Will the Moon Really Glow Green Tonight?

The internet has once again come down with a case of viral infection. Or this time, reefer madness. If social media is to be believed, the Moon will glow green in the sky tonight, bathing us all in light reflected from Uranus.

According to Snopes.com, the "green Moon" is a hoax originating on social media in 2016. A post originally claimed the Moon would turn green on May 29 (which it did not). Then, the original post was hijacked and the date changed to April 20, presumably reflecting what has become unofficial National Weed Day. The last known green moon supposedly took place 420 years ago, the post stated.

A comment from the original poster alleged the Moon would sit just four degrees from the planet Uranus, which reflects blue-green light. The Moon would supposedly reflect the light coming from the planet and itself glow green.

Read more: NASA's 4K Moon Video Tour Will Blow You Away

Unfortunately, Uranus will not bathe the Moon in its eerie hue this evening. According to Earthsky.com the Moon will appear about half a sky away from Uranus. Even if it did appear closer to the Moon when looking from Earth, it's actually much too far away to be able to light up the surface of the Moon. Depending on the solar system's orbital gyrations, Uranus can sit between 1.6 billion miles and nearly two billion miles away from Earth.

A plane flies in front of the Moon, January 1, 2018. Uranus will not bathe the Moon in a green hue on April 20. Toby Melville/Reuters

Originally intended as a joke, this post has taken on a life of its own, spawning new iterations in 2017 and again this year.

It's not entirely clear how the number 420 became associated with cannabis culture, but a number of suggestions have been put forward over the years. Former High Times editor Steven Hager told the New York Times that the date is inspired by the daily 4.20 p.m. pot-smoking ritual of a group of San Rafael High School students in California.

According to Snopes.com, a Grateful Dead concert flyer detailed 420's high school origins. Back in 1990, another High Times editor, Steve Bloom, told magazine staff about the flyer. They started using the phrase shortly after.

Read more: How to Get High on 4/20

Another popular suggestion is that 420 is either police radio code for cannabis smoking or the penal code section for pot use in California. Snopes debunks both of these claims, as well as claims 420 recognises the death date of Jim Morrison, Jimi Hendrix or indeed, Janis Joplin. None of these performers died on April 20 of any year.

Even though it won't glow green, it's certainly still worth gazing up at the Moon tonight. A sliver will be illuminated as our satellite passes through its waxing crescent phase. Stargaze for long enough and you might just catch a shooting star as we are just two days from the peak of the ongoing Lyrids meteor shower.