Roy Exum: Gracious! It’s A Comet!

  • Tuesday, July 14, 2020
  • Roy Exum
Roy Exum
Roy Exum

There is a once-in-a-lifetime experience going on above us and it will put any child under the age of 99 years young absolutely in awe. On March 27, a NASA spacecraft known as NEOWISE (that stands for ‘Near-Earth Object Wide-Field Infrared Survey Explorer) was circling planet Earth in an effort to categorize as many asteroids as possible that are non-threatening yet orbit close to Earth and near the USA. On that day, the team aboard realized they had discovered something they never expected to find – a huge and quite rare comet.

Asteroids have been around in space for an estimated 4.6 billion years.

About once in, oh, best guess a lifetime, there will come along an asteroid that is more than just a big dry rock. No, if the asteroid is a special something, it will contain vast ice fields and emit gases such as water, carbon dioxide, ammonia, and similar stuff. 

As its orbit nears the sun, the asteroid gets all heated up, and these gases create a spectacular fuzzy coat over the asteroid, making it appear fuzzy and creating a tail which most can see with the naked eye. It became a comet!

Most people go their entire lives and never see a comet, or even know what one is. This one is huge, which is why we can see it – after all, the thing is 64 million miles away. Since the NASA Space Station discovered it, the official name is “Comet C/2020 F-3 NEOWISE,” or NEOWISE for short, and this one is about three miles wide. 

“When you take something that is a really big hunk of ice and rocks all mixed together, and you park it very close to the sun, it’s going to set off some real fireworks,” explained Amy Mainzer. “It isn’t enough to destroy the comet – we don’t think – but enough the make the surface sizzle and throw off a lot of material.”

Mainzer, the principal investigator of NEOWISE, who is at the University of Arizona, said the astrophysicists and astrophotography experts have had a bonanza these last two weeks every dawn and now the early-night opportunity is just as enticing.

In early July people anywhere in the United States could see the NEOWISE comet best before dawn. But over last weekend it has now started appearing just after nightfall. You can see it in the northwestern sky, just under the constellation “The Big Dipper,” and, while it is better seen with binoculars, telescopes and cameras with magnifying lens, many a naked eye has seen it as well.

Sunset tonight will be at 8:55 p.m. As darkness rapidly follows, the NEOWISE comet will linger for an hour or two.

It is hoped the comet will be visible for this week and more, but Mainzer warns, “Comets are very funny, fickle creatures, and it really depends on what this comet decides or what it does in reaction to this close passage by the sun,” she explained. “If we are really lucky, (the comet) in going to stay nice and active, and really bright for us.”

The comet will orbit our way again, but the bad news is the NEOWISE comet takes 7,000 years to orbit the sun. “We will never see it again. This is truly a once-in-a-lifetime experience.” 

Mainzer explained our fascination. “Comets are a way for us to get in touch with that history and understand where we come from a little bit. And even though this moment in time is difficult (with the coronavirus), the comet connects us to the bigger universe.”

No matter. In less than three weeks, the NEOWISE comet will slip from view for another 7,000 years. Never allow such a special opportunity to go unnoticed.

royexum@aol.com

Comet NEOWISE over Chattanooga
Comet NEOWISE over Chattanooga
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