In the summer of 2019, a team of astronomers from NASA, the ESA, and the International Scientific Optical Network (ISON) announced the detection of the comet 2I/Borisov. This comet was the only second interstellar visitor observed passed through our Solar System, coming on the heels of the mysterious ‘Oumuamua. For this reason, astronomers from all over the world watched this comet intently as it made its closest pass to the Sun.
One such group, led by Martin Cordiner and Stefanie Milam of NASA’s Goddard Space Flight Center, observed 2I/Borisov using the ESO’s Atacama Large Millimeter/submillimeter Array (ALMA) in the Chilean Andes. This allowed them to observe the gases 2I/Borisov released as it moved closer to our Sun, thus providing the first-ever chemical composition readings of an interstellar object.
In 2019, amateur astronomer Gennadiy Borisov discovered a comet, which now bears his name. There’s a long history of amateur astronomers discovering comets, as they approach our inner Solar System on their elongated orbits. But this one was different: it was moving much too fast to be gravitationally bound to the Sun.
It was an interstellar comet. And now, it looks like it has split into two chunks.
On August 30th, 2019, astronomers with NASA, the ESA, and the International Scientific Optical Network (ISON) announced the detection of the interstellar comet C/2019 Q4 (2I/Borisov). News of the object was met with a great deal of excitement since it was only the second interstellar object to be detected by astronomers – the first being the mysterious object known as ‘Oumuamua (which astronomers are still unsure about)!
After a lot of waiting and several follow-up observations, 2I/Borisov is about to make its closest approach to Earth. To mark the occasion, a team of astronomers and physicists from Yale University captured a close-up image of the comet that is the clearest yet! This image shows the comet forming a tail as it gets closer to the Sun and even allowed astronomers to measure how long it has grown.
For over a century, proponents of Panspermia have argued that life is distributed throughout our galaxy by comets, asteroids, space dust, and planetoids. But in recent years, scientists have argued that this type of distribution may go beyond star systems and be intergalactic in scale. Some have even proposed intriguing new mechanisms for how this distribution could take place.
For instance, it is generally argued that meteorite and asteroid impacts are responsible for kicking up the material that would transport microbes to other planets. However, in a recent study, two Harvard astronomers examine the challenges that this would present and suggest another means – Earth-grazing objects that collect microbes from our atmosphere and then get flung into deep-space.
When the mysterious object known as ‘Oumuamua passed Earth in October of 2017, astronomers rejoiced. In addition to being the first interstellar object detected in our Solar System, but its arrival opened our eyes to how often such events take place. Since asteroids and comets are believed to be material left over from the formation of a planetary system, it also presented an opportunity to study extrasolar systems.
Unfortunately, ‘Oumuamua left our Solar System before any such studies could be conducted. Luckily, the detection of comet C/2019 Q4 (Borisov) this summer provided renewed opportunities to study material left by outgassing. Using data gathered by the William Herschel Telescope (WHT), an international team of astronomers found that 2I/Borisov contains cyanide. But as Douglas Adams would famously say, “Don’t Panic!”