If you look to the heavens this week, you might catch a glimpse of a green comet streaking through the night sky.
That comet is the newly discovered C/2022 E3 ZTF which should be visible for most of this week. It will make its closest orbit to earth 26 million miles away on Wednesday.
Teacher at Riverview Collegiate in Moose Jaw and science enthusiast James Irving said one of the most common questions he gets about the comet is “why the long name?”
He broke it down that C/2022 refers to a comet that was discovered in 2022. For E3, he said in astronomy the date of discoveries is broken down into half-months and assigned a letter. In this instance, the ‘E’ is for the fifth half-month and the ‘3’ is the third object discovered in that half-month.
Finally, ZGF refers to the Zwickie Transient Facility at the Palomar Observatory near San Diego where the comet was discovered by astronomers Bryce Bolin and Frank Masci.
The last time this comet came near earth was about 50,000 years ago.
Although it will be the closest on Wednesday, Irving said that isn’t necessarily the best day to see it depending on a number of factors.
One of those factors is light pollution. Irving said you won’t be able to see the comet from the city limits and your best bet is to head out to the country where it is dark. He added that there will be a full moon on Sunday which could also play a factor.
Irving said seeing the comet with the naked eye could be tough, but you should get a decent view with binoculars or a telescope with a clear sky. He said the cold weather is actually a blessing for stargazers as the air holds less moisture and dust, giving you a clearer view.
He explained the difference between asteroids and comets.
“An asteroid is a solid rock and metallic material, whereas a comet, I think the best way to describe it is like a big snowball or shaved ice ball would be the best way of putting it,” Irving said.
Because of the frozen gases that make up the comet, C/2020 E3 ZTF has a distinct coloured glow. As the gases and dust vapourize, the reflection from the sun gives it a greenish colour as it streaks through the sky.
Irving said the best time to view the comet is just after dusk as the sky gets pitch black but before there is any moonlight. The comet should be visible a bit to the northeast just above the horizon between the Big Dipper constellation and the North Star for the next few days.
This particular comet will likely not pass this close to the earth for another one to two million years. Irving said what’s interesting about this comet is that it has an open orbit so there is a possibility it could completely exit the solar system instead.
"There are a lot of factors on whether it will continue the orbit it has or if it will radically change based on a lot of things like out-gassing and scientific stuff, so millions of years from now we may see it again,” he explained.
For those interested in looking for the comet, Irving says there are several good websites and apps available for tracking comets.