Here’s how to see a once-in-a-160,000-year comet next week

Here’s something that you’ll kick yourself if you miss – a comet that only grazes the Earth every 160,000 years will be visible next week.

Comet G3 ATLAS (C/2024) was first spotted in April 400 million miles away when it was 158,000 times dimmer than the faintest star.

But by Monday, astronomers expect the comet to be so vibrant it could rival the brightness of Venus in the night sky.

The comet will reach peak perihelion – when it is closest to the sun – on Monday before returning to the darkest depths of the cosmos.

As you read this, the comet is around 151,800,000 kilometres from Earth, according to the observational tool TheSkyLive, and is getting closer by the second.

What is a comet?

Like all comets, G3 ATLAS is basically one big dirty snowball. Made of the icy leftovers from when the solar system first formed, it begins to melt as it approaches our star, causing it to grow a wispy tail.

G3 ATLAS is no stranger to Earth. Scientists believe that it has at least once before made the trip from its home a trillion miles away, the icy bubble around our solar system called the Oort Cloud, to the sun.

This means that unlike some comets, which melt altogether when passing a searing hot star, G3 ATLAS may survive to soar another day.

To give some perspective on its 160,000-year-long orbit, Neptune, the planet furthest away from the sun, takes 165 years to do a solar lap. Pluto, meanwhile, takes 248 years.

The Asteroid Terrestrial-impact Last Alert System (ATLAS) discovered the comet on April 5.

When and where will I see the comet?

In what could be humanity’s last chance to see the comet, we’ve either got good news or bad news for you, depending on where in the world you are.

G3 ATLAS will be in the constellation Sagittarius, meaning it’ll only be visible in the Southern Hemisphere.

Your best chance is right after sunset from mid-January to the rest of the month, visible low on the horizon in the eastern sky just before sunrise or the western sky just after sunset.

Monday, however, will be when it’s at its brightest; you won’t need a telescope or binoculars to see it. The comet will be coming three times closer to our star than Mercury and 10 times closer than the Earth.

Astronomer Gideon van Buitenen predicts that the comet will be three times brighter than Venus on the day. This is because of something experts like him call forward scattering – dusty space debris scatters light from the sun directly to those down below on the Earth.  

In-The-Sky predicts G3 ATLAS will be as bright as magnitude -6.9 on Monday, so will be visible in the daytime. It will, however, come within five degrees of the sun, making it dangerous to look at in the daylight without specialist equipment.

Astronomers believe G3 ATLAS will be low in the sky at first but after January 16 will gradually leave the sun’s glare.

There’s a slim chance that people on the other half of the globe will be able to spot it, just not with the naked eye. The further south in the Northern Hemisphere you are, the higher your chances.

The snowball was captured as a tiny wisp against the orange sunrise above Sicily by a photographer earlier today, according to Astronomy Magazine.

After perihelion early next week, stargazers in the Northern Hemisphere are recommended to try to catch a glimpse of G3 ATLAS after sunset.

How can I see G3 ATLAS?

As with most celestial events, artificial light and tall buildings are your biggest enemies. Use maps like this one to see where the darkest place near you is.

Grab a pair of 7×50 binoculars if you can and either head out to your nearest, tallest hill or take a trip to a flat shoreline.

Spend about half an hour outside in the dark before you start viewing, this gives your eyes some time to adjust.

Get in touch with our news team by emailing us at webnews@metro.co.uk.

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