[AngleWyrm]

Thanks for clarifying the sound-barrier. That makes much more sense.

I read that article on "speed of gravity" several years ago; that it is now on top of the google search is interesting to me. However discussing credibility of the author avoids the subject material. They called Galileo a worker of black magic when he showed that a grape and a grapefruit fall at the same speed.

Is it true that the calculation of planetary locations must take the force of gravity to be instantaneous?