# Sonic Boom Effects on Human Anatomy

I'm looking to do an action (possibly clapping), and have the force be so percussive as to cause a sonic boom (like in cartoons). The way this is actualized doesn't matter, just the sonic boom itself. The speed of the action just barely surpasses the speed of sound, but goes no faster (it doesn't travel Mach 3 for instance).

Ignoring the effects of the initial impact that caused it, which are the effects of the sonic boom itself on the body when a sonic boom happens in close proximity?

Bonus: Is it surviveable?

Note: This isn't about the effect on the Earth, nor about how much damage it could do. This is also not at speeds approaching light. This is a basic sonic boom near a human.

• @Mołot Are you, perhaps, thinking of Thunder Clap Armageddon? They do seem remarkably similar. – Frostfyre Apr 11 '17 at 15:41
• Possible duplicate of Thunder Clap Armageddon – Frostfyre Apr 11 '17 at 16:13
• FWIW, the answer in the proposed duplicate discusses damage to the world at clapping speeds beginning at 1e-4 times the speed of light. this question seems to be about damage to the clapper at speeds closer to 2e-6 times the speed of light. – cobaltduck Apr 11 '17 at 17:42
• Would something like a localized sonic boom work? en.wikipedia.org/wiki/Mantis_shrimp#Claws (Note that whip tips create sonic booms too, so just because you can make a sonic boom doesn't mean it'll do anything other than potentially cause damage to the thing making it.) – JAB Apr 11 '17 at 20:19
• Can you survive a sonic boom? Yes. Suppose someone discharges a firearm and the bullet passes right besides your head. That is not only survivable but presents a next to negligible impact on you. No, no, no.... all your nutters that were about to say "If it was a.50 caliber, you would be DEAD!!!", no... you are completely wrong. So yes, a sonic boom can be very easily survivable. – MichaelK Apr 12 '17 at 11:51

In short, the impact on the body is practically nil!

Sonic booms are pretty harmless. I used to live near a primary school where children were allowed to play with them in their breaks. It drove me nuts, but the children remained unharmed. How can children play with sonic booms? Whips. Those first graders had little problems getting their whips to supersonic speed. While I think it was pretty irresponsible of the teachers to let them to this unsupervised, what I feared was the children hitting each other with the whips, not anything to do with the sound or the super sonic boom in general.

Since you rephrased your question to make it pretty different, I'll describe the sound in more detail: It's not a single "boom" sound. When it's caused by aircraft or bullets, it sounds like a boom because those things pass the listener very fast. But if you stay at a constant distance of the source, then it's a continuous roar. Depending on what causes it, the sound can vary a lot. With whips it sounds like a metallic clap, something you would expect from a metal-working factory. When the tip of the whip stays supersonic for a longer amount of time (not that easy, thankfully, at least for first-graders) then the sound is drawn out over a longer amount of time without changing pitch. It's highly annoying when, say, you would like to sleep, but not painful or dangerous in any way.

To get a sonic boom from a clap, you would need to move your hands with supersonic speed. The sound wouldn't be caused by the clap, but by the movement of the hands in the surrounding air (an observer would probably not notice the difference, too fast). If you assume a symmetrical clap, then each hand moves maybe half a meter at most. In that space, accelerate to $v_{max}=340\frac{m}{s}$ and decelerate back to 0, so with constant acceleration you go from 0 to $v_{max}$ in $d=\frac{1}{4}m$. For constant acceleration there is $t=\frac{v_{max}}{a}$ and $\frac{1}{2}at^{2}=d$ so combined $\frac{1}{2}\frac{v_{max}^{2}}{d}=a$ which is $a=2\cdot340^2\frac{m}{s^2}$ which seems a tad much. I guess if you could have some magic accelerate the hand smoothly (i.e. not pressing against its sides, but accelerating the whole including insides directly), then the hand could survive with no damage, but there is no way to do it with improved muscles, exoskeletons or something like that. The mass of the air which is in the way of the hands+arms is in the range of single digit grams. I'm not sure how I would best estimate the maximum impact of this in the biological structure of the hands+arms, but I don't think it would be a lot.

It should be clear from my descriptions, but this is not a percussive sound, and it's not caused by impacts, i.e. it's not caused by two things hitting each other. If you want something caused by impacts, then sonic booms are not what you are looking for.

According to this table, a typical Homo sapiens modernus will:

• feel pain in their ear at the range of 130-140 dB,
• may lose hearing at 120 dB,
• and endure damage to their hearing at 85 dB.

It depends on distance according to the inverse proportional law in this formula, when sound level $L_{p_1}$ is measured at a distance $r_1$, the sound level $L_{p_2}$ at the distance $r_2$ is:
$$L_{p_2} = L_{p_1} + 20 \log_{10}\!\left( \frac{r_1}{r_2} \right)\!~\mathrm{dB}$$

• Like with pharmaceutics, the dosage is everything. – can-ned_food Apr 14 '17 at 15:35
• Thanks. I suspect there could be a relation between sound pressures and speed, cross section, distance squared and air density, maybe (speed)^2*(mass density of air)*(cross section)*(distance)^-2. That would have the correct unit at least... But I don't know for sure whether that makes sense, one would need to try. – Nobody Apr 14 '17 at 16:59

Its not a sonic boom, it is a shockwave.

The big trick is that in a superclap the hands would not be exceeding the speed of sound, the air being expelled from between them does, creating a shockwave. If the hands were moving faster than the speed of sound then the boom could be produced by just waving one hand that fast. Just like a normal clap the sound/blast wave is being caused by expelled air, but in the super case the air being expelled exceeds the speed of sound producing a shockwave just like an explosion does.

This means the hulk's (or insert fictional super) clap is not a sonic boom as much as it is a normal explosive shockwave.

But you are going to need someone who is more familiar with the working equations for explosives and the human thresholds to calculate if it will damage a person.

• I like this answer for what would cause a sonic boom by clapping, but the question isn't about the clap but rather the effects of the sonic boom. Could you please add information regarding the sonic boom? – Anoplexian - Reinstate Monica Apr 13 '17 at 22:33
• well the answer is there is no sonic boom, so I you can't even estimate the magnitude of the sonic boom to predict how it will effect a body. – John Apr 14 '17 at 4:09

According to Wikipedia, more powerful sonic booms can shatter any nearby glass. However, the strongest shockwave ever recorded was 7000 pascals, (~12 psi) but it did no harm to the researchers, although I'm sure they were pushed back a bit. So no sonic boom that you'd be able to create with your hands (unless they're as big as city blocks) would have much effect on people, if any.

Edit: Not to mention that every bone in your hand would be shattered, your skin burning from the heat of the impact, your fingernails being launched outwards, your muscle being crushed, and the shockwave going up your arms breaking most of the bones in your body as well (not good for your health)

• Where did you get the strongest pressure as 12 psi? Nuclear weapons readily exceed that value. 12 Psi overpressure would be extremely dangerous to be exposed to as well. – Joe Kissling Apr 13 '17 at 17:55
• @JoeKissling wikipedias sonic boom page – arthurz12345 Apr 13 '17 at 17:56
• @JoeKissling and I was describing the strongest shockwave, not pressure, and do you really think people in Hiroshima were standing there with barometers? – arthurz12345 Apr 13 '17 at 17:58
• A shockwave and a sonic boom are one in the same, shockwave and overpressure are also the same. The united states conducted hundreds of nuclear tests, each one was extensively studied. Blast effects, specifically overpressure, were key points of interest for destructive capability. – Joe Kissling Apr 13 '17 at 18:04
• @JoeKissling then wikipedias wrong :\ – arthurz12345 Apr 13 '17 at 18:05