The Comet A3 has been dubbed by many as the brightest comet of the year. While it has already been visible from Earth once, this weekend will be the last time it is viewable for an entire century.
That’s the bad news out of the way, now time for the good. This weekend will be when Comet A3 is at its brightest.
The brightest period of the brightest comet in years? That sounds like an event not to miss.
While there are no special tools needed to see the comet, there are a few things you need to know to make the most of the experience. We’ve listed these below, along with the best times to see it.
How and where to view the comet?
On 12 October, the comet may be visible in the sky during the evening in the UK and US. At this time, it will be at its closest point to Earth. While that might sound dangerous, it will still be 44 million miles away.
The comet will also be visible on the 13 and 14 October in the early evening.
To spot the comet passing by, look towards the western horizon straight after the Sun has set. Speed is important here as there is only a small window to catch it. The comet will disappear roughly 30 minutes after the Sun sets.
What is Comet A3?
Comet A3 originates from the Oort Cloud, a massive, distant region of icy space debris that surrounds our solar system. This cloud, sometimes called the Öpik–Oort Cloud, is believed to contain billions, possibly trillions, of objects, many of which are as large as mountains.
The comet was first spotted in January 2023. It was discovered by the Tsuchinshan Observatory, before later being identified by the South African ATLAS telescope. It was given the nickname Comet Tsuchinshan-ATLAS based on these discoveries.
The comet visits the inner solar system roughly every 80,000 years, making this quite literally a once-in-a-lifetime opportunity.
Why was Comet A3 not visible temporarily?
The comet was first visible at the end of September. Then, for a short period, it couldn't be seen. So why is Comet A3 now visible again, even brighter than before?
During this period, the comet reached perihelion – the point in its orbit where it comes closest to the Sun. As it passed, the comet was positioned almost directly between Earth and the Sun, making it nearly impossible to see.
Although the Sun made the comet difficult to see earlier, it also caused the comet to become more visible in October. After passing so close to the Sun, the comet developed a larger coma (the glowing atmosphere around it) and a longer tail due to the Sun's rays. This makes the comet brighter and more spectacular to observe.
Do you need binoculars to see Comet A3?
Comet A3 will be most visible at sunset on the days mentioned above, but you can enhance your view with a telescope or binoculars.
The comet will be easier to see in areas with little to no light pollution. So, if you're in a city, driving to a darker, more rural location will improve your view. If you're trying to spot the comet toward the end of October, when it becomes dimmer, binoculars will be essential for a clearer view.
When can I see Comet A3 next?
Comet A3 will be visible throughout October, slowly becoming harder to see as the month goes on. However, after that, there will be a long time to wait.
Comet A3 completes an orbit roughly every 80,000 years. While science is trying its best to extend our average life expectancy, 80,000 years might be pushing it.
What is a comet and why can we see them from Earth?
From Earth, comets may seem intimidating – bright, glowing balls of light streaking through the sky. However, they have a fascinating composition and origin.
Comets are massive icy bodies made of frozen gases, rocks, and dust, all remnants from the formation of the solar system billions of years ago.
They follow long, elliptical orbits that can take hundreds or even thousands of years to complete. Most comets come from the Kuiper Belt or the Oort Cloud, both located in the far reaches of our Solar System.
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