Yes, it's true that it probably wouldn't be as much fun-at least not in one respect. The images of astronauts swallowing floating blobs of water and turning somersaults while catching candy in their mouths die hard. But, there would be many, many advantages-no space sickness, no bone decalcification, no muscle atrophy-and anyway, if you absolutely had to swallow a floating blob of water, you could always turn the gravity off. Right?
Well, that depends.
Unfortunately, true artificial gravity is a long, long way off. By true artificial gravity, I refer to that combination of magical devices that allows the people of Star Trek to float up into the air and fall back down to the deck at the flick of a switch, to endure staggering accelerations without being reduced to something vaguely resembling runny chili, and to sleep in real beds. In fact, as it happens that business of floating back up into the air whenever the gravity shuts down is plain silliness; inertia would keep you right where you were until you tried to move. Oh, and here's a delightful piece of trivia: on the original Star Trek, whenever there had been a major event in space-which is to say, the people on the bridge had just stopped tossing themselves around and the camera had just finished shaking-the background noise of damage reports and the like always included the phrase, "Gravity is down to point-eight!" But, I digress.
I love Star Trek.
As a matter of fact, the artificial gravity that may one day be put into place by NASA will only accomplish one of the achievements with which I credited the artificial gravity of Star Trek-namely, permitting the crew to sleep in real beds. That's because it has nothing to do with gravitons or inertial dampers or superstator coils. Instead, it relies entirely on a little piece of imaginary physics: centrifugal force.
You see, there's not really any such thing as centrifugal force. Engineers speak of it as a convenience, and you can calculate it if you like, but the plain truth is that it does not exist in the same way that centripetal force exists. Instead, centrifugal force is plainly an effect of inertia; there is not really some magical force keeping the water in the bucket that you are slinging around your head from soaking you. But, in the end, it doesn't matter; whatever the cause, it is convenient to speak of "centrifugal force", convenient to calculate it, and yes, convenient to use it.
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