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IllustriousSignal575 t1_j98rffe wrote

Thats a very American way to measure the sound of something.

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camcamcam710 t1_j9bli0o wrote

“It’s like ten football fields filled with Rice Krispies and a massive bag of milk, with all bags popped simultaneously”

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solidcordon t1_j98t0ka wrote

So is that 40 mega-RiceKrispies or is the scale logarithmic?

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websterhamster t1_j98s3tz wrote

I love how they used the extremely technical and scientific benchmark of Rice Krispies to compare the noise level of the Artemis I launch.

I mean, forget explaining decibels. Rice Krispies is something everyone can understand.

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evanc3 t1_j99dk3g wrote

So if you're at postion, and you change position, we call that velocity. If you change between two velocities we call that acceleration. If you learned this in school you would call these derivatives. Well when you take the derivative of acceleration, you get something called jerk. And the derivative of jerk is called jounce.

But jounce is a horrible name, so they started calling it "snap". Naturally this lead to the next two derivatives being called "crackle" and "pop".

These aren't the official names, but they don't have official names so "position, velocity, acceleration, jerk, snap, crackle, pop" is officially unofficial

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marketrent OP t1_j98sh5l wrote

From the linked release:^1

>At 1.5 km from the pad, the maximum noise level reached 136 decibels. At a 5.2 km distance, the noise was 129 decibels, nearly 20 decibels higher than predicted by a prelaunch noise model.

^1 The Roar and Crackle of Artemis 1, AIP Publishing, 14 Feb. 2023, https://publishing.aip.org/publications/latest-content/the-roar-and-crackle-of-artemis-1/

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RollinThundaga t1_j990ccl wrote

For general reference; a 10 decibal increase in sound intensity is an apparent doubling of the loudness.

130 decibels is the human pain threshold. A lawn mower is around 90 decibels. A normal conversation is about 60 decibels.

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marimbawarrior t1_j9b6arb wrote

Key word: apparent. Actual doubling of sound pressure levels is every 3dB. Every 10dB added is 10x the energy. (Sound energy and volume are two different things but they’re directly proportional)

Honestly surprised that it’s only 136 dB around the rocket. Also surprised that they didn’t also state the C-weight, as that would highlight more of the low end you get from the rocket itself. There’s a ton of low end that’s being tossed out (for good reason) when they A-weight.

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mmgoodly t1_j9dkgev wrote

No bone to pick with most of what you wrote... but

> around the rocket

1.5 kilometers from the rocket.

IMMEDIATELY around the rocket (which is what I'd mean if I said simply "around the rocket") would be a different story. Obvs.

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marimbawarrior t1_j9dtbw4 wrote

True! Inverse square law can help us out here.

Just punched the numbers in, 26 dB louder if you were located 80 meters away from the rocket, or roughly 162 dB. So yeah, 136 dB from 1.6 km would make total sense.

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Raed-wulf t1_j9a9jew wrote

Yeah but 40 million is a hard number to grasp.

If they were being true Americans about it, they’d say it sounded like being 2 football fields away from a machine gun firing full auto into the side of a tractor trailer.

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tomixcomics t1_j99pk9i wrote

This is why you don't do interviews while hungry.

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felixlightner t1_j9994fi wrote

That works out to 3.8 olympic size pools full of rice krispies.

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marketrent OP t1_j98r4w9 wrote

Excerpt from the linked release^1 by AIP Publishing about noise measurements taken at five stations located 1.5 km to 5.2 km from the launch pad:^2

>When the Artemis 1 mission was launched by NASA’s Space Launch System, SLS, in November, it became the world’s most powerful rocket, exceeding the thrust of the previous record holder, Saturn 5, by 13%.

>With liftoff came a loud roar heard miles away.

>In JASA Express Letters, published on behalf of the Acoustical Society of America by AIP Publishing, researchers from Brigham Young University and Rollins College in Florida reported noise measurements during the launch at different locations around Kennedy Space Center.

>The data collected can be used to validate existing noise prediction models, which are needed to protect equipment as well as the surrounding environment and community.

>These data will be useful as more powerful lift vehicles, including the SLS series, are developed.

> 

>“We hope these early results will help prevent the spread of possible misinformation, as happened with the Saturn 5,” author Kent Gee said.

>“Numerous websites and discussion forums suggested sound levels that were far too high, with inaccurate reports of the Saturn 5’s sound waves melting concrete and causing grass fires.”

>A characteristic feature of rocket launches is a crackling sound from shock waves.

>These shocks represent instantaneous sound pressure increases that are much louder than crackling noises encountered in everyday life.

>Author Whitney Coyle said, “We found the Artemis-I noise level at 5 km had a crackling quality about 40 million times greater than a bowl of Rice Krispies.”

^1 The Roar and Crackle of Artemis 1, AIP Publishing, 14 Feb. 2023, https://publishing.aip.org/publications/latest-content/the-roar-and-crackle-of-artemis-1/

^2 Kent L. Gee, et al. Space Launch System acoustics: Far-field noise measurements of the Artemis-I launch. JASA Express Letters 3, 023601 (2023); https://doi.org/10.1121/10.0016878

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solidcordon t1_j98swey wrote

Melted concrete....

Yes, definitely NASA's fault, not the contractor who provided the concrete. /s

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Mr_Kittlesworth t1_j9anzu2 wrote

Yeah, but how many bananas away from the launch do you need to be before the sound is below 367 grape nuts hitting a hardwood floor from a height of 15 aeronautical engineering textbooks?

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Evening-Top-4245 t1_j98v27l wrote

It was fucking loud. And blinding. Haha. I was ‘up-range’ from the launch. Loud and blinding! Like any awesome show should be.

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ComplexToxin t1_j99pinn wrote

That was a sentence I didn't expect to read today. How American.

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sixpackabs592 t1_j9akxuf wrote

Just tell us the decibel level you dumb fucks I don’t care about how many Olympic swimming pools or statues of liberty or fucking rhode islands can fit in it just give us the numbers

/rant

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mcc9902 t1_j9emzna wrote

~130 decibels, so basically as loud as a gunshot at 1.5km. I’m assuming this is a continuous thing that gradually decreases as it gets further away. I knew they were loud but that’s more than I expected.

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ManyFacedGodxxx t1_j99rtoc wrote

What was the noise level compared to bananas? /s

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New_Poet_338 t1_j9a3woc wrote

This is 3x as loud as me after I eat a banana. Banana's don't agree with me at all.

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Loud-Intention-723 t1_j9agqby wrote

Ah glad they aren't using the how many classrooms away from the gunfire meter that is becoming popular in America.

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