While scientists have managed to recover and examine thousands of meteorites, finding their origin or even whether they are from icy comets or rocky asteroids has proved elusive. Now, for the first time, a team of international researchers has traced the source of a boulder-sized rock that landed in Botswana to an asteroid named Vesta. Boasting a diameter of about 300 miles, it is one of the largest and brightest rocks in the asteroid belt that circles the sun between Jupiter and Mars.