From satellite parts to hail, the skies teem with hard objects, and every now and then those objects fall to Earth. Then again, the sky is a big place, as is the surface of the earth, and a human being is relatively tiny. So just how likely is it to be hurt by something from aloft?
With that thought in mind, albeit at a potentially catastrophic scale, the US Congress a decade ago asked NASA to track all “near-Earth objects”—asteroids, meteors, and meteorites—larger than 1 kilometer in diameter. In 2005, this size requirement was reduced to 140+ meters, or roughly the height of the Washington Monument. Today, NASA no longer has the funds to track these smaller NEOs. Pending further government appropriations, NASA may not be able to sustain its NEO-detection at all.
Minus a detection system, will the odds of getting hit by a falling object go up? Not particularly, no. The average Earth denizen just won’t know about it ahead of time.
Still, Chicken Little may have had a point about the sky falling, or at least providing a good reason to look up every now and then. Here are falling objects to consider:
Asteroids and meteorites. Major asteroid collisions with Earth—involving objects larger than 1.5 kilometers, the minimum size required for “global consequences”—happen very rarely, roughly once every 100,000 years. Congress’s concern, then, extends mainly to objects large enough to do significant damage. Like whatever caused the Tunguska Explosion. In 1908, something detonated over a remote region in Siberia, leveling a region of land the size of Rhode Island. Scientists believe it was a meteorite with a diameter of roughly 200 feet. Objects of that magnitude, however, only fall to Earth about once in a millennium. Smaller meteorites enter Earth’s atmosphere daily, of course, but most burn up long before reaching the ground.
The odds of actually being hit by a meteorite are infinitesimal: only four people in recent history have been struck by one. The most famous (and documented) is Ann Hodges, who in 1954 was struck by a 7-inch meteorite in Sylacauga, AL. The object crashed through her roof and bounced off a wood-console radio before striking her in the side. In another case, in 1927, a meteorite struck a Japanese girl in the head—whether directly or indirectly is unclear. More recently, a Ugandan boy was indirectly struck in the head by a marble-sized meteorite (it ricocheted off a palm tree first), and just this year a pea-sized meteorite struck German teen Gerrit Blank in the hand—the only direct hit ever recorded, not to mention survived. However, according to Discover Magazine’s ” Bad Astronomy” blog, Blank’s story is either a hoax or drastically embellished.
Hail. The odds a person will be injured by hail in a year are 1 in 5,114,000. According to the National Weather Service, 718 people were injured by hail between 1995 and 2007. And the number killed? Just five. The odds a person will be killed by hail in a year, then, are 1 in 734,400,000.
Blue Ice. There are several known cases of houses being struck by frozen airplane-lavatory waste, euphemistically known as “blue ice.” The ice can form when a plane’s lavatory develops an external leak; frozen at high altitude, the waste warms and dislodges as a plane descends. Luckily, there are no known instances of people being struck by blue ice.
Aerospace Junk (Satellites, Space Stations, Weather Balloons). In the 52 years since the launch of Sputnik 1, there have been no recorded instances of death caused by falling satellite, shuttle, or space station parts. (The US and Russian space programs have certainly seen their share of fatalities, but all of them occurred to aerospace personnel.) Weather balloons, because their payloads deploy parachutes when falling, rarely cause injuries. In September of this year, however, a boy in Colorado, while not struck by a falling National Weather Service balloon, was subsequently electrocuted when he tried to pick it up.
Suicide Jumpers. At least one case exists in which a person has been struck and killed by another (falling) person: just this year, a Ukrainian man was crushed and killed in Barcelona by a 45-year-old woman who had thrown herself out of her 8th-story window in an act of apparent suicide.
Bricks. Like Newton’s apple, falling masonry can, and occasionally does, provide a painful reminder of gravity’s existence. Just last year, Yuet Lau (58, of New York City) was struck in the head by falling bricks. Fortunately, Lau was not seriously injured. Further instances, while not always recorded, occur every year. The Bureau of Labor Statistics reports an average occupational death-toll of 16.5 fatalities per year caused by “bricks, blocks, [and] structural stone” (1992-2002).
Pennies. Empire State Building + dropped penny = fatality, or so the myth goes. In reality, there are no recorded instances of a falling penny (or any coin, for that matter) injuring/killing a pedestrian. The popular science show Mythbusters disproved this urban legend based on a penny’s light weight and low terminal velocity (64 mph), going so far as to fire a penny at a co-host’s hand at the correct velocity. It merely left a welt.
Coconuts. They do not, as occasionally claimed, “kill around 150 people worldwide each year” (see the Straight Dope’s thorough debunking of this claim), but coconut-related injuries are reported every year. A report by the ANZ Journal of Surgery states that, in 5 years, 19 people were admitted to the Solomon Islands’ Central Referral Hospital with falling-coconut-related injuries: “16 patients had a coconut fruit fall on them,” and a further “three patients had a coconut palm [i.e. the whole tree] fall on them.