Comet 252P/LINEAR will zip past Earth on Monday, 21 March at a range of about 3.3 million miles. The following day, comet P/2016 BA14 will safely fly by our planet at a distance of about 2.2 million miles, or nine times the distance to the Moon. This will be the second closest flyby of a comet in recorded history next to comet D/1770 L1 (Lexell) in 1770.

The possibility that water and organic molecules were brought to the early Earth through cometary impacts has long been the subject of important debate. Now, ingredients crucial for the origin of life on Earth, including the simple amino acid glycine and phosphorus — key components of DNA and cell membranes — have been discovered at Comet 67P/Churyumov-Gerasimenko.

Rosetta mission scientist Matt Taylor says the science team is jubilant after the Philae lander captured the historic, first close up images of the surface of a comet and began returning data from its science instruments.