Scientists have recently been studying how Mars is being struck by planetesimals, and how it has affected the development of the planet. Planetesimals are small protoplanets that can reach 1,200 miles in diameter. Scientists from Southwest Research Institute have begun to create simulations of what these different impacts did to the history and formation of the Red Planet. Some of these projectiles have been predicted to have their own mantles and cores, causing new materials to be added to the composite of Mars on impact. “This can lead to different interpretations on the timing of Mars’ formation than those that assume that all projectiles are small and homogenous,” commented Dr. Robin Canup.