Lightsecond

[nwhyte]

Read this passage, lightly redacted from one of this year's Hugo nominees, and tell me if you think "lightsecond" is being used (correctly) as a unit of distance or (incorrectly) as a unit of time. A docking-mouth opened, a whirlpool of matter spinning out and away, and the comet plunged into this vast funnel. For the first lightsecond, magnetic

Comments

[benrosenbaum]

Hi, hadn't seen this discussion before. I think I wrote the passage in question (though it might have been Cory) and I can tell you what I was thinking, although, of course, the author is dead and the story is the reader's, so it means whatever you think it means:

1. Yes, I know a light-second is a unit of distance. :-) It's supposed to be analogous to "the first half mile of braking"
   
2. the comet is moving quite fast because
   1. it's accelerated by its own propulsion systems, the ones it uses to cross the galaxy -- it's actually a ship of sorts, made out of a comet, after all. The book begins with Nadia having this Beebe fry the asteroid it used to live on, and setting out with the comet,
   2. it's further accelerated by Nadia blowing up part of the comet during her struggle with Paquette, and
   3. it is falling straight into a massive body, Byzantium, which is composed of the matter of several solar systems. Your google search is, I reckon, discussing comets in orbit around stars -- which are the ones we generally see, right? -- not comets falling

[benrosenbaum]

"Magnetic fields induced its breaking" -> um, braking. The lasers are doing the breaking... :-)

[nickbarnes]

OK, cool.

The fact that the comet is falling into Byzantium is of relatively little consequence (given that Byzantium has several solar masses and is several light-seconds across); regular comets are essentially falling into the solar system - have parabolic or near-parabolic orbits - and have a maximum speed - at perihelion - equal to (hmm) root-2 times the speed of a circular orbit at perihelion distance. That is, maybe tens of km/s. A body such as this comet - in hyperbolic orbit with a large surplus velocity - will be accelerated by much less than this: delta-v = delta-E/2mv.

I really will get around to reading it some time....