A comet with a core larger than Rhode Island has been on a journey to the Sun for more than a million years. In February, researchers discovered that the comet was 85 miles wide, and new observations from NASA’s Hubble Space Telescope now confirm that it is indeed the largest comet nucleus ever observed, according to new research. Traveling at 22,000 miles per hour, comet C / 2014 UN271 is expected to make its closest approach to Earth in 2031. It will probably not be visible to the naked eye, but this visit to the inner solar system will give astronomers an exciting opportunity to to observe an Oort Cloud object up close. Comets are often described as “dirty snowballs” with a tail made up of gas and dust and a solid core at their center made up of ice mixed with dust. Most comet nuclei are a few miles in diameter, but C / 2014 UN271 has them all hitting, with a nucleus 50 times larger than that commonly found in most known comets. It also has an estimated mass of 500 trillion tons, 100,000 times the mass of a typical comet, according to NASA. The comet was discovered by astronomers Pedro Bernardinelli and Gary Bernstein in 2014. At the time, C / 2014 UN271 was about 3 billion miles from the Sun, or about the distance of Poseidon, the most distant planet in the solar system. “This comet is literally the tip of the iceberg for many thousands of comets that are too dim to see in the most remote parts of the solar system,” said David Jewitt, a professor of planetary science and astronomy at the University of California, Los Angeles. and co-author of the new study in The Astrophysical Journal Letters, he said in a statement. Since its discovery, astronomers have studied it carefully with telescopes on Earth and in space. In January, astronomers used Hubble to take five pictures of the comet. Using the combined data, they were able to determine the comet’s measurements, giving it the record for the largest nucleus ever observed. C / 2014 UN271 comes to us from the Oort Cloud, a theoretical shell that surrounds the Sun far beyond the orbits of the outermost planets. Long-period comets are believed to have originated in the Oort Cloud, although scientists have not yet directly observed any objects in the cloud itself. The comet has been following an elliptical orbit of 3 million years around the Sun and has been falling towards the star for more than a million years now. It will complete its orbit around the Sun before returning to the distant region from which it came.
