# How fast does a bullet travel on the moon? **URL:** \ **Category:** Factual Questions\ **Created:** [September 2, 2004, 10:19pm UTC](https://boards.straightdope.com/t/how-fast-does-a-bullet-travel-on-the-moon/262849 "2004-09-02T22:19:06Z")\ **Posts on this page:** 9\ **Page:** 3
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 3, 2004, 9:09pm UTC](https://boards.straightdope.com/t/how-fast-does-a-bullet-travel-on-the-moon/262849/41 "2004-09-03T21:09:34Z")
> [@](#): > > The Earth is in fact the densest of all planets and moons. It is the densest large object in the solar system except the Sun itself. It’s denser than the Sun, too, by about a factor of three. Of course, the core of the Sun is probably denser than anything on or in the Earth, but then, that’s likely true of the gas giants, as well. As an interesting tidbit, the surface orbital period around a circular body depends only on density (I think this came up in another thread recently). Since the Moon is a little less dense than, but comparable to, the Earth, it stands to reason that the bullet would take a little longer than, but be comparable to, the time it takes a satellite to orbit the Earth, which is an hour and a half. So two hours sounds right. ---
**Author:** ![ShibbOleth](https://avatars.discourse-cdn.com/v4/letter/s/848f3c/32.png) [@ShibbOleth](https://boards.straightdope.com/u/ShibbOleth)\ **Post date:** [September 3, 2004, 9:25pm UTC](https://boards.straightdope.com/t/how-fast-does-a-bullet-travel-on-the-moon/262849/42 "2004-09-03T21:25:50Z")
> [@CurtC](#): > > So the Moon is only about 10 km in circumference? > > Assuming your calculations of the speed are correct, it would take almost two hours for the bullet to come around. I was wondering about this same question as I read through this thread. So, the gunman would have to fire a weapon with exactly the correct muzzle velocity, hold perfectly still, and fire across a path that had no rises into the flight path of the bullet? Is that all about correct? Any other minor inconveniences to deal with? ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [September 3, 2004, 9:48pm UTC](https://boards.straightdope.com/t/how-fast-does-a-bullet-travel-on-the-moon/262849/43 "2004-09-03T21:48:52Z")
Well, since the Moon bulges out on the side towards the Earth, I assume that you’d need to be standing on that bulge, or your shot would run aground when it got there if you fired from a lower spot. ---
**Author:** ![InvidiousCourgette](https://avatars.discourse-cdn.com/v4/letter/i/e47c2d/32.png) [@InvidiousCourgette](https://boards.straightdope.com/u/InvidiousCourgette)\ **Post date:** [September 3, 2004, 9:56pm UTC](https://boards.straightdope.com/t/how-fast-does-a-bullet-travel-on-the-moon/262849/44 "2004-09-03T21:56:55Z")
Thanks for the correction **CurtC**. I got my decimal point shifted 3 places. Should have been 6500 seconds not 6.5 🙂 Thinking about this I was wondering if you could shoot yourself in the back with a lower muzzle velocity if you pointed the gun slightly upwards? If you could, what would be the minimal required velocity? ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [September 3, 2004, 10:20pm UTC](https://boards.straightdope.com/t/how-fast-does-a-bullet-travel-on-the-moon/262849/45 "2004-09-03T22:20:51Z")
> [@sturmhauke](#): > > I don’t think standard bullets have their own supply of oxygen for the propellant. That would be a problem. What? No Oxygen? No Problem! A cartridge, sometimes called a bullet, consists of a metal, usually brass, casing, a primer pressed into the primer pocket, and a plain or copper jacketed lead alloy, bullet crimped into the front of the casing. This is a closed system with no access to oxygen! The gun or rifle powder contains all that is required for an explosion more correctly a detonation to produces the hot gaseous products to drive the bullet through the barrel. ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [September 4, 2004, 3:18am UTC](https://boards.straightdope.com/t/how-fast-does-a-bullet-travel-on-the-moon/262849/46 "2004-09-04T03:18:30Z")
> [@InvidiousCourgette](#): > > Thinking about this I was wondering if you could shoot yourself in the back with a lower muzzle velocity if you pointed the gun slightly upwards? If you could, what would be the minimal required velocity? Yeah, I thought about that too. But a body in orbit will trace out the same elliptical path over and over. So the bullet, in order to pass by you and retrace its upward path, would have had to come from behind and below you. It can’t do it because it would have hit the ground before it got to you. ---
**Author:** ![kniz](https://avatars.discourse-cdn.com/v4/letter/k/c37758/32.png) [@kniz](https://boards.straightdope.com/u/kniz)\ **Post date:** [September 4, 2004, 4:44am UTC](https://boards.straightdope.com/t/how-fast-does-a-bullet-travel-on-the-moon/262849/47 "2004-09-04T04:44:27Z")
> [@RickJay](#): > > One thing; if you’re angling your gun upwards, and it’s sufficiently powerful, your bullet might never land. I was wondering if you could accidently shoot yourself in the back? :smack: ---
**Author:** ![kniz](https://avatars.discourse-cdn.com/v4/letter/k/c37758/32.png) [@kniz](https://boards.straightdope.com/u/kniz)\ **Post date:** [September 4, 2004, 4:49am UTC](https://boards.straightdope.com/t/how-fast-does-a-bullet-travel-on-the-moon/262849/48 "2004-09-04T04:49:12Z")
Sorry! I’ll read the entire thread next time. :o ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [September 4, 2004, 5:18am UTC](https://boards.straightdope.com/t/how-fast-does-a-bullet-travel-on-the-moon/262849/49 "2004-09-04T05:18:29Z")
> [@spingears](#): > > What? No Oxygen? > No Problem! > A cartridge, sometimes called a bullet, consists of a metal, usually brass, casing, a primer pressed into the primer pocket, and a plain or copper jacketed lead alloy, bullet crimped into the front of the casing. This is a closed system with no access to oxygen! The gun or rifle powder contains all that is required for an explosion more correctly a detonation to produces the hot gaseous products to drive the bullet through the barrel. Gun powders all the way from 22 pistol to 16" gun are not supposed to [detonate.](http://guns.connect.fi/gow/nitro.html) The object is that they burn rapidly in a controlled fashion. [Previous page](https://boards.straightdope.com/t/how-fast-does-a-bullet-travel-on-the-moon/262849.md?page=2)