# More about Physics *The Whorl list — 1 messages, 1 voices, 08 Oct 1997* > Exported from an unofficial mirror of a public mailing list. Copyright > in each message remains with the person who wrote it. > Email addresses are obscured as `user at host`, the form the original > archive published. This file was rebuilt from parsed fields rather than > retained headers, so it is faithful in content but not byte-exact. --- ### m.driussi *08 Oct 1997, 02:33* A few more thoughts-- "Zero Gravity" is experienced by the jumping child at apogee; by the cannonball at apogee; by the passengers of the infamous "vomit comet" astronaut trainer B-52 when it goes into a steep dive. Or people in a free-falling elevator. So since Silk's floater flight is basically as ballistic as a cannonball ride, we can try to time the arc, estimate the altitude at apogee, gauge the time of "true" zero gravity, etc., all as another approach to analyzing the whole thing and therefore the physical nature of the whorl. (The vomit comet goes for ten minute bursts--or was it shorter? More like three minutes? They talked about it regarding the filming of motion picture "Apollo 13" which used the vomit comet.) (And while Silk sees things "falling up" in the floater cabin, suggesting true zero gravity, doesn't it turn out to be the fact that the floater has rolled over and is upside down? So that when Silk pokes his head out for a peek he nearly plummets?) FWIW, since THE SCIENCE IN SCIENCE FICTION gives 16 km as the max diameter for a generation starship (as I'm sure I mentioned before), I ran the formula with that diameter of 10 miles and get a groundspeed of 628 mph. =mantis= ---