Where's the postbox?
glyburide micronase From their calculations, the researchers found that 10 percent of their sample of asteroids only cross Mars' orbit, and not Earth's. DeMeo explored other potential causes of asteroid refreshing, calculating the probability of asteroids colliding with each other, as well as the possibility for a phenomenon called "spin-up," in which energy from the sun causes the asteroid to rotate faster and faster, possibly disrupting its surface. From her calculations, DeMeo found no conclusive evidence that either event would significantly refresh asteroids, suggesting that "Mars is the only game in town," Binzel says.