John Pyle’s post on Light Speed, Not so Much, reminded me about something I wanted to look into based on my Space Engine experience. In this wonderful simulator you can go anywhere in the universe with the engine kindly accelerating you to fantastic speeds, as necessary. As part of the experience, you get to experience the Star Trek warp effect: stars go sailing by all around you as a readout at the bottom of the screen shows your current speed. It might be km/s over a planet or AU/s in a planetary system. Between stars, you typically get to go parsecs per second (a parsec is 3.26 light years). Hop over to the next galaxy and you’ll be travelling at hundreds of kilo-parsecs per second. This is a good thing, because otherwise travel would be tediously slow.
One of the neat things about Space Engine is that it doesn’t just pop you over to your destination, you travel to it, accelerating and decelerating. You fly through dusty arms of galaxies, through nebula, globular clusters. As I mentioned stars zip by a la Star Trek. This got me to wondering: I think Space Engine has a pretty solid model of spatial relationships and velocity. Therefore, I can use it to gauge what Star Trek warp factor I’d need to be traveling to get the same visual effect of star motion that we’ve seen since the original series. Of course, I had a feeling the TV show was way off but it is fun to do the numbers.
First, I’ll use the newer series’ definition of warp. You can find a great definition of what warp factors mean at Star-fleet.com’s engineering department: Warp Factors Defined. At warp 5, you’re going 215 times the speed of light and at warp 9 you’re going 1516 times the speed of light. That’s pretty fast, right? Indeed it is but as the old cliché goes, space is really big. At warp 5, it’s 40 hours per light year. Not bad for the local neighborhood but not too zippy. At warp 9, it’s only 5.9 hours per light year, so several light years per day.
So what would the star motion look like? Fire up Space Engine, play around with your speed and… you’ve got to be going around a light year per second to start to notice much star motion. Pick a densely populated region like the heart of a star cluster and maybe you can get away with 0.1 light years per second. But at those speeds, you are just starting to notice star motion. If you really want to be seeing stars zip by, like in the opening credits, you might be looking at 1 to 5 or more light years per second.
Even at warp 9.99, at 7912 times the speed of light, you’re crawling by at one light year per hour+, or ~4000 times slower than the speed you need to get the stars to zoom by. I’m not sure how to turn that back into a warp factor but since warp 10 is the max, it is something like warp 9.9999, perhaps?
This means that if you intend to use that cool “star gliding” effect in your own stories, you better be having your star ships travel much, much faster than they do in Star Trek, so fast that your ship could get to the Andromeda galaxy in a few days. That’s probably too fast for most science fiction stories, unfortunately. Put another way, the Star Trek apparent star motion isn’t really practical, although it sure does look cool.
Just goes to show that space is really, really big.