ANSWER: Comet 252P/LINEAR, comet P/2016 BA14
Explanation:
Astronomers all over the world trained their high end telescopes on the sky on Monday to observe the closest flyby of two comets that may be twins of some sort. Comet 252P/LINEAR, approximately 750 feet in size, will zip past Earth on 21st March at a range of about 5.2 million kms. On 22nd March, comet P/2016 BA14 will safely fly at a distance of about 3.5 million kms. This will be the third closest flyby of a comet next to D/1770 L1 (Lexell) in 1770 and comet C/1983 H1 (IRAS-Araki-Alcock) in 1983.