3 ms·

Life “not as we know it” might be possible on Titan

40 points by weatherlight 10y ago

dogma1138 10y ago
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-evidence-of-surprising-activity-on-europa http://www.nasa.gov/press-release/nasa-to-hold-media-call-on...
lawpoop 10y ago
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
- gonvaled 10y ago
  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 10y ago
    > 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?
evincarofautumn 10y ago
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.
gonvaled 10y ago
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.

40 points by weatherlight 10y ago

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

lawpoop 10y ago

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

gonvaled 10y ago
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 10y ago
  > 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?

evincarofautumn 10y ago

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.

gonvaled 10y ago

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.