miked10270 0 #26 October 17, 2003 QuoteSo...in theory.. if the temperature and pressure were high enough, a brisk walk would do it ? No. The speed of sound (mach 1) increases with density of the medium, so a "brisk walk" would do it if the pressure were low enough, but then the sonic boom would be extremely weak because there would be almost no air to carry it. Mike, Taking the piss out of the FrenchAmericans since before it was fashionable. Prenait la pisse hors du FrançaisCanadiens méridionaux puisqu'avant lui à la mode. Quote Share this post Link to post Share on other sites
aero04 0 #27 October 17, 2003 Quote>So...in theory.. if the temperature and pressure were high enough, a >brisk walk would do it ? Sure, if you're an antelope and you're on Venus. Bwhahahahahahah!!! Quote Share this post Link to post Share on other sites
QuickDraw 0 #28 October 17, 2003 My brain hurts. -- Hope you don't die. -- I'm fucking winning Quote Share this post Link to post Share on other sites
lawrocket 3 #29 October 17, 2003 So, does anybody here even have a SWAG at what altitude the Shuttle would make its first sonic boom? My wife is hotter than your wife. Quote Share this post Link to post Share on other sites
miked10270 0 #30 October 17, 2003 QuoteMy brain hurts. Same here... I blame the hangover. Alcohol? 'Tis the pi$$ of te devil! I'm not touching another drop until tonight Mike. Taking the piss out of the FrenchAmericans since before it was fashionable. Prenait la pisse hors du FrançaisCanadiens méridionaux puisqu'avant lui à la mode. Quote Share this post Link to post Share on other sites
yardhippie 0 #31 October 17, 2003 QuoteSo, does anybody here even have a SWAG at what altitude the Shuttle would make its first sonic boom? Im back to assuming it makes no sonic boom. Why, cuz when it "enters" the atmosphere, it makes its boom, but its at such an altitude it is unaudible, b/c the air is nearly a vacume. God, my brian hurts too...Goddam dirty hippies piss me off! ~GFD "What do I get for closing your rig?" ~ me "Anything you want." ~ female skydiver Mohoso Rodriguez #865 Quote Share this post Link to post Share on other sites
sundevil777 102 #32 October 17, 2003 Posted previously on the Kittenger-speed of sound thread... edit: The link doesn't seem to work anymore http://www.aerospaceweb.org/question/atmosphere/q0112.shtml So the speed of sound is greater at 400,000 ft than at 40,000. Even way out in space there are still molecules flying around, just not very many. And there is still a temperature in deep space, so sound still should travel, just not very far before it dissipates.People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
lawrocket 3 #33 October 17, 2003 So, you are saying that the first time it happens it is undetectable? hmm. I'd never thougth about it that way. If I had a brain, it would hurt. But, I'm blond and... My wife is hotter than your wife. Quote Share this post Link to post Share on other sites
yardhippie 0 #34 October 17, 2003 yea there is temperature, but its super cold, to measure it youd have to fill some vessel w/ a medium of some kind insert "thermometer" and wait for the temp inside to adjust. Right? B/c temp is really the frequency of particles being in an excited state and "bouncing" off each other. Gawd.. what am I doing...Goddam dirty hippies piss me off! ~GFD "What do I get for closing your rig?" ~ me "Anything you want." ~ female skydiver Mohoso Rodriguez #865 Quote Share this post Link to post Share on other sites
yardhippie 0 #35 October 17, 2003 QuoteSo, you are saying that the first time it happens it is undetectable? hmm. I'd never thougth about it that way. If I had a brain, it would hurt. But, I'm blond and... yes.. thats my uneducated assumptionGoddam dirty hippies piss me off! ~GFD "What do I get for closing your rig?" ~ me "Anything you want." ~ female skydiver Mohoso Rodriguez #865 Quote Share this post Link to post Share on other sites
aero04 0 #36 October 17, 2003 QuoteSo, does anybody here even have a SWAG at what altitude the Shuttle would make its first sonic boom? Ok, tell you what, I'll email one of my aerospace profs, and I'll post the response probably tomorrow. Quote Share this post Link to post Share on other sites
LouYoung 0 #37 October 17, 2003 How sure are you guys that the speed of sound is temperature dependent? I'm pretty sure it's density of the medium dependent (although air density is affected by temperature). In fact, try to measure the speed of sound in water (very dense). It's much faster than in air. At altitude the speed of sound should be slower since the air is less dense. A sonic boom isn't a momentary thing. An aircraft doesn't make a sonic boom as is passes through Mach 1. A pressure wave is generated starting at Mach 1 and you hear a boom when that pressure wave passes by your ears. People ten miles away from you will hear the same boom when the wave passes by their ears. If you look at a boat on a lake, you can consider the wake generated by the front of the boat (the V-shaped wave) to be a "sonic boom" in the sense that the wake starts to be generated once the boat starts moving faster than the water can carry the wave. As the wave passes by you, sitting in your inflated tire tube, you're rocked by the "shock" wave. A while later, the wave will rock your buddy in a tube 100 ft away. If the boat is far enough away from the shore, the wave will dissipate before anyone on the shore experiences the rocking. To answer the original question, I'm guessing that the sonic boom can happen at any altitude where there's a medium to generate a shock wave. If it's too high however, and the medium is too thin, the wave will never reach the surface for you to hear it. Lou Quote Share this post Link to post Share on other sites
Lostinspace 0 #38 October 17, 2003 Do you want to be a smart-ass? Take some fuel on your trip {to the height you bet on}. Burn the fuel in your prolusion system and develop some shock waves in the exhaust. Serious, if I had to guess, it would be the limit where distance between molecules is greater then the wave length or thickness of the shock. Quote Share this post Link to post Share on other sites
sundevil777 102 #39 October 17, 2003 QuoteHow sure are you guys that the speed of sound is temperature dependent? I'm pretty sure it's density of the medium dependent (although air density is affected by temperature). In fact, try to measure the speed of sound in water (very dense). It's much faster than in air. At altitude the speed of sound should be slower since the air is less dense. Speed of sound in a nearly incompressible fluid like water may be higher because of the imcompressibility, not the density. Sure seems like it should be more dependent on density doesn't it, but no... http://www.grc.nasa.gov/WWW/K-12/airplane/sound.htmlPeople are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
aero04 0 #40 October 17, 2003 QuoteHow sure are you guys that the speed of sound is temperature dependent? Absolutley certain. speed of sound= square root(gamma*R*T). Gamma~1.4, R~287 if using metric units, T can vary. Gamma and R are constant, T varies. Therefore, speed of sound is temperature dependant. Quote Share this post Link to post Share on other sites
yardhippie 0 #41 October 17, 2003 QuoteQuoteHow sure are you guys that the speed of sound is temperature dependent? Absolutley certain. speed of sound= square root(gamma*R*T). Gamma~1.4, R~287 if using metric units, T can vary. Gamma and R are constant, T varies. Therefore, speed of sound is temperature dependant. well yea.... if ya put it that way, geeze! Goddam dirty hippies piss me off! ~GFD "What do I get for closing your rig?" ~ me "Anything you want." ~ female skydiver Mohoso Rodriguez #865 Quote Share this post Link to post Share on other sites
Lostinspace 0 #42 October 17, 2003 QuoteQuoteHow sure are you guys that the speed of sound is temperature dependent? I'm pretty sure it's density of the medium dependent (although air density is affected by temperature). In fact, try to measure the speed of sound in water (very dense). It's much faster than in air. At altitude the speed of sound should be slower since the air is less dense. Speed of sound in a nearly incompressible fluid like water may be higher because of the imcompressibility, not the density. Sure seems like it should be more dependent on density doesn't it, but no... http://www.grc.nasa.gov/WWW/K-12/airplane/sound.html like it's a stiffer spring Quote Share this post Link to post Share on other sites
Blahr 0 #43 October 17, 2003 QuoteWell, that's kind of my point. Does the sound just dissipate, or is there no sonic boom at 400,000 feet... Dats 75 miles up bro. Theres no atmosphere at that altitude :-) No atmosphere, no booms, sonic or otherwise. Quote Share this post Link to post Share on other sites
sundevil777 102 #44 October 17, 2003 QuoteDats 75 miles up bro. Theres no atmosphere at that altitude :-) Ya, it is really high, but there still is some air and the speed of sound is faster there than at 40,000 feet. I didn't believe it either at first. The Aerospace.web link in my earlier post isn't working. I'll try to find another site that gives the same info. edit: the link is working again, check it out: http://www.aerospaceweb.org/question/atmosphere/q0112.shtmlPeople are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
