Comet NEOWISE has been entertaining space enthusiasts across the Northern Hemisphere. Although its official name is C\/2020 F3, the comet has been dubbed NEOWISE after the Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE) space telescope that first noticed it earlier this year. This \u201cicy snowball\u201d with a gassy tail made its closest approach to the sun on July 3 and is now heading back from whence it came: the far reaches of the outer solar system. Its long, looping orbit around our star ensures that after passing closest to Earth on July 22, Comet NEOWISE will not return for some 6,800 years.<\/p>\n
Even though the comet is now bright enough to observe with unaided eyes, inexperienced stargazers might have trouble knowing when and where to look. Scientific American<\/em> spoke to Jackie Faherty, an astronomer at the American Museum of Natural History in New York City, for observing tips and a better appreciation of why comets are so special.<\/p>\n [An edited transcript of the interview follows<\/em>.]<\/p>\n How does one prepare to watch Comet NEOWISE with the naked eye?<\/strong><\/p>\n Find the darkest possible swath of sky and make sure your eyes are adjusted so that you give yourself the best possible opportunity to see faint objects. It means: don\u2019t just walk outside after staring at lights or screens and expect to see [the comet] really well. You need 15 minutes or so to adjust your eyes, so that your pupils are adjusted, and they\u2019re used to seeing fainter things. It\u2019s the same as walking into a dark room, and everybody knows that [you] can\u2019t see [things] first\u2014and then, all of a sudden, you start seeing things. You need to do the same thing when you walk outside. And use the Comet NEOWISE app developed by astrophysicist Hanno Rein of University of Toronto Scarborough to see exactly where it is, so that you know what direction you need to look. And then the key would be to find yourself a place that is the darkest possible, that [has] no lights.<\/p>\n Which direction should one look?<\/strong><\/p>\n [The comet] appears [in the evening] in the northwestern sky. But the easiest thing is [to use] the app to help you [find it].<\/p>\n When is the best time to watch?<\/strong><\/p>\n We\u2019re going to catch [the comet] in the evening sky. We\u2019re calling it primetime viewing, which is when the sun has just set.<\/p>\n Will Comet NEOWISE be brightest when it\u2019s closest to us?<\/strong><\/p>\n Well, it\u2019s a trade-off. When [the object is] closer to the sun, it\u2019s getting heated up. And so it\u2019s brighter because it\u2019s outgassing [warming so that its ice turns to vapor], and it\u2019s got the light reflecting off of [the gas]. [But] you couldn\u2019t really see it [earlier], when it was in the glare of the sun.<\/p>\n And when it\u2019s closer to us, it gets brighter, because of [the decrease in] distance. Something that\u2019s closer to you is going to be easier to see, even if it\u2019s fainter.<\/p>\n Would we be able to see the comet in megacities such as New York and Los Angeles?<\/strong><\/p>\n I have seen shots [from] residential areas in L.A. And I can\u2019t believe that people saw the thing through the light pollution in L.A., which I would have thought would be worse than [in] New York City.<\/p>\n What I often advise people during meteor showers, which are similar in some ways, is to go to rooftops. A rooftop can give you a very clear view to the horizon, and it\u2019ll let you get away from light pollution.<\/p>\n Upper Manhattan\u2019s Inwood Hill Park is always an excellent spot for low light pollution in [New York City], or toward the piers on the West Side. New Jersey is not so bad with light pollution when you\u2019re looking in that [northwestern] direction. The Intrepid Sea, Air & Space Museum used to have an excellent spot for stargazing on [its] platform. And amateur astronomers used to go to the High Line [in the neighborhood of Chelsea]\u2014that\u2019s a nice darkish area.<\/p>\n Does it matter where in the U.S. you\u2019re located?<\/strong><\/p>\n [Your location] will change how high above the horizon [the comet] gets for you. But because this is Northern Hemisphere\u2013accessible, the U.S. has a visibility window that\u2019s excellent for the country. I\u2019ve seen the shots from New York to California to Florida.<\/p>\n Would someone be able to take a good picture using a smartphone?<\/strong><\/p>\n Your best [bet is] to have [a smartphone\u2019s camera] on a longer exposure. The longer the exposure, the better the picture, because [the comet] is faint, and you will see it as this fuzzy thing. Your eye can\u2019t quite do that for you. You make your eye open, but it can’t record the photons and let them accumulate, and that\u2019s what the camera is able to do.<\/p>\n What is the comet going to do next?<\/strong><\/p>\n [After] July 22, it gets dimmer and dimmer as it gets farther from Earth. And it very quickly becomes something that you cannot see with your naked eye, even on the clearest night. But [with] binoculars or a telescope, we\u2019ll still be good for seeing it for a while. Then it goes off to the outer part of the solar system, and it\u2019ll be gone for a couple thousand years before it makes the trip back. It has a long orbit around the sun; most comets do. It takes them hundreds or thousands of years in order to go around the sun. They [mostly] hang out in the outer part of the solar system.<\/p>\n Why should anyone care about comets?<\/strong><\/p>\n If you could capture the comet and bring it back down to Earth and study it in a lab, you would have one of the holy grails for understanding the ingredients to make a planet\u2014and possibly to make it habitable. Like, \u201cHow did life get delivered here?\u201d Comets are one of the things we look to for answers. They\u2019ve got all that primordial material that was around to form the planet that would become Earth\u2014being filled with water and have life teeming on it. So from that perspective, a comet is a really important object to study. But we can\u2019t capture it and bring it back down here.<\/p>\n We\u2019ve attempted to land on a comet before. We did this with Comet 67P. It was a European mission, and the whole thing was called Rosetta, with this Philae lander. [Now] we have a really cool mission called OSIRIS-REx. And this is a mission to an asteroid called Bennu that is going to land, acquire a sample and return it to Earth, which is awesome and crazy.<\/p>\n Comets were often markers\u2014omens\u2014before we understood what they were. That\u2019s how people saw them\u2014the bearers of good things, the bearers of bad things. I find it fascinating that in this year 2020 we have a marker in the sky. And it\u2019s a reminder that we should look up more. We should pay attention to the sky [and what] it brings us.<\/p>\n Can anyone predict when the next bright comet will come?<\/strong><\/p>\n Can we predict the next naked-eye-exciting comet, the one that\u2019s going to come in and wow us all the way that NEOWISE is wowing us right now? There are some that are lining up that will make a good appearance\u2014such as Halley\u2019s Comet, for instance. That orbit is like 80 years or something. So we know when [that comet is] coming; we know when it\u2019s going. But [what] you want to know is: \u201cIs there going to be one next year? Is there going to be one next month?\u201d Unfortunately, comets are just unpredictable, erratic beasts. You don\u2019t know what\u2019s going to happen to them as they get close to the sun. Sometimes they just break apart. Comets are notoriously unpredictable. So I can’t tell you the next one.<\/p>\n The NEOWISE space telescope is monitoring the sky, looking for these kinds of things. And there are several different surveys that are on the lookout for objects that are going to come close to Earth. But who knows when they will find them. That is the beauty of science: scientists are looking at the data every day and trying to find something.<\/p>\n<\/div>\n![\"Comet](\"https:\/\/static.scientificamerican.com\/sciam\/assets\/Image\/2020\/GettyImages-1255846108.jpg\")
![\"Comet](\"https:\/\/static.scientificamerican.com\/sciam\/assets\/Image\/2020\/GettyImages-1255954895.jpg\")