Falling debris from the sky might be space junk.

The object that crashed through the roof of a house in New Jersey and landed in the bathroom, making headlines across the U.S. in January, was initially thought by experts to be a meteorite. However, laboratory tests revealed that it was not a meteorite, but rather a piece of alloy debris, likely part of space junk.

On the evening of January 2, Naswaran, a 46-year-old resident of Newark, entered the second-floor bathroom of his home and noticed a hole in the ceiling, with small pieces of plaster and insulation scattered on the floor beneath it. On the tiled floor...