A comet that hasn't been seen from Earth since Neanderthals were alive has reappeared in the sky, and astronomers say it can be seen with the naked eye.
Comet C/2023 A3 (Tsuchinshan-Atlas) was discovered by astronomers early last year and is thought to orbit the Sun every 80,000 years on a highly elongated path.
Dr Gregory Brown, senior astronomer at the Royal Observatory Greenwich, said the comet is thought to have originated in the Oort cloud, which lies beyond Neptune's orbit.
"[It is] the huge, roughly spherical region around the Sun that has icy remnants from the formation of the solar system," he said.
But now the comet is at our end of the glactic. After making its closest approach to the Sun late last month, it is expected to do the same to Earth around October 13.
"Comets are brighter the closer they are to us, to Earth, but also the closer they are to the Sun, the brighter they are. So the closest approach doesn't necessarily have to be the brightest," Brown said, noting that it could happen around Oct. 9 instead.
At that point, however, the comet will be almost exactly between Earth and the Sun. As a result, Brown said, the best time to look would be a few days before and after.
"Comets that are visible to the naked eye are rare enough, and this one has the potential to be among the brightest we've seen in the last few decades. So it's certainly worth a try," he said.
Brown said it is difficult to determine how bright the comet will become as it gets closer. "It seems that under good conditions it is already visible to the naked eye and is likely to get significantly brighter," he said. "But how bright? Frankly, we don't know."
Brown added that observers in the northern and southern hemispheres have a chance of catching a glimpse of the comet.
Currently, he added, viewers should look east early in the morning before sunrise, toward the constellation Sextant. | BGNES
