COLUMBIA, S.C. (WIS) – Outside of Earth, the Universe is vast and ever-changing. Recently, there was a big discovery in our celestial backyard.
Dr. Dave Jewitt, an astronomer at UCLA, says, “People have been looking at this idea that comets can change their own spin for a long time.” Dr. Dave Jewitt is a renowned astronomer with plenty of discoveries to his name already, including 4 dozen minor planets. He also studies rotating comets, which involves a delicate dance of physics.
When it comes to this delicate dance, he says, “Comets go around the sun in these very elliptical orbits, very egg-shaped orbits… and when they’re near the sun, the ice in the comet nucleus basically turns to a gas, it sublimates. It’s like melting, but it turns straight to a gas with no liquid.” This gas that escapes can sometimes form jets, acting like rocket thrusters that can make a comet rotate in a certain direction or at a certain speed.
In 2017, a comet known as 41P came close to Earth and the Sun, offering an opportunity for a case study. Over the span of a couple of months, its rotation rate slowed from once every 20 hours to once every 46 hours. Upon further review, not only did 41P slow its spin, but it reversed too. Dr. Jewitt explained this phenomenon, saying, “Once they can change their own spin by outgassing, then their spin accelerates… and the only natural limit to the spin is breaking up.”
Given its spin rate and small size, Dr. Jewitt gives Comet 41P a few more decades before it tears apart. He suggests this discovery has offered more questions than answers, saying, “You go out to answer one question and then 10 more appear… and it’s kind of a divergent thing, it’s not a convergent thing, which is really why it’s so much fun.” As Comet 41P spins across the Universe, astronomers will look for answers to this recent discovery.
Feel more informed, prepared, and connected with WIS. For more free content like this, subscribe to our email newsletter, and download our apps. Have feedback that can help us improve? Click here.
Copyright 2026 WIS. All rights reserved.