Last week in my post on this website, I blogged about the vast distances between star systems and how difficult it would be to travel between them. It’s a contention of mine that those immense distances are at least one of the main factors, if not the main one, that keeps aliens from other planets from visiting us here. How would you get that far?
But science fiction has been doing that sort of thing for years. It’s not at all difficult to imagine a fictitious spaceship that can travel between stars as easily as we here on Earth travel to the supermarket. Take Star Wars for example. They have spaceships (the Millenium Falcon, for one) which can travel at lightspeed. Sounds fast, doesn’t it? But if the Millenium Falcon were to travel from Earth (hypothetically, of course) to the nearest star, only 4.3 light years away, it would take 4.3 years. That would never do. It would never fit in with any of the plots or story lines of the franchise. So, they went to something else that cuts flying time down to a reasonable time within the general running time of a movie. In The Empire Strikes Back, Luke Skywalker travels from the Hoth Ice Planet to the Dagobah system in an X-wing fighter. The distance he travels isn’t mentioned, but if he’s traveling from one star system to another, it’s a good bet those two systems are light years apart. Yet he arrives at his destination in only a few hours. That has to be much faster than the speed of light, putting the Millenium Falcon to shame.
(I sure would like to get my hands on one of those X-wing fighters.)
The same goes for Star Trek. They use “warp” speed (though I’m still not sure exactly what that is). The star ship Enterprise travels the galaxy, not in hours, but in days or, sometimes, weeks. Perhaps not Star Wars fast, but fast enough. (Maybe that’s because they don’t have R2-D2 in the rumble seat.) But all this travel in excessively fast spaceships leads me to wonder how they measure their speed. Let’s take a look.
Speed (or its more scientific cousin, velocity) is measured by the distance an object can travel in a specific length of time. Like how many miles a car can travel in one hour, or mi/hr. If a car travels 100 miles in one hour, it is said to be traveling 100 mi/hr. Or by how many feet a runner can cover in one second, or ft/sec. If a runner can run the 100-yard dash in 10.00 seconds, he’s traveling 10 yards/sec, or 30 ft/sec.
But science fiction has upped the speed measurement by—if my calculations are correct—10 (perhaps 11) orders of magnitude over that speeding car, and that puts it in a range of speed where the distance has to be measured in light years, though the time would be measured in the more conventional hours. So, Luke Skywalker or the Enterprise could be clocked going in a speed that we might call lightyears per hour, or ly/hr. That’s fast.