# If someone were to fire a gun in space, would the bullet travel normally?

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If someone were to fire a gun in space, would the bullet travel normally?

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In a straight line at a constant velocity, unless acted upon by an outside force, yes. As would the person who fired it, but in the opposite direction.

If would travel pretty much indefinitely, as there is no air to slow it down, it’ll keep on going until it’s pulled in by the gravity of a planet or it hits something

A bullet fired from a gun in space would travel continuously until affected by an external force, like striking an asteroid or other space debris, or gravity.

Yes and no. It will travel normally, however in space there is an equal and opposite reaction for every action. On Earth, you’re standing on the ground, so you won’t move backwards when you fire. But in space, there’s nothing to hold you, so you will be gently thrown backwards a little bit. It’s *not* like the movies where someone gets shot with a shotgun and they get knocked off their feet and go flying from the impact — that’s just Hollywood. But you would be able to feel a push and you would begin to slowly drift backwards. You could also fire in different directions to move yourself around. Which is basically how rockets work (just using gas instead of bullets).

Yes, gun cartridges will fire in space as they don’t require oxygen from the atmosphere (like a car engine).

The bullet is accelerated from the expanding gases out of the barrel so it would move even faster than normal as there is no air pressure working against the expanding gases.

The bullet wouldn’t experience negative acceleration from friction (air resistance) either so it wouldn’t slow down.

The gun itself would have to be designed to higher pressure of the expanding gases as there is no atmospheric pressure counteracting it.

Also note that the gun would be accelerated backwards by the expanding gases as well, it wouldn’t speed like the bullet as it’s more massive but it would be accelerated in the opposite direction.

With modern ammunition, the only things that would be different would be lack of sound, the bullet wouldn’t stop until it hits something and the smoke from the barrel would be spherical.

There are no straight lines in space, gravity is everywhere.

Depending on where it is fired, it will travel at a near constant velocity (very very extremely small drag due to the occasional particle it hits) in an orbit around the most massive nearby celestial object (unless the muzzle velocity is greater than the escape velocity of that particular object, and it ends up orbiting something much more massive but further away eg. galactic core). The eccentricity of the orbit is determined by the direction it is fired and the velocity vector of the shooter relative to the same celestial object. Unless the trajectory intersects a planet or star or other object, it will orbit for a very long time.

It will travel according to the laws of physics just like it does on Earth, but it would ‘look’ pretty different than we’re used to on Earth because in space there’s no atmosphere to provide air resistance and slow it down, and because on Earth due to gravity the bullet pretty quickly ends up impacting the ground (if it doesn’t hit something else first).

Assuming you were in somewhere still close to the Earth, the bullet would almost certainly remain gravitionally bound to the Earth and eventually fall into the atmosphere, but since you’re so far away from the Earth’s surface, from your point of view you’d just see the bullet travel off in a seemingly straight line and just keep going until it was too far away to see (Obviously bullets travel too quickly to really see anyways, but we’ll ignore that here).

But guns can fire in space because the cartridge contains both a propellant and oxidizer in an enclosed space, so it can produce the required combustion even when surrounded by vacuum. And then without an atmosphere the bullet will just travel in a straight line with basically only gravity affecting it. Space isn’t a perfect vacuum, especially closer to planets or other celestial objects, so the bullet would be interacting with tiny particles constantly, but we’re talking like millions of years before that would stop it.

Gravity would affect its flight path over time, but exactly how that would look would depend a lot on the specific conditions where/when it was fired.

Yes, It wouldn’t be slowed down at all by air resistance or similar and not be affected by the usual aerodynamic considerations we have here on earth, but otherwise it would travel just fine.

In fact it would fly just the tiniest bit faster than it ever would on earth, since there is no air in the way inside the barrel as it gets shot. (at least in reference to the gun itself.)

Once fired it would simply keep going with no air slowing it down.

It would be subject to the normal orbital dynamics of things in space, but other than that it would simply keep going.

Firing a gun in space is pretty normal since bullets have their own oxidizer to burn and don’t need any air can fire in the vacuum of space and even underwater.

If you fire a gun too much in space you may run into overheating problems because there is no air to take heat away from the gun. You may also encounter weird effects where any grease or oil will evaporate away in vacuum and moving metal parts may get vacuum welded together if they are in contact long enough.

But otherwise the gun will fire just fine.

The shooter on the other hand will become acquainted with newtons. The recoil will be problem and push the shooter back and unless the gun was lined up with their center of mass cause them to spin and tumble.

The bullet itself will become just another object that orbits whatever the shooter was orbiting when he fired, just on a slightly different orbit. (The speed of the bullet will usually not be enough to deorbit it or push it up to escape velocity.)

“Normally”? No.

Normally (on Earth) the bullet immediately begins to fall toward the center of the Earth. If fired level, it’s trajectory will be out and down. When firing at any target on earth, no matter the distance, you must fire ‘up’ to arc the bullet to the target. Your bullet also loses speed over time due to air resistance.

In space, the trajectory will depend on the nearest objects of substantial mass. Say you’re way out near the orbit of Pluto, stationary in the solar plane, and fire a bullet in toward the Sun. The trajectory will be almost flat. It may be perturbed by some masses in the solar system, but unless it comes close to one it will not be by much.

There will also not be any air resistance (maybe Solar Wind resistance..but neg liable). So it will accelerate or decelerate (and curve) depending on the masses it passes. If there is nothing close enough to have a large effect on it, over time the bullet will accelerate due to the gravity of the Sun.

“An object in motion will remain in motion until acted upon by another force”

In pure space like the areas between galaxies the bullet would fly on it’s original trajectory until such time as it comes in contact with some other force.