Each year, when Earth collides with the comet's orbit, vaporizing debris comes flying into our atmosphere at a whopping , miles per hour, according to NASA , making the meteors well known for their speed. Fast meteors tend to leave glowing dust "trains" behind them, producing magnificent "shooting stars. Under normal conditions, the annual meteor shower typically produces about 30 meteors per hour. It's named for its radiant, or direction of origin, which appears to come from the constellation Aquarius.
The Eta Aquarids are one of the best meteor showers of the year for people in the Southern Hemisphere, because Aquarius is higher in the sky there — but it's visible in the northern hemisphere, too. The shower is visible in both hemispheres, with the best viewing occurring just before dawn on Wednesday. Locating the radiant point is not necessary for viewing — all you need to do is look up.
Viewing in the southern hemisphere is preferable, but not necessary. Another appearance of the comet in possibly inspired Italian painter Giotto's rendering of the Star of Bethlehem in "The Adoration of the Magi," according to the Britannica encyclopedia. Halley's most famous appearance occurred shortly before the invasion of England by William the Conqueror. It is said that William believed the comet heralded his success.
In any case, the comet was put on the Bayeux Tapestry — which chronicles the invasion — in William's honor. Astronomers in these times, however, saw each appearance of Halley's Comet as an isolated event. Comets were often foreseen as a sign of great disaster or change. Even when Shakespeare wrote his play "Julius Caesar" around , just years before Edmond Halley calculated that the comet returns over and over again, one famous phrase spoke of comets as heralds: "When beggars die there are no comets seen; The heavens themselves blaze forth the death of princes.
Astronomy began changing swiftly around the time of Shakespeare, however. Many astronomers of his time held that Earth was the center of the solar system, but Nicolaus Copernicus — who died about 20 years before Shakespeare's birth — published findings showing that the center was actually the sun.
It took several generations for Copernicus' calculations to take hold in the astronomy community, but when they did, they provided a powerful model for how objects move around the solar system and the universe. The comet appeared in , and Halley suggested the same comet could return to Earth in Halley did not live long enough to see its return — he died in — but his discovery inspired others to name the comet after him.
On each successive journey to the inner solar system, astronomers on Earth turned their telescopes skyward to watch Halley's approach. The comet's pass in was particularly spectacular, as the comet flew by about On that occasion, Halley's Comet was captured on camera for the first time.
It is coming again next year, and I expect to go out with it. When Halley's Comet came by Earth in , it was the first time we could send spacecraft up to look at it.
That was a fortunate occurrence, as the comet ended up being underwhelming in observations from Earth. When the comet made its closest approach to the sun, it was on the opposite side of that star from the Earth — making it a faint and distant object, some 39 million miles away from Earth. Several spacecraft successfully made the journey to the comet.
We know this because it returns to the inner Solar System every Others think it could evaporate within 25, years, or collide with something.
Halley's Comet over Uluru, outback Australia, Largely because we were able to get a close look. Or, at least, the science community was. Many people alive at the time think they saw it, but it was only slightly brighter than Polaris, the North Star. Now look down towards the horizon to find the very bright star Sirius. Because of what English astronomer Edmond Halley deduced about it.
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