On Monday amateur astronomer John Mckeon captured an unusual flash on the limb of Jupiter while he was filming the planet through a telescope. He posted the video on Reddit, wondering if it might be some sort of meteor or comet impact. It was soon confirmed that the flash was also observed by Gerrit Kernbauer. It does indeed appear to have been an impact event.
Such impact events have been recorded before. Similar impacts were recorded by amateurs in 2010 and 2012. Because such events are unexpected, we rely upon the luck of observers. While such impacts happen fairly regularly, the only time we had a heads-up on an impact was when comet Shoemaker-Levy 9 impacted Jupiter under the watchful eye of Hubble and other telescopes.
Since comet and meteor impacts occur on Jupiter so regularly, it’s a commonly held idea that Jupiter actually protects Earth from comet collisions by deflecting them, or even colliding with them. But in fact Jupiter can deflect a comet toward us just as easily as it can away from us. So the role of Jupiter as Earth’s protector is still unclear, though it’s suspected that it did play a role in the early stages of our solar system.