Water on Ceres

[anonymous-user]

The initial message was deleted from this topic on 07 November 2020 at 05:00

[thatdude]

Well, maybe if under the surface there are caverns of liquid water, warm enough to allow some chemistry to occur, with the right organic building blocks, some minerals and a little acid...maybe there is something living. It might be something really simple, perhaps even sub-life like an enzyme-like entity just casually catalysing the conversion of something into another thing.

I often wonder, at what point does something become "living"? Is it the ability to replicate itself? That would seem a strong definition of "life"

[ewenm]

thatdude said:

I often wonder, at what point does something become "living"? Is it the ability to replicate itself? That would seem a strong definition of "life"

Difficult question. Crystallisation could be defined as something replicating itself...

[Terminator X]

Bacteria can live pretty much anywhere can't they which = life. Liquid water and reasonable temps seems a pre-requisite for animal life though (plus billions of years) from which intelligent life should follow.

TX.

PS IANAS

[Simpo Two]

thatdude said:

I often wonder, at what point does something become "living"? Is it the ability to replicate itself? That would seem a strong definition of "life"

Replication or respiration IIRC.




Crystal growth is simply physica; copper sulphate makes nice crystals but is certainly not alive.

[ewenm]

Simpo Two said:

thatdude said:

I often wonder, at what point does something become "living"? Is it the ability to replicate itself? That would seem a strong definition of "life"

Replication or respiration IIRC.

Crystal growth is simply physica; copper sulphate makes nice crystals but is certainly not alive.

I agree crystals are not alive, but it just demonstrates that "self-replication" on it's own is not enough of a definition for life.

[CrutyRammers]

Simpo Two said:

thatdude said:

I often wonder, at what point does something become "living"? Is it the ability to replicate itself? That would seem a strong definition of "life"

Replication or respiration IIRC.




Crystal growth is simply physica; copper sulphate makes nice crystals but is certainly not alive.

It's a question which has exercised biologists for many years.
Respiration is a good one, though it excludes viruses, which are a bit of a fly in the ointment.

[Simpo Two]

CrutyRammers said:

Respiration is a good one, though it excludes viruses, which are a bit of a fly in the ointment.

Viruses fail on the 'replication' parameter because they don't have the molecular machinery to replicate without a host.

Note that respiration in this context is not breathing but the conversion of chemicals to make energy, with or without oxygen.

[Eric Mc]

The presence of water is just one factor in determining whether a planet, moon, asteroid etc might be suitable for life. There are lots of other important factors too.

It seems water is quite common in the universe and is turning out to be quite common in the solar system too. Europa, Gannymede, Enceladus, Mars and possibly even our own moon appear to have substantial reservoirs of water. However, it's most likely that water is in a frozen or gaseous state on these worlds - although there are tantalising indicators that liquid water is present on Europa and Enceladus and possibly even Mars.

[Simpo Two]

Eric Mc said:

The presence of water is just one factor in determining whether a planet, moon, asteroid etc might be suitable for life

Here we hit the 'life as we know it' thing. Life as we know it needs water - but IIRC my chemistry it could be possible to have life based on ammonia as a solvent.

[Eric Mc]

Possible.

However, water seems to be far more abundant in the universe than ammonia.

[Catatafish]

Simpo Two said:

Here we hit the 'life as we know it' thing. Life as we know it needs water - but IIRC my chemistry it could be possible to have life based on ammonia as a solvent.

Life as we know it is limited to what we have seen in an infinitesimally small part of the universe. Until we've been out there and charted a few ammonia clouds/planets etc. I would say all bets are off...

[Eric Mc]

Ceres might still be affected by gravitational stretching and compressing as it moves in its orbit around the sun.

[MartG]

Quite apart from the possibility for life, the presence of water on Ceres makes it an ideal destination for a space mission which can use some of the water as fuel for the return trip

[Eric Mc]

Good point.

These "useless lumps of rock" are turning out to be anything but "useless".

[thatdude]

Simpo Two said:

Here we hit the 'life as we know it' thing. Life as we know it needs water - but IIRC my chemistry it could be possible to have life based on ammonia as a solvent.

That would be interesting to discover. Ammonia has a lone-pair of electrons, and has acidic and basic character (although is far more basic than water i.e. a higher pKa). It has the potential to solvate metals (I regularly dissolved sodium in ammonia during my PhD) (important for nerve functions). I should think its strong nucleophilic character would lead to interesting and clever biochemistry of a given life-form...

[Eric Mc]

I've always loved this little chap -