
Life “not as we know it” might be possible on Titan - weatherlight
http://www.sciencealert.com/life-on-titan-might-be-completely-different-than-the-life-we-re-familiar-with?perpetual=yes&limitstart=1
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lawpoop
This is a theoretical idea for how a cellular membrane might form in this
environment, but the membrane isn't the key part of life-- it's the self-
replicating molecule, which they haven't modeled.

The RNA World theory posits that an RNA molecule, acting as both as the data
store and the enzyme that catalyzes its' own replication, was the original
self-replicating module. Eventually, DNA later evolved as a molecule purely
for data storage, and other enzymes that promoted replication.
[https://en.wikipedia.org/wiki/RNA_world](https://en.wikipedia.org/wiki/RNA_world)

I think to call something "life", they would have to propose something
similar, a self-replicating molecule, in this environment.

If this idea intrigues you, Jack Szostack has a great series of youtube videos
explaining the theory and the experiments he and his students have carried out
to help flesh out the theory. He describes how lipid cellular membranes could
have originated to combine with RNA molecules to become what we would think of
as a "cell".
[https://www.youtube.com/watch?v=MPzWrv6l9l0](https://www.youtube.com/watch?v=MPzWrv6l9l0)

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gonvaled
Is self-replication a requirement for life? What if there is an
indestructible, non-replicating individuum which exhibits some of the
properties we attribute to life?

It is difficult to understand how it came to be, but maybe there are other
mechanisms than replication, mutation and natural selection.

~~~
lawpoop
> Is self-replication a requirement for life?

I don't know if there is an "official" definition, but how would you define
life, without that?

For instances, rock crystals grow, and fire uses energy. Would you consider
those living phenomena?

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dogma1138
Not completely related but just as a reminder we might be getting something
about the other likely place to be habitable tomorrow.

[http://www.nasa.gov/press-release/nasa-to-hold-media-call-
on...](http://www.nasa.gov/press-release/nasa-to-hold-media-call-on-evidence-
of-surprising-activity-on-europa)

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evincarofautumn
If life can have many different bases, I wonder if we’ll even be able to
identify extraterrestrial life when we do encounter it.

I have a hunch that we will, soon enough, but it’ll be a _much_ longer time
before we encounter anybody near enough to us in size, shape, longevity,
intelligence, chemistry, and temperament that we could really interact with
them.

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gonvaled
It is very naive to think that the universe is only capable of producing
water-based life. Conditions are so varied that we can expect life based on
completely different concepts, starting with a different chemistry, and with a
different structure - maybe not cellular based.

And that life would exhibit completely different properties: size, velocity,
morphology, ...

And everywhere you look, whether in sci-fi films, literature, and even serious
research programs, they are looking for simmetrical bipeds, roughly our size,
with minimal morphological differences, water and carbon based, moving and
reacting roughly at our speed, etc. Very shortsighted.

