The comet was first discovered in 2010 by astronomers Pedro Bernardinelli and Gary Bernstein. However, scientists have only recently verified the size by comparing Hubble images with a computer model of the coma (the “atmosphere” of the comet as it releases gas) and data from the Atacama Large Millimeter / Millennium Array. About 2 billion miles from Earth, C / 2014 UN271 is too far for Hubble to visualize the core. And before you ask: no, there is no risk of a collision that will destroy the Earth. C / 2014 UN271 is on a 3-million-year-old elliptical orbit that will take it no closer than 1 billion miles from the Sun, or a little farther from Saturn, in 2031. It appears to come from the Oort Cloud (the still theoretical comet nest at a distance of at least 2,000 AU from the Sun) and can travel up to half a light year away. The temperature of -348 F may seem icy, but it is hot enough to cause a carbon monoxide coma. Size confirmation is not just about bragging rights. This finding expands humanity’s understanding of comet sizes and adds to the still small list of very distant comets. It could also provide more evidence for the existence of the Oort Cloud and, consequently, help explain the role of the cloud in the development of the Solar System.
