Re: S paceTime

On 2/16/25 7:23 PM, The Starmaker wrote:

et me put it simply this way...
 if our Sun were to simply disapear..
out Earth will feel it's disaperance..immeditaly, ...not minutes later.

Not a bad thought :)
You're nearing the questions I had in last year of high school and first year of undergraduate physics.
My guess is that the information of its disappearance will travel towards Earth at, or below, the light's speed (i.e. max speed for any physical quantity) and when it reaches Earth, the path of Earth motion becomes almost linear from that moment on.
But I vaguely remember that in general relativity changes in gravity travel _at_ the speed of light although (again claimed) to be not of electromagnetic nature.
Another weirder feature of gravity is that the anti particle's gravity force is not repulsive toward ordinary particles! They all attract. These and other weird questions got us many times busy wondering in those years :)
And if you think of it, even the "simple" coordinate systems, say, a Cartesian coordinate system, is very weird if you look at it closely. If you have an apple hanging from a tree, giving you three coordinates components on your system, when you go to the spot where one of the components say the apple is, you see no apple there. You'd only see a short line segment. And you see none on the other two coordinate axes either other than two short line segments. Yet, the three components will algebraically give you _all_ the information you can have about that apple! Magically, three short pieces of line intervals will give you the correct shape of the apple in three dimensions.
These stuff got some of us busy in those good old days.