It got here from past our solar system. However, the solar wasn’t content material to let it depart in peace, or in a single piece. Comet 2I/Borisov, an Eiffel Tower-sized clod of mud and ice, plunged into our solar system last fall, exhaling vapor because it buzzed nearest to our sun around Christmas. This alien customer will need to have shaped around a distant and unknown star.
It slumbered because it crossed the frozen Gulf of the interstellar area. However, now, out of the blue, the sleeper is awake and kicking. The motion started final month — March 2020, of all occasions — when the Hubble telescope noticed a minimum of one chunk of the comet breaking off like a calving iceberg.
These fireworks supply astronomers a novel glimpse of the uncovered guts of this interstellar object; simply the second humanity has ever noticed. A number of competing groups of scientists had already booked coveted slots to check the comet over the following few months with Hubble. Spurred by the information out of Poland, they rushed to maneuver up to their very own observations, hoping to catch the comet performing up.
Astronomers had hoped, even predicted, that Borisov may crack up this spring, whereas heading again out of the solar system to as soon as once more sojourn among the many stars. However, the first indicators it was stirring got here in early March, proper because the coronavirus pandemic ramped up. That’s when ground-based astronomers in Poland spotted the comet suddenly brighten, although it ought to been dimming because it received farther from the solar.