A 20-year-old satellite is expected to crash into Earth later this week, and the debris has a roughly 1-in-3,200 chance of hitting a person, NASA officials say. (To be clear: that's the odds that any of the wreckage will hit any of the planet's 7 billion people, not the odds of hitting any specific person.)
NASA’s current projections show that the Upper Atmosphere Research Satellite – or UARS (pronounced: YOU-arz) if you want to sound cool – will finally succumb to the Earth’s gravity in the next several days, with an expected impact on Friday.
But, as the Washington Post explains, even actual rocket scientists can’t say for certain when – or where – impact will occur:
Out-of-control crashing satellites don’t lend themselves to exact estimates even for the precision-minded folks at NASA. The uncertainty about the “when” makes the “where” all the trickier, because a small change in the timing of the reentry translates into thousands of miles of difference in the crash site.
NASA officials have said that the drop zone for the UARS could be anywhere between the latitudes of northern Canada and southern South America, an area that includes pretty much the entire planet. Still, they say that the chances that someone will be injured during the impact is extremely remote and that, most likely, the satellite will land with a splash in a body of water, according to Space.com.
The satellite is expected to partially burn up during reentry, but plenty of space souvenirs will likely survive. Scientists predict the satellite will break into about 100 pieces, with about a quarter of them likely to remain after the re-entry burn. The largest surviving piece could weigh as much as 300 pounds
http://slatest.slate.com/posts/2011/09/1...riday.html
