Extending about 80 miles (129 kilometers), the comet’s core (or solid center), known as C / 2014 UN271 (Bernardinelli-Bernstein), is larger than the state of Rhode Island, according to a NASA statement. And it is about 50 times larger than the average comet nucleus. “This comet is literally the tip of the iceberg for the many thousands of comets that are too dim to see in the most remote parts of the solar system,” said David Jewitt, co-author of a new study confirming the size of the comet and professor of planetary Science and Astronomy at the University of California, Los Angeles (UCLA), NASA said in a statement. “We always suspected that this comet had to be big because it is so bright at such a distance. “Now we confirm that it is.” This comet is currently far from Earth, with a zoom speed of approximately 22,000 mph (35,405 km / h). Comet Bernardinelli-Bernstein has been in the sun for over 1 million years. But do not worry. The closest it will get us, according to NASA, is about 1 billion miles (1.6 billion km), which will not even reach 2031. Previously, the comet with the title of “largest nucleus” was C / 2002 VQ94, which was located in 2002 and was estimated to be about 60 miles (96 km) in diameter. This new comet giant was first observed in 2010. A few years later, astronomers Pedro Bernardineli and Gary Bernstein found the object in archival data collected by the Dark Energy Survey at the Cerro Tololo Observatory in Chile. Since its inception, the object has been studied using a wide range of instruments, including both ground-based telescopes and space telescopes such as the Hubble. With observations from Hubble, the researchers were finally able to officially confirm the mammoth size of this “dirty snowball”. (Comets are called “dirty snowballs” because they are made up of rocks, ice, and other materials and debris, although objects may differ in composition.) 2 billion miles (3.2 billion kilometers) from the sun, the frozen object is about minus 348 degrees Fahrenheit (minus 211 degrees Celsius). While icy, this temperature is warm enough to allow carbon monoxide to sublimate (a process in which solid material becomes gaseous) from the comet’s rocky surface, creating a “coma”, a shell of dust and gas surrounding the solid center of a comet. “This is an amazing object, given how active it is when it is still so far from the sun,” said lead author of the study Man-To Hui, a researcher at Macau University of Science and Technology, in the same NASA statement. “We guessed the comet might be big enough, but we needed the best data to confirm it.” So his team used Hubble to take five pictures of the comet on January 8, 2022. The main challenge the team had to confirm the size of the nucleus was to differentiate between the nucleus and the comet coma. Bernardinelli-Bernstein is too far away for Hubble to pinpoint its core, but the team spotted a light signal with the telescope showing the comet’s position. They were then able to use Hubble’s observations and, using a computer modeling technique to show where the object’s coma would be, were able to determine the size of its core. The team compared its data with previous observations made by the Atacama Large Millimeter / submillimeter Array (ALMA) array in Chile and found that previous size estimates made with ALMA were in line with Hubble’s new findings. And ALMA’s radio observations allowed them to sharpen the object’s reflectivity, showing that the comet’s surface was darker than they expected. “It’s big and it’s blacker than coal,” Jewitt said. Scientists believe that the Bernardinelli-Bernstein comet travels from the Oort cloud, the most distant region of our solar system where huge numbers of comets live. The comets in this huge, diffuse cloud are thought to have formed closer to the sun, but ejected much farther away from gravitational interactions with the newborn giant planets in our solar system. And they tend to stay out there, unless another gravitational pull pushes them in our path. This comet, located so far from Earth and coming from the farthest reaches of our solar system, is believed to be traveling in an elliptical orbit of 3 million years around the sun. Scientists believe it can travel about half a light-year away from the sun to the farthest reaches of its orbit. These findings were described in a study published today (April 12) in The Astrophysical Journal Letters. Copyright 2022 Space.com, a future company. All rights reserved. This material may not be published, transmitted, rewritten or redistributed.
