Mercury: Up Close and Personal

The NASA probe Messenger has sent back images of Mercury on it's first of three passes over the next few years that will conclude with the spacecraft entering orbit of Mercury in 2011. The flyby revealed some images that perplexed the scientists at NASA; specifically the image shown below:


The confusion lies around the crater where there seems to be the cracks or splits in the surface of Mercury. Personally my first reaction was that it was a asteroid that impacted the surface and allowed lava to flow out, hence the large stream looking pattern toward the bottom of the picture. The proximity of the planet to the sun would seem to allow the planet to have a molten core. It also seems that many scientists agree with my assessment of the cracks. Read more at nasa.gov

Also another oddity of the planet is that the probe found a magnetic field produced by the planet, something that is not found on any other planet besides Earth. This also seems to support the conclusion of a molten core, but I won't say I know much about planetary magnetic fields.