I picked up a Heinlein book I hadn't read in 20 years. From the library, of course.
I had wanted Tunnel in the Sky, but the library doesn't have it. Instead, Farmer in the Sky.
What this is: 1950sh era boy life novel set in space. Eagle Scout Farmers on Gandymede.
I read 130 pages in one go. There's a good chance I'll finish it tomorrow.
The good: The style! The prose! Space is big! Communicating across distances is hard! Orbital mechanics are important, and thankfully simplified. Ecology is awesome. There's finances and economics to space! Woot, it almost makes sense and it's clear Heinlein is thinking about how to make this a reasonable scenario.
The bad: Girls and women are, at best, second-class characters. Our young protagonist lives with his dad, and has a dead mom. His dad remarries a woman with a daughter, which makes it possible for all four of them to migrate.
Our protagonist is running around being awesome on Ganymede, while his new sister is stuck in a hospital room. Boys are given perks and privileges girls are not, and this is considered acceptable by the narrative.
The weird: Engineers who don't know what'd happen if, while going very close to the speed of light, you increased acceleration. Answer: Mass increases as you get close to C, such that the energy required to increase velocity asymptotically approaches infinity as V approaches C.
I mostly understand that. What I don't understand is how two light rays emitted from an LED, both travelling at C away from the LED are also travelling at C relative to each other. That I cannot grasp.
The personal: It's clear I picked up some things from this and other Heinlein books. There's some dreadful arithmetic here, things I've been accustomed to through this and other novels.
Thoughts and comments, either on this or Heinlein or scifi?
Subscribe to:
Post Comments (Atom)
Are the two light rays travelling at C relative to each other? I'm not sure that is a thing: as far as I know there is no inertial reference frame where any given photon is at rest, so you can't measure photon-vs-photon.
ReplyDeleteThe "shining a light from a spaceship" puzzle maps directly to time dilation. To an outside observer, the light seems to be moving slightly faster than the relativistic rocket. To passengers on the rocket, the light is zooming ahead at C. Both can be true because of the time dilation experienced on the rocket.
Or so I am led to believe. I may have misunderstood your question, though.
That is, just about, what has never clicked.
ReplyDeleteIn any event: the chief engineer of a torch ship should be able to explain why you can't reach C.
Yes. Yes they should.
ReplyDeleteThe thing I never got, is the idea of what happens to two relativistic ships both travelling towards each other at 0.6C or something.
ReplyDeleteAn astronomer once explained the Lorentz Velocity Transformation to me, but all I understood was "Some magic is supposed to happen to prevent that scenario from occurring"
... Because to an observer in the middle, both are going at 0.6 C.
ReplyDelete... and o, intuitively, the closing speed is 1.2 C.
Which is impossible. It's got to have to do with time contraction: time will pass different on those ships, such that they approach each other at a lower speed.
Mark Zicree just finished (I think they're finished) a series of vid casts (avail on YouTube) on the history of SciFi. One of the neat tidbits I discovered is that Heinlein is one of the few authors of his time who was willing to do YA titles under his own name. Almost all of the YA sci-fi authors of the period were pseudonyms for authors who didn't want to be associated with kids books, but needed the money.
ReplyDeleteWilliam Nichols, yes, time contraction. Years ago I found a readable intro to relativity and FTL,which you might like:
ReplyDeletephysicsguy.com - Relativity and FTL Travel: Introduction
One of the few useful things I took away from a brief flirtation with a college physics survey course was this heuristic: If you're confusing yourself about what is happening in a relativistic situation, you're almost certainly imagining an omniscient point of view, where your spatial reference frame is that of a ship at velocity, but your temporal reference frame is that of an object at rest (or vice-versa).
ReplyDeleteIn terms of Heinlein juvenalia, have you read Podkayne of Mars?
ReplyDeleteTony Lower-Basch Yeah. I think I've read them all, twenty years ago. I don't want to go back down the rabbit hole of Heinlein's novels, as if I do I'll wind up at Stranger and Starship troopers, which'll pass to For Us, The Living. From there, it's a quick hope to We The Living and then, shudder, Atlas Shrugged.
ReplyDeleteAnd that's not a faint I want for anyone!
Didn't PodKaine have a brother extremely good at poker? Or, am I conflating stories?
It's been a while since I read it. My fond memories are of the bits where a young girl studies (and exposits) all of the mass, volume, and environmental restrictions of space travel, because of her firm intention of smuggling her cat to Mars.
ReplyDeleteOh, and I have different literary off-ramps, clearly. From Starship Troopers the exits are Forever War and Old Man's War.
ReplyDeleteThose are much better directions for sure. But, that leads me down the entire series -- both to Forever Peace and, say, The Human Division. I don't want to head back to that well-hewed road, either.
ReplyDeleteEspecially when I've got The Fifth Season on loan from the library.