This pair of images, showing Comet Atlas on April 20 and 23, show its nucleus breaking up as it nears the Sun. Although such an event eliminates the comet’s chances of a magnificent apparition, it may clue astronomers in on why such breakups happen.
NASA, ESA, D. Jewitt (UCLA), and Q. Ye (University of Maryland)
Breaking up can be the hardest thing to do. But a comet breaking up as it soars through the inner solar system is an exciting event for astronomers.
Amateur and professional astronomers alike have been watching Comet C/2019 Y4 (ATLAS) since it was discovered in December 2019. When astronomers first spotted the comet, they believed it would be one of the brightest comets to sweep past Earth in the last two decades. But now, two teams working with the Hubble Space have captured the clearest snapshot yet of the comet breaking up, causing it to dim instead of brighten.
Some of the pieces are as large as a house. Astronomers believe the nucleus of the comet may have been about the size of two football fields before the breakup.
Beginning of the end
Amateur astronomer Jose de Queiroz discovered that ATLAS was falling apart when he photographed the comet in three pieces on April 11. Prior to the discovery, the comet brightened until mid-March and then it started dimming. Astronomers thought the core may have been disintegrating or fragmenting.
“This is really exciting — both because such events are super cool to watch and because they do not happen very often,” Quanzhi Ye of the University of Maryland, leader of one of the observing teams, in a press release. “Most comets that fragment are too dim to see. Events at such scale on happen once or twice a decade.”
Observing comet fragmentation is rare because it happens quickly and unpredictably. This makes it difficult for astronomers to know exactly what causes the breakups. But after observing ATLAS, researchers now believe it’s common for comets to experience breakups like this. And by examining the Hubble data, astronomers are hoping that they’ll be able to figure out why comets disintegrate.
Right now, ATLAS is inside the orbit of Mars. It’s believed that it will make its closest approach to Earth on May 23, but it may not be visible to the naked eye due to the breakup.
While this breakup may have ended the chances of seeing a spectacular comet fly through the sky, it could ultimately give astronomers some much-needed answers to the mysteries of comets.
