marine soldiers prepare come fire a total salute throughout a interment at sea. This would be catastrophically... <+> unsafe in any an ar where the bullets can come down and land on a human. Picture credit: U.S. Navy photo by Mass interaction Specialist 3rd Class Kevin J. Steinberg.

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Would you fire a gun into the waiting in celebration if you knew that, once the bullet comes down, it could kill somebody? It"s no surprise that bullets fired towards a target deserve to easily destroy whatever they run into: a cartridge from one AK-47 leaves the rifle travel at over 1,500 miles per hour (670 meters every second): about double the speed of sound. Despite only having actually a fixed of around five grams -- under a fifth of an ounce -- it"s obtained the energy of a brick dropped native a 30 story building. Focused into a tiny surface ar area in ~ the bullet tip, it can easily break v your skin. And also once that does, the energy and momentum tears v your body, ripping a hole with blood vessels, muscle, and potentially an essential organs. No wonder it have the right to kill you.

A 0.50 caliber cartridge wound of the face. The patient was injured while heater a 0.50 caliber... <+> incendiary device gun bullet through a blowtorch in a civilization War II-era accident. Picture credit: the nationwide Museum of Health and also Medicine.

But what if the bullet is fired up, rather than straight at a target? If girlfriend performed the experiment ~ above the Moon, if the bullet went up in ~ 1,500 miles every hour, then no matter what edge you fired it at and also how lengthy it required to come ago to the lunar surface, it would certainly come under at 1,500 miles per hour. A cartridge fired away from the Moon"s surface would be just as lethal as one fired throughout it. But on Earth, we have actually our atmosphere, which method we additionally have waiting resistance. A bullet fired right up, through no wind, might reach a height of 10,000 feet (about three kilometers), yet will come earlier down in ~ only approximately 150 miles every hour: just 10% of the speed and with only 1% that the energy as the initially fired bullet.

Ultra-high speed photograph of cartridge fired out of a Smith and Wesson revolver. Photo credit: Wikimedia... <+> Commons user Niels Noordhoek.

But in reality, there space extra determinants at play:

we do have actually wind, which deserve to make bullets fired even straight increase come under up to 2 miles away. No every bullet is fired straight up; many are fired in ~ an angle. If the bullet never ever stops or tumbles, it have the right to maintain much better speeds: plenty of hundreds the miles every hour.
all a bullet needs to perform to be potentially lethal is break the skin, which wake up at various speeds for various bullets and also different people.

So in order to recognize whether a bullet will break your skin or not, we have to look at two things: the bullet type and her skin type.

various weights, sizes and also calibers of bullets. Also at the same muzzle velocity, as soon as fired up,... <+> this bullets will all come down at various speeds. Photo credit: Bobbfwed in ~ the English language Wikipedia.

The generally welcomed threshold for breaking the skin barrier is 136 miles per hour, although some bullet/skin combine will cause the cartridge to bounce turn off you at approximately 225 miles every hour. The pointier a bullet is, the slow it have the right to be moving and also still break her skin. (Hollow suggest bullets are much more dangerous not since it"s much easier for them to puncture your skin, but since they create much more damage once they do.) Bullets of different sizes and also calibers can puncture skin an ext easily: buckshot will perforate skin in ~ 145 miles every hour and bullets native a .38 caliber revolver will perform so at just 130 miles every hour. Bullets indigenous a 9mm handgun may max out at speeds as low as 102 miles every hour. And a .30 caliber bullet, follow to Mattoo"s equation, might do for this reason at only 85 miles per hour.

miscellaneous thicknesses the skin are discovered on varying areas on the person body, and also often correlate... <+> with hairy regions. Your armpits have an especially thin skin. Picture credit: Wikimedia Commons individuals Madhero88 and also M.Komorniczak.

In addition, skin thickness varies from person-to-person and also at various places on your body. The skin top top your upper lip is 50% thicker 보다 the skin on her cheek, and the skin just below your cheekbones by your nose is also thinner, an especially in the elderly. Babies and also young kids have very thin skin relative to adults, and while the elderly have actually thicker skin in general, it has actually less elasticity and also is much easier to tear and puncture.

The only method to insurance a bullet will bounce off of her skin? be Superman. Photo credit: Leo... <+> Leung of flickr, via https://www.flickr.com/photos/mleung311/8854935471.

According come Hatcher"s Notebook, wherein U.S. Army significant General Julian Hatcher report on a vast suite of military ballistics tests, a .30 caliber bullet has actually a terminal rate of 200 miles every hour, not 150. When you fire a bullet right into the air, it typically takes between 20 and also 90 seconds for it come come down, depending on the edge it was fired at, that muzzle velocity and its caliber. New years and July 4th, in the USA, are an especially dangerous in urban areas for this, as injuries from falling bullets and even sometimes deaths result. While reports indigenous hospitals are often debated by police, there are well-documented instances that prove how lethal this have the right to be. In 2010, Marquel Peters, four years old, was killed by a stray falling bullet in Decatur, GA.

As long as a bullet can puncture your skin, the damages it deserve to do come you internally has the potential... <+> to be lethal. Windy domain image.

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If you should fire a gun into the air, the way to minimization your potential threat to yourself and also others is to:

fire the bullet together close to vertical as feasible (where that will lose the most speed), native a low altitude place (where air resistance is higher), in a rural, low-population-density area (where it"s much less likely come hit a person), and to fire a lighter, larger bullet (with a reduced terminal velocity).

And finally, as a bystander, understand that you aren"t fully safe indigenous a hail of fall bullets until 2 minutes have passed because the final gunshot. Shoot a gun into the air might be very unlikely to death the human being firing it, but there"s a factor that most major cities have actually outlawed it: your liberty to memory ends once your celebration starts to kill innocent bystanders.

I to be a Ph.D. Astrophysicist, author, and science communicator, who professes physics and astronomy at assorted colleges. I have actually won countless awards for science writing