Leave it up to the good ole Hubble Space Telescope. The workhorse telescope has given us a photo of the new interstellar comet 2I/Borisov. Take that, fancy new telescopes.

2I/Borisov has wandered into our Solar System from the deep cold of interstellar space, but nobody knows from whence it came, or how long its been travelling. Boris only the second object weve observed thats come into our Solar System from somewhere else in the galaxy, and the Hubble snapped photos of it speeding along at about 177,000 kph (110,000 mph.) So far, the Hubble images are the sharpest ones yet.

Our first interstellar visitor was Oumuamua, which sped through our Solar System in 2017. But that object didnt give up its secrets easily. It came and went and generated a lot of clicking and conjecture, and panicky headlines in some quarters. But it had not coma, and no tail, meaning it had no ice. But Boris is clearly a comet.

Comets contain a lot of water ice and other volatiles. When they get close enough to the Sun, some of that ice sublimates into gas, creating the characteristic coma and tail that is clear in many comet images. A coma and a tail are clearly visible in these Hubble images of 2I/Borisov.

Whereas Oumuamua appeared to be a rock, Borisov is really active, more like a normal comet. Its a puzzle why these two are so different, said David Jewitt of the University of California, Los Angeles (UCLA), in a press release. Jewiit is the leader of the Hubble team who observed the comet.

Of course its more than just a transient piece of curious eye candy. Boris will contain the same building blocks as any other bodies, including planets, in its home solar system. The fact that its behaving like comets in our own Solar System is intriguing too, though its too soon to assume too much as a result of that.

Though another star system could be quite different from our own, the fact that the comets properties appear to be very similar to those of the solar systems building blocks is very remarkable, said Amaya Moro-Martin of the Space Telescope Science Institute, Baltimore, Maryland.

Hubble captured these images of Boris when it was 418 million km (260 million miles) from Earth. At its closest approach itll be two astronomical units away from the Sun, on December 27th, 2019. As it approaches and recedes, other telescopes will observe it, and well learn more about it.

But we wont have long. At 177,000 kph (110,000 mph) it wont stick around for a portrait session. Its going to fall past the Sun and in mid-2020 itll be as far away as Jupiter. Then itll disappear into interstellar space again. Its traveling so fast it almost doesnt care that the Sun is there, said Jewitt.

Amateur astronomers have discovered a lot of comets, and this one is no exception. Amateur astronomer Gennady Borisov, from Crimea, discovered this one on August 30th, 2019. More observations from other amateur astronomers followed (they all talk to each other, you know.) Professional astronomers got involved too, and eventually the IAUs Minor Planet Center and JPLs Center for Near-Earth Object Studies calculated the trajectory. That confirmed the objects interstellar origins.

We know where most comets come from. They have two sources: the Kuiper Belt and the Oort Cloud, which is still hypothetical at this point. So to have an interstellar comet come barging through our Solar System means we need to update our encyclopedias.

Astronomers think theres probably many more interstellar objects thatll come through our neighborhood. In fact, there may be more passing through right now, but we just cant see them. But we may see more of them once the Large Synoptic Space Telescope gets up and running in 2020. (It may be renamed the Vera Rubin Space Telescope by then.)

We may never know exactly where Boris came from. But we do know that there is a circumstellar disk of icy debris around young stars in other solar systems. Theres a lot of gravitational shenanigans going on those situations, before a solar system settles down. Its possible that the chaos in young solar systems ejects comets and sends them out into interstellar space.

But for now, astronomers will use Hubble to keep an eye on this one as it gets closer. Its likely that as it gets closer to the Sun, therell be more activity and we can find out what its made of.

New comets are always unpredictable, said Max Mutchler, another member of the observing team. They sometimes brighten suddenly or even begin to fragment as they are exposed to the intense heat of the Sun for the first time. Hubble is poised to monitor whatever happens next with its superior sensitivity and resolution.

Thanks Hubble. Keep us informed, please.

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Here's the Picture We've Been Waiting for. Hubble's Photo of Interstellar Comet 2I/Borisov - Universe Today