Status Report

Mars Odyssey THEMIS Image: Syrtis Major

By SpaceRef Editor

May 1, 2002

Filed under Daily Themis Pictures, Mars Odyssey THEMIS, US

Image Context:

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

The Science

The Story

This image is from the region of Syrtis Major, which is dominated by a
low-relief shield volcano. This area is believed to be an area of vigorous
aeolian activity with strong winds in the east-west direction. The effects of
these winds are observed as relatively bright streaks across the image,
extending from topographic features such as craters. The brighter surface
material probably indicates a smaller relative particle size in these areas,
as finer particles have a higher albedo. The bright streaks seen off of
craters are believed to have formed during dust storms. A raised crater rim
can cause a reduction in the wind velocity directly behind it, which results
in finer particles being preferentially deposited in this location. In the
top half of the image, there is a large bright streak that crosses the entire
image. There is no obvious topographic obstacle, therefore it is unclear
whether it was formed in the same manner as described above. This image is
located northwest of Nili Patera, a large caldera in Syrtis Major. Different
flows from the caldera eruptions can be recognized as raised ridges,
representing the edge of a flow lobe.

[Source: ASU THEMIS Science Team]

In the 17th century, Holland was in its Golden Age, a time of cultural greatness and immense political and economic influence in the world. In that time, lived a inquisitive person named Christian Huygens. As a boy, he loved to draw and to figure out problems in mathematics. As a man, he used these talents to make the first detailed drawings of the Martian surface – – only 50 years or so after Galileo first turned his telescope on Mars.

Mars suddenly became something other than a small red dot in the sky. One of the drawings Huygens made was of a dark marking on the red planetís surface named Syrtis Major. Almost 350 years later, here we are with an orbiter that can show us this place in detail. Exploration lives!

It’s great we can study this area up close. In earlier periods of history, scientists were fascinated with Syrtis Major because this dark region varied so much through the seasons and years. Some people thought it might be a changing sea, and others thought it might be vegetation. Early spacecraft like Mariner and Viking revealed for the first time that the changes were caused by the wind blowing dust and sand across the surface.

What we can see in this image is exactly that: evidence of a lot of wind action. Bright dust patches streak across this image, formed through wind interference from craters and other landforms. These wispy, bright streaks are spread on the surface by a vigorous, east-west wind that kicked up huge dust storms, scattering the fine particles of sand and dust in an almost etherial pattern. The bright streaks in the top part of the image might have formed in a slightly different way, because there is no landform standing in the windís way.

Beneath the bright surface dust are raised ridges that mark the edges of earlier lava flows from Nili Patera, a Martian “caldera.” A caldera is a collapsed, bowl-shaped depression at the top of a volcano cone.

Can you imagine how Christian Huygens would feel if he lived today and could see all of this knowledge unfold? Or how it would feel to be the first person to stand in this dark volcanic and cratered region, knowing how many discovers had paved the way to that moment? Yes, exploration lives!

[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