Originally published 1 September 1986
Thirty-one years ago [in 1954], Ann Hodges was sleeping on her living room couch in Sylacauga, Ala., when a 8‑pound rock crashed through the roof of her house and hit her on the side. Life magazine published a full-page photograph of Hodges displaying her bruise and her unwanted trophy from the sky.
Hodges’ bruise has become a permanent footnote in the history of astronomy. Hers is the only well-documented case of a person being hit by a meteorite.
There is lots of stuff flying around out there. Chunks of rock and iron rain down upon the Earth all the time. It has been estimated that every year the Earth gathers up 100,000 tons of meteoric material from space. Most of this material burns up in its passage through the atmosphere, but five or six times each year someone witnesses the fall to the surface of a meteorite of substantial size.
Especially in late summer, when we have several of the brightest meteor showers, one is inclined to look up into the night sky a bit apprehensively. And although one does not generally think about meteors in daytime, they are falling down on us then too, out of the blue. It is natural to wonder if Hodges’ cosmic accident could happen again.
Charting the odds
As reported recently in Sky & Telescope magazine, a trio of Canadian astronomers have tried to estimate a person’s chance of being struck by something from the sky. Ian Halliday, Alan T. Blackwell, and Alan A. Griffin of the Herzberg Institute of Astrophysics studied photographs of meteor tracks made over a period of nine years in Western Canada by 60 automatic cameras. They combined the results of the photographic survey with data on the size, number, and weight of meteorite fragments recovered on the ground.
The Canadian astronomers confined their study to North America. And they made the assumption that the typical North American spends 95 percent of the day indoors, which would protect that person from any meteorite weighing less than about half a pound. Putting it all together — the photographs, the recovered fragments, and population characteristics — the Canadians calculate that on an average of once every 180 years, a North American will be struck by something falling from the sky. An extrapolation to the world’s 5 billion people suggests a hit rate of once every nine years. Hodges’ accident is rare, but apparently not unique.
The history of human interest in things falling from the sky has had several curious twists and turns. Pliny the Elder, the Roman natural philosopher, described stones that fell from the sky and chunks of iron that resembled sponges. In this, he was a perceptive observer. But he also recorded a rain of milk and blood, and a rain of flesh. Once, he tells us, wool fell from the sky, and on another occasion it rained baked bricks.
Denial by decree
The less credulous contemporaries of Galileo and Newton thought stories of rocks from the sky — not to mention wool and baked bricks — smacked of superstition. In the 18th century, the prestigious Academy of Sciences at Paris attempted to put an end to the nonsense once and for all by simply decreeing that objects could not fall from the sky, whereupon European museums tossed out valuable collections of authentic meteorites. In America, when two Yale professors described a meteorite that fell in Connecticut, Thomas Jefferson is said to have remarked, “It is easier to believe that Yankee professors would lie, than that stones would fall from heaven.”
But the Yankee professors didn’t lie, and eventually their view prevailed. Stones do fall from heaven. The largest metallic meteorite that has been recovered weighed 60 tons and fell in South West Africa. The largest recovered stony meteorite fell in the Kirin Province of China in 1976 and weighed about two tons. Meteorites show no preference for geographic location. About 25,000 years ago a chunk of iron weighing 20,000 tons smashed into Arizona and knocked a hole in the ground a half mile wide.
Stones will continue to rain down from heaven, and there is nothing we can do to stop them. If an object the size of the Arizona meteorite fell into the Atlantic, it would set up a tidal wave that would devastate coastal cities. At intervals of tens of millions of years something is going to hit the Earth that will wreak havoc for entire populations. There is growing evidence that it was some sort of celestial bombardment that wiped out the dinosaurs.
Should we take out insurance against the possibility of being struck by a meteorite? Of course not. But if the Canadian astronomers are right, every decade or so, someone, somewhere is going to get knocked on the head.
Your writing is fantastic.