Life Without a Sun

[Kmurphy22]

I have lately been pondering the possibility of life existing on a planet that does not have a sun. So far the little research I've done has suggested that the core would have to be hot enough, coupled with a much thicker atmosphere in order to hold an appropriate temperature to sustain life. Other than that I'm pretty stuck.

 

What would be the parameters of such a core and/or atmosphere?

 

Also, the biggest mystery to me is how plant life would be able to thrive, or if life could possibly thrive without plants at all (probably a topic for a different thread).

 

Any information would be much appreciated. Thank you!

Edited June 29, 2016 by Kmurphy22

[Daecon]

I can't copy/paste text on my Vita, but NASA's website has an interesting article from 2001 on creatures discovered living by a hydrothermal vent, if you do a Google (or whichever) search for NASA and hydrothermal vent life, the title of the piece is "Life as we didn't know it".

[ajb]

The term you should 'google' (if you have not already) is 'extremophiles' - these are organisms here on the Earth that live in environments that were thought not to be able to support life. Understanding these orgamisms may give us some clues as to what is possible eleswhere in the Univrerse.

[Moontanman]

A recent NASA video asserted that a somewhat bigger than earth planet with a thick hydrogen atmosphere could maintain a surface temp high enough to allow liquid water oceans even drifting among the stars with no sun. It would be a planet type we don't see in our solar system... maybe 8 to 10 earth masses... twice the diameter of the earth. Radioactive decay would keep the core hot and the heat would diffuse to the surface. A large moon would also help create heat energy. surface pressure of 100 bar or so. chemical energy like the black smokers hydrothermal vents mentioned above.

 

It would be a very strange place. I wonder if the hydrogen atmosphere could also be used as an energy source. Photosynthesis breaks apart water to get hydrogen, possibly that reaction wouldn't be necessary to get hydrogen on such a planet.

[CharonY]

Photosynthesis is a somewhat later development. The point is not really the acquisition of hydrogen per se, but essentially liberation of electrons (or reducing equivalents) for energy conservation. Chemolithotrophy basically covers these range of oxidative processes. Of note, many, but not all chemolithotrophs are also extremophiles.

 

Forgot to add: because of this process, some bacteria (hydrogen oxidizers) can utilize hydrogen as an electron donor.

Edited July 6, 2016 by CharonY

[J.C.MacSwell]

A recent NASA video asserted that a somewhat bigger than earth planet with a thick hydrogen atmosphere could maintain a surface temp high enough to allow liquid water oceans even drifting among the stars with no sun. It would be a planet type we don't see in our solar system... maybe 8 to 10 earth masses... twice the diameter of the earth. Radioactive decay would keep the core hot and the heat would diffuse to the surface. A large moon would also help create heat energy. surface pressure of 100 bar or so. chemical energy like the black smokers hydrothermal vents mentioned above.

 

It would be a very strange place. I wonder if the hydrogen atmosphere could also be used as an energy source. Photosynthesis breaks apart water to get hydrogen, possibly that reaction wouldn't be necessary to get hydrogen on such a planet.

Sounds like a lot more efficient scheme than having a great fusion furnace 93 million miles away and relying on a very small percentage of the energy given off...

 

Another might be having a radioactive moon glowing with the equivalent heating. Might last long enough to sustain life for a while, though I suspect not much time for higher life to evolve.

Edited July 18, 2016 by J.C.MacSwell

[Sensei]

Tidal heating of moon orbiting around lonely planet without star, could produce enough heat and temperature for life to appear or at least sustain existing one.

https://en.wikipedia.org/wiki/Tidal_heating_of_Io

Living organisms requiring visible light, like plants, would be not possible, without light obviously.

Edited August 11, 2016 by Sensei

[tomwalker154]

I heard somewhere that there is no life for us in the time of 3 or 4 months from the Sun disappears

[billiards]

The term you should 'google' (if you have not already) is 'extremophiles' - these are organisms here on the Earth that live in environments that were thought not to be able to support life. Understanding these orgamisms may give us some clues as to what is possible eleswhere in the Univrerse.

+1

 

Also https://en.wikipedia.org/wiki/Chemotroph

[freekundli]

I can't imagine life without sun.

[Sensei]

I can't imagine life without sun.

You have not been in Russia, Alaska, North Canada, Sweden, Finland, Norway or North/South Pole.

They have day/night taking up to ~half year.

https://en.wikipedia.org/wiki/Polar_night

Instead they have Aurora

https://en.wikipedia.org/wiki/Aurora

Highly accelerated particles from the Sun, and cosmos hitting upper level of atmosphere.

[Radrook2]

Without the sun there goes gravity! Without its gravity Earth would become a rogue planet. That means that it would perhaps be gravitationally caught in another star's orbit, plunge into it, or else travel forever in the frigid vastness of space. There are rogue stars in our galaxy right now which have been observed being ejected from the galactic core area at high velocity and heading for intergalactic space. Rogue planets a believed to be common.

Edited October 14, 2016 by Radrook2

[Ophiolite]

Without the sun there goes gravity! Without its gravity Earth would become a rogue planet. That means that it would perhaps be gravitationally caught in another star's orbit, plunge into it, or else travel forever in the frigid vastness of space.

The last option is by far the most likely and what this thread is about: could the internal heat of the planet, derived from the kinetic energy of construction and radioactivity, possibly supplemented by tidal heating if it has a moon, be sufficient to provide an environment suitable for life.