At present, a gigantic comet, possibly the largest ever seen, is hurtling towards our solar system. Comets are so massive that astronomers initially thought they were dwarf planets!
Pedro Berardinelli and Gary Bernstein discovered the comet C/2014 UN271, nicknamed Comet Bernardinelli-Bernstein, from the University of Pennsylvania earlier this year.
Observed just past the orbit of Neptune, at 29 astronomical units, it also sets a record for being the most distant comet to have ever been observed, mostly thanks to its brightness.
At first glance, astronomers estimated it to be around 100 kilometers in length, but they found the comet to be longer than that on further observations. The was observed to be at least 150 kilometers in length, based on its brightness. It is the giant comet ever to have been observed in history (for comparison, the famous Halley’sHalley’s comet is only 80 kilometers in length).
The orbit of 2014 UN271. Credit: JPL Solar System Dynamics
After the discovery, Gary Bernstein said, “We have the privilege of having discovered perhaps the largest comet ever seen – or at least larger than any well-studied one – and have been able to watch it evolve as it approaches and warms up.”
By 2031, it won’t get any closer to the Sun than just outside Saturn’sSaturn’s orbit, so there’s no need to worry about its size. Astronomers think the comet is making its first foray into the solar system in more than three million years based on its current orbit.
The comet’s elliptical orbit is so long that it is over two trillion kilometers away from the Sun at its farthest. According to astronomer Phil Plait, the Sun’s gravity is so weak at that distance that just a whisper could push the comet into interstellar space.