Eager sky watchers are turning to the heavens as Comet NEOWISE, one of the brightest comets in a generation, begins to climb higher and higher among the evening stars.
Most comets fly through the solar system invisible to humans, generally too small and dark to be seen with the naked eye. The last frozen ice ball that gave us a great show was Hale-Bopp, a comet that was visible for nearly 18 months around its closest approach to Earth in 1997.
Officially designated C / 2020 F3, Comet NEOWISE was discovered on March 27 and until this week had only been visible to committed kite viewers willing to wake up in the early hours of sunrise. But on Monday, NEOWISE fell into the sky after sunset and has even been seen by people living near urban centers with all the light pollution.
“It is the first time in 23 years that this is possible,” said Federica Spoto, an astronomer at the Harvard & Smithsonian Center for Astrophysics. “You can see it from your backyard and you don’t need a telescope.”
How to see the comet
To catch NEOWISE yourself, look up into the northwest skies about an hour and a half after sunset. Experts suggest going to the darkest area you can for better viewing. Find the Big Dipper and follow his bucket as he arches in the direction of the horizon.
NEOWISE will appear below the Big Dipper at about 10 degrees above the horizon and will be as bright as the stars in that constellation. If you extend your arm, 10 degrees is about the part of the sky covered by your fist. In the coming days, NEOWISE will move higher in the sky and be easier to detect, peaking on July 23, when it gets closer to Earth.
Good binoculars will allow you to see more of the comet and its spectacular tail of dust. Lucky viewers could even catch the fainter blue ion tail, made of charged particles flying out of the comet’s icy core. NEOWISE is only visible to observers in the northern hemisphere and should remain bright enough to detect in mid-August.
For those looking to capture a memory of their experience, a digital camera attached to a tripod and configured for a five or 10 second exposure could be the solution, said Ernesto Guido, an amateur astronomer in Italy. Many cell phones allow users to change their camera settings and achieve surprisingly good results. Guido suggested that you try to frame NEOWISE against a nice background like a tree.
An ice ball that beat the odds
Comet NEOWISE is named after NASA’s Near-Earth Near-Field Infrared Survey Explorer (NEOWISE), a space-based infrared telescope dedicated to detecting potentially dangerous comets and asteroids. Researchers running the observatory discovered the comet in March as it headed toward the sun.
Comet NEOWISE made its closest approach to our star on July 3, reaching Mercury’s orbit.
“A smaller or weaker comet would have collapsed under the pressure,” said Amy Mainzer, principal investigator for the NEOWISE mission.
That’s exactly what happened earlier this year with Comet SWAN, which was barely visible to viewers with the naked eye in the southern hemisphere, before fading while circling the sun. Another comet, ATLAS, disintegrated into more than two dozen pieces in April.
NEOWISE comes to us from the far reaches of the solar system, having spent most of its life in a frozen field of frozen bodies called the Oort Cloud. When away from the sun, comets are inert and lack their beautiful dust tails, which can be 10 million miles long. The sun’s heat causes them to expel gas and dust, forming an atmospheric layer called a coma, and then the pressure of solar radiation extends this structure into a long tail.
Comets like NEOWISE are remnants of the creation of our solar system. Since they retain the building blocks of planets in their frozen ice, they can provide scientists with important information about our origins. Mainzer compared his approach to a mission that collects samples and returns them to Earth, except that “the sample is coming to us.”
NEOWISE will not return to the inner solar system for 6,800 years. So enjoy it while you can.
“Things are really difficult right now for a lot of people,” said Mainzer. “But this is an opportunity to look up and reconnect with the big picture.”
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