As you know, space is a vacuum. This means there is no friction. Using this reasoning I ridiculed the characters of the low-budget 1970s Star Wars knock-off Battlestar Galactica when they claimed they could only turn off the engines to their spaceship and drift for a small amount of time. Couldn't they just accelerate to a fast speed, turn off their engines, and just coast to their destination. After all, there is no friction to slow them down. This would greatly expand their range and cut down on fuel costs. Unfortunately, it turns out I may have been wrong. Space is not as empty as we have been led to believe. In fact, there are many things in space such as hydrogen gas and space dust. These should have an extremely low drag coefficient and provide negligible friction. However, the drag equation shows that drag force is proportional to velocity, so if the ship were going at a very high speed (as intergalactic spacecraft must), it would undoubtedly encounter some friction. This explains why a ship cannot just coast indefinitely and why the actors on the television show were right and I was wrong.