The space junkyard

8,082

The number of man-made satellites in Earth’s orbit as of December, according to a list from the United Nations’ Office for Outer Space Affairs. Since the launch of Sputnik in 1957, the number of man-made objects in low Earth orbit steadily increased by a few dozen on average each year for decades until rapidly accelerating recently. Increasing satellite and debris traffic has scientists worried about possible collisions, like one in 2009 when a dead Russian satellite smashed into a working communications array. Scientists worry that the crowdedness of orbit will lead to collisions, more debris, and even more crowdedness.

23,000

The approximate ­number of softball-sized or larger chunks of space debris NASA tracks in orbit.

21M

The total mass in pounds of all man-made objects in Earth’s orbit, according to the European Space Agency (that’s equivalent to the mass of 90 blue whales).

1,500

The total number of pieces of trackable space debris created when Russia destroyed its own dead satellite in November during an anti-satellite missile test.

15,700

The speed in miles per hour at which space junk travels in orbit, making even stray chips of paint potentially dangerous to ­sensitive craft and satellites.