Don’t Know Much About Geography

I’m reading Old Man’s War by John Scalzi, and while it’s entertaining, I was irritated early on by technical errors in it. In the discussion about the “beanstalk” (which I can only infer is a space elevator), the supposed physics professor explains that it’s used so that that it’s not necessary to “reach escape velocity” with a rocket to get to earth orbit. Of course, it’s not necessary to reach escape velocity to get into orbit–in fact, it’s not possible to do so. Escape velocity is the velocity necessary to leave orbit, and depart from the gravitational pull of the body you’re orbiting altogether.

This one is forgiveable, though, and a common error. What really boggled my mind was the next one, in which he explained that the earth physicists didn’t understand what “held it up.”

Either Scalzi is appallingly ignorant of physics himself, or this is some future in which the people of earth have forgotten basic physics (though if that’s the case, this is the only hint of it that I’ve seen in the book so far). The physics of space elevators is well understood. A space elevator is “held up” in exactly the same way that water is held inside a bucket being swung in circles on a rope–through inertia which appears as a centrifugal “force” in the rotating reference frame. The intergrated mass of the elevator times its centripital acceleration exceeds its weight if it extends sufficiently far beyond its natural orbital altitude (in this case, geostationary orbit, since it rotates with the earth once every twenty-four hours).

Scalzi has been compared to early Heinlein by many reviewers, but Heinlein always worked pretty hard to get his basic science right (which is one of the reasons that I liked to read him–it was entertainingly educational). It’s disappointing that Scalzi doesn’t seem to take the same care in his exposition, particularly since many may take his descriptions at face value.

[Update a few minutes later]

I discussed this topic more extensively last fall.

[Sunday night update]

When I was a kid, if I had a question about one of Bob Heinlein’s books, it would remain a question. There was no place to discuss it, except with my (few) friends who’d also read the book. But now, I can read a book, I can make a comment on it, and the author himself shows up to clarify the issue in my comments section. Just how cool is that?

And I’ve no idea how he knew that I was whining about the book. I’d be both flattered and amazed to learn that he reads this blog daily, so I’m guessing that one of my other readers emailed him to tell him.

Of course, if you visit his bio section, and read the comments (including his), in addition to being a very imaginative and entertaining writer, Mr. Scalzi seems to be a genuinely good guy.

Anyway, don’t consider this post a book review. It’s just a comment that occurred to me shortly after beginning reading it. Other than what I wrote above (which may be just a consequence of misreading on my part, as noted in comments), I expect to enjoy it quite a bit.

Don’t Know Much About Geography

I’m reading Old Man’s War by John Scalzi, and while it’s entertaining, I was irritated early on by technical errors in it. In the discussion about the “beanstalk” (which I can only infer is a space elevator), the supposed physics professor explains that it’s used so that that it’s not necessary to “reach escape velocity” with a rocket to get to earth orbit. Of course, it’s not necessary to reach escape velocity to get into orbit–in fact, it’s not possible to do so. Escape velocity is the velocity necessary to leave orbit, and depart from the gravitational pull of the body you’re orbiting altogether.

This one is forgiveable, though, and a common error. What really boggled my mind was the next one, in which he explained that the earth physicists didn’t understand what “held it up.”

Either Scalzi is appallingly ignorant of physics himself, or this is some future in which the people of earth have forgotten basic physics (though if that’s the case, this is the only hint of it that I’ve seen in the book so far). The physics of space elevators is well understood. A space elevator is “held up” in exactly the same way that water is held inside a bucket being swung in circles on a rope–through inertia which appears as a centrifugal “force” in the rotating reference frame. The intergrated mass of the elevator times its centripital acceleration exceeds its weight if it extends sufficiently far beyond its natural orbital altitude (in this case, geostationary orbit, since it rotates with the earth once every twenty-four hours).

Scalzi has been compared to early Heinlein by many reviewers, but Heinlein always worked pretty hard to get his basic science right (which is one of the reasons that I liked to read him–it was entertainingly educational). It’s disappointing that Scalzi doesn’t seem to take the same care in his exposition, particularly since many may take his descriptions at face value.

[Update a few minutes later]

I discussed this topic more extensively last fall.

[Sunday night update]

When I was a kid, if I had a question about one of Bob Heinlein’s books, it would remain a question. There was no place to discuss it, except with my (few) friends who’d also read the book. But now, I can read a book, I can make a comment on it, and the author himself shows up to clarify the issue in my comments section. Just how cool is that?

And I’ve no idea how he knew that I was whining about the book. I’d be both flattered and amazed to learn that he reads this blog daily, so I’m guessing that one of my other readers emailed him to tell him.

Of course, if you visit his bio section, and read the comments (including his), in addition to being a very imaginative and entertaining writer, Mr. Scalzi seems to be a genuinely good guy.

Anyway, don’t consider this post a book review. It’s just a comment that occurred to me shortly after beginning reading it. Other than what I wrote above (which may be just a consequence of misreading on my part, as noted in comments), I expect to enjoy it quite a bit.

Don’t Know Much About Geography

I’m reading Old Man’s War by John Scalzi, and while it’s entertaining, I was irritated early on by technical errors in it. In the discussion about the “beanstalk” (which I can only infer is a space elevator), the supposed physics professor explains that it’s used so that that it’s not necessary to “reach escape velocity” with a rocket to get to earth orbit. Of course, it’s not necessary to reach escape velocity to get into orbit–in fact, it’s not possible to do so. Escape velocity is the velocity necessary to leave orbit, and depart from the gravitational pull of the body you’re orbiting altogether.

This one is forgiveable, though, and a common error. What really boggled my mind was the next one, in which he explained that the earth physicists didn’t understand what “held it up.”

Either Scalzi is appallingly ignorant of physics himself, or this is some future in which the people of earth have forgotten basic physics (though if that’s the case, this is the only hint of it that I’ve seen in the book so far). The physics of space elevators is well understood. A space elevator is “held up” in exactly the same way that water is held inside a bucket being swung in circles on a rope–through inertia which appears as a centrifugal “force” in the rotating reference frame. The intergrated mass of the elevator times its centripital acceleration exceeds its weight if it extends sufficiently far beyond its natural orbital altitude (in this case, geostationary orbit, since it rotates with the earth once every twenty-four hours).

Scalzi has been compared to early Heinlein by many reviewers, but Heinlein always worked pretty hard to get his basic science right (which is one of the reasons that I liked to read him–it was entertainingly educational). It’s disappointing that Scalzi doesn’t seem to take the same care in his exposition, particularly since many may take his descriptions at face value.

[Update a few minutes later]

I discussed this topic more extensively last fall.

[Sunday night update]

When I was a kid, if I had a question about one of Bob Heinlein’s books, it would remain a question. There was no place to discuss it, except with my (few) friends who’d also read the book. But now, I can read a book, I can make a comment on it, and the author himself shows up to clarify the issue in my comments section. Just how cool is that?

And I’ve no idea how he knew that I was whining about the book. I’d be both flattered and amazed to learn that he reads this blog daily, so I’m guessing that one of my other readers emailed him to tell him.

Of course, if you visit his bio section, and read the comments (including his), in addition to being a very imaginative and entertaining writer, Mr. Scalzi seems to be a genuinely good guy.

Anyway, don’t consider this post a book review. It’s just a comment that occurred to me shortly after beginning reading it. Other than what I wrote above (which may be just a consequence of misreading on my part, as noted in comments), I expect to enjoy it quite a bit.

Now That’s Confusion

In States of Confusion in today’s New York Times, we find the following paragraph:

Abortion-rights states would undoubtedly respond in kind [if other states made out of state abortion a crime]. For example, Rhode Island, where 63 percent of residents favor abortion rights, has rebuffed efforts at regulation in the past. Just as Utah could make it a crime for a resident to go to Rhode Island for an abortion, Rhode Island could forbid Utah’s law-enforcement officials from interfering with her decision to get one. Similarly, if an anti-abortion state places a fetus in protective custody, an abortion-rights state might do the same for the woman. And so on.

How does putting a woman in protective custody help her?

Now That’s Confusion

In States of Confusion in today’s New York Times, we find the following paragraph:

Abortion-rights states would undoubtedly respond in kind [if other states made out of state abortion a crime]. For example, Rhode Island, where 63 percent of residents favor abortion rights, has rebuffed efforts at regulation in the past. Just as Utah could make it a crime for a resident to go to Rhode Island for an abortion, Rhode Island could forbid Utah’s law-enforcement officials from interfering with her decision to get one. Similarly, if an anti-abortion state places a fetus in protective custody, an abortion-rights state might do the same for the woman. And so on.

How does putting a woman in protective custody help her?

Now That’s Confusion

In States of Confusion in today’s New York Times, we find the following paragraph:

Abortion-rights states would undoubtedly respond in kind [if other states made out of state abortion a crime]. For example, Rhode Island, where 63 percent of residents favor abortion rights, has rebuffed efforts at regulation in the past. Just as Utah could make it a crime for a resident to go to Rhode Island for an abortion, Rhode Island could forbid Utah’s law-enforcement officials from interfering with her decision to get one. Similarly, if an anti-abortion state places a fetus in protective custody, an abortion-rights state might do the same for the woman. And so on.

How does putting a woman in protective custody help her?

Not Quite Like Being There

But, hey, if it was, no one would bother to shell out a couple hundred thousand for the real thing, right?

Chuck Lauer of Rocketplane emails that they have a streaming video of a computer-generated movie of one of their suborbital flights over at Pure Galactic (apparently a new spaceline on the block). I was surprised to see that the modified Learjet has a “V” tail.

He’s interested in comments on the soundtrack. It’s a little too new agey and native Americany for my taste, and the musical transitions don’t evoke the visual ones to me. But what do I know?

Saving The Earth From Rocket Exhaust

Thomas James beats the eternally clueless Bruce Gagnon with a heavy cluebat. One could say that he beats him senseless, but it’s so short a journey that it would be pointless.

It does bring to mind an interesting issue. If we do ever achieve the desideratum of low-cost, high-volume launch, will it become a significant contributor to atmospheric pollution? As Thomas points out, Jet A and oxygen overwhelm rocket exhaust by orders of magnitude, so it’s hard to imagine lox/RP, lox-hydrogen or even lox-methane as being a problem, but I can see a point at which solids might be banned (though I suspect that they’d have long before that point been eliminated as unsafe and uneconomical).

Biting Commentary about Infinity…and Beyond!