Status Report

Daily THEMIS Picture: Cerberus

By SpaceRef Editor

April 24, 2002

Filed under Daily Themis Pictures, Hughes Electronics Corp., US

Image Context:

Context image credit: NASA/Mars Orbiter Laser Altimeter (MOLA) Team

The Science

The Story

The Cerberus feature is a relatively dark region at the southeastern
edge of the huge Elysium Mons volcanic complex. It was visible to early
astronomers of Mars because it was a distinctive dark spot on a large
bright region of the planet. Today we recognize that the Cerberus
region encompasses a range of geologic terrains from relatively young
and smooth lava flows to the very rugged, ancient eroded landscape seen
in this THEMIS image. The Cerberus feature has also proven to be
ephemeral. Compared to just 20 years ago when the Viking orbiter
instruments viewed the planet, the Cerberus feature has shrunk down from
its original length of roughly 1000 kilometers to just a few isolated
dark splotches of just a few 100 kilometers. This is testament to the
active eolian environment on Mars where global dust storms can lift and
then later deposit significant amounts of dust, brightening formerly
dark surfaces. The THEMIS image occurs in a portion of Cerberus that
remains relatively dark and dust-free although in the bottommost portion
of the image are faint, criss-crossing lines that likely are dust devil
tracks. The abundant dune-like features covering many of the low,
smooth surfaces are similar to those found in many places across the
planet. They are evidence of the interaction of wind and movable
particles at the surface but not necessarily in today’s environment. In
many other places on Mars they are clearly inactive; relicts of a
different climate.

[Source: ASU THEMIS Science Team]

Hellhound of Greek mythology, Cerberus was the three-headed, dragon-tailed dog that stood guard at the opening to the underworld. This rough-and-tumble Mars terrain looks just as fierce and foreboding. At the edge of the huge Elysium Mons volcano complex, the Cerberus area appeared as a dark spot to early Mars astronomers in an otherwise bright region of the planet. If this dark area seems somewhat hellish to your imagination too, you’ll be glad to know that the Martian wind has been brightening up the area.

Just twenty years ago, the Viking orbiters reached Mars for the first long-term studies of Mars up close. The Cerberus feature was then almost 600 miles long, but has now been vanquished down to few small splotches about 60 miles long. Call that a triumph of lightness upon the surface, but don’t think that the force bringing back the light is gentle and kind. The Martian wind can kick up a fierce global dust storm that lifts up the bright Martian dust into the air and then blankets the surface with the brighter material as it settles down again.

The ancient, eroded terrain in this image is still rather dark and dust free, so you might say it’s one area where a mythical Cerberus still guards its shrinking territory. The wind teases it, however, by kicking up small, whirling dust devils that leave long, dark, scratchy tracks upon the land. Fields of dunes wrinkle the surface in places as well, but they may be permanently cemented upon the surface now, no longer able to blow and drift as they did in their younger days.

[Questions? Email marsoutreach@jpl.nasa.gov]

[Source: NASA/JPL Mars Outreach]

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA’s Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA’s Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Image Credit: NASA/JPL/Arizona State University