A widely spread story on social media claims that Jan. 4 is a "Zero Gravity Day," when a supposed long-awaited alignment of planets will decrease gravity on Earth for five minutes and will cause people to experience partial weightlessness.

At first glance, the story, which appears and spreads like wildfire online particularly on Facebook, looks legitimate because it comes with an image of a Twitter message that seems to have been posted by NASA, the authority when it comes to subjects relating to astronomy.

"Jan. 4th, 9:47 a.m. PST, the long-awaited planetary alignment will cause a gravitational fluctuation that will leave you weightless for a short period of time #beready," the 135-character supposed tweet reads.

The story has also gained enough traction on social media that the hashtag "ZeroGDay" now exists. A closer look at the story, however, would reveal that it is a hoax. For one, it gained popularity online after it was featured in the Daily Buzz Live, a website known to publish fictional stories, on Dec. 15.

The article cited British astronomer and broadcaster Patrick Moore to be the source of information about Pluto passing right behind Jupiter relative to Earth and this supposed rare planetary alignment will combine the gravitational forces of the two planets that could temporarily counteract the gravity of the Earth and make people weightless.

Moore indeed made the claim about people experiencing weightlessness due to an astronomical phenomenon but it was supposed to be a joke for an April Fool's day prank made on BBC Radio 2 about four decades ago.

On April 1, 1976, Moore announced that a rare astronomical event would cause listeners to experience a temporary sensation of weightless if they jump that day at 9.47 a.m., a phenomenon he called the Jovian-Plutonian Gravitational Effect. Interesting, BBC received many calls from its listeners claiming they experienced the sensation regardless that it was a spoof. It would be impossible for Moore to pull off the same prank again though because he already passed away two years ago.

The planetary alignment that was supposed to occur is not also true because Pluto and Jupiter are now on the opposite sides of the Earth's skies and should Jupiter and Pluto indeed align, Jupiter is thousands of times more massive than Pluto, which means that the latter would not likely alter Jupiter's gravitational effects and eventually cause weightlessness on Earth. The Twitter message supposedly by NASA, on the other hand, was a photoshopped image.