John T3d ago
It looks like my #infrasound monitor (a #RaspberryBoom) might have caught the sonic boom from a meteor that passed over the #Houston area this afternoon. Time is in UTC here.
Show threadJohn T3d ago

The problem is - lots of things create infrasound. This is the loudest thing within that hour, and approximately the right time, but is it a sonic boom?

Sonic booms should have an N-shaped profile, as shown in this figure from their wikipedia article: https://commons.wikimedia.org/wiki/File:N-wave.png#/media/File:N-wave.png

File:N-wave.png - Wikimedia Commons

Show threadJohn T3d ago

That figure shows the whole thing lasting ~.2s.

If we zoom in on my own data, you have to stretch a little bit to believe that it has the same N-shape, but it's not entirely wrong.

The initial peak is ~.1s, but the whole thing takes ~.6s (from 21:42:26.4 to 21:42:27)

Show threadJohn T3d ago

It was certainly one of the loudest things today, and a broad-spectrum 'boom'.

(Ignore the really huge thing in the recent lower left, that was me rebooting the RaspberryBoom because I thought it was offline 😬)

The big thing in the quiet nighttime hours is a helicopter - those have a very distinct signature.

Show threadJohn T
Helicopters are easy to spot because you can *see* the infrasound doppler shift as they go past your location.
Mar 22 at 2:06amWeb
Show threadJohn T3d ago
So my verdict is that *maybe* this was the sonic boom, but it's awfully hard to be sure.
Show threadJohn T3d ago
Here's the official notice of the event and the timing - which fits just fine: https://fireball.amsmeteors.org/members/imo_view/event/2026/1959
American Meteor Society

We received 105 reports about a fireball seen over TX on Saturday, March 21st 2026 around 21:39 UT.

Show threadJohn T3d ago
Oh! And magnitude-wise, that's ~8 Pascals of overpressure, which equates to just under 0.2 lb/ft^2 on the wikipedia graph.
Show threadJohn T2d ago

Oh! This is fun. RaspberryShake now lets you download 'audio' of these events (sped up many times, and therefore frequency shifted higher).

Here's what this event sounded like.

Show threadJohn T2d ago
Here's what the helicopter shown earlier sounds like with the same settings - this should give you a feel of how 'not actual sound' this is.
Show threadJohn T2d ago
The (possible) sonic boom event also appeared on the seismometer as well. Note that for whatever reason this one starts 10s before the infrasound one, so it's the same event at ~52s that appears at ~42s on the infrasound recording.
Show threadvxo2d ago
@grajohnt okay well now I know I need a Raspberry Shake to capture the periodic little 3.1 burblings that happen here in Sacramento and turn them into PHAT BEATS
Show threadJohn T2d ago
@vxo they have gotten absurdly pricey since I bought mine many many years ago
Show threadvxo2d ago
@grajohnt I noticed that when my coworker was looking at them
Show threadJohn T2d ago

@vxo there's a good chance there's one very near you, and you can just take the data from that :)

https://stationview.raspberryshake.org/#/?lat=38.57607&lon=238.47038&zoom=9.516

Oooh - there's only one in Sacramento, and it's pretty noisy.

Station View: Raspberry Shake Network & EQ Activity Map

Global map showing all live seismograph and infrasound Stations on our seismic network, with one of the most complete lists of recent earthquake activity.

Show threadAlfred Chow - Maker of Things2d ago

@grajohnt
Sue has become very good at distinguishing the local police helicopter and the air ambulance helicopter just by their sound as they become audible.

Seeing the hospital helipad light up is a good confirmation of an incoming air ambulance.

Show threadSue Archer2d ago

@Maker_of_Things @grajohnt

Random thing the other day - I heard the air ambulance, looked up and yes, it was flying low over our house, away from the hospital. But then I looked at the hospital, and the air ambulance was on the helipad. But I'm sure it was an air ambulance I saw in the sky. I didn't know there were two....

Show threadAbhijit Menon-Sen2d ago

@suearcher There's a lot of involuntary teleporting going on these days!

@Maker_of_Things @grajohnt

Show threadSue Archer2d ago

@amenonsen @Maker_of_Things @grajohnt

Teleporting would be an even easier way to transport patients!

Show threadJohn T2d ago
@suearcher @Maker_of_Things you would have been a great sonar operator on submarines... 😁
Show threadSue Archer2d ago

@grajohnt @Maker_of_Things

As long as the submarine was hunting two specific helicopters....