Space Junk Around Earth. Is It a Problem or Not?

I love watching my garbage hauled away. Maybe it’s a guy thing; I don’t know. Whatever the reason, I get a thrill when the weekly truck arrives. I watch them approach with all the excitement of a teenager getting a call from their new boy or girlfriend. I see them as saints and sometimes visualize them clothed in saffron robes.

What has this to do with astronomy? More than you’d think. 

• You’ve read about the hundreds of old, nonfunctioning satellites that simply orbit, waiting to collide with another. 
• You’ve perhaps heard of Ann Hodges, who was injured on her thigh by a meteorite that was an asteroid fragment (they all are, actually) in 1954 in Sylacauga, Alabama. 
• You’ve seen movies and maybe played video games depicting asteroids as menaces—scary risks for future astronauts heading out to Mars and beyond, where they’re most numerous. 
• And, anyone with a telescope can see the result of countless asteroidal rocks that created craters after impacting the lunar surface at speeds averaging 20 miles a second. There’s junk up there!

What is Space Junk?

We’re mainly talking about disused satellites, debris from rocket-launching material, and other man-made fragments left behind in space. 

Once the junk’s left behind, it doesn’t usually come down. If it did, the junk reenters Earth’s atmosphere would burn up before it ever reached Earth. 

I collect it. When I was on Letterman, I surprised him by suddenly standing up, fishing in my back pocket, and plopping a baseball-sized meteorite on his desk. He asked about the value of it, and I sensed he would have loved for me to gift it to him, but I couldn’t do it since I used it regularly in my classes and to demonstrate how genuine meteorites attract a magnet. 

The point is that there’s a definite fascination with all this celestial debris, which raises the central question. Is there too much? Is it worrisome?

Is Space Junk a Problem?

Despite occasional talk about trying to clean up all those old satellites and those consulting firms looking to make a buck, 
the “junkosphere” surrounding our planet is pretty harmless. 

And asteroids are fascinating. Four of them are hundreds of miles wide, and one, Vesta, is white enough to be dimly seen by the naked eye every few years for those who live under dark skies outside of cities.

The rest can be divided into any of several classification schemes. 

1. One is based on composition, which in turn arose depending on whether it was originally part of a larger body’s interior or exterior. This means it can be stony, with visible interior flecks of material, or else nickel-iron, which is uniform through and through. If etched with acid, its interior will form a strange criss-cross pattern called Widmanstatten lines.
2. The other class is based on where it orbits. Though most roam between Mars and Jupiter, many have orbits that intersect our own, and then there’s a collision risk. These are the NEAs or Near Earth Asteroids. If big enough, one of these can cause a mass extinction like the one that crashed just off the Yucatan Peninsula 66 million years ago and changed the view out our windows from dinosaurs to chipmunks.

However, we can generally relax since there are far fewer solar system objects than most imagine. That’s why they call it space.

What are the chances of an object hitting Earth? Read on.