The space shuttle Atlantis and the International Space Station are separately flying around the Earth until Friday, and they can be seen as a pair of bright lights in the sky at certain times over the next few days.
Weather permitting, the orbiting objects should be visible to the naked eye throughout the United States and Canada, according to SpaceWeather.com. It's a special opportunity to see the two largest man-made objects in the sky at once.
Atlantis undocked from the space station early Wednesday, ending a week-long stay to supply the outpost with spare parts. The shuttle is scheduled to land at Kennedy Space Center in Cape Canaveral, Fla. on Friday morning at 9:44 a.m. EST (1444 GMT).
Several sites can tell you when the two spacecraft are visible from your location between now and landing day:
Seeing a satellite from Earth isn't that rare: The myriad communications satellites flying around Earth regularly appear at night as stars that look to be transiting across the heavens. But the shuttle and station are both larger than any other vehicle in orbit, and should appear much brighter than the average satellite.
On a good night, the station approaches magnitude -5 in brightness, which rivals the planet Venus and is more than 25 times brighter than Sirius, the brightest star in the night sky.
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