Spacecraft Finds Mars Has Magnetic Field

In its first major discovery, the American spacecraft that went into an orbit of Mars on Thursday has solved one of the planet’s long-standing mysteries: Mars does have a magnetic field. Its magnetism may be weak, compared with that of most other planets, but is considerably stronger than scientists had suspected.

Scientists said the existence of a planetary magnetic field has important implications for the geological history of Mars, the nature of its deep interior and the possibility that life of some kind could have emerged there. Previous Russian spacecraft had reported hints of magnetism but nothing conclusive.

The confirmation of Martian magnetism was announced Wednesday by the National Aeronautics and Space Administration after an analysis of the first scientific data transmitted by the Mars Global Surveyor, just beginning what is expected to be a two-year mapping survey of the neighboring planet.

“A magnetic field shields a planet from fast-moving, electrically charged particles from the sun which may affect its atmosphere, as well as from cosmic rays, which are an impediment to life,” said Mario Acuna, a magnet specialist at NASA’s Goddard Space Flight Center in Greenbelt, Md.