Bad news for life on Enceladus?

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Bad news for life on Enceladus?

Post by Lazarus on 30th May 2009, 2:39 pm

It may well be that Enceladus undergoes periodic freeze-thaw cycles over millions of years, spending most of its time frozen but occasionally melting due to interactions with the outer moon Dione. The cycles arise from the different tidal properties of the moon when it is frozen and when it contains an ocean.

The implications for life on Enceladus don't seem particularly good.

New Scientist story
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Re: Bad news for life on Enceladus?

Post by marasama on 6th June 2009, 3:03 pm

Some bacterium can hibernate for long times until they hit water.
So, why not on Enceladus?

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Re: Bad news for life on Enceladus?

Post by Sirius_Alpha on 7th June 2009, 12:10 pm

With Enceladus, those long times may be millions of years.

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Re: Bad news for life on Enceladus?

Post by marasama on 8th June 2009, 11:40 pm

I don't know the name. But there are bacterium that can loose majority of the water inside the cell and go into a hibernated state. As long as the DNA is not destroyed, they will stay that way until water touches it.

I'll try finding it to make sure I'm not crazy on that thought. So...
Don't quote me on this.

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Re: Bad news for life on Enceladus?

Post by Juramike on 16th June 2009, 11:54 am

Dunno if this would be bad for life on Enceladus...

It would certainly make life "interesting", and prone to evolutionary forcing as any critter populations would be forced to drop to low numbers during the freeze, only to reexpand and recolonize during the thaw. (Think of the changes in Earth's fauna during it's freeze cycles)

Has anyone done calculations about how long it would take for a current subsurface Enceladus ocean to freeze solid? (Taking into account the concentration of all the salts and other things that would lower the eutectic.)

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Re: Bad news for life on Enceladus?

Post by Sirius_Alpha on 16th June 2009, 11:59 am

Thermodynamics isn't my best subject, but I think those calculations would require knowledge as to how much water is there. As far as I know, that is not well constrained.

Here's an interesting story from UniverseToday.
Scientists have revived bacterium trapped under kilometres of ice in a Greenland glacier. The bacterium had been dormant for 120,000 years. The bacterium is a small, apparently simple micro-organism. Perhaps the sort of stuff we might find at Enceladus, Europa, or elsewhere.

This newscientist article mentions bacteria that are 8 Myr old that have been resuscitated. Apparently their DNA had become very degraded over the 8 Myr due to cosmic rays, causing them to grow slowly.

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Re: Bad news for life on Enceladus?

Post by Lazarus on 16th June 2009, 3:58 pm

I suspect there is a difference between the environments conducive to abiogenesis, and the range of environments life can adapt to inhabit though.
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Re: Bad news for life on Enceladus?

Post by Sirius_Alpha on 16th June 2009, 6:40 pm

Are you saying that you expect that the sort of life forms that have been found hibernating in such extreme environments were probably descendants of life forms from more favorable conditions?

I'm moving this thread to the extrasolar life section sometime tomorrow, if no one has objections.

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Re: Bad news for life on Enceladus?

Post by Sirius_Alpha on 23rd July 2009, 1:22 am


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