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Enceladus is one of Saturn’s many moons,
and it’s a very small moon

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that people tend to kind of ignore because it is so small

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about 500 kilometers in diameter. 

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But decades ago, in the 1980's from ground-based observing, 

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we found out that the location of Enceladus relative to Saturn

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happened to coincide nicely with Saturn’s E ring 

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and so we were thinking that Enceladus had
something to do with the E ring

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particulates, that icy material, but we weren’t sure.

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What we later find from Cassini was that we
directly determined

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that there are indeed plumes jetting out of
the south polar region from cracks

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in the south pole of Enceladus in the crust. 

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And it’s dominantly water-rich material
just jetting out into space. 

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And so the way we saw it, Cassini happened to
be located where Enceladus was backlit

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from the Sun, and so you saw this curtain
of beautiful, diffuse material 

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jetting out of the south polar region –
quite breathtaking actually. 

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Even more, we were able to use the different
compliments of instruments 

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onboard Cassini to go after the chemical
composition of the plumes, 

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and that’s where things got really interesting.
So number one, that’s because of liquid water. 

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There’s definitely a liquid water reservoir subsurface
below the icy crust, but that is there. 

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Number two, the chemical composition of the plumes
told us that there is a lot of organics

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things that make up amino acids and things
on life that are very interesting.

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And number three, what we were really
looking for was a source of energy.

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On Enceladus, photons from the Sun aren’t going
to work because you can’t penetrate

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the tens of kilometers of icy crust to get down
to where the liquid water reservoir is. 

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But, what Enceladus does have is hydrothermal vents.

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It’s very hot with the liquid water, that has a lot
of analogies with the ocean floor

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where we have a form of releasing chemical energy
via something called serpentinization.

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And so we think that Enceladus might have that potential 

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to have an energy source being chemical, not sunlight. 

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And so you put all that together and Enceladus
has all the ingredients, 

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or most of what we need for life. 

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That makes it a very astrobiologically
interesting object to study.

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