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Posted at 11:00 AM ET, 09/20/2011

Crashing NASA satellite: Are you more likely to be struck by lightning?

On Monday, Joel Achenbach wrote that “a 12,500-pound NASA satellite [the Upper Atmosphere Research Satellite (UARS)] the size of a school bus” will plummet to Earth Friday, give or take a day. NASA has calculated the odds of satellite debris beaning a person at 1-in-3,200. Multiply that by the human population of about 7 billion and your individual odds of getting whacked are about 1-in-22 trillion. That’s pretty tiny. But how do those odds compare to the odds of being struck by lightning?

Before conducting the lightning versus satellite strike comparative analysis, here are a few things to understand about this satellite and its impending collision with our planet:

* Achenbach reported this dead satellite represents the biggest piece of NASA space junk to fall to Earth in more than 30 years

* A large portion of the hefty space bird will burn up as it passes through the atmosphere. Still, Space.com notes: “re-entry specialists do expect about 26 different components from UARS to survive the plunge — a total leftover mass of 1,170 pounds (532 kilograms) – components made of titanium, aluminum, steel and beryllium.” Achenbach wrote the debris field may span 500 linear miles, with the largest surviving debris chunk 300 pounds.

* Much more likely than not, the debris will fall over the ocean.

* The U.S. land area makes up a very small part of the possible strike area (and where you happen to be much, much smaller), which spans 57 degrees north latitude north and 57 degrees south latitude.

Depending on your risk tolerance, this may or may not sound threatening. The Federal Emergency Management Agency is taking no chances and has developed a response plan in case debris impacts U.S. soil says Space.com.

But, objectively, no one should be panicking or heading into a bunker. A 1-in-22 trillion risk of being hit is truly small. So let's look at how this risk compares to the risk of being struck by lightning.

According to NOAA, the odds of being struck by lightning in a given year are 1-in-a million. Scaling that down over a period of three days, the window during which the satellite debris may rain down on Earth, the odds drop to about 1 in 120 million. So if we compare the odds of being struck by lighting or being hit by satellite debris Thursday through Saturday, you’re about 180,000 times more likely to be struck by lightning.

Feel safer now?

(Also, consider the odds of winning the Powerball grand prize are about 1-in-195 million - so you’re 110,000 times more likely to win millions than get smacked by falling space objects.)

By  |  11:00 AM ET, 09/20/2011

Categories:  Latest, Space, Astronomy

 
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