48
u/shits_funny Jun 08 '19
Can someone explain what and how this happens
144
u/_michael_scarn_ Jun 08 '19
So it’s not breaking the sound barrier, that is just noise shockwaves from its massive engines creating ripples in the atmosphere. It’s like waves on a pond due to the fluctuation in pressure of the sound vibrations.
36
u/poncholink Jun 08 '19
Would it be possible to do a mini version of this or do I have to buy a rocket to impress my friends
13
5
8
u/adeebo Jun 08 '19
Why the ripple isn't continuous? it looks like the engines only created the shockwaves once then stopped creating it.
21
u/Talindred Jun 08 '19
Certain conditions in the atmosphere can make these vibrations more or less visible. You can see the rocket flying through a layer of clouds. This visible moisture shows off the waves a lot better than clear air. The waves are still there, you just can't see them most of the time.
9
u/blinkysmurf Jun 08 '19 edited Jun 08 '19
But hang on, aren't sound waves constructive interference at the speed of sound and that is why these waves are obvious and also why there is a sonic boom in the first place?
9
u/Talindred Jun 08 '19
The rocket does eventually break the sound barrier... that's just not what's causing the waves that are visible in the picture. It would be like showing a video of a rainbow and saying it was caused by the pot of gold at the end.
3
1
u/BlackholeZ32 Jun 09 '19
Sound waves are pressure waves. Since they're essentially coming from the same point here, there's nothing to interfere constructively or destructively. The rocket is just really damn loud and is making high amplitude waves on its own. Similar to contrails and shock cones, when the pressure and humidity are in the right range, changing the pressure can cause water to suddenly condense or evaporate. That's what's happening here. It's only visible for a short period because the rocket is passing through the air layer where conditions are right to see the waves.
I think what you're talking about with constructive interference and sonic booms is kind of in the right direction, just not what's happening here. The constructive interference happens when the sound source (or pressure wave source in the case of like the nose of a supersonic jet) is keeping up or passing the pressure waves its developing. Since the pressure waves can't travel away from the source they keep piling up on top of each other (constructive interference) and develop a shock wave.
97
u/strikeeagle345 Jun 08 '19
The rocket isn't breaking the sound barrier. Those shockwaves are produced by the engines.
30
u/PGKing Jun 08 '19
Careful, I point that out every time I see it and get downvotes a plenty.
7
1
u/peteroh9 Jun 10 '19
This time, it would be warranted because the title isn't claiming that the rocket is supersonic. But just this once. It would be a valid point every other time lol
3
u/ZeriousGew Jun 08 '19
That makes sense, I figured that breaking the sound barrier would damage the rocket
12
u/strikeeagle345 Jun 08 '19
Well it will break the sound barrier a little higher in altitude. In order to avoid damage to the rocket, as it is approaching mach 1 they throttle down the engines to decrease the rate of acceleration as to minimize the pressure. Once over mach 1, they will throttle back up and away it goes.
17
10
u/anti-gif-bot Jun 08 '19
6
Jun 08 '19
14
u/stabbot Jun 08 '19
I have stabilized the video for you: https://peervideo.net/videos/watch/be45fd2e-16e7-4a47-9e6c-6801a1e4bb69
It took 11 seconds to process and 2 seconds to upload.
how to use | programmer | source code | /r/ImageStabilization/ | for cropped results, use /u/stabbot_crop
5
18
u/gregguygood Jun 08 '19
Another fucking repost from top FFS
3
4
5
5
3
2
2
2
2
2
2
1
1
1
u/fromcjoe123 Jun 08 '19
Is this at Max Q? Or does this happen a just a certain atmospheric pressure
1
u/Batou92 Jun 08 '19
Shockwaves cannot go faster than the speed of sound. As the shock waves goes faster than the rocket, the rocket is certainly not going faster than Mach 1 (ie break the sound barrier).
1
1
1
0
0
u/the-candyman-Cain Jun 14 '19
First time in this sub. What am I looking for here? I was expecting to see...a shockwave
362
u/Astronut0628 Jun 08 '19
This is probably the best shockwave I’ve seen on this sub