A fireball from the Eta Aquarids meteor shower, caused when Earth passes through comet junk. Deposit Photos
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The peak of the Eta Aquarids shower, a flurry of up to 30 meteors an hour, will happen soon: The best time to catch this year’s display is between May 5 and May 6. It’s the result of Earth barging through a cloud of space debris—imagine driving on the highway behind a sloppy gravel truck—but the stuff that’s disintegrating above our heads is actually dust and flakes left behind by Halley’s Comet, aka 1/P Halley.
Halley’s Comet is named after English astronomer Edmond Halley, who in 1705 used Isaac Newton’s theories of physics to calculate the its orbit. The ball of dirty ice cruises around the sun, orbiting opposite Earth’s motion to pass beyond Neptune’s path, and swings back into Earthlings’ view every 75 or so years.
This happens with such regularity that Mark Twain, born in 1835, wrote that he “came in with Halley’s Comet“; the author expected “to go out with it” when it returned in 1910. (Sure enough, Twain died in April of that year.) The last time humans could spy the object in the sky, unaided, was in 1986. Those of us around in mid-2061 will have the chance to see it again.
Humans have been spotting Halley’s Comet since at least 240 BCE, when a reference to it appears in records by Chinese astronomers. The Bayeux Tapestry, an 11th-century linen artwork showing scenes of the Norman conquest of England, includes the oldest known image of the object, depicted as a flaming star in colored yarn. Deposit PhotosHarper’s Weekly celebrated the comet’s passage with a cover illustration for its May 1910 issue. The drawing, by Elizabeth Shippen Green, shows the moon and Venus below the object. That year, Popular Sciencealso published an infographic of the comet’s orbit. The Library of CongressIn 1986, Halley’s Comet passed by our planet once again. This time, skygazers joined forces to form the International Halley Watch, bringing the most powerful array yet of telescopes and other sensing instruments to bear on the primordial dustball. Observations revealed its long ion tail contains water, ammonia, and carbon compounds. W. Liller/International Halley Watch/NASAHalley’s Comet has had its close-ups, too. In March 1986, the European Space Agency’s Giotto spacecraft took a photo tour of the comet. This montage, made by the ESA, shows snapshots of the craft’s approach. When it took the image in the bottom right, Giotto was within 1,200 miles of the comet’s dark, pear-shaped core, ultimately getting as near as 376 miles while being battered by dust in Halley’s wake. ESAHalley’s Comet is responsible for not one but two annual meteor showers: Like May’s Eta Aquarids, the Orionid shower, which peaks in the late fall, occurs when our planet collides with the comet’s remnants. Deposit Photos
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