NASA's Messenger spacecraft sped past Mercury about two weeks ago and beamed some 1,213 images of the planet back to Earth. Scientists examining these images are puzzled over some of the distinctive characteristics present on the surface of solar system's first planet.
One image that has surprised scientists is a "spider" like impression on the surface of the planet. The picture shows a central dent on the planet's surface and more than 100 lines radiating from this dent. Messenger kept its January 14 date with Mercury and in the ensuing flyby captured close images of the planet.
Messenger is the first craft to photograph Mercury after the Mariner 10 spacecraft executed a flyby past the planet in 1975. Messenger is due to fly past Mercury two more time before settling into a designated orbit in 2011.
The Messenger has sophisticated instruments on board, which allowed it to get a detailed picture of the magnetic field on Mercury as well.
“Our little craft has returned a gold mine of exciting data,” said Messenger's principal investigator Dr. Sean C. Solomon of the Carnegie Institution of Washington. "Messenger has sent back data near perfectly, and some of it confirms earlier understandings, and some of it tells us something brand-new. The Spider is definitely in the category of something we never imagined we'd find."
Another surprising feature on Mercury is the presence of ancient volcanoes on its surface. Scientists had assumed that the planet resembled the moon, but there are plenty of features that make the dynamic planet a different entity altogether.
Scientists are interested in Mercury because it happens to have a magnetic field that is almost identical to the one on Earth. By using Messenger's data, they hope to understand how such planets were formed.
