New research may suggest there is more to be learned about asteroids and the meteorites they send crashing to Earth, especially regarding their relationship with planets like Mars and Jupiter.
According to a press release from MIT, researchers from the school have offered a potential answer for why asteroids appear to be redder than their meteorites. Asteroids that orbit in the Earth's main belt are exposed to cosmic radiation between Jupiter and Mars, altering their chemical nature and reddening their surface.
Richard Binzel, a professor of planetary sciences at MIT, found in 2010 that asteroids that pass near Earth "quake" under pressure of the planet's gravity. This has a refreshing effect on the asteroids grains, as it forces them out on the surface and replaces them with newer ones. The asteroids then break apart and come crashing to Earth in the form of meteorites.
In a new study, Binzel and Francesca DeMeo that Mars has a similar refreshing effect on asteroids as they pass by the Red Planet.
"We don't think Earth is the only major driver anymore, and it opens our minds to the possibility that there are other things happening in the solar system causing these asteroids to be refreshed," said DeMeo, a postdoctoral candidate in MIT's Department of Earth, Atmospheric and Planetary Sciences.
The study, authored by Binzel, DeMeo and research associate Matthew Lockhart, has been published in the journal Icarus.
"Mars is right next to the asteroid belt, and in a way it gets more opportunity than the Earth does to refresh asteroids," Binzel said. "So that may be a balancing factor."
DeMeo conducted her research using a database of 300,000 asteroids and their orbit patterns, 10,000 of which considered to be near-Earth. Binzel and his colleagues have been tracking the brightest of these and have been looking for color to determine which had recently been refreshed. From that group, they closely monitored 60 and determined when they intersected with Mars and Earth.
"Picture Mars and an asteroid going through an intersection, and sometimes they'll both come through at very nearly the same time," said Binzel. "If they just barely miss each other, that's close enough for Mars' gravity to tug on [the asteroid] and shake it up. It ends up being this random process as to how these things happen, and how often."
Of the 60 sample planets, DeMeo estimated about ten percent, or six in total, crossed only Mars and not Earth. While that may seem insignificant, Mars' small size may cause some to underestimate its power, she said.
"You think about these asteroids going around the sun doing their own thing, but there's really a lot more going on in their histories," said DeMeo. "This gives you a dynamic idea of the lives of asteroids."
