Perseid Meteor Outburst

Aug. 18, 2021: 28 years ago, the Perseid meteor shower killed a satellite. On Aug. 11, 1993, a Perseid meteoroid hit the Olympus-1 telecommunications satellite, making it spin. The $850 million spacecraft was lost after it ran out of fuel trying to regain control.  Many researchers blame a dense ribbon of comet dust now known as “the Perseid Filament.”

This week, the Perseid Filament came back. Probably.

Above: The Perseid outburst of Aug. 14, 2021, captured by Carl Bracken of the Cedar Amateur Astronomers in Iowa using his AMS42 camera. More images.

On Aug. 14, 2021, night skies over North America filled with meteors. P.  Martin of Ottawa, Canada, reported “multiple Perseids per minute with many bursts, sometimes 3-4 in a second.” In San Diego, Robert Lunsford of the International Meteor Organization also witnessed rapidfire streaks, 2 to 3 at a time. “It made me realize something unusual was going on,” Lunsford says, “especially so far from the predicted maximum.”

To say that astronomers were surprised would be an understatement. The Perseid’s annual peak had occurred the night before. Most observers had already given up watching. Fortunately, a network of automated cameras operated by the Cedar Amateur Astronomers in Iowa captured the display. Overnight they recorded almost 3000 meteors.

Above: Meteor rates during the 2021 outburst. More.

Peter Jenniskens, an astronomer at the SETI Institute and NASA/Ames, believes it may have been the Perseid Filament. “I think so,” he says. “The width of the outburst is similar to that of past Perseid Filament returns.”

The Perseid Filament is a ribbon of dust inside the broader Perseid debris zone. Comet 109P/Swift-Tuttle supplies the raw material. The comet loops around the sun every 133 years, shedding dust as it goes. Over time, much of Swift-Tuttle’s dust is perturbed by the gravity of Jupiter, helping scatter it into the diffuse cloud that we experience every year as the Perseid meteor shower. But there is a part of the comet’s orbit in a “mean motion resonance” with Jupiter where dust can accumulate instead of dispersing. This is the Perseid Filament.

Forecasters still can’t predict when the Perseid Filament will return. It came for many years in a row around 1993, and it may have grazed Earth again, slightly, in 2018, 2019 and 2020. No one predicted a direct hit in 2021.

This uncertainty naturally raises the question: Was it really the Filament? The jury’s still out. Observers may have stumbled upon an entirely new ribbon of Perseid dust. Either way, researchers are looking forward to next year to see if it comes back again. And they probably won’t stop watching when the peak is “done.”

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