For all early risers who ventured to the US this week, you may have seen a tiny but spectacular sight in the sky before sunrise. A comet with a bright, opulent tail graced the sky early in the morning before sunrise and gave the photographers quite a show last week.
The comet is known as Comet C / 2020 F3 NEOWISE – or NEOWISE for short. Scientists just discovered the rock on March 27th. It takes its name from the NASA mission it discovered, also called NEOWISE, for Near-Earth Object Wide-Field Infrared Survey Explorer. The mission consists of a spacecraft in orbit around the Earth, which has the task of cataloging as many asteroids as possible near Earth ̵
“It was immediately clear in the discovery pictures that something was going on,” says Amy Mainzer, the lead investigator for NEOWISE at the University of Arizona The edge. “Instead of [appearing] it looked clearly blurry as a point. And that’s a good sign that this is a comet versus an asteroid. “
Comet NEOWISE and the city of Toronto, Ontario, Canada! I was up very early for this shot. It does not happen very often that we get the opportunity to see or photograph a comet of this brightness and with a tail. I hope you like it! https://t.co/BFyxFFw2DE pic.twitter.com/sGZBiEVryM
– Kerry LH (@weatherandsky), July 5, 2020
The difference between an asteroid and a comet is mainly due to ice. Asteroids are usually quite rocky. While they may have some ice in them, they look more or less like large pieces of dry rock. Comets, on the other hand, are often a mixture of rocks and all sorts of ice – including water, carbon dioxide, ammonia and more. These types of ice are mixed quite well in a comet, and it is this material that gives comets their typical fuzzy tails. The sun warms the ice and turns it into gas that envelops the comet.
This is exactly what is happening with NEOWISE. On July 3, NEOWISE came closer to the sun than Mercury’s orbit, and this flyby boiled much of the icy material and broke out as gas and dust. NEOWISE is also a fairly large comet about 3 miles (or 5 kilometers) in diameter, which is why we can get this great view from Earth. “You take something that is a really big piece of ice and stone and you park it very close to the sun. It will trigger fireworks,” says Mainzer. “Not enough to destroy it, we don’t think, but enough to really sizzle the surface and throw away a lot of material.”
NEOWISE is not a threat to our planet. In fact, this is really the only chance that any of us can see this comet with our own eyes. The path NEOWISE takes around the sun takes almost 7,000 years. This is really a one-time event. “Once in our lives and in the lives of our great, great, great, great, great, great, great grandchildren,” jokes Mainzer.
For much of the past week, NEOWISE has appeared in the northern hemisphere just above the northeastern horizon about an hour before sunrise. People could best see it with binoculars, although some claim they can see it with the naked eye. And many astrophotographers have taken stunning images of the comet in all its glory just before the sun comes out, including the astronauts aboard the International Space Station.
Around July 11, however, the comet appears shortly after sunset in the evening. It will be in the northwest sky, below the Big Dipper constellation (or Ursa Major). Mainzer expects the comet to be visible for at least another week, maybe even longer. But it all depends on how the comet behaves. “Comets are very funny, moody creatures, and it really depends on what this comet does or what it does in response to this narrow passage through the sun,” says Mainzer. “If we’re really lucky, it will stay nice and active and it should stay very bright for us.”
But it won’t take forever. NEOWISE constantly crosses away from the sun and will eventually disappear from view so that our generation will never see it again. The bright tail falls off as the comet moves further away from the heat source of our solar system. “The outer layers of the comet will settle down again and return to the cold, dark room from which it comes,” says Mainzer.
Since this is such a fleeting moment, Mainzer really encourages everyone to take a look at this tiny piece of our solar system, especially given what comets represent. These space rocks have existed since the solar system was formed 4.6 billion years ago. So you carry the ancient history of our cosmic neighborhood with you. And experiencing a little reverence for the origins of our cosmic neighborhood can be a nice break from the hardship the world is currently facing with the COVID-19 pandemic.
“Comets are a way for us to get in touch with this story and understand where we come from,” says Mainzer. “And although this moment is difficult, it connects us to the larger universe.”