WVU astrophysicist explains science behind once in a lifetime comet

The night sky is shown on a crisp, fall evening in Terra Alta. Stargazers should be able to spot a once-in-a-lifetime comet through the month of October as it approaches the sun on an 80,000-year journey across the solar system. (WVU Photo/David Malecki)

A West Virginia Universityastrophysicist said a once-in-a-lifetime comet will become brighter through the month as it approaches the sun on an 80,000-year journey across the solar system.

Comet Tsuchinshan-ATLAS, also known as C/2023 A3, is passing by Earth and will be visible through the second half of October. Stargazers may spot it with the naked eye if conditions are favorable, according to WVU Planetarium and ObservatoryDirector Jason Ybarra.

Quotes:

"Comet Tsuchinshan-ATLAS likely came from the Oort Cloud, a region of space that is between 2,000 times the distance between Earth and the sun and a light-year. This region is so far away that the gravitational force from the sun competes with the gravitational force from passing stars and the Milky Way galaxy as a whole.

"The larger the orbit, the longer it takes a comet to complete that orbit. For comets that originate from the Oort Cloud, their orbits take so long that gravitational interactions with other objects in the solar system can alter the orbit and it becomes difficult to predict their future behavior. Comet Tsuchinshan-ATLAS might never return if it gets enough energy from those interactions. At minimum, you'll have to wait another 80,000 years. Either way, it is a once-in-a-lifetime event.

"Comets are a combination of frozen gas, water, ice, rocks and dust. Astronomer Fred Whipple nicknamed them 'dirty snowballs' in the 1950s. The ratios vary - some may have little ice and mostly rock, while others could be mostly ice. Comets spend most of their time in the outer solar system, beyond the orbit of Neptune in what is called the Kuiper Belt, where Pluto is, or even further out in the Oort Cloud.

"Like the planets and asteroids, comets orbit the sun, but they do so in a very eccentric orbit. Instead of a circle, the orbit is like a very squished oval. This means for a short time the orbit brings the comet very close to the sun. As it approaches, the light causes it to heat up. This releases the gas and dust that surround the core of the comet - called the nucleus - and these get pushed out by the solar wind into a tail. Most of the light from a comet is sunlight reflected by the dust and ice crystals. The closer it gets to the sun, the more dust gets released and it becomes brighter." - Jason Ybarra, teaching assistant professor and director, WVU Planetarium and Observatory

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lj/10/11/24

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