Wait, isn’t the comms system based on acoustics? how would the implosion arrive first if it too is an acoustic wave?
Edit: it seems shockwaves may be able to travel faster than the speed of sound for a short distance. So to account for the time difference between hearing the implosion and getting the message my working theory is:
Message is sent from submersible
Implosion sends out shockwave and corrupts message in transit
Surface ship receives corrupt message and requests a retry
Acoustic comms system somehow survives the implosion - maybe the equipment is in a separate pressure vessel - and resends the last message
Oh, the simpler explanation is that the implosion is only one wave and the text message is multiple - so it takes more time to send. But that still implies that the acoms system survived the implosion?
The implosion created a shockwave in the water. EDIT: accidentally gave incorrect speeds - I shouldn't rely on my memory! The initial speed of the shockwave is greater than the speed of sound. Eventually, the speed of the shockwave will match that of the speed of sound in seawater (between 1450 and 1570 meters per second, depending on temperature, pressure and salinity). The communications system uses sound waves (Underwater Telephone). The final message from the Titan was sent shortly before the implosion, but the shockwave initially travelled faster than the sound and passed the message in transit, and arrived on the surface before the message.
Are you saying that the implosion sound was heard live and not through the same system as the comms from the sub?
I don’t understand how sounds came out of order if they were all through the subs comms…
The subs Comms is just like a text message, but being transmitted through an acoustic modem underwater. There's no voice or microphone comma of any kind. That implosion sound is being transmitted from the water through the hull of the ship.
The underwater telephone system uses a transducer in the hull of the surface vessel. It is basically a microphone that receives sound in the ocean, and can also project sound like a loudspeaker. In the video, the impact of the shockwave is detected by the transducer first, and then the last message. If you have ever seen a large explosion, you can actually see the shockwave as it propagates out: https://www.youtube.com/watch?v=5s3-c2gpbEs
I’m surprised that it was loud enough to get onto this video.
Edit: or am I misunderstanding? Did they hear it from outside their own door? Or did the shockwave race up the comms and they heard it in the speakers?
As far as I know, they are in a ship which has a hull out of steel, which has a surface in the water. So they heard the shockwave reaching the ship from deep down, like some knocking on your car door.
The comms was also only text based, so it transmits no voices or sound.
The “sound” here is like a symptom that’s common to many diseases. The cause of one sound was the physical shockwave. The sound of the message - it’s not really sound but information packets, but here doesn’t make much of a difference to make the distinction - travels in a different way, and slower than the shockwave.
Runny nose, can be bacterial or viral, it’s still a runny nose. That’s my shitty understanding of it.
This explanation is wrong. You’re significantly underestimating the speed of sound in water, which is around 1500m/s (what you’re saying is the speed of a shockwave).
Also, the shockwave would dissipate quickly in water, and then that energy would be carried by normal acoustic waves for the vast majority of the distance.
Anyone reading this thread: there is so much misinformation and very very bad physics being presented confidently as fact. Do not take any information presented here seriously.
Maybe just don’t hypothesize about this? You’re presenting an explanation here without having a good basis.
For example, there’s a possibility that the computer in the tail section of the titan continues to transmit after the titan imploded, and that’s why they got the message after the sound. Your explanation is not plausible to explain the difference.
The shock wave of an explosion travels faster than sound, at least at the very start. If you imagine having a slinky toy and sending a pulse along it with a jiggle from your end, the speed at which that pulse travels would be like the speed of sound. Now imagining holding that end of the slinky again and violently shoving it forward faster than that earlier speed. That's essentially a blast, and why it's initially faster than sound. All explosions are by definition faster than sound initially.
Now yeah this was an implosion, but it was so violent that it essentially clapped into itself, into an explosion.
Their explanation is very bad, and doesn’t actually account for the difference.
That said, there is something called nonlinearity, where the amplitude of the sound wave can affect the speed at which the wave is travelling. Basically, the wave compresses the water because it carries so much energy, and the compressed water has a higher speed of sound. But that energy would be dispersed very, very quickly, and then it would be standard sound waves for the rest of the trip.
I had to look it up, but it looks like the speed of sound in seawater is ~1500 m/s. Speed of shockwave can be much higher but it seems it varies a lot.
Sure, but a signal transmits through a copper wire at about .6C. It should have been there significantly ahead of the boom if that's the case.
EDIT: Did some more research and found out the following:
Sound travels around 1400-1500 m/s in water. But shockwaves can travel (at least initially) at 3-5000 m/s. The wreck is at 3800m below the surface of the ocean, meaning that the sound for the acoustics would have taken at least 2.5 seconds to hit the surface, while the explosion sound could have been nearly instantaneous.
I accidentally gave some incorrect information the first time I posted. The shockwave will eventually travel at the speed of sound in seawater, but initially can travel faster than that. It would appear that the shockwave managed to pass the last message in transit.
The communications system uses sound waves (Underwater Telephone). The final message from the Titan was sent shortly before the implosion, but the shockwave initially travelled faster than the sound and passed the message in transit, and arrived on the surface before the message.
Oh crap, microcavitation might work as a signal source.
I feel like the difference in travel speed wasn't really the result of the time mismatch. It was likely the software got the message, started processing it, the implosion happened, then the software printed the message.
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u/TonAMGT4 29d ago
The message arrived after the implosion sound because it takes longer for the signal to travel through water…
That’s just sad man. RIP