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Space junk to come crashing down

Global warming may cause satellites to fall back to Earth.

By Rich_Maloof Nov 12, 2012 5:15PM

Don’t look now, but there are tons of junk floating over your head.

In the past half-century we’ve launched thousands of artificial satellites into space, and they remain up there, circling our planet, whether they’re operational or not. NASA’s Orbital Debris Program estimates there are more than 6,000 tons of space junk in lower Earth orbit.

Photo: Pete Turner/Getty ImagesIgnoring for a moment that we’ve actually managed to pollute space (space!), the orbiting junkyard would seem to be a threat only to other satellites and spacecraft — that is, as long as it stays up there in orbit.

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But scientists are now concerned that global warming may cause more collisions between “dead” satellites and space debris, in turn increasing the risk of space junk crashing down to earth.

If you want to know what kind of impact a crashing space object can have on Earth, visit a town-sized impact site like Meteor Crater in Arizona. Or ask a dinosaur. Many of them are still bitter.

The problem is carbon dioxide emissions are cooling the upper atmosphere where most satellites and debris orbit. Though the greenhouse effect warms the lower atmosphere, where gases are trapped and heated by the sun, carbon dioxide has the opposite effect at greater altitudes. A cooled upper atmosphere exerts less “drag” on satellites, so that rather than orbiting through a thick soup they stream through a thinner thermosphere. The cooled upper atmosphere allows the debris to draw collectively closer to Earth and increases the chances of pieces crashing into one another.

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Even a tiny paint chip in orbit becomes a missile capable of smashing a satellite into thousands of pieces. With more debris comes a greater chance of collisions (a scenario known as the Kessler syndrome, named for Don Kessler, the "father of space junk") and more space scraps potentially in uncontrolled descent toward Earth.

A similar phenomenon is what caused Skylab to crash down. Space.com notes that nobody was hurt when pieces of Skylab rained down southeast of Perth, Australia, though the nearby town of Esperance did charge NASA $400 for littering. We also dodged disaster when the Russian space station Mir, which was as large as six school buses, fell into the South Pacific near Fiji.

But with more satellites in orbit, more collisions, and a thinning upper atmosphere, we won’t always be so lucky. More frightening was when the nuclear-powered Cosmos 954, a Soviet spy satellite, came down and spread radioactive debris over northwestern Canada.

We earthlings have become reliant on artificial satellites for communication and scientific experimentation, and we've left the dead ones up there based on the principle that what goes into orbit, stays in orbit. Until it doesn’t.

Photo: Pete Turner/Getty Images

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Nov 16, 2012 4:22AM
Silly me, I though it was because of Gravitation. I knew Galileo Galilei  and Sir Isaac Newton were a couple of wack jobs
Nov 13, 2012 8:48PM
New penalty for littering is Astral community service. Orange spacesuits for offenders who have to retrieve junk for recycling.
Nov 13, 2012 8:47PM
I was driving in my car the other day and got to work a bit shakey.  I had some object come at my car windshield at about 200 mph.  (It seemed like).  I caught it out of the corner of my eye for a very brief, brief second.  When it hit the windshield it was so hard that it only knicked it but it left a circle of white dust.  It was so fast and so hard that the glass turned into a powder.  There were NO cars in front of me, NO cars across or behind me.  I was alone driving in a wide open area.  It scared me to death!  What glimpse I got I would say it was the size of a quarter maybe.  I got to work and called my husband and told my boss.  I told them that moonrocks flew out of the sky and hit my BMW windshield..."ya right" they said.  You had to be there to understand.  Oh well.  I know and that's all that matters!
Nov 13, 2012 8:46PM
Wow, never read a more idiotic article and idiotic conclusions. Wow, just Wow!
Nov 13, 2012 8:43PM
Let me get this right as I am having difficulty grasping this science. Cooling temps in outer atmosphere cause CO2 to expand(this is opposite to what i was taught, cooling causes things to condense) causing less drag on spacecraft drawing them closer to earth(another opposite) and then the debris from the spacecrafts that collect mysteriously in close Earth orbit all of the sudden come crashing down and makes a hole in Arizona killing the dinosaurs? Is this what the writer basically said?
Nov 13, 2012 8:42PM
I have to say; The mush for brains person who wrote this article; 1. Has no clue of orbital mechanics. 2. Is promoting their own political agenda. MSN, This kind of crap should never make it to this site.
Nov 13, 2012 8:36PM
Although the science is faulty here-thinner upper atmosphere means objects retain higher velocities and stay in orbit LONGER, atmospheric drag and tidal gravity will eventually bring it all down.  Even the moon is slowing down infinitesimally, but that won't be a problem for some time.  The space junk danger is a catch-22, though.  The more launches there are, the more junk there is.  The ISS has to be moved every so often to avoid collisions.  And a paint chip impact almost penetrated a window on one of the shuttles.  Blowing up the larger pieces, like boosters and satellites would only make THOUSANDS more pieces to keep track of.  Don't know if vaporization by laser is feasible yet, but would be good practice for the world's militaries.
The good news is that approximately 100 tons (per NASA) of natural and man-made space debris falls every DAY!  Mother Nature is tidy-who knew.  If we could find a way to put less clutter up there, the skies would get clearer naturally.  I'm pulling for super-conductor powered anti-gravity ships.  Humor me, they said faster-than-sound was impossible, too.  Have a Nice Day.....Chicken Little

Nov 13, 2012 8:34PM
Interesting that the author of this is comparing the damage of a falling space object (such as a satellite) to a "town-sized impact site like Meteor Crater in Arizona", you have the scare factor cranked way up with that one, a shame there is no man made object up there that could replicate that type of damage. But it was an entertaining fictional article.
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