There is hardly any reason at all for anyone to worry.
However, you should be generally aware there is a 12,500-pound dead research satellite flying around the world these days, lower with each orbit.
And sometime in the next few days or maybe two weeks -- no one call tell really -- this thing the size of a school bus will hurtle into the incinerating influence of the Earth's atmosphere going thousands of miles an hour and fly apart into hundreds maybe thousands of flaming pieces.
It could be quite a fiery show, even in daytime.
Scientists estimate that much of the supersonic debris will burn up during its fall to the Earth's surface.
Which is another way of saying that not all of the plummeting metal will burn up on reentry.
Although officials say they have no way of knowing where remnants of the Upper Atmosphere Research Sateliite will land, they are predicting that 26 larger pieces of the satellite totaling 1,170 pounds, will reach the Earth's surface.
But not to worry, the largest only weighs as much as an average football lineman. Kerplumpf!
Since the dawn of the space age there have been no confirmed reports of injury from falling space debris.
With the knowledge that no one else is counting, NASA officials say there is precisely a one-in-3,200 chance of anyone being struck by said unguided missiles. Which sounds pretty remote until someone notes that's much better odds than winning the lottery.
Falling space debris is actually fairly common, about one piece a day. From Vandenberg Air Force Base, the Joint Space Operations Center tracks about 22,000 manmade objects in orbit larger than four inches (there's another half-million objects between 4 inches and .4 inches).
Don't ask how they track this stuff; they'd have to kill you. But only 1,000 of those objects are working, they say; the rest is junk, like the dead satellite.
It was placed in orbit in 1991 by space shuttle Discovery to study the ozone and upper atmosphere. Superseded by more sophisticated satellites, UARS was turned off six years ago and its propellants fired to lower its path for an eventual funeral orbit.
NASA will post more frequent updates online here as reentry hour nears. While the debris footprint is likely to be 500 miles long, where that footprint will be is unpredictable. If you come upon any debris and are still alive, NASA advises not to touch it. Instead, notify law enforcement authorities.
-- Andrew Malcolm
Photo: NASA (the Upper Atmosphere Research Satellite just before release from the space shuttle arm of Discovery in 1991).