Learning About Mercury

Two new studies using data collected by NASA's Messenger probe are painting a new picture of the planet Mercury.

One study, using Messenger's laser altimeter, finds a smaller range between the highest and lowest points on Mercury's surface than there is on either Mars or Earth's Moon. Further, it notes that some impact craters-- including the largest-- have been partially filled in, which suggests Mercury was more active in volcanism, for a longer period, than previously thought.

The other study probably goes along with that increased volcanism. It suggests Mercury's iron core is much larger than previously thought. The study also found mascons (mass concentrations) within the planet. Mascons have also been found inside Mars and Earth's Moon, suggesting they might be a common feature of terrestrial worlds.