Science Question

[TeenageRepublican]

This question has been bugging me since 6th grade.
What would happen if you shot a gun in space?
I've asked all my science teachers that question and they all gave different replies. Does anybody know the answer to this question?

[Timberwolf]

Depends on one thing...was the cartridge sealed?

If it was, the gun would fire normally, since there'd be air in the cartridge to ignite the gunpowder. Mind you, since there's less pressure in space, it might damage the barrel due to the slight expansion of the slug.

If it wasn't, nothing would happen.

[TeenageRepublican]

Depends on one thing...was the cartridge sealed?

If it was, the gun would fire normally, since there'd be air in the cartridge to ignite the gunpowder. Mind you, since there's less pressure in space, it might damage the barrel due to the slight expansion of the slug.

If it wasn't, nothing would happen.

Okay. That answers it. Now this leads me to another question, why couldn't my science teachers answer this?
:question:

[Eagle1]

because you science teachers are products of the public education system and have no real desire for the development of the mind

there are many many teachers out there doing good things and interested in the enlightenment of the young, apparently you just havent had one in science yet

[Teenager]

Depends on one thing...was the cartridge sealed?

If it was, the gun would fire normally, since there'd be air in the cartridge to ignite the gunpowder. Mind you, since there's less pressure in space, it might damage the barrel due to the slight expansion of the slug.

If it wasn't, nothing would happen.

But, how far would the bullet travel (normally?)?

[TeenageRepublican]

because you science teachers are products of the public education system and have no real desire for the development of the mind

there are many many teachers out there doing good things and interested in the enlightenment of the young, apparently you just havent had one in science yet

I actually like this Science teacher. He was my football coach last year. I honestly don't blame him because of what's currently on his plate.
-Wife's pregnant
-Coaching football
-Grading

He goes around a lot.


But, how far would the bullet travel (normally?)?

It would go quite a ways, since there's less force effecting the bullet. But it goes at the same velocity as it would on Earth. Also another reason why it goes a quite a ways is because, depending on what moon or planet your near, the gravitational pull is a lot less than that of Earth.

Holy crap, did I just type that? I hate Science class, but somehow I remember that? Wtf...
I'm sure I screwed something up with that explanation.

[Gonzo67]

Actually, with no gravity, no atmosphere, it would travel indefinitely, until it entered the gravity of another object. If it encountered no such object, there is no counter force stopping it's momentum.


A tougher question to answer would be, if you are traveling in a space ship, at the speed of light, and you turn on your headlights, what will happen?

[Elgalad]

Actually you can't forget about action/reaction.. :shame:

How far and how fast the bullet would be travelling upon exiting the barrel depend primarily on the mass of the gun and the person(?) holding it, as well as the density of the medium they are in.

Equal expanding force is exerted on the bullet and on the back of the chamber (effectively, the gun and person holding it) at the moment of the powder's combustion. Therefore, both the projectile And the shooter would accelerate in opposite directions at different speeds.

Feel free to check my math in the following example.. :)

Hypothetical: an astronaut is holding a .22 rifle (with sealed long rifle cartridges!). He fires the weapon straight ahead. Assuming the bullet weighs about 33 grains (7000 grains to a pound) and the astronaut plus rifle weighs about 360 pounds (don't forget the suit..), then the ratio of bullet projectile to launcher is roughly 33/7000/360 or 0.0000131.

Flipping that around reveals that the bullet will accelerate 76,364 times faster than the astronaut (in opposite directions). That may not seem like much.. but since there is very little friction in space, it would probably be quite noticeable, assuming the astronaut had other nearby objects as a frame of reference.

Another interesting point arises here:

Because that explosive force is being divided, the bullet actually travels slower when it leaves the rifle than it would on the Earth. Why, you ask?

On Earth, you feel that force against you as a 'kick' when you fire the weapon. Since you're usually braced against the ground when you fire it, the weight ratio changes enormously because you are adding the Earth's weight to your own. The bullet assumes greater acceleration because of this. Keep in mind that while we never notice it, the Earth actually Does accelerate in the opposite direction very very very slightly every time someone fires a weapon. :ooo:

In Space of course, the force only has to act on the bullet and the astronaut/spacesuit/gun. So the force gets divided a Lot more equally (if 76,000 to one could be considered equal that is...)

Regarding distance though, since Space is a near-vacuum, the bullet encounters almost negligible friction from the diffuse particles it contacts as it travels, so it would travel an incredibly farther distance than it could on Earth where it would encounter friction/drag from comparatively dense air molecules. This assumes it doesn't get caught in a gravity well or collide with another object, obviously.

Anyways, to sum all this up:

In Space: Bullet travels slower initially, but ends up traveling much farther.
On Earth: Bullet travels faster at first, but has a much shorter range.

Final Note:

This concept is actually being considered as one of the most feasible forms of propelling space vehicles long distances. Several different designs have been proposed, including a massive ship that actually drops nuclear bombs out the back and 'rides' on the wave of their explosive force, or a ship that uses a laser to fuse deuterium (hydrogen) pellets and spits them out the back, and even oddly enough, an actual "Ion Thruster" (http://en.wikipedia.org/wiki/Ion_thruster) that accelerate very slowly at first, but could potentially reach speeds approaching the speed of light.

And I'll remove my geek cap now. :biggrin:


-Elgalad

[Elgalad]

Actually, with no gravity, no atmosphere, it would travel indefinitely, until it entered the gravity of another object. If it encountered no such object, there is no counter force stopping it's momentum.

Space isn't a vacuum (http://en.wikipedia.org/wiki/Outer_space#The_.22vacuum_of_space.22), but it Is much more probable that the bullet would be caught by a gravity well or object before it slowed down to a stop. :thumb:

A tougher question to answer would be, if you are traveling in a space ship, at the speed of light, and you turn on your headlights, what will happen?

It depends.. If you are inside a warp bubble (http://en.wikipedia.org/wiki/Alcubierre_drive) it would appear to you exactly as if you were turning on your lights on an car in motion. Everything inside a warp bubble is only relative to other objects inside it. Outside the bubble, you and your headlights do not exist until you emerge from the bubble.

The concept of warp bubbles doesn't violate the constant of the speed of light because they do not travel faster than the speed of light. Instead, they change the distance of space itself between two points. An independent light beam outside a warp bubble might arrive at a distant point later than a ship inside a warp bubble, but the ship did not 'outrun' it. It just travelled a shorter distance.

-Elgalad

[DoctorDoom]

Elgalad's treatise is excellent. However, since there is no air in the rifle's barrel to resist the bullet's acceleration, it would most likely exit the barrel at a faster speed than an Earth-bound rifle could provide.

[Rhino]

Space isn't a vacuum (http://en.wikipedia.org/wiki/Outer_space#The_.22vacuum_of_space.22)...It is also not entirely frictionless.

[Teenager]

My head hurts.

[Rhino]

Actually, with no gravity, no atmosphere, it would travel indefinitely, until it entered the gravity of another object. If it encountered no such object, there is no counter force stopping it's momentum.Unless you use the force.

Or.... The SCHWARTZ!!!

[Gonzo67]

Yeah, well my Schwartz is bigger than yours. Yogurt told me.

[Rhino]

:rotflmbo:

[Nutrider99]

Regarding the headlights, the lights would come on but there would be no beam because you would traveling at the same speed UNLESS you were traveling in reverse (direction not stipulated).
Eglad beat me to the opposing reaction answer, but one must think also about the direction of the barrel, and whether the astronaut was free floating or standing on his space ship. It the latter was the case, the mass of the spaceship would need to be considered in determining how much it would move, since he is braced against it. Again, a complete answer cannot be given until complete circumstances are known.

[Nutrider99]

Elgalad's treatise is excellent. However, since there is no air in the rifle's barrel to resist the bullet's acceleration, it would most likely exit the barrel at a faster speed than an Earth-bound rifle could provide.
The premise was a gun, not a rifle. Not that it matters much, but a smooth bore gun would have less friction and therefore greater acceleration.

[Rhino]

Silly conservatives! Space is a gun free zone!

[DoctorDoom]

The premise was a gun, not a rifle. Not that it matters much, but a smooth bore gun would have less friction and therefore greater acceleration.All rifles are guns, but all guns are not rifles. IAC, a bullet moving rapidly in a barrel in an atmosphere expends energy by compressing the air trapped in front of it. Therefore, whether the gun is a rifle or a handgun, if it is fired in a vacuum, the bullet will still exit the muzzle moving slightly faster than in an atmosphere.

As well, if by space we assume a gravityless situation, the bullet will have no weight and thus will not be pressed against the bottom of the barrel. This too will reduce the energy loss slightly.

In practical terms, the above factors are trivial and can be ignored, leaving only the issues of action/reaction during the firing and Newton's first law once the bullet is moving.

[Nutrider99]

However, by nature of the design rifle barrels squeeze the round into the rifling to generate spin, whereas the compression and thus the friction of a smooth bore gun is less.

[hdmundt]

A tougher question to answer would be, if you are traveling in a space ship, at the speed of light, and you turn on your headlights, what will happen?

Would the impulse from the power supply be able to reach the headlights?

[Rhino]

Yes. The electrons move in relation to the medium (the wire).

[TeenageRepublican]

My head hurts.

You'd hate being in my honors science class then. My head hurts everyday from that.


Actually you can't forget about action/reaction.. :shame:

How far and how fast the bullet would be travelling upon exiting the barrel depend primarily on the mass of the gun and the person(?) holding it, as well as the density of the medium they are in.

Equal expanding force is exerted on the bullet and on the back of the chamber (effectively, the gun and person holding it) at the moment of the powder's combustion. Therefore, both the projectile And the shooter would accelerate in opposite directions at different speeds.

Feel free to check my math in the following example.. :)

Hypothetical: an astronaut is holding a .22 rifle (with sealed long rifle cartridges!). He fires the weapon straight ahead. Assuming the bullet weighs about 33 grains (7000 grains to a pound) and the astronaut plus rifle weighs about 360 pounds (don't forget the suit..), then the ratio of bullet projectile to launcher is roughly 33/7000/360 or 0.0000131.

Flipping that around reveals that the bullet will accelerate 76,364 times faster than the astronaut (in opposite directions). That may not seem like much.. but since there is very little friction in space, it would probably be quite noticeable, assuming the astronaut had other nearby objects as a frame of reference.

Another interesting point arises here:

Because that explosive force is being divided, the bullet actually travels slower when it leaves the rifle than it would on the Earth. Why, you ask?

On Earth, you feel that force against you as a 'kick' when you fire the weapon. Since you're usually braced against the ground when you fire it, the weight ratio changes enormously because you are adding the Earth's weight to your own. The bullet assumes greater acceleration because of this. Keep in mind that while we never notice it, the Earth actually Does accelerate in the opposite direction very very very slightly every time someone fires a weapon. :ooo:

In Space of course, the force only has to act on the bullet and the astronaut/spacesuit/gun. So the force gets divided a Lot more equally (if 76,000 to one could be considered equal that is...)

Regarding distance though, since Space is a near-vacuum, the bullet encounters almost negligible friction from the diffuse particles it contacts as it travels, so it would travel an incredibly farther distance than it could on Earth where it would encounter friction/drag from comparatively dense air molecules. This assumes it doesn't get caught in a gravity well or collide with another object, obviously.


-Elgalad

So, would you actually be able to catch the bullet if it is fired at you since it's going slower? Or is it still fast enough to blow you away?

You answered another question I had already, would the gun and the person shooting it go different ways? It's like you read my mind.

Silly conservatives! Space is a gun free zone!

Well, we're just preparing for War of the Worlds and the hippies that will say this war is bad while they sit in their cloud of pot smoke.

[DoctorDoom]

Now hear this. Ludicrous Speed!

[ThomasMore]

Now hear this. Ludicrous Speed!

<object width="425" height="355"><param name="movie" value="http://www.youtube.com/v/HB7tc9pVvYg&rel=1"></param><param name="wmode" value="transparent"></param><embed src="http://www.youtube.com/v/HB7tc9pVvYg&rel=1" type="application/x-shockwave-flash" wmode="transparent" width="425" height="355"></embed></object>

[DoctorDoom]

So, would you actually be able to catch the bullet if it is fired at you since it's going slower? Or is it still fast enough to blow you away?Everything is relative. If you're moving in the direction and speed of the bullet, you can reach out and grab it. The speed of the bullet relative to the speed of the catcher determines the safety of the attempt.

[TeenageRepublican]

Everything is relative. If you're moving in the direction and speed of the bullet, you can reach out and grab it. The speed of the bullet relative to the speed of the catcher determines the safety of the attempt.

Cool.
Can you imagine how goofy a gunfight in space would look like?
That's "Comedy for Stoners" right there.

Do you know if NASA has ever attempted this or not? I'd like to see that on video.

[DoctorDoom]

NASA didn't try anything like that. However ...

I believe that there is only one instance of a self-shootdown. Here are a couple of writeups the self-shootdown Sep 21, 1956 by an F11F-1.

http://www.aerofiles.com/tiger-tail.html

A Tiger Bites Its Tail

On Sep 21, 1956, Grumman test pilot Tom Attridge shot himself down in a graphic demonstration of two objects occupying the wrong place at the same time — one being a Grumman F11F-1 Tiger [138260], the other a gaggle of its own bullets..

It happened on the second run of test-firing four 20mm cannon at Mach 1.0 speeds. At 20,000' Attridge entered a shallow dive of 20°, accelerating in afterburner, and at 13,000' pulled the trigger for a four-second burst, then another to empty the belts. During the firing run the F11F continued its descent, and upon arriving at 7,000', the armor-glass windshield was struck, but not penetrated, by an object..

Attridge throttled back to slow down and prevent cave-in of the windshield, flying back to Grumman's Long Island field at 230 mph. He radioed that a gash in the outboard side of the right engine's intake lip was the only apparent sign of damage other than for the glass, but that 78 percent was maximum available power without engine roughness occurring..

Two miles from base, at 1,200' with flaps and wheels down, it became evident from the sink rate that the runway could not be gained on 78 percent power. Attridge applied power and said "the engine sounded like it was tearing up." It then lost power completely. He pulled up the gear and settled into trees less than a mile short of the runway, traveling 300 feet and losing a right wing and stabilizer in the process. Fire broke out, but, despite injuries, Attridge managed to exit the plane and get away safely, to be picked up by Grumman's rescue helicopter.

Examination of the F11F established there were three hits — in the windshield, the right engine intake, and the nose cone. The engine's inlet guide vanes were struck, and a battered 20mm projectile was found in the first compressor stage..

http://www.aerofiles.com/20mm-culprit.jpg

How did this happen? The combination of conditions reponsible for the event was (1) the decay in projectile velocity and trajectory drop; (2) the approximate 0.5-G descent of the F11F, due in part to its nose pitching down from firing low-mounted guns; (3) alignment of the boresight line of 0° to the line of flight. With that 0.5-G dive, Attridge had flown below the trajectory of his bullets and, 11 seconds later, flew through them as their flight paths met..

http://www.f-16.net/library/stories/owngoal.html
The Grumann-made F-11 Tiger achieved some notoriety as being the first aircraft in history to "shoot itself down". Two F-11s were experimentally fitted with massive J-79 engines, giving them thrust-to-weight ratios of nearly 1 to 1. Although their increased weight and limited fuel capacity made them unsuitable for carrier duty and impractical as fighters, the two aircraft were nonetheless tested extensively.

On one such test flight, an F-11 was making passes on a gunnery target. The pilot fired a short burst to clear his guns and began a shallow dive at full power. After several seconds, the pilot pilot pulled the aircraft into a shallow climb and simultaneously began a rapid deceleration maneuver. Almost instantly, the F-11 was racked by a series of explosions, forcing the pilot to abandon his stricken aircraft. The accident investigation board concluded that the F-11 had outrun its own cannon fire, only to have the cannon fire catch up with the aircraft when it decelerated!Explosive decompression (http://www.thehighroad.org/showthread.php?t=61836&page=2)

[Elgalad]

So, would you actually be able to catch the bullet if it is fired at you since it's going slower? Or is it still fast enough to blow you away?

Ooh, a word problem.. Okay, I'll give it a shot.

Now bear with me because I'm going to make up the terms of the problem as I go, and the answer will be anything But a precise one. I'll be using estimates, you see..

What say we go back to the example I used earlier, a suited astronaut (360 lbs mass) firing a .22 rifle filled with 30 grain sealed long rifle cartridges? That'll work, but we need a little more data before we can calculate the answer to your question.

On Earth, the muzzle velocity (speed upon exiting the weapon's barrel) is roughly 1700 feet/second. For the purposes of this example, let's assume that because the ratio of the bullet's mass to the Shooter's (on Earth) is so tiny that it approaches infinity. (I realize it doesn't, but I'm cheating so that we can get a 'constant' value for the speed imparted by the cartridge's combustion.)

We'll also pretend that the conditions inside the weapon's barrel in Space are virtually identical to those on the Earth.

So we start with an explosive force that will accelerate 30 grains of matter to 1700 fps or about 1159 miles per hour. (Remember, we assumed that the 'shooter' was an immovable object of infinite mass (the Earth) so the entire force is directed at the bullet.

In Space, this force will have to be divided between the bullet and the 360 lb. shooter. They will still be travelling away from each other at 1700 fps/1159 mph but at different speeds relative to other objects (namely you, the target of the bullet who wants to try to grab it before it hits you!).

Okay, the formula for how fast each object should be travelling after the weapon is fired relative to external observers is..

vb=vt-[(mb/(mb+ma))*vt] {speed of the bullet}
va=vt-[(ma/(mb+ma))*vt] {speed of the astronaut}

where:

vt is the total relative velocity between bullet and astronaut (1159 mph)
mb is the mass of the bullet (0.0047 lbs)
ma is the mass of the astronaut (360 lbs)

vb = 1159-((.0047/(.0047+360))*1159) = bullet travelling forwards at 1158.98 mph
va = 1159-((360/(.0047+360))*1159) = astronaut flying backwards at .02 mph

I guess it still wouldn't be wise to try to catch the bullet if it was fired At you. :sad:

You answered another question I had already, would the gun and the person shooting it go different ways? It's like you read my mind.

Nah, I'm nowhere near psychic. I just have a wee bit of OCD that makes it impossible for me to pass up trivial problems like your question without trying to answer them. Call it benign geekitis.. I don't think there's any cure. :smirky:

[TeenageRepublican]

Ooh, a word problem.. Okay, I'll give it a shot.

*Shotgun Cocks* Bang! (Sorry, I couldn't resist :biggrin:)


vb = 1159-((.0047/(.0047+360))*1159) = bullet travelling forwards at 1158.98 mph
va = 1159-((360/(.0047+360))*1159) = astronaut flying backwards at .02 mph

I guess it still wouldn't be wise to try to catch the bullet if it was fired At you. :sad:


Ouch. That would hurt in the morning.
I still want to catch a bullet that's fired from a gun though. I know that's an incredibly stupid (and painful) idea. But it's not as stupid (and painful) as listening to Hillary Clinton rant.
Yes, I said it. I would rather try catching a bullet than sitting through a Hillary Clinton speech. Her voice is so freaking annoying.
Okay, that was off track. ADHD moment.
I got another question, I don't know where I keep on coming up with these things, btw.
If a bullet somehow entered our O-zone, would it gain acceleration or it would it dissolve? Here's another, if an un-shot bullet entered the O-zone, would it fire?