Everyone see the article knocking #1 off the list of myths? Or rather, taking out of science fantasy and placing it firmly in the realm of hard SF.
Ian, you are confusing the matter. While you are being very precise in you terminology, you are not being very practical in as far as this discussion is concerned. Centrifugal Force is a lay expression for the force felt when spinning an object, such as a centrifuge, bucket on a rope, or those fun amusement park rides. The proper scientific name is centripetal force and is as valid for creating the illusion of gravity as the vomit comet or the space shuttle are for creating the illusion of lack of gravity (both are technically freefall). For most practical purposes, especially in fictional storytelling, the illusion is as good as the real thing.
centrifugal = moving or tending to move away from the centre
centripetal = moving or tending to move towards a centre
So the artificial gravity induced by spinning a spacecraft is centrifugal force as the people are being pushed outward from the centre.
http://en.wikipedia.org/wiki/Centrifugal_force and http://en.wikipedia.org/wiki/Centrif...eference_frame)
(I should have put "reaction to centripetal force" earlier, which is reactive centrifugal force. But in the context of rotating something to generate gravity, centrifugal force is considered a fictitious force - see http://en.wikipedia.org/wiki/Artific...avity#Rotation)
Last edited by ian_sales; September 19th, 2012 at 01:24 AM.
From the list:
This makes me think of a corollary myth:4. Ships traveling at faster than light can communicate with other ships or planets.
Ships traveling at faster than light can use sensors to examine the space around them.
If a ship was traveling FTL, no light or other particles should be able to interact with it, outside of those directly in front of it, without becoming severely dopplered... and the light or particles couldn't catch up from behind. Therefore, an FTL ship should be totally blind to anything happening behind it, and tunnel-blind to anything happening ahead of it. And, of course, by the time they detect anything ahead of it, it would be behind them before the signal even made it through the ship's electronics, much less through the human passenger's optic nerves.
"Hyperspace" should have been given a prominent spot on the original list, given that we don't know whether it exists, whether we can access it, what rules apply to it, and how it will make FTL travel workable. Hyperspace is the ultimate Handwavium.
One of the confusions about hyperspace is how Asimov used the term. Herbert later had a more mystical process but a better label - folding space. That describes Asimov's concept better. Hyperspace has come to mean more of a different dimension such as in Star Wars or Babylon 5. I found the book Hyperspace, my Michio Kaku, to be enlightening about how highly theoretical it might be.
In my fiction, I consider it a different but parallel dimensional space where all the high gravity objects in real space are echoed, but in a smaller scale. As I prefer the more theoretical end of physics, I have no problem pulling different theories into something that works, sometimes in dramatic ways, for my stories. But then, I consider what I have written, and most of what I plan to write in the future, to be space opera, so it fits what I write.