November SkyTalk | Polluting Space

Pollution in its various forms is a major environmental issue today, seriously impacting the water, land and air, and the quality of life in general. In this column in the past, we have discussed one type of special concern to skywatchers everywhere—that of light pollution. But an even more disturbing and alarming one has been brought on resulting from the age of space we’re living in.

If you go outdoors and look up on any clear dark night, you typically will see one or more artificial satellites slowly crossing the sky. These range from the spectacularly bright International Space Station to faint lights at the limit of vision. Experienced skywatchers including myself have often seen as many as a dozen satellites in the sky at the same time! And binocular and telescopes users constantly see objects crossing through the field of view.

We’ve discussed various aspects of satellite-watching in this column in the past. All told, several hundred satellites are bright enough to see with the unaided eye, making it fun to lay out on a lawn chair watching for them. But these are only the vanguard of a vast horde of man-made objects now orbiting our planet. NORAD itself is currently tracking some 17,000 separate objects in Earth orbit, ranging in size from hundreds of feet across (the ISS) to objects the size of a golf ball, including shattered pieces of rockets and spacecraft.

An abrupt rise in the number of orbiting objects occurred in 2007 when the Chinese government intentionally destroyed one of its own weather satellites with an anti-satellite missile. This resulted in more than 2,000 pieces of trackable fragments and an estimated 150,000 pieces of space debris!

Several years ago one of the Space Shuttle’s multi-layered windows was nearly penetrated by a tiny piece of space debris and several satellites have been damaged or taken out of operation by collisions with larger pieces of junk. One major worry is that of something impacting the International Space Station itself. A recent plot of objects in low-earth orbit shows our beautiful Planet Earth ominously surrounded by what looks like a swarm of bees. There seems to be little respect or concern for the environment of space by the dozen countries now launching objects into orbit on a routine basis.

In his inspiring and delightful autobiography Starlight Nights: The Adventures of a Star-Gazer, famed observer Leslie Peltier laments having constantly seen satellites during his all-night vigils of the sky: “All too well I realize that I have been witness to mankind’s latest pollution in the names of progress—the contamination of the skies. So much that man touches he destroys.” (All nature- and star-lovers should read—and reread—this book, available from ).

— James Mullaney
Former assistant editor at Sky & Telescope magazine & author of nine books on
stargazing. His latest, Celebrating the Universe!, is available from