[sjastro]

Originally Posted by Archy

An acceleration produces a real force, not a pseudo force.

You change the subject matter when it's convenient for you.
This has nothing to do with the context of the equivalence principle.

"All fictitious forces are proportional to the mass of the object upon which they act, which is also true for gravity.[17] This led Albert Einstein to wonder whether gravity was a fictitious force as well. He noted that a freefalling observer in a closed box would not be able to detect the force of gravity; hence, freefalling reference frames are equivalent to an inertial reference frame (the equivalence principle). Following up on this insight, Einstein was able to formulate a theory with gravity as a fictitious force; attributing the apparent acceleration of gravity to the curvature of spacetime. This idea underlies Einstein's theory of general relativity."

Mass distorts space see: Slide 17 www.physics.ucsd.edu/~tmurphy/phys10/lectures/15_gen_rel.ppt. from which we see the statement "Mass tells space-time how to curve and Space tells mass how to move....Gravity is a property of the geometry of spacetime"

And what do you think is the property of mass that causes this, it is density. It's why low mass high density Neutron stars cause space time to distort.

Since frequency is a function of inverse time (eg beats per second) a change in frequency, which is what is implied by a redshift, requires a change in time (since there are the same number of beats), which agrees with what I have said that the mass of the earth causes a change in space-time

You haven't explained anything. There is no relationship between frequency and geometry.

Re the GPS see

: Pogge, Richard W., “Real-World Relativity: The GPS Navigation System” where in the seventh para graph there is the statement:


"Further, the satellites are in orbits high above the Earth, where the curvature of spacetime due to the Earth's mass is less than it is at the Earth's surface. A prediction of General Relativity is that clocks closer to a massive object will seem to tick more slowly than those located further away (see the Black Holes lecture). As such, when viewed from the surface of the Earth, the clocks on the satellites appear to be ticking faster than identical clocks on the ground. A calculation using General Relativity predicts that the clocks in each GPS satellite should get ahead of ground-based clocks by 45 microseconds per day." (Bold and underlining are mine.)

Red shift (or time dilation due to gravity) is independant of space time geometry. It can occur in flat space or curved space and is dependant on the gravitational potential differences between earth and satellite clocks.

As I have already mentioned gravitational redshift has been mathematically formulated using flat space (and the equivalence principle).

You, of course, are free to believe that the earth does not distort spacetime because it is not dense enough, or whatever else you wish.

I certainly did not state the Earth does not distort space time, but on the basis of observation the effects are not apparent.
And on that note this thread is concluded.