Randy Korotev with a sample meteorite found in Siberia.The mysterious orb you find in your backyard that wasn’t there just the day before has to be a meteorite, right? Wrong. Overwhelmingly the chances are it’s a meteorwrong, says Randy Korotev, Ph.D., research associate professor of earth and planetary sciences in Arts & Sciences at Washington University in St. Louis. He says that 998 out of 1,000 meteorites are from asteroids, one out of 1,000 is from the Moon, and one out of 1,000 is from Mars. Of the hundreds of meteorites that have been found in the United States, none has been a lunar meteorite, and only one has been a Mars meteorite.