Mysterious Craters Seen on Mercury

Craters come in all shapes and sizes, some more bizarre than others. Recent photos of Mercury have revealed two new categories of crater that scientists are puzzling over how to explain.

When NASA's MESSENGER spacecraft flew by the planet Jan. 14 it snapped pictures of several craters with strange dark halos and one crater with a spectacularly shiny bottom.

"The halos are really exceptional," said MESSENGER science team member Clark Chapman of the Southwest Research Institute in Boulder, Colorado. "We've never seen anything like them on Mercury before and their formation is a mystery."

Two of the craters are located in Mercury's giant Caloris Basin, a thousand-mile-wide depression formed billions of years ago when Mercury was struck by a comet or asteroid. The larger of the two is about 40 miles wide. Both craters have dark rims or "halos," and one is partially filled with an unknown shiny material.



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Also see Top ten Mysteries of Mercury

reply to post by Enceladus

Some interesting finds on Mercury. Looking forward to some explanations about the craters. Also, from the OP:

Fortunately, MESSENGER may have gathered the data researchers need to solve the puzzle. Spectrometers on-board the spacecraft scanned the craters during the flyby; the colors they measured should eventually reveal the minerals involved.

"The data are still being calibrated and analyzed," Chapman said.

If they don't solve the mystery, scientists hope MESSENGER's two upcoming flybys — one in Oct. 2008 and another in Sept. 2009 — will do the trick.

[edit on 12-3-2008 by anhinga]