"Most anticipated" comet of 2024 returns this weekend after 80,000 years

Image Credit: NASA/ Brian Valente/ Greg Stein

Something absolutely fascinating is headed our way. For the first time in 80,000 years, the comet C/2023 A3 — also known as Tsuchinshan-ATLAS — is making its grand return to our skies.

The last individuals to witness this celestial spectacle were our ancestors who first ventured out of Africa.

Return of comet C/2023 A3

The comet, appearing as a faint, star-like smudge trailed by a hazy tail, should be visible just before dawn on four consecutive mornings – from Friday to Monday.

It’s important to note that comet C/2023 A3 was only discovered last year, yet scientists have determined that it visited our planet around 80,000 years ago. This estimate is based on its elliptical trajectory.

Bend in the comet’s tail

Matthew Dominick, a NASA astronaut currently aboard the International Space Station, shared a captivating video of the comet, giving us a unique perspective.

“The comet tail is noticeably longer each day. Pause the video at about 15 seconds…you can see the tail of the comet looks like it is bending,” noted Dominick.

“The atmosphere is more dense the closer you get to Earth. Changes in the density of the atmosphere change the refractive index and thus make the comet tail appear bent.”

“I was in my crew quarters reviewing the imagery when I first saw the bend in the comet’s tail. I did not see it real time when taking the images.”

Closest approach to the sun

Comet C/2023 A3 will make it closest approach to the sun on September 27. The comet will then spin around the sun and head back toward Earth.

“If this comet survives its passage by the sun, and if the amount of gas and dust it gives off does not decrease significantly, this might be one of the best comets in a long time,” said NASA’s Gordon Johnston.

“If it strongly scatters sunlight towards the Earth it might even be visible in the glow of dusk just after its closest approach to Earth on October 12.”

Spectacular sight in the skies

When the comet swings by the sun on September 27, it is expected to light up spectacularly. The comet’s diameter can stretch up to 25 miles.

Tsuchinshan will be faintly visible with a telescope in the pre-dawn hours through October 4th across most of the United States.

According to Johnston, the comet will be hidden through October 11, but will reappear in the evening sky just as it makes its closest pass to Earth on October 12.

Where to look for comet C/2023 A3

Look out for the moon in its waning crescent phase and you’ll have a guide to catch the comet. Do keep in mind, the position of the comet can change in relation to the moon, depending on the date.

Comet C/2023 A3 is approximately 157.1 million miles away from Earth and is moving closer at about 70km per second (150,000 miles per hour).

Unpredictable comet C/2023 A3

Minjae Kim, a space expert at the University of Warwick‘s astronomy department, elaborated on the comet’s behavior.

“C/2023 A3 has an orbital period of approximately 80,000 years, classifying it as a long-period comet. This means its behavior and appearance can be unpredictable, with potential changes in brightness and tail development as it approaches the sun,” Kim said.

“If predictions hold, it could be visible to the naked eye, appearing as a fuzzy star with a tail stretching across the sky. Otherwise, binoculars or a small telescope may reveal more detail in the comet’s structure and tail.”

Dusty snowballs in space

Comets are essentially balls of ice, dust, and rocks from the ring of icy material known as the Oort cloud that skirts our solar system’s outer edge.

They bring along small remnants from the formation of our solar system 4.6 billion years ago, effectively making them ancient storytellers of space.

One of the most enchanting aspects of comets like C/2023 A3 is the artwork they create in the skies.

As comets approach the sun, they begin to heat up, releasing gas and dust that form a glowing coma and a tail that streams away from the sun.

This luminous dance is a result of solar wind and radiation pressure affecting the released particles, creating two distinct tails – one of ionized particles and another comprised of dust.

Observing these tails can offer a deeper understanding of a comet’s composition and the solar forces at play – a true spectacle for both scientists and stargazers alike.

Most anticipated comet of the year

In the words of Starwalk, an astronomical app for stargazers, comet C/2023 A3 is the “most anticipated comet of the year.” And sure enough, it’s creating quite a buzz in the astronomical community.

The best viewing opportunities are expected between October 12 and October 20. During this time, Comet C/2023 A3 will climb higher in the sky each night and will slowly fade in visibility as it continues its journey out of the solar system.

Johnston noted that the best time to catch a glimpse of Tsuchinshan should be the evenings on and shortly after October 12 with the comet above the western horizon after sunset.