Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The Sound So Loud That It Circled the Earth Four Times

nautil.us

Post reply on HN
Print view View original

91–100 of 111 posts

Re: The Sound So Loud That It Circled the Earth Four Times

#91

Post by fanf2 »

dingaling wrote: post #50
Arjuna wrote: post #38

Earlier quoted context omitted.

Speaking of the Saturn V... it's one of the most powerful machines that humans have ever created. It was equipped with five F-1 rocket engines, with each engine producing an absolutely staggering 1,500,000 pounds of thrust; that's a total of 7,500,000 pounds of thrust! Can you imagine being tucked into the small, cramped Command Module, sitting on top of this magnitude of power at lift-off? The whole thing, the techn…

> Speaking of the Saturn V... it's one of the most powerful machines that humans have ever created. In the interest of completeness, here are the two most powerful launchers even flown in terms of first-stage lift-off thrust N-1: 4,600 tonnes / 10 million lb Energia: 3,600 tonnes / 7.9 million lb Saturn V is currently in third place but will be pushed down if / when Falcon Heavy flies.

The Falcon Heavy total thrust is supposed to be 3.9 million lbf, according to Wikipedia. However it will have a larger specific impulse than a Saturn V (282 sec vs 263 sec).

Re: The Sound So Loud That It Circled the Earth Four Times

#93

Post by jonifico »

disillusioned wrote: post #58
dandelany wrote: post #28

Earlier quoted context omitted.

Yes! My favorite example of this is the sound made by the space shuttle's solid rocket boosters at liftoff. Techies who have seen recordings of shuttle launches generally assume the guttural crackling, popping roar sound they hear is due to a badly adjusted microphone clipping the loud sounds. In fact, this was a physical phenomenon that could be heard in real life, due to the pressure waves physically "clipping" aga…

I had the privilege of watching STS-134 launch from the press site and everyone tells you: "it's loud. louder than loud. you will be surprised by how loud it was." and that still wasn't enough to prepare me. It is loud. It is literally like the sound is clipping, the brapping noise moves through your teeth, it vibrates your clothes, you feel it inside of you. It is incredible, and I was so lucky to have watched it fr…

Wow! That sounds like an amazing experience. Kind of a dumb question, but were you also impressed by how fast it goes up, or does it 'float' into the sky?

Re: The Sound So Loud That It Circled the Earth Four Times

#94

Post by Shivetya »

jbert wrote: post #5

Nice. I hadn't thought of there being a limit (due to vacuum) to sound intensity. Reminds me of this recent comment on reddit: http://np.reddit.com/r/space/comments/2h9y9g/the_first_launc... "the Saturn V rocket produced a SWL (Sound Power Level) of about 220 decibels, which is sufficient to melt concrete nearby and set grass aflame a mile away,"

following links within yours leads to http://www.makeitlouder.com/Decibel%20Level%20Chart.txt which indicates that there were other volcanoes before measurement could be done that would have been more severe.

Essentially telling us that one volcano could change our lives, if not end a substantial number of them.

Re: The Sound So Loud That It Circled the Earth Four Times

#95

Post by antimagic »

disillusioned wrote: post #58
dandelany wrote: post #28

Earlier quoted context omitted.

Yes! My favorite example of this is the sound made by the space shuttle's solid rocket boosters at liftoff. Techies who have seen recordings of shuttle launches generally assume the guttural crackling, popping roar sound they hear is due to a badly adjusted microphone clipping the loud sounds. In fact, this was a physical phenomenon that could be heard in real life, due to the pressure waves physically "clipping" aga…

I had the privilege of watching STS-134 launch from the press site and everyone tells you: "it's loud. louder than loud. you will be surprised by how loud it was." and that still wasn't enough to prepare me. It is loud. It is literally like the sound is clipping, the brapping noise moves through your teeth, it vibrates your clothes, you feel it inside of you. It is incredible, and I was so lucky to have watched it fr…

Well, except for the suckers sitting atop the stack of course...

Re: The Sound So Loud That It Circled the Earth Four Times

#96

Post by astrodust »

marcosdumay wrote: post #22
BrandonMarc wrote: post #15

Earlier quoted context omitted.

Wait, the sound caused the grass to catch fire?!

A 220 dB sound is quite strong. As an example, its intensity (in W/solid angle) is 14 orders of magnitude (AKA 100 billion times) highter than the 80 dB people usualy use as a safety limit.

Saying "quite strong" here is like saying a thermonuclear explosion is "warm".

Sound that loud wouldn't just kill you, it'd rip you apart.

Re: The Sound So Loud That It Circled the Earth Four Times

#98

Post by nezza-_- »

dingaling wrote: post #50
Arjuna wrote: post #38

Earlier quoted context omitted.

Speaking of the Saturn V... it's one of the most powerful machines that humans have ever created. It was equipped with five F-1 rocket engines, with each engine producing an absolutely staggering 1,500,000 pounds of thrust; that's a total of 7,500,000 pounds of thrust! Can you imagine being tucked into the small, cramped Command Module, sitting on top of this magnitude of power at lift-off? The whole thing, the techn…

> Speaking of the Saturn V... it's one of the most powerful machines that humans have ever created. In the interest of completeness, here are the two most powerful launchers even flown in terms of first-stage lift-off thrust N-1: 4,600 tonnes / 10 million lb Energia: 3,600 tonnes / 7.9 million lb Saturn V is currently in third place but will be pushed down if / when Falcon Heavy flies.

(For completeness: 7,500,000 pound = ~3,400 tonnes)

Re: The Sound So Loud That It Circled the Earth Four Times

#99

Post by EGreg »

sillysaurus3 wrote: post #65
EGreg wrote: post #64

Earlier quoted context omitted.

Why don't you think that the sound waves would go in all directions, and be absorbed / redirected at the edges? What you see following the curvature of the Earth is the result of that, and once you factor in the second-order wave reflection, it's still on the order of 1/r^2 isn't it?

Nah, imagine a point on the earth. Now trace rays from that point in every possible direction. All of those rays will eventually lead to space or to the ground, and none will reach the other side of the Earth. Since molecules are physically further apart the higher you go in the atmosphere, it seems unlikely that the energy would be redirected at the edges, only dispersed. That must mean the wave is literally followi…

This supports even more that the remaining energy is on the order of X/r^2 and attenuated with the SQUARE of the distance traveled around the globe.

Re: The Sound So Loud That It Circled the Earth Four Times

#100

Post by jonsen »

EGreg wrote: post #99
sillysaurus3 wrote: post #65

Earlier quoted context omitted.

Nah, imagine a point on the earth. Now trace rays from that point in every possible direction. All of those rays will eventually lead to space or to the ground, and none will reach the other side of the Earth. Since molecules are physically further apart the higher you go in the atmosphere, it seems unlikely that the energy would be redirected at the edges, only dispersed. That must mean the wave is literally followi…

This supports even more that the remaining energy is on the order of X/r^2 and attenuated with the SQUARE of the distance traveled around the globe.

The /r^2 factor is due to the fact that the surface of a sphere grows proportional to r^2. That will hold for the wavefront half way around the earth, but from there it will be reverse. The energy will converge to full strength at the point opposite from the origin. That is if there were no loss. A significant portion of the energy is converted to heat and otherwise dispersed from being a compact wavefront.
Post reply on HN