In the early morning hours of Thursday (May 5), a camera in Waycross, Georgia spotted a mysterious object moving across the sky.
Shiny, sharp, and surrounded by a dazzling oblique aura, the object looked like a space jellyfish, as Chris Combs, a professor of aerodynamics and mechanical engineering at the University of Texas at San Antonio, put it. on twitter,
Of course, as Combs pointed out, this Space Jelly wasn’t a UFO—it was a SpaceX Falcon 9 rocket launching from Kennedy Space Center in Florida, about 250 miles (400 kilometers) south of the camera.
Dozens of rockets leave the launchpad at Kennedy each year, but some of them can be mistaken for a bioluminescent invertebrate in the sky. So, what happened here?
According to Combs, it is a combination of physics and perfect timing.
From today’s SpaceX launch. beautiful pic.twitter.com/98mzIGHDOm
— Chris Combs (@DrChrisCombs) 6 May 2022
For starters, the long, blobby “body” of the jellyfish is the only exhaust except for the Falcon 9’s rocket engine nozzle, Combs wrote.
The reason for the exhaust in such a bulbous shape has to do with the pressure difference inside and outside the nozzle.
In this case, the exhaust exiting the nozzle is “under-expanded”—meaning the gas is under a higher pressure than its surrounding ambient air as the exhaust leaves the engine’s nozzle.
According to Combs, to match the ambient background pressure in the atmosphere, the rocket’s exhaust expands as it exits the nozzle, reducing its pressure.
“In the low-expansion exhaust you get expansion fans on the nozzle exhaust to reduce pressure and match the background: jellyfish, at high altitudes,” Combs tweeted,
This explains the blob. But what about brightness?
It’s too easy to square, Combs said — and it comes down to timing.
Because the rocket’s launch took place on Thursday morning (in the pre-dawn hours of 5:45 a.m. local time (UTC)), light from the sun came from just above the horizon, illuminating the exhaust plume, making it dark. To shine against the sky.
Physics plus perfect timing equals space jellyfish. A simple equation for the high-altitude spectacle.
Of course, if you want to see a real space jellyfish, you’ll need to look a little further into space—about 300 million light-years further away, to be exact.
How far is this galaxy cluster from Abell 2877; When astronomers recently looked at the object with a radio telescope, they saw ghostly outlines of jellyfish floating in distant space.
That large jelly in the sky is also the result of a massive gas explosion — in this case, a massive explosion from a cluster of ancient black holes, Live Science previously reported.
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This article was originally published by Live Science. Read the original article here.