Slideshow: Mercury's Mysteries


"Mercury is the closest planet to the sun, yet still has shadowy secrets."

Source: Download time: Mar 2 2011 9:39 AM ET

The closest planet to our sun, and the smallest in the solar system, is also one of the least understood. Compared to more glamorous planets like Mars, Jupiter and Saturn, Mercury has received much less attention from scientific study missions. But NASA's Messenger probe is set to reveal the secrets behind the odd planet. The probe has flown by Mercury three times and will enter orbit around the planet in March — the first spacecraft ever to do so.

Here's a look at some of Mercury's most enduring mysteries. In the words of Messenger science team member Robert Strom, "The best is yet to come. What you're seeing here is just the tip of the iceberg."…

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