Just in time for the holidays, our inner solar system is about to receive a visitor that may add a green glow to December’s night sky.
46P/Wirtanen, a three-quarter-mile-wide periodic comet that comes our way roughly every 5.4 years, will make its closest approach to Earth on Dec. 16. Categorized as a “hyperactive” comet, it belongs to a small family of comets that appear to emit more water than they should for the size of their nucleus.
Despite a distance of 7.2 million miles, or 30 times the distance from the Earth to the moon, Comet Wirtanen will be the 10th closest comet to graze Earth since 1950. It could also, just maybe, become the brightest of the lot.