Loading the cannon: how do asteroids from the belt between Jupiter and Mars get into near-Earth orbits?
But NEOs are still abundant, so how does their population get replenished? According to the most widely accepted hypothesis, most NEOs arrive in our local neighborhood from the main asteroid belt, a zone of rocky bodies between the orbits of Mars and Jupiter. Now a research team led by Simone Marchi, an astronomer at the University of Padua, Italy, has found supporting evidence for that hypothesis. Vesta, the third largest asteroid in the solar system, lies in the main asteroid belt, nearly 130 million miles farther from the Sun than Earth does. Yet fragments of Vesta have been found scattered throughout the solar system. Marchi’s analysis shows that among those fragments of Vesta are four NEOs, discovered in 2003. Vesta itself was discovered 198 years ago by the German astronomer Heinrich W. M. Olbers. Perhaps its most remarkable feature is a gargantuan impact crater on its surface, stretching some 280 miles across–more than three-quarters of the 330-mile diameter of Vesta itself. Lo
