How scientists know Pittsburgh’s New Years boom was an explosive meteor

The New Year has started with a bang in Pittsburgh.

Astronomer Diane Turnshek was in her kitchen on Saturday morning when she heard a “huge crash noise” that shook all the sun catchers on her window.

She was not alone. People all over the city said they heard the boom.

After ruling out a weather event or any type of local phenomenon as an explanation, she came to the same conclusion that NASA and the National Weather Service would eventually come to – it was a meteor exploding above Earth.

“A meteor just makes sense,” said Turnshek, a professor at Carnegie Mellon University. As it happens guest host Helen Mann.

Eliminate all the rest

When she heard and felt the impact at around 11:26 a.m., Turnshek’s mind immediately turned to the stars.

“As an astronomer, my immediate thought is that this is something heavenly,” she said.

But first, she says she had to eliminate all other possibilities. For example, could it have been some kind of local incident? A car accident, a shootout or a fireworks display, maybe?

It didn’t make sense. A quick online search showed people within 50 miles of her said they heard the boom.

“This ruled out any local explosion, train wreck or car crash or anything that had a nearby source,” she said.

What about an earthquake?

“I work at the Allegheny Observatory and we have a very sensitive seismograph,” she said. “The seismograph didn’t show anything at all.”

Diane Turnshek is a Carnegie Mellon University astronomer who heard and felt the comet explode over Pittsburgh on New Years Day. (Submitted by Diane Turnshek)

Meanwhile, officials from the National Weather Service (NWS) and NASA were also busy investigating the sound.

Shannon Hefferan, NWS meteorologist in Pittsburgh, said they were able to rule out lightning using GOES-16, a weather satellite operated by NASA and the National Oceanic and Atmospheric Administration.

The NWS tweeted on Saturday that a meteor was “the most likely explanation.

It was only an educated guess, Hefferan said, but NASA then used the same satellite to confirm that it was indeed a meteor, specifically a piece of rock from an asteroid. .

“The way we know it’s a meteor is that it was moving directly from north to south,” said William J. Cooke, head of NASA’s Meteoroid Environment Office. “All the data points were in a straight line and lightning doesn’t behave this way. Only meteors behave this way.”

The National Weather Service has ruled out lightning as the cause of the boom using the GOES-16 weather satellite. (NOAA / NASA)

NASA was able to glean more information about the fireball thanks to scientists at Western University in London, Ont., Who examined data from an infrasound station in Pennsylvania that captured the sound wave.

They estimated that the meteor was spinning at a speed of 72,420 kilometers per hour.

If it hadn’t been for clouds in Pittsburgh on January 1, people could have seen it illuminate the night sky with a light 100 times brighter than a full moon, Cooke wrote on the Meteor Facebook page. NASA Watch.

NASA estimates it was about a meter in diameter with a mass of about 450 kilograms. Cooke says a meteor this size crashes on Earth 100 times a year, or three to four times a day, but it’s extremely rare in Pennsylvania.

“It was terribly noisy”

Turnshek spends a lot of time stargazing and says she’s never seen anything like it.

“I saw cars [large meteors] before the night. They make a sizzling sound and you can sometimes hear a reverberation in the air, “she said.” But I didn’t think there could be one that big, that big, [and] that noisy. I mean, it was awfully loud. “

The next step, she says, is to search for the meteor’s remains. It would certainly have crashed into Earth, she said, but it’s hard to say if it would have shattered into tiny shards spread over a large area, or if there are “good sized pieces” somewhere. go there.

“I want to go hunting,” she said.

She says a nice piece of meteorite could be worth a pretty penny, but for her, that’s not the point.

“I’ve bought and given hundreds of meteorites to my students over the years, and I just think it’s wonderful to have someone touch a piece of rock that was in space,” a- she declared. “That’s the value of it to me, here is a heavenly wonder right in your hand.”

Written by Sheena Goodyear. Interview conducted by Chris Harbord.

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