More than 500,000 known objects are orbiting planet Earth, and around 20,000 of them are at least as big as a softball, reports NASA. Now a University College London professor has used data from space-track.org to create a video to help us visualize how quickly that space junk has accumulated thanks to space traffic and collisions, reports Wired UK. NASA notes that there have been few disastrous collisions, but it points to two recent ones—a Chinese missile test in 2007 and the collision of two satellites in 2009—that threw 5,000 items of debris into orbit.
In his video, lecturer Stuart Grey first takes us back to 1957, with the launch of Sputnik 1 and the space race, reports the Orlando Sentinel. The few minor objects multiply rapidly, and he has to pan out to view the entire array. NASA says it works with the Department of Defense to maintain a "highly accurate satellite catalog on objects in Earth orbit that are larger than a softball," and Houston and Moscow mission controls work together to help avoid debris "encounters." So far, no practical way of cleaning up the junk has emerged, notes CNET. Meanwhile, about one piece of debris has fallen to Earth every day for the past 50 years. (Here are five weird examples of space junk returning to our planet's surface.)