The White Fields of Enceladus

1
The White Fields of Enceladus
Christopher OConnell
? Presenting The Restless World of
Enceladus by Carolyn Porco ?More
Reading http//en.wikipedia.org/wiki/Enceladus_(m
oon) http//saturn.jpl.nasa.gov/multimedia/flash/E
nceladus/enceladus.html http//solarsystem.nasa.go
v/planets/profile.cfm?ObjectEnceladus
2
Whats This?

• Not, as may be presumed, Europa, but rather,
  Enceladus
• Clear evidence of geological activity in 1981
  when Voyager made the first flyby of Enceladus

Image NASA/JPL
3
Enceladus

• 6th Moon of Saturn
• Only 500 km in size (roughly the size of Arizona)

• Centered in Saturn's E ring, the wide, diffuse
  outermost ring
• Albedo of .9

4
Enceladus Surface
What appeared to be smooth plains in the Voyager
images, were, in fact, highly structured evidence
of significant geological activity.
But how could a tiny, tidally locked moon so far
from the sun possibly have enough energy for
geological action?
5
Tiger Stripes
In July of 2005, Cassini performed one of the (at
the time) closest flybys of a planetary body
(168km) over Enceladus south pole, and observed
massive cracks in the ice, dubbed Tiger Stripes.

• Cracks and Ridges Suggest Geological Activity
• Green areas are house sized boulders of ice
• Means area is young, as crystalline ice gradually
  breaks down into fine grained ice over time

Image NASA/JPL Note False color image
6
Active Stripes
Additional flybys determined that the Tiger
Stripes are significantly warmer than the rest
of Enceladus, approaching 180K, in contrast to
the 70K surface elsewhere on the surface.
The tiger stripes are geysers, ejecting
particulate into space, and serve to create
Saturns E ring.
Image NASA/JPL Yellow mark approximates
Cassinis closest flyby (25Km)
In a perilously close flyby (25 Km from the
surface), Cassini was able to fly through
Enceladus geysers collecting particles. Among
the particles found were acetylene, ethane,
benzene and formaldehyde.
Enceladus has water, energy and organic compounds!
Image NASA/JPL
7
Silly Putty Enceladus
In a nutshell, the interaction between Enceladus
and Diones orbits (21 locked) cause stretching
and contraction of Enceladus which result in
internal heating.
Images Scientific American
8
Life on Enceladus?
Enceladus does contain the basic ingredients that
suggest the possibility of life liquid water,
energy, and organic compounds.

• But, the same problems that apply to Europa apply
  to Enceladus
• Its too far away from the sun for significant
  photosynthesis
• The surface is very cold (70K or less)
• As a mitigating factor, Enceladus does not
  receive the same damaging radiation from Saturn
  that Europa does from Jupiter
• It is unknown whether the Tiger Stripes are
  consistently warm, or whether they undergo
  alternating periods of melting and refreezing.
• Melting an refreezing would make life much less
  likely.

Enceladus does contain the distinct possibility
of life, but the vast distance involved, as well
as the difficulty of ever detecting it mean that
finding such life will be difficult in the near
term.