Earlier this month, astronomers in Arizona spotted an unidentified space object that will fall to Earth on November 13th. The object, appropriately dubbed WT1190F, is only a couple feet in diameter and not very dense. That means it's probably man-made — likely a leftover piece of a rocket that remained in space instead of falling back down to Earth. The object orbits our planet every three weeks or so on a highly elliptical path that takes it out twice the distance from the Earth to the Moon. But eventually gravity will drag it down, and the object will burn up in the atmosphere somewhere over Sri Lanka.
The European Space Agency notes that the object poses very little risk to anyone on the ground. Most, if not all, of it will disintegrate as it passes through our atmosphere. If anything's left of the object, it will harmlessly fall into the Indian Ocean about 60 miles off the Sri Lankan coast. The reentry is supposed to provide a fun show for those nearby, as the object will brighten up the sky for a few seconds around 2:19PM ET. However, you might not want to get too close to it. "I would not necessarily want to be going fishing directly underneath it," Bill Gray, who tracks space debris with NASA's Jet Propulsion Laboratory, told Nature.
Space object WT1190F observed on 9 October 2015 with the University of Hawaii 2.2-meter telescope on Mauna Kea, Hawaii. (B. Bolin, R. Jedicke, M. Micheli)
ESA and NASA are actually pretty excited about this piece of debris, as it will give them a good opportunity to collect data about how space objects fall back down to our planet. Scientists only know about a few pieces of man-made debris that orbit around the Earth-Moon system right now, and none is supposed to return to Earth anytime soon. This is one of the few times we know well in advance when and where a man-made object will reenter our atmosphere. It's possible that others like this have fallen back to Earth before, but they were so small or discreet that we missed them.
Researchers plan to track the object until it burns up, helping to refine orbital models and the tools they use to predict atmospheric reentry. That will be beneficial when we spot other man-made objects in space — or when much more dangerous asteroids are headed our way. Knowing where and when an object will hit us will make us better prepared to respond accordingly.
Correction: A previous version of this article suggested this was the first time we knew when man-made space debris would fall to Earth. It's one of the first times we can accurately predict re-entry location for this type of object.