Comets are some of the most captivating and mysterious celestial bodies in our solar system. These decaying leftovers from the dawn of time consist of rock and dust formations made up of elements in chemical compounds from the earliest days of our solar system. From ancient times, cultures believed comets to be signs of something wondrous to come or a harbinger of terrible fortune, with some even claiming that the Star of Bethlehem guiding the three wise men to see the newly born Jesus Christ was actually a comet. In 2023, a new discovery unveiled that we will soon have a never-before-seen comet passing through our sky, rapidly approaching Earth.
On February 22nd, 2023, a telescope in South Africa, part of the Atlas Project, spotted a new comet making its way toward Earth, approximately 1.095 billion kilometers away. The Atlas Project is a robotic system designed to detect near-Earth asteroids and other potentially dangerous objects in our solar system and calculate the likelihood of impacts on our planet. Initially thought to be an asteroid, further analysis from the Purple Mountain Observatory in China revealed that it was a comet designated C 2023 A3 Su-chinshan Atlas.
Astronomers calculated that C 2023 A3 Su-chinshan Atlas has an orbit period of 80,000 years and is positioned between Jupiter and Saturn, racing through space at 290,644 kilometers per hour. As of September 27th, 2024, C 2023 A3 will approach the perihelion of its journey, the point of the orbit of a planet, asteroid, or comet at which it is closest to the Sun. This will put the comet near Mercury’s orbit, approximately 58 million kilometers away from our star. At this distance, the Sun could cause the comet’s intrinsic luminosity to be 17 times brighter than normal.
It is anyone’s guess as to whether C 2023 A3 Su-chinshan Atlas will astound us with a cosmic light show worthy of legendary tales from the days of old or if it will disappoint with a meager streak in the night sky recorded in science books but not in our hearts. Long-period comets like C 2023 A3 are thought to have originated in the Oort cloud, a flexible collection of icy objects from other stars defining our solar system’s boundary, approximately three light-years away. While it has not been directly observed, it is believed to resemble a spherical ball with a wall thickness that begins approximately two thousand to five thousand astronomical units (AU) from our Sun and extends 100,000 to 200,000 AU from our Sun. An AU is a unit of measurement equal to 149.6 million kilometers, which is the mean distance from the center of the Earth to the center of the Sun.
If the comet’s eccentricity or deviation of its orbit from circularity indicates that it may have a parabolic orbit, then C 2023 A3 may have never passed by the Sun before. Furthermore, it is likely that the surface of the comet is covered by highly reactive frozen nitrogen, carbon monoxide, and carbon dioxide. As it nears the Sun for the first time, a type of burn-off effect could cause A3 to have a considerable surge in brightness. However, more precise calculations predict an elliptical orbit, which is more oblong and circular in shape.
