Mars Probe Finds Magnetic Field

An American spacecraft that went into orbit around Mars last week has found the first conclusive evidence the Red Planet has a magnetic field, the National Aeronautics and Space Administration said Wednesday.

The Mars Global Surveyor detected the magnetic field Monday as its instruments began gathering data. The field is no more than 1/800th as strong as Earth’s.

But scientists said even that is stronger than expected and suggests that Mars may once have had a more robust field, perhaps generated by the same sort of internal geologic mechanisms as Earth’s.

A better understanding of the Martian magnetic field should give clues to the early history of the planet and why it evolved so differently from Earth, they said. It also may shed light on whether conditions once were more conducive to primitive life on Mars.

“This is a nice, exciting result,” said Mario Acuna of NASA’s Goddard Space Flight Center in Greenbelt, Md.

Acuna said previous studies by Russian spacecraft had been inconclusive regarding the presence or absence of a global magnetic field. The possibility had been debated by researchers for years. The new finding, while preliminary, seems solid, Acuna said. “We had no dissent on our team,” he said.

“I think it’s very interesting,” agreed Margaret Kivelson, a UCLA specialist on magnetic fields who is not associated with the Global Surveyor team. “It certainly will be revealing,” she said, as the spacecraft gathers more data on the strength and geometry of the Martian magnetic field.