NASA's Upper Atmosphere Research Satellite (UARS) weighs nearly 6.5 tons and it's tumbling toward Earth faster than expected. However, the chance that some of the debris that survives the entrance into Earth's atmosphere will actually hit someone are quite small.
NASA's estimated human casualty risk following UARS's re-entry is 1 in 3,200. But what does that number really mean? Orbital Debris and Meteoroid Consultant Don Kessler has an answer.
"The 1-in-3,200 probability has been interpreted by some as being 'per person,' rather than 'per 7 billion people.' That makes the chance of any one person having to worry about it to be less than 1 in 10 trillion," Kessler told Space.com.
As far as time and place of UARS's re-entry, NASA's official UARS page says it's expected during the afternoon of Sept. 23, Eastern Time. The post says the satellite will not be passing over North America during that period, but also points out that it's still too early to predict the exact time and location of UARS's re-entry.
NASA also warns against touching the debris from UARS if you happen to encounter any. Instead, you should contact a law enforcement official for assistance.
Although the risk of human casualty is very small, the story about the doomed satellite prompted some very amusing tweets. Below you'll find our choice of some of the best tweets; if you've seen others worthy of inclusion here, please share them in the comments