Serenity non-spoiler

[xiphias]

Lis bought the book that has the shooting script in it. In a line of dialogue cut from the movie, a character says that "If we make a direct run within the hour, we're only 367,442 miles out. At full burn, we'd reach him inside of four hours."

That's referring to the title ship.

So: assume that that means max acceleration to the halfway point, then max deceleration to their goal. That means that they'll go 183,721 miles in two hours, for an average velocity of 91,861 miles per hour. Figuring that they're starting at 0 mph, they're going to hit 91,861 mph at the one-hour mark, meaning that their acceleration is 91,861 miles per hour per hour.

In order to convert that to Gs, I just plug it into the handy-dandy Google calculator, and find out that (91 861 miles) per (hour squared) = 1.16319996 g

So, the acceleration of a Firefly-class transport is about 1.16 g's.

Comments

[copperpoint.livejournal.com]

Aren't you assuming that their acceleration is constant? I seem to recall something from physics class (which, admitedly, was 10 years ago) about it being more difficult to accelerate when you're already moving (hence the need for gears in cars, as my teach explained it).

[xiphias.livejournal.com]

That's true for wheels. Not so much true in space.

(Okay, there is the whole "exhaust velocity"/"thrust"/impulse thing, and so there ARE cases where something analagous to "shifting gears" can come into play, but I think I'm pretty safe in ignoring that for right now.)

Basically, movement in space is actually a lot simpler, as far as physics goes, than movement on the ground. At least, until you get going fast enough that relatavistic effects start being significant. Which they're not going to be, if you're talking about only a third of a million miles in four hours.

[querldox.livejournal.com]

Trying to apply real numbers and physics to a Joss script is just asking for trouble...:- ) Particularly since the planetary system/economics for the Serenity universe just doesn't make any sense in terms of distance/travel time and the effects on relative economic and technological development.

[xiphias.livejournal.com]

I know. But . . . c'mon. They gave a distance in miles, and a travel time. Would you have been able to resist working it out for G's?

[(Anonymous)]

Well, it could be higher, actually. They don't need to come to rest again at the end, for aerobraking will help slow them down (and they're planning on making a landing anyhow). And it might vary depending on what kind of mile they're talking about. If it's nautical miles, it's a bit further out than you're assuming.

Kind of sad that they use miles in the future, though. I would have thought it'd be leagues for sure.

[mattblum.livejournal.com]

You're also assuming that the time period they refer to as an "hour" is the same as the one we refer to. If an "hour" is a 24th of a day, then its length depends on the length of the day, which of course depends on what planet you're from.

[xiphias.livejournal.com]

Yes, but I just don't see Joss really thinking about an "hour" meaning anything other than 3600 seconds and a "mile" meaning 5280 feet.

Geek!

[tendyl.livejournal.com]

I love being friends with someone who is such a geek!

Re: Geek!

[(Anonymous)]

Of course Joss uses hours defined as 3600 seconds which are defined in terms of atomic clocks!

Since he is an American he probably does not understand SI units like kilometer.

(Incidentally - did you know the speed of light is a billion feet per second?)

Re: Geek!

[xiphias.livejournal.com]

Approximately. It's actually 983,571,056 feet per second. According to Google, my source for all weird units conversions.