Look up and you might see a bird, a plane, or 200-pound chunks of China's space lab falling from the sky. Actually, the chance of that last one is remote, but technically possible, and now more than ever. China acknowledged last year that its Tiangong-1 lab, launched in 2011, was likely to plunge toward Earth this year or next. As the Orlando Sentinel explains, it's time to start keeping an eye skyward because the 9-ton craft has dropped below 185 miles in altitude, and things will only start accelerating from here. (You can actually track the craft here; the altitude level fluctuates.) China has narrowed the time frame of the final descent to somewhere between now and April 2018, and while most of the lab is expected to burn up in the atmosphere, astrophysicist Jonathan McDowell tells the Guardian that chunks weighing about 200 pounds could make it through.
China says it will alert the UN when the craft begins its descent, but the astrophysicist says six or seven hours is the most notice we can expect. Still, it's all but impossible to figure out where any debris might land, given that a tiny change in atmospheric conditions could move it "from one continent to the next," McDowell says. The odds are in your favor, however. No injuries have ever been reported as a result of falling spacecraft, despite the crashing of the Soviet Union's Salyut 7 space station in 1991 and the fall of NASA's 85-ton Skylab in 1979. China might be concerned, however, with what the failure of Tiangong-1, or "Heavenly Palace," means for its progress in the "new space race," per Wired. (Still, China might be heading to the moon.)