ScienceShot: Jupiter Impact Left No Mark

When amateur astronomers spotted a brief white blaze near Jupiter's midsection on 3 June, scientists thought the planet had been hit by a large asteroid or comet. But when they began looking for the telltale dark cloud of debris, they didn't find it. That means, Hubble Space Telescope scientists announced today, that the object that struck Jupiter 2 weeks ago must have been a much smaller asteroid or comet than the impactor that scarred the planet in 2009—and the string of cometary fragments that left multiple pockmarks in Jupiter's cloud tops in 1994. Indeed, the object was so small that it vaporized completely in Jupiter's atmosphere, instead of surviving long enough to blast out a cloud-forming plume of dust and debris.