Posted: Sat, Mar 10, 2012, 9:38 AM ET (1438 GMT)
A giant asteroid hitting the Moon's south pole four billion years ago may explain the magnetic field anomalies found there, scientists reported this week. The existence of highly-magnetic material in regions of the lunar crust had confounded scientists for decades. In a study published in the latest issue of the journal Science, a team of scientists explain that the most likely source of that material is from a large asteroid that crashed into the Moon's south pole about four billion years ago, creating the South Pole-Aitken Basin. Most of the magnetic material is scattered along the rim of that basin, and models of that collision show how the magnetized, iron-rich rock would be distributed as seen on the Moon.

Related Links:

•  New Scientist article
•  Los Angeles Times article
•  Science News article
•  Harvard Univ. press release (via Eurekalert)