Short Video: How Do Guns Work in Space?

This video from Michael Stevens at Vsauce takes a look at the use of guns in space. For example, fire a bullet on the moon at 1,600 meters per second and it will orbit the moon and hit you in the back of the head! What about firing a water pistol at the Sun? Adding water to the Sun would increase its mass and it would burn brighter, but at the same time shortening its expected life. Unless you could add so much water that you could reduce the density of the Sun so much that fusion could no longer occur. But fire a bullet in empty space and that bullet will never reach another galaxy. Never.