On March 22 this year, the comet P/2016 BA14 Panstarrs will fly by our Earth. It will pass by a record close 2.1 million miles, which equals to 9 times the distance between Earth and our Moon.
The last time a comet came this close to Earth was back in the year 1770. In July of that year, Lexell's Comet came within 1.4 million miles of our planet. The event took place when Captain Cook was sailing for Australia. He spotted it and managed to measure its tail at 42 degrees on August 30. Astronomer Charles Messier noted that its core looked to be 4 times that of the full moon.
Panstarrs's flyby won't be quite as spectacular a sight as Lexell's Comet was. It will pass close to our planet but will be far from the Sun, making it look quite faint.
Astronomers believe that P/2016 BA14 Panstarrs is a piece of the comet 252P/LINEAR 12 which will pass by a day earlier, on March 21, about 3.2 million miles from us, roughly the distance that Halley's Comet passes closest to Earth. The distance equates to 14 times that between Earth and our Moon but to see it, you'll need a pair of binoculars. It will also be rather dim due to its distance from the Sun.
Astronomers from around the world will be keeping an eye on the 2 comets with telescopes. The Hubble Telescope will record the light they emit, the astronomical equivalent of a fingerprint. It will enable scientists to determine whether they were a single object initially.
