How Jupiter and Pluto Teamed Up to Make People Feel Silly

There’s no doubt that celestial bodies have an impact on gravity here on Earth — just go to the ocean and hang around for a while and, sooner or later, the tide will go in and out. As TimeAndDate.com explains, “the gravitational force of the Moon and the Sun pulls the water in the oceans upwards making the oceans bulge, which creates high tide in the areas of Earth facing the Moon and on the opposite side.” That water has to come from somewhere, though, so the other parts of the world experience low tide — and, again, the gravitational effects caused by the Moon and Sun are to blame.

But while that celestial pull can move water, it doesn’t impact people to any noticeable degree. That would take a much greater force. And if you were listening to BBC Radio 2 forty-three years ago today, you would have learned that such an event was about to happen. That day, British astronomer Patrick Moore was an on-air guest, and he had some pretty fantastic news to share. The Earth, for the first time in recent memory, would align with Jupiter and Pluto. When the three were colinear, the gravitational effect on Earth of the two other planets would be significant — so significant that regular people could feel it. The “Jovian–Plutonian gravitational effect,” as he called it, would have its peak intensity at 9:47 AM local time in the UK, and if you jumped at that exact minute, you’d experience a momentary sense of weightlessness.

And Moore was there to help. He was on air at that magical minute, and, at 9:47, as promised, he announced over the air two simple words: “Jump now!” A minute later, the BBC’s phone lines were flooded with joyous listeners who felt themselves float away as if they were astronauts. Hundreds of people called in to share their stories, most notably one who, per the Guardian, “said that she and 11 friends had been wafted from their chairs and orbited gently around the room.”

And if any of these callers looked at a calendar shortly thereafter, that feeling of weightlessness would have immediately given way to a feeling of foolishness. Not only was the “Jovian–Plutonian gravitational effect” not listed, but something else was. It was April Fool’s Day.

Moore’s prank wasn’t an idle one, though. He was trying to make a point — that the relative location of Jupiter, Pluto, and the other planets don’t really matter to those of us on Earth. At the time, this fact wasn’t one which everyone agreed on. In the 1970s, astronomers correctly predicted that all the planets in the Solar System would align momentarily in 1982, an event which happens once every 179 years. In anticipation of the event, two scientists writers authored a book called “The Jupiter Effect,” outlining the carnage that this alignment would cause. As the Museum of Hoaxes explains, the book concluded that “through an extended chain of events, it would trigger a series of massive earthquakes on Earth. Los Angeles in particular, the authors said, would be completely destroyed.”  The book was a best-seller despite the fact that the gravitation pull of other planets has a negligible effect on Earth.

Moore’s stunt was intended to rebut the book by showing how ridiculous the claim — but unfortunately, it didn’t have the desired effect. Despite the fact that Moore fooled a bunch of people, the warnings of The Jupiter Effect continued to stoke fear in thousands of others. Of course, it was easily disproven by 1983 as Los Angeles, despite the authors’ conclusions, didn’t disappear from the planet. Much like the prank pulled by Moore, Jupiter had no effect after all.

Bonus fact: Jupiter’s size and gravitational pull do, however, have an indirect effect on life here on Earth. Because it is so large, Jupiter gets hit by a lot more asteroids and the like — per some estimates, Jupiter has seen about 8,000 times as many asteroid hits as the Earth has. In 1994, for example, shards of a broken-up comet (Shoemaker-Levy 9) struck Jupiter, causing Earth-sized scars on the planet — it (and many others) could have wiped out life on Earth had it hit us, instead. As the Big Think concludes, “if Jupiter were not there to suck up all of these other asteroids and comets, life may not even have had a chance to begin on Earth at all. ”

From the Archives: Dormant and Tired: An elaborate April Fool’s joke.