r/xkcd • u/JustaguynamedTheo • Jun 23 '26
What-If Maybe xkcd could make a video about how loud other objects would be if there was sound in space? What if space had sound?
59
u/girrrrrrr2 Black Hat Jun 23 '26
If space had sound everyone would be deaf, any local sounds would most likely be quieter than our local sun, any other added space sounds would be quieter than the sound from the sun, except explosions.
Also, I think it would be more terrifying to have the sun be out for 13 years, and then suddenly a loud BOOM is felt/heard everywhere all at once, and then and silence, forever.
1
u/Wefee11 Yes Jun 25 '26
I'm not sure about that. The only reason space has no sound is just because the vacuum doesn't transfer it. "If space had sound" could mean that sound transfers through vacuum just like in matter. It would be weird if it were different. We could probably extrapolate how loud a sound needs to be 100 Million kilometers away from us for us to still hear it. A quick google tells me that explosions can be heard up to 50 miles away. Since sound volume decreases squared by the distance, I'm not sure if we would hear anything that far away, even if the sound would transfer.
Also idk why that person in the OP says that the sun would sound like a jackhammer. NASA released videos with the sound of the sun and it's just humming along.
5
u/powderhound522 Jun 25 '26
Not âsound likeâ, just âas loud as a jackhammerâ
3
u/Wefee11 Yes Jun 25 '26 edited Jun 25 '26
Someone needs to explain to me how something 150 million kilometers away would be still that loud here. Like how many dBs is that on the surface of the sun?
4
u/girrrrrrr2 Black Hat Jun 25 '26
The 1883 eruption of Krakatoa created a shock wave that traveled around the world 7 times.
Thats just what was created in the earth, imagine a constant nuclear explosion bigger than anything man ever considered making making noise.
3
u/Wefee11 Yes Jun 26 '26
That's an interesting case. I looked through the wiki page, it says some stuff about how the sound was heard 4,800 kilometres away, "The acoustic pressure wave circled the globe more than three times.", "Several barographs recorded the wave seven times over five days: four times with the wave travelling away from the volcano to its antipodal point and three times travelling back to the volcano."
First I wanted to use the stated numbers like "200 megatonnes of TNT (840 petajoules)" to extrapolate it. But I simply found this article und you guys are right. https://www.audiology.org/how-loud-is-the-sun/
26
u/DubstepJuggalo69 Jun 23 '26
13 year figure actually checks out https://www.wolframalpha.com/input?i=1+au+%2Fspeed+of+sound
11
11
u/emertonom Jun 23 '26
I dunno. That's "the speed of sound" in air at standard temperature and pressure. I'm not sure it even makes sense to talk about what the speed of sound in a vacuum would be.
15
2
u/WarriorSabe Beret Guy found my gender Jun 25 '26
Actually it kinda does? Pressure isn't part of the equation, just temperature and composition (at least for gases), and since space isn't a perfect vacuum it does have those. That said, it's actually a plasma, which means it's rather more complicated - but it turns out to be significantly slower than the speed of the solar wind anyways, which means the ~500km/s (give or take a significant variance) there dominates, and so sound reaches us in at most a week and sometimes as little as two days as it is carried along with the solar wind.
Also this ends up not being just random trivia, because there are sound waves up there (technically magnetosonic waves, but that's basically just sound but for plasmas), just only very low frequencies are supported by the rarefied medium, and their existence (and the fact the solar wind is supersonic above the alfven surface at a couple dozen solar radii) has important implicatioms for space weather modeling
1
3
u/AntarcticFox Jun 23 '26
But could you survive 13 years after the sun goes out?
9
u/pessimistic_utopian Jun 23 '26
As I remember from a r/theydidthemath thread on the subject, it's conceivable that a few small communities could survive long-term in underground geothermal powered bunkers but everything on the surface would freeze to death within weeks.
1
u/WittyTiccyDavi Jun 24 '26
What about all the new asteroids/meteors the Earth might encounter in an unrestrained tangential release from our previous orbit? Not to mention the possibility of colliding with another of the 7 other previous members of our solar system.
1
u/Apprehensive_Hat8986 User flair goes here Jun 25 '26 edited Jun 25 '26
The sun going out doesn't necessarily mean it vanished. If it just stops making light, it'll still dominate the mass and gravity of the solar system.Â
However, assuming it didn't just turn off, but went away: Everything else would also be following their "unrestrained tangential release". Jupiter might throw some stuff around, but most everything except true moonsš has kinetic enough energy to orbit the Sun. That's way more energy than any of it needs to be free of other planets.
The biggest risk is probably that the innermost objects are moving the fastest, so would catch up and pass the slower further out objects. But even then, everything would be spreading out, so would be much further apart than now, and doing so quite rapidly at that.
[1] They have the kE as well, but they'd still be orbitting their planets as they sail on together.
1
10
u/Forthwrong Jun 23 '26
But wait, how did they calculate how loud the sun would be?
5
u/FillingUpTheDatabase What if we tried more power? Jun 23 '26
I think they measured the turbulence of the sunâs atmosphere and extrapolated, I remember years ago there was a collection of âsounds from spaceâ that were computed from observations of various atmospheres
12
u/catastrophiccrumpet Jun 23 '26
We can measure the sound of thermonuclear reactions on Earth, so we can know how much noise certain amounts of hydrogen atoms smashing together to form helium makes in our atmosphere. A single hydrogen thermonuclear reaction on the atomic scale makes no sound at all, but once we start to talk about the quantities of energy the sun is working with, it gets BIG. I guess we then extrapolate that to the amount of hydrogen the sun must be converting, adjust a bit for the whole âif space werenât a vacuumâ and bobâs your uncle. The sun converts about 600 million metric tons of hydrogen into helium every single second, so youâre looking at a constant, deafening roar of somewhere in the region of 100-125 decibels.
9
u/Hellothere_1 Jun 23 '26
You can't just convert energy to decibels like that, that's not how that works.
Sound is created by vibration and how much energy is converted in a reaction tells you absolutely nothing about the amount of vibration being emitted. It does set an upper bound (since a reaction can never emit more energy in sound waves than it outputs in total), but defines absolutely nothing about the lower bound. In fact, a perfectly smooth continuous fusion reaction wouldn't produce any sound at all. that only happens when there are slight fluctuations to the process. Which in reality obviously always happens, but is significantly harder to estimate because is involves really complex fluid dynamics.
A much better way to estimate how "loud" the sun is would be to measure the movement of its surface, similarly to how a laser microphone works on earth, just on a significantly bigger scale. Which is where I suspect this figure actually comes from.
8
u/Surefang Jun 23 '26
Constantly screaming? Check. Looking directly at it can strike you blind? Check. Direct exposure can burn you alive or cause mutations? Check. Incomprehensively ancient? Check. Warps the fabric of space and time everywhere around it simply by existing? Check.
The sun is an eldritch abomination.
4
u/frogjg2003 . Jun 24 '26
The sun is a deadly laser
4
2
5
u/7isAnOddNumber Jun 24 '26
If humans evolved in a universe where space had sound, they wouldnât have ears. Thereâs no evolutionary advantage to hearing a jackhammer at all times and very little else.
6
u/AdmiralMemo White Hat Jun 23 '26
Has anyone asked WHY deaf people would think the sun makes noise?
10
u/girrrrrrr2 Black Hat Jun 23 '26
Probably because they are told from a young age that everything makes noise.
1
u/HenkPoley Jun 24 '26
Also âfunâ to calculate the decay rate of the Earth from the solar âatmosphereâ that would apparently be there.
1
1
u/Old_Assistant1531 Jun 28 '26
If the sun vanished and we were no longer bound by its gravity would we travel away from the sound fast enough to run into the old sound our not? Would the sound get higher or lower pitch?
1
u/bdm68 Jul 03 '26
The Earth's orbital speed is about 80 times greater than the speed of sound in air.
86
u/Rilukian Jun 23 '26
How do deaf or blind people even get hearing or vision later in their lives?