Sometimes it takes a long time to figure out exactly what distant objects in our solar system happen to be doing. Back in 2014, an icy object was discovered by Pedro Bernadinelli and Gary Bernstein while Benadinelli was working on his doctoral research. At the time, this object was about 29 times the Earth’s distance from the Sun; a distance that put it out near Neptune, and since they were looking for trans-Neptunian objects, this object was nice and consistent with what they were looking for. With a diameter estimated around 150 kilometers, it initially looked like a totally normal, fairly boring, apparently round chunk of ice.

But not all was as it seemed.

In the years since then, additional observations, with new data from the Dark Energy Survey, and historic images that happened to include this object have allowed researchers to update their understanding of this object’s orbit. That orbit is actually anything but boring. It looks like this object is actually a comet, with an orbit that will carry it inside Saturn’s orbit where it will make its closest approach to the Sun in 2031.

What’s more, this object originates from out toward the outermost edges of our solar system. This orbit is highly elongated, with its greatest distance from the Sun being 4,000 times larger than its closest approach to the Sun.

This is the third comet from the Oort Cloud identified while still on its way in toward the Sun, and it is by far the largest comet seen with modern instruments; comets are typically under a mile to a few miles across – not ninety miles across!

So we have found an object that comes from the outer edges of the solar system that, for comets, is huge, and it is coming our way, but won’t get even as close as Jupiter, so there is no reason to worry. [Ed. note: Beth went off on a rant against clickbait headlines here.]

But there are a lot of reasons to get excited.

We get to watch almost the entire process of the comet lighting up and growing a coma. Already, a coma rich in carbon dioxide and ammonia has been spotted. This object will get bright enough for at least small telescopes, and we have no way of predicting just how bright and amazing this will be! What’s more, there is actually time to possibly launch a mission to this object, but it will require quick action.

Calculations by Adam Hibberd indicate a launch by 2029 is necessary, so everyone get your funding together, and let’s do something amazing. Go!

More Information

One of the largest comets ever seen is headed our way (National Geographic)

“C/2014 UN271 (Bernardinelli-Bernstein): the nearly spherical cow of comets,” Pedro H. Bernardinelli et al., to be published in The Astrophysical Journal Letters (preprint on arxiv.org)