NASA has released never-before-seen photos of the interstellar comet 2I/Borisov during its closest approach to the sun earlier this month. The Hubble Space Telescope captured the breathtaking photographs that include the most recent one on December 9th.
This is a one-time visit that 2I/Borisov is making to our solar system. It is travelling at a tremendous speed of 100,000 miles per hour. In fact, it is travelling at such a high speed that the sun’s gravity won’t have any effect on it, meaning that it will leave our solar system and continue on its way.
Comet 2I/Borisov is the second interstellar object that has been seen in our solar system (along with Oumuamua) and has been tracked for the past several months by the Hubble telescope. It was first discovered on August 30, 2019 by Crimean amateur astronomer, Gennady Borisov.
The Hubble took a photograph of Comet 2I/Borisov on October 12th when it was 260 million miles from Earth. Then on November 16th, another image was taken when the comet was 203 million miles from our planet. This photo, however, was even more exceptional as it was passing in front of a distant spiral galaxy. The most recent photograph, taken on December 9th, shows the comet travelling at its closest approach to the sun and 185 million miles from Earth. Comet 2I/Borisov will make its closest approach to Earth later this month at a distance of 180 million miles before making its way out of our solar system. Images of the comet captured by the Hubble Space telescope can be viewed here.
Scientists say that the comet’s nucleus is made up of a mixture of ice and dust and is probably no bigger than 3,300 feet (or one kilometer) in diameter. David Jewitt, who is a UCLA professor of planetary science and astronomy, stated, “Hubble gives us the best upper limit of the size of Comet Borisov’s nucleus, which is the really important part of the comet,” adding, “Surprisingly, our Hubble images show that its nucleus is more than 15 times smaller than earlier investigations suggested it might be. Our Hubble images show that the radius is smaller than half-a-kilometer.”
He went on to say, “Knowing the size is potentially useful for beginning to estimate how common such objects may be in the solar system and our galaxy.” “Borisov is the first known interstellar comet, and we would like to learn how many others there are.”
Even though only two interstellar objects have been discovered so far, scientists think that they in fact visit our solar system on a regular basis. It’s hard to detect them because they travel exceptionally fast and are often quite dim.