Author Topic: A very simple question that may be impossible to "answer"  (Read 2054 times)

Offline Zoomer30

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For those of you who have seen both daytime and nighttime launches of the shuttle:  Does it seem louder at night or during the day.  I ask since in my experience with thunderstorms it seems like at the night the thunder is louder.  Any opinions?

Offline MKremer

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Re: A very simple question that may be impossible to "answer"
« Reply #1 on: 09/14/2006 06:49 AM »
Subjective, and maybe relative - daylight has noises most people are 'used to' as far as traffic, nature, and weather.
At night things sometimes tend to be magnified, psychologically, so things like thunder, choppers, airplane takeoffs, and, yes, Shuttle launches, would tend to seem louder than what would be expected during daytime hours.


Offline Dana

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RE: A very simple question that may be impossible to "answer"
« Reply #2 on: 09/14/2006 06:58 AM »
All a sound wave is, is moving air. Changes in air density, barometric pressure and humidity also effect the way sound travels. As the temperature cools off at night and other such atmospheric changes take place in that area, it can make quite a difference. It would not surprise me at all to hear that people think a night launch is louder and more "boomy" than a day launch.
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Offline Jim

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Re: A very simple question that may be impossible to "answer"
« Reply #3 on: 09/14/2006 11:46 AM »
Having worked at the spaceport since '88, I have notice volume variations.   The weather has a large effect on the volume of a launch.  Variations in temp, RH, wind (as Dana states) effect it and therefore the weather differences in day vs nite also affect it.  

Major 'players":  lower RH is louderf.  Wind blowing towards you also

Offline Zoomer30

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RE: A very simple question that may be impossible to "answer"
« Reply #4 on: 09/19/2006 01:37 AM »
Of course then it could just be a simple matter of "Most things are asleep at night" :)  I could imagine a big difference at KSC from daytime to night.  More wildlife making noise during the day.  I would have to be down there for both a daytime and a nighttime lauch to see for myself, dont see that happening ;)

Offline Rocket Guy

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Re: A very simple question that may be impossible to "answer"
« Reply #5 on: 09/19/2006 02:54 AM »
The wind has a big affect on sound at distance. I would have to, on the contrary, say that the higher the humidity the louder from my experience. Base travels very well in wet conditions; similarly, airplanes and thunder always sound louder during overcast and rainy conditions.

As for the 'seemingly' aspect, you are right that there is less general noise in the atmosphere at night. While the launch is not really louder, it may seem so when you are out watching at night due to that.

I have seen launches from one to ten miles away. From one mile or three, there is hardly a louder or softer one. But from ten miles, I have heard bone shaking in terms of audible sound, to 'heard nothing but felt the base' only.

Offline Jim

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Re: A very simple question that may be impossible to "answer"
« Reply #6 on: 09/19/2006 11:37 AM »
Quote
Ben - 18/9/2006  10:41 PM

The wind has a big affect on sound at distance. I would have to, on the contrary, say that the higher the humidity the louder from my experience. Base travels very well in wet conditions; similarly, airplanes and thunder always sound louder during overcast and rainy conditions.
.

There is the key: "overcast".  It channels the sound (I think) .  WRT RH, I meant a clear "winter"  (50-70%) florida day vs a clear summer day (80-95%).

I guess we both have our opinions.  We need a more scienitific method or explanation

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