Recent content by Bob R

How does GR predict the Earth's orbit around the sun? Newtonian mechanics predict a gravitational force that is a function of the two masses. Is the geodesic path of the Earth a function of both the sun's and Earth's curvature of space?

If Earth's motion about the sun is described by General Relativity why was Eddington's experiment with the bending of starlight needed to confirm the theory? In other words, don't we see enough common phenomena in our every day experiences to confirm GR without verifying subtle phenomena such as...

Thank you, Dale. Amazing! Bob R

Thank you for your answer, Nugatory. I understand from what you say that the ball's wordline and the 4-D path of the person tossing it are nearly the same. They deviate from one another by at most 5 m. What we witness of the ball's worldline is the 3-D projection of that line in space. I can't...

I've been thinking about the worldline for the sample ball tossed 5 meters in the air over two seconds. I have to wonder about the ct component along the time axis being 6 e8 meters and what this means physically. It suggests that what we witness of this event is only the spatial movement of the...

Thank you to PeterDonis and A.T. I wasn't expecting such rapid detailed answers. It will take me a bit longer to digest your remarks. Thanks so much, Bob R.

[Moderator's note: this post has been spun off into its own thread.] I'm a retired engineer trying to get my head around GR, its effects in our everyday non-relativistic world, and its reduction to Newtonian gravity. I hope this is not too much of a digression from the current string. As I...