On July 9, 2020, astronaut Robert Behnken captured an image of comet NEOWISE (Near-Earth Object Wide-field Infrared Survey Explorer) from the International Space Station. NASA
If you're old enough to remember the epic blaze of Halley's comet, which blasted by Earth in 1986, you understand how awe-inspiring a comet sighting can be.
Now, Mother Nature is back with another brilliant beacon of hope: NEOWISE (or more technically, C/2020 F3), which has returned to visit Earth as part of its 6,800-year orbital period. In the Northern Hemisphere, you can see NEOWISE on the northwestern horizon, starting after sunset. It's not visible in the Southern Hemisphere. NEOWISE is the first visible comet in decades (the last one before this was the Hale-Bopp comet of 1996-97) and is a recent find. Staerkel Planetarium at Parkland College in Illinois via email. The comet, which could be described as a carbon-laced snowball roughly 3 miles (5 kilometers) wide, traveled perilously close to the sun as it hurtled toward Earth. Comets are basically frozen leftovers from the formation of the solar system and are full of dust, rock and ice, according to NASA.
"Some comets break up near the sun, but NEOWISE stayed together and stayed bright, being visible in the morning sky in late June and early July," says Leake. "It now swings into the evening sky where it can be found in binoculars. It will be closest to our Earth on July 23 at a safe distance of 64 million miles [103 million kilometers]."
In other words, in a year that's felt apocalyptic at times, NEOWISE isn't here to blast us into extinction like the dinosaurs. Instead of doom, humanity will be treated to an amazing light show. Leake says it's pretty rare for comets to be this visually accessible to the public. Roughly a half dozen comets are discovered each year, but most don't reach a brightness suitable for backyard viewing, he says.
Just one note: This comet is not super-bright, not what astronomers call a "great comet." But it promises to be a wonderful "binocular comet," as EarthSky puts it. " Many observers have reported that - once you spot it with binoculars - you can remove them and glimpse this comet as a fuzzy object, using only the unaided eye. Using binoculars or other optical aid is a must, though, if you want to see this comet's splendid split tail," the astronomy website noted.
Comet NEOWISE is seen before sunrise, upper left, over Washington, D.C., Sunday, July 12, 2020.
NASA/Bill Ingalls
NEOWISE promises to be a sight to behold, but only for a limited time - perhaps until mid-August. Until then, its brightness - as with all comets - will be unpredictable.
"Though you may be able to see the comet from your backyard, you'll see more detail beneath a darker sky, away from city sky glow," says Leake. "Go to a spot where you have a good view of the northwestern sky and take a pair of binoculars."
Any binoculars will help but Leake advises to look for one with specs like 7x50 or 10x50. "Start looking soon after sunset when the sky isn't full dark but maybe a deep blue and you still have some of the oranges from sunset," says Leake. "Look northwest along the horizon, scanning left to right and back again, moving a bit higher in the sky with each pass."
He says the comet will almost appear star-like, but with a tail that projects to the upper right. NEOWISE's path will parallel the bottom of the Big Dipper's bowl, but just a bit further below it.
Whatever you do, don't wait. "Though we can't accurately predict the comet's brightness, as it moves away from the sun, it will fade in brightness and, maybe by the end of July, you may need a telescope to catch it," says Leake.
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The beauty of a comet happens amid the incredible forces it encounters in space. "When the comet approaches the sun, the ices vaporize, liberating the dust," says Leake. "The dust can stream behind the comet, reflecting the sunlight." That's the comet's tail, which can be millions of miles long. Comets can have a dust-based tail, which appears yellowish in photographs, and a gas tail, which looks bluish in images. The gas tail always points away from the sun.
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