APOD: Meteor Fireballs in Light and Sound (2021 Mar 15)

[APOD Robot]

Meteor Fireballs in Light and Sound

Explanation: Yes, but have you ever heard a meteor? Usually, meteors are too far away to make any audible sound. However, a meteor will briefly create an ionization trail that can reflect a distant radio signal. If the geometry is right, you may momentarily hear -- through your radio -- a distant radio station even over static. In the featured video, the sounds of distant radio transmitters were caught reflecting from large meteor trails by a sensitive radio receiver -- at the same time the bright streaks were captured by an all-sky video camera. In the video, the bright paths taken by four fireballs across the sky near Lamy, New Mexico, USA, are shown first. Next, after each static frame, a real-time video captures each meteor streaking across the sky, now paired with the sound recorded from its radio reflection. Projecting a meteor trail down to the Earth may lead to finding its impact site (if any), while projecting its trail back into the sky may lead to identifying its parent comet or asteroid.

<< Previous APOD

This Day in APOD

Next APOD >>

[LMMdT]

Scary!!

[crancowan@yahoo.com]

While watching the Perseids one year, I heard a distinct 'fizzle'-like sound during one fireball in my left ear. I had long hair and wire frame glasses at the time.

[Simen1]

Meteors that go below about 30 km height also makes an infrasound roar at a few Hz. If there are several infrasound microphones within reach, it can be combined with wind data to triangulate the path even during the dark flight period. Infrasound triangulations may be very accurate due to the low speed of sound, if the recording are combined with an accurate clock signal.

In december there was found a 14 kg meteorite in Sweden. The meteor fell in november and was both filmed with cameras and had one infrasound recording. In norwegian: http://norskmeteornettverk.no/wordpress/?p=3288

It would be interessting to hear the roar tuned up to hearable frequency.

[JohnD]

At the end of February,a fireball fell over the UK. It was tracked, the fall area predicted and a search started.
But that night, a family heard a "rattling noise" and next morning the fragments on their driveway! They knew nothing of the search, but contacted the right people, while collecting pieces of meteor from their garden. Even better, it's a carbonaceous chondrite meteor, exceedingly rare, and a lot of it has been found!

See: https://www.nhm.ac.uk/discover/news/202 ... shire.html

[orin stepanek]

Kapow!

Kitty listens to meteor flash?

[neufer]

Click to play embedded YouTube video.

Click to play embedded YouTube video.

[Chris Peterson]

While watching the Perseids one year, I heard a distinct 'fizzle'-like sound during one fireball in my left ear. I had long hair and wire frame glasses at the time.

It's called electrophonic sound. It's not well understood, but is probably caused by mechanical transduction of audio-frequency EM into sound by conductive materials around or on (as with your glasses) the observer. Low (audio) frequency EM can be generated in the turbulent wake of ionized gases produced by a meteor.

[neufer]

Click to play embedded YouTube video.

While watching the Perseids one year, I heard a distinct 'fizzle'-like sound during one fireball in my left ear. I had long hair and wire frame glasses at the time.

It's called electrophonic sound. It's not well understood, but is probably caused by mechanical transduction of audio-frequency EM into sound by conductive materials around or on (as with your glasses) the observer. Low (audio) frequency EM can be generated in the turbulent wake of ionized gases produced by a meteor.

[sillyworm 2]

Adds a new dimension to Name That Tune.

[Blastov]

I have HEARD a meteor. I was on a northern California hill top one quiet night. A particularly spectacular fireball turned night into vivid green daytime and I was so mesmerized that I completely failed to take a photo. (to be fair my camera was set to some odd settings for time exposures, so i would have had to fiddle a bit and i figured wouldn't have enough time)
As i was sitting in awestruck repose, a good minute or more after the bolide, a very sonorous, low frequency rumble like a distant buffeting thunder resonated across the landscape. Sort of how a distant jet washes in and out but much deeper. It was unmistakable and very definitely the sound of that fireball exploding through the upper atmosphere. It gives me goosebumps just recalling it. This was a noteworthy meteor, as pieces of it were recovered in Marin County.
...of course the good people of Chelyabinsk may recall having certainly heard a meteor there as well...

[Chris Peterson]

I have HEARD a meteor. I was on a northern California hill top one quiet night. A particularly spectacular fireball turned night into vivid green daytime and I was so mesmerized that I completely failed to take a photo. (to be fair my camera was set to some odd settings for time exposures, so i would have had to fiddle a bit and i figured wouldn't have enough time)
As i was sitting in awestruck repose, a good minute or more after the bolide, a very sonorous, low frequency rumble like a distant buffeting thunder resonated across the landscape. Sort of how a distant jet washes in and out but much deeper. It was unmistakable and very definitely the sound of that fireball exploding through the upper atmosphere. It gives me goosebumps just recalling it. This was a noteworthy meteor, as pieces of it were recovered in Marin County.
...of course the good people of Chelyabinsk may recall having certainly heard a meteor there as well...

Yes, you can hear the sonic boom created by a meteor in those rare instances when they drop low enough into the atmosphere, below about 30 miles (50 km). Few large meteors make it that low, but when they do, they produce enough sound that many people hear them and they produce strong signals on seismometers.

[Knight of Clear Skies]

A daytime fireball was heard over much of South-West England on Saturday afternoon. Can anyone give me some idea of how much energy was released please? I'm guessing something like this is above a kiloton.

Hopefully it will be possible to find some fragments, as with the Winchcombe meteor on 28th Feb.

[neufer]

A daytime fireball was heard over much of South-West England on Saturday afternoon. Can anyone give me some idea of how much energy was released please? I'm guessing something like this is above a kiloton.

• Yes, probably around a kiloton of TNT.

<<Stony asteroids with a diameter of 4 meters enter Earth's atmosphere about once a year. Asteroids with a diameter of 7 meters enter the atmosphere about every 5 years with as much kinetic energy as the atomic bomb dropped on Hiroshima (approximately 16 kilotons of TNT), but the air burst is reduced to just 5 kilotons. These ordinarily explode in the upper atmosphere and most or all of the solids are vaporized. However, asteroids with a diameter of 20 m, and which strike Earth approximately twice every century, produce more powerful airbursts. The 2013 Chelyabinsk meteor was estimated to be about 20 m in diameter with an airburst of around 500 kilotons, an explosion 30 times the one over Hiroshima. Much larger objects may impact the solid earth and create a crater.>>

[Knight of Clear Skies]

Yes, probably around a kiloton of TNT.

Thanks neufer.