Wednesday, December 14, 2005

Enceladus Is the New Hoth

Image: NASA/JPL/Space Science Institute

So the ice volcanoes continue to be intriguing! It seems that the general consensus is that Enceladus is, in fact, the source of Saturn's gossamer "E" ring. From the Cassini website:

"Saturn's remarkable E-ring is the largest planetary ring in our solar system, spanning all the way from Mimas' orbit to Titan's orbit, about 1 million kilometers (621,370 miles). It is by far the most extended ring around Saturn.

"Until recently scientists assumed that the dust at Enceladus was produced by a process similar to that observed at the Galilean moons of Jupiter: micrometeoroids striking the moon's surface blasting dust particles loose. However, the Cassini data show that the E ring is being replenished not only by dust particles from micrometeoroid hits on the surface of Enceladus but also from grains expelled from possible vents located in the south polar region. The possibility of vents is revealed by a higher surface temperature detected by Cassini's composite and infrared spectrometer, which detected temperature differences at the south pole."


For years, we have heard about the moons of Jupiter, particularly the Galilean Satellites: Io, Europa, Ganymede and Callisto. Io is a volcanic moon, Europa is an ice moon that may hold a salty sea beneath its surface (and some speculate that it is one of the most likely places in the solar system where we might find life). With Cassini's arrival at Saturn on July 1, 2004, we have heard plenty about its incredible satellites- Rhea, Dione, Hyperion Mimas, Iapetus... The Huygens probe has given us pictures of Titan that have stoked the imaginative fires. We have seen a landscape that looks like shorelines, cliffs, and rivers. People have speculated that it might be an active place full of volcanism, and (of course) life. Titan has brought up more questions than answers- are those features really shorelines? Is there really a methane sea that is replenished by "rain?"

Now Enceladus has given us an amazing picture: scientists expected to find ammonia in the ice volcanoes. Ammonia would help keep the water in a liquid or gas state at lower temperatures. So far, they have not found any! Additionally, this moon has the highest albedo (99%- the same value as fresh ice) of any body in the solar system. This means that of all the radiation to hit the surface, 99% of it is reflected. Enceladus, it turns out, is a bright, giant snowball, where it may even snow (hence the Hoth reference. For the Star Wars illiterate, Hoth is the ice planet that hosted the rebel Echo Base (and the AT-AT walker battle scene) in "The Empire Strikes Back")! And (the speculations fly), if an energy source beneath the surface is warm enough to melt the ice, perhaps it is warm enough to support life..? What a much more complex picture we have of our solar system! I remember my sixth grade science teacher telling us that scientists know for a fact that there is no life in the solar system outside of this planet. Now we don't seem to be so sure.

By the way, there is a really interesting video on how Saturn's moons interact with its rings here.

Wednesday, December 07, 2005

Mailing List Crossover- Sound in Film

These are some ideas that I posted to a mailing list (edited):

A few weeks ago Robert Breer was at the First Person Cinema program at the University of Colorado at Boulder. This is a program that brings film artists from around the world to the University to present their films and answer questions about their work. It's a great chance to see some unique works of art and talk to the artists.

I'd seen all of the films shown, most of which remind me of a sort of comic book of the unconscious mind (this is NOT, to me, an insult, by the way). While I'm watching his films, I feel like I get to see the world through an animator's eye. This is particularly true in his film "Fuji" in which he sometimes cuts the "raw" footage of his train in with his rotoscope animation, subtly reminding the viewer that the (sometimes) abstract shapes are based on "photographed" images (technically, they're all photographed, since they ended up on the film print...) This is kind of what my mind does as I'm staring out the window of a plane, car, train, etc. I can sometimes see the world as a web of interacting patterns, motions, shapes, colors...

In the Q&A portion of the program, one of the film-goers asked him about the significance of the sound in his films. He responded by saying that he felt sound was a natural consequence of motion. I'd never really though about this, but it does seem odd (to a hearing person, at least) to see an object move and not hear it make a sound. It's creepy somehow. I wonder if this could be at least one of the reasons why most people tend to get antsy while watching a silent film. You do have to kind of learn how accept the silence. Of course, and he did go into this, the sound doesn't have to be "synched," so to speak, and often works great (or even better) if it isn't. He mentioned watching a boy with a basketball coming up his street and how the sound of the ball hitting the ground was not synched with the image. As the boy got closer, the two phenomena became more synched (speed of sound vs speed of light- I've often said that of all the things that stick in my mind the most after watching the Trade Center towers fall from my Brooklyn home was the fact that I saw them fall and then the Roar of the Earth came several seconds later- it suspended time somehow).

As a filmmaker who often makes silent films, it gave me quite a bit to think about...

Monday, December 05, 2005

Explosives Limited?

Okay so part of my new office job is to open mystery mail, determine whose it is and deliver it to the proper person. I just received a mystery letter from "Explosives Limited." Now, I'm not a paranoid person, but...

Friday, December 02, 2005

Volcanoes of Ice


What you are seeing is an errupting ice volcano on Enceladus, a moon of Saturn. It is thought that the powerful eruption deposits ice particles in one of Saturn's outer rings. This image was taken by Cassini last week.

ETA I thought I should add this snip to clarify (taken from As an artist, I hear something like "ice volcano" (or its uber-cool techie term "cryovolcanism") and I get inspired, excited, etc. But I don't wish to misinform (the scientist in me):

"At present, it is not clear if the plume particles emanating from the south pole arises because of water vapor escaping from warm ice that is exposed to the surface. Another possibility is that at some depth beneath the surface, the temperatures are hot enough for water to become liquid, which then, under pressure, escapes to the surface like a cold Yellowstone geyser. "

Image credit: NASA/JPL/Space Science Institute.