Strange Moons: Enceladus, The Frozen Water World
Diameter: 513 x 502 x 496 km
Average Surface Temp: 75 Kelvin ( -198 C )
Back in 1789, William Herschel discovered a moon in orbit around Saturn. He found it when he used his brand new 1.2 meter telescope for the first
From that time until the first Voyager craft flew by Saturn, little was known about Enceladus. All we knew was it's orbital characteristics, and
estimations of it's mass, brightness and density.
That and it orbits Saturn.
Voyager 1 made it's flyby of Saturn first, but the images of Enceladus were from too far and so little detail was gleaned. However, Voyager 1 was
able to tell that Enceladus had a highly reflective surface, and that it was embedded in Saturn's "E" ring.
Voyager 2 was able to pass by Enceladus within 87,000 km, which allowed us to obtain higher resolution images of the moon:
The images showed areas of the moon devoid of craters, suggesting a younger surface in some areas than others. It was a surprise to scientist as no
theory at the time predicted that such a small body could have a geologically active surface (unlike larger Jupiter moon Io).
The answers to this and other issues came when the Cassini probe arrived at Saturn. The images it was able to take left no doubt as to what the
surface was: Ice. Lots of it!
Looking at Enceladus, I was reminded of Jupiter's Europa: an ice covered moon with cracks and crevasse all over it. A water world frozen in time.
However, while it's surface is frozen, it ends up being reborn due to tidal forces that heat up water under that ice and ends up changing the face of
If you look at the image above, the lower left hand half of the moon reminds me of images of frozen lakes here on Earth that have cracked and refrozen
We have to remind ourselves that Enceladus is a small moon. It would fit inside the state of Texas just fine:
Enceladus sitting next to the Earth:
I've seen pictures of glacial flows here on Earth.....but seeing them on a small moon over 750 million miles away from us seems sureal to me:
Here is another view of a different side to enjoy:
Many of the cracks in the surface remind me of frozen rivers:
Sometimes, if I let my imagination run a bit, it looks like some of the cracks, especially in the craters, were made by machines of some sort (I
don't really believe that, but it's fun to imagine that we're there mining the ice):
Cassini also discovered a few other things about this moon, placing it in my "Strange" catagory. For one thing: it's the source of Saturn's "E"
"How is it doing that?" You ask?
It's doing it because of something else Cassini discovered: Geysers of material are spewing out of Enceladus from it's south pole:
Here is a much closer view:
All of these observations made by Cassini, it's mass, density, how it's surface looks and what it's made out of, and the fact it's spewing
material out that is helping make a ring around Saturn, made scientist realize that under all that ice are areas of liquid water.
It's able to be water due to tidal forces that the rocky core of Enceladus has that get's squished and tugged on heats that rock up, which keeps the
It also builds up pressure and forces it to spew out from Enceladus:
So it's just water......right?
Cassini has made many flybys of Enceladus, and on one of those flybys, was able to pass through one of these geysers. The ion and neutral mass
spectrometer on Cassini was able to identify what is in these geysers, and the answer was surprising:
It contains Methane, Simple and Complex Organics!
This discovery alone propled Enceladus to the status of possibly having life below it's icy surface.
So will we ever find out more about Enceladus?
Well there was a joint NASA/ESA mission proposed called the Titan Saturn System Mission
) to explore the moons of Titan and Enceladus. Estimated price tag of 2.5
billion dollars, with a proposed launch date of 2020 and arriving in 2029.
But the mission to Jupiter and it's moons were given priority. So this mission has been put on the back burner. I doubt that I'll see it happen in
my life time.