Explosion Spotted on Jupiter: A Comet or Asteroid? A bright flash was spotted on Jupiter early Monday morning, and astronomers are trying to figure out exactly what hit it. The flash was first spotted by Dan Peterson, an amateur astronomer from Racine, Wisc., who saw the flash through a telescope. He posted about his sighting on the Association of Lunar & Planetary Observers message board with the subject line, "I observed an explosion on Jupiter this morning!" He reported that the explosion occurred inside the southern edge of Jupiter's northern equatorial belt of clouds. "My best guess is that it was a small undetected comet that is now history, hopefully it will sign its name on Jupiter's cloud tops," he wrote. Astrophotographer George Hall of Dallas was shooting video of Jupiter at the time and caught the flash on camera at 6:35 a.m. Glenn Orton, a senior research scientist at the Jet Propulsion Laboratory in Pasadena, Calif., said he believes a frozen comet may be the culprit. "Most things in that part of the solar system are called Jupiter-family comets," Orton said. They're ice balls that move in and have started co-orbiting around Jupiter.  The explosion doesn't appear to have left any trace, Orton said. It was quickly swallowed up by Jupiter's thick atmosphere. Orton said he and other researchers will publish a paper about their observations in the next few months. In August 2009, a space rock hit the planet leaving a giant black mark and sending debris into Jupiter's clouds. In June 2010, another explosion caused an Earth-sized fireball to emerge from Jupiter, much like Monday's sighting. Orton believes Monday's impact was about the same size as that in 2010. "It's the big gravitational vacuum cleaner of the solar system," Orton said.