Mercury space probe finding surprises

BALTIMORE, Sept. 30 (UPI) -- A spacecraft sent to explore Mercury is providing data that may rewrite what is thought about the growth of planets, researchers say.

NASA's Messenger space probe, in orbit around the small, rocky planet, has determined Mercury possesses a lopsided magnetic field, much more sulfur than expected and strange "hollows" across its surface that may hint at present-day geologic activity, the Los Angeles Times reported Friday.

The planet's magnetic field is shifted about 300 miles north from the equator, suggesting the churning liquid metal in the core may be undergoing strange, lopsided internal dynamics.

"There's something very intriguing going on with that that we don't understand yet," Brian Anderson, a space physicist at Johns Hopkins University, said.

Messenger also revealed strange, bright bluish depressions inside some of the planet's craters researchers have dubbed "hollows," possibly created after an impact by space debris carved out a crater, exposing volatile elements such as sulfur.

Bombarded by heat from the sun, the sulfur would have evaporated, causing the rock in which it was embedded to crumble, forming the hollows.

That may still be going on today, researchers said.

"Mercury's a small planet," planetary scientist David Blewett said. "It was sort of considered to be like the moon -- an old, burned-out cinder. … But to find some landscape modification apparently taking place today, and producing these spectacular and unique features, is a first."