Planetary alignment & 'decreased gravity': Keep your feet on the ground about this 70s-era hoax

Story claims that the combined gravitational force of Jupiter and Pluto will let you float in the air for several seconds - don't believe a word

Sometimes the internet is delightfully old fashioned in its approach to hoaxes, as a recent viral article about a planetary alignment causing a ‘decrease in gravity’ has proved – it’s copied from an April Fools’ joke dating back to 1976.

In its current incarnation (facts unchanged; dates tweaked for the sake of truthiness) the hoax claims that on the 4th of June at “exactly 9:47 am, the planet Pluto will pass directly behind Jupiter, in relation to the Earth.”

“This rare alignment,” the article claims, “will mean that the combined gravitational force of the two planets would exert a stronger tidal pull, temporarily counteracting the Earth's own gravity and making people weigh less.”

Well, it won’t. To be completely clear: this is just never going to happen. For a start the influence of the planets’ gravity on the Earth is too tiny to have this sort of effect – and I mean way too tiny. Think about it, you’re able to break the effect of Earth’s gravity (if temporarily) every time you jump in the air and Earth is well documented as being the closest of all the planets to Earth.

As the astronomer and science blogger Phil Plait has noted, even if all of the planets were aligned their combined gravity is “only about 2 percent of the Moon’s, and it’s not like the Moon can fling you around the room uncontrollably when it’s up in the sky.”

In addition to this, there’s also no planetary alignment on the 4 of June at all (click here and adjust the counter at the bottom to the correct date), something that is fairly immaterial when you consider how often this ‘planetary alignment’ hoax has been copy-and-pasted.

Ignoring the fact that the site in question has tweaked the date on it several times (before the 4 of June it was slated for the 4 of April, and before that it was the 4 of January), as we mentioned in the intro the original idea dates back to 1976.

In one of the more successful April Fools’ Day pranks, BBC Radio 2 aired a program in which respected astronomer Patrick Moore warned listeners of the ‘Jovian-Plutonian gravitational effect’.

The pseudoscience was exactly the same, but with Moore’s respected public image adding far more to the story’s credibility than a Facebook-powered news site. Still, with listeners phoning in to report that they’d felt the ‘floating sensation’ at 09.47 am, it seems that human credulity has changed much.