As the Mars Global Surveyor orbits the Red Planet, magnetometers aboard the spacecraft have been sending home some astounding data. The instruments have confirmed indications from earlier missions that, if Mars has a global magnetic dipole at all, it is more than 10 000 times weaker than Earth's. Nevertheless, the magnetometers find, Mars's surface is dotted with local regions where the magnetic fields are over ten times greater than any perturbations in Earth's global field. Most likely, the local fields stem from an early time when the planet's core was still molten and a magnetic dynamo imprinted its field in the rocks. But the most intriguing discovery by far is the large, linear magnetic structure evident in Mars's southern hemisphere: Along a band extending nearly 2000 km from east to west, the crustal magnetic moments are aligned in one direction; those in adjacent bands appear to be magnetized in the reverse direction, and so forth—for five or six flips of the magnetic field.
Skip Nav Destination
Article navigation
June 1999
June 01 1999
New Data from Mars Hint at a Dynamic Past
Magnetic measurements suggest that a process akin to Earth's seafloor spreading once operated on Mars.
Physics Today 52 (6), 17–18 (1999);
Citation
Barbara Goss Levi; New Data from Mars Hint at a Dynamic Past. Physics Today 1 June 1999; 52 (6): 17–18. https://doi.org/10.1063/1.882709
Download citation file:
PERSONAL SUBSCRIPTION
Purchase an annual subscription for $25. A subscription grants you access to all of Physics Today's current and backfile content.
Sign In
You could not be signed in. Please check your credentials and make sure you have an active account and try again.
Citing articles via
The lessons learned from ephemeral nuclei
Witold Nazarewicz; Lee G. Sobotka
FYI science policy briefs
Lindsay McKenzie; Jacob Taylor