According to NASA, one comet will pass closely by Earth beginning on Monday, March 21. Comet 252P/LINEAR will come within 3.3 million miles (5.2 million km) on Monday, March 21 while comet P/2016 BA14 will come a bit closer, passing within 2.2 million miles (3.5 million kilometers) on Tuesday, March 22.
If reports are to be believed, this will be third closest flyby of a comet in recorded history, next to comets in 1770 and 1983. "While both comets will safely fly past at relatively close distances, anyone hoping to see them will need powerful, professional-grade telescopes, due to their relatively small size," said NASA.
Since the comets are remarkably in similar orbits, its quite possible that they are related. Both the comets are too small to be seen with the naked eye, so you need powerful, professional-grade telescopes to view them.
The approaches of these two comets will be the closest when they come to Earth for the foreseeable future, said Paul Chodas, manager of NASA's Center of NEO Studies (CNEOS).
Scientists are viewing it as an excellent opportunity for the scientific advancement on the study of comets.