Borek View Post
We are not talking about supporting life, but about starting one.
yes .
Quote Quote by adjacent View Post
What kind of atmosphere?
There have to be the right amount of gases to support life.
I mean it has all the things that are essential for life on earth , the only thing is that the planet is not rotating itself .
adjacent
#9
May26-14, 05:43 AM
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Quote Quote by Borek View Post
We are not talking about supporting life, but about starting one.
So what? Do you mean that life can start even when the atmosphere is say,100% ##SO_2##?
Borek
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May26-14, 05:57 AM
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Quote Quote by adjacent View Post
So what? Do you mean that life can start even when the atmosphere is say,100% ##SO_2##?
I don't know, do you?

Besides, it is not what the question is about, which you apparently missed. See the latest post by OP.
Torbjorn_L
#11
Jul20-14, 12:11 PM
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Quote Quote by vrmuth View Post
suppose a planet is in the right distance from its star and it is rocky , has water and atmosphere but the only thing is it's not rotating itself , i mean it's always facing it's star , then will it support life to evolve ?
Likely, yes.

What on them would prohibit life? The presence of tidal lock changes the HZ boundaries a bit as well as it changes the ideal size and starting atmospheres for life emergence. E.g. it induces a runaway greenhouse easier so the HZ edges moves, it makes the atmosphere more convective so you may want to go for more massive and more dense atmospheres to efficiently move heat without super-convection. (E.g. on the nearly tidal locked Venus the surface winds are still lenient enough that you may stand up.)

If such effects change the number of potentially habitable planets much is unknown. In a linear estimate tidal lock wouldn't mean much for habitability.

Quote Quote by Borek View Post
I recall reading theories postulating tides are an important factor (that is, presence of a shore that is washed twice a day). I don't think you can have serious tides on a tidally locked planet.
Not serious tides, but the tidal bulge would move around a bit, compare with Moon as seen by LRO.

Tides may or may not have advanced land life, they do allow for more nutrients but also a harsher strand zone. The time to invade land from the tidal zone was short, so the effect is likely minute either way.

There are a few chemical cycles that are proposed to augment emergence of life, e.g. abiotic polypeptide linking, that are based on tides. But today they seem unnecessary since we have plenty of chemical pathways. So their importance are open.

Quote Quote by jim mcnamara View Post
Nobody knows definitely, but the possibilities for abiogenesis would be very different than what were on planet Earth 4+ billion years ago. Atmospheric differences would be large from side to side.
The question was about habitable planets in general though.


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