Do you not think the explanation I gave with air travel gives a difference between UA and gravity? From my point of view and understanding of reality, it seems pretty obvious the earth is not coming at me at 99.9 percent the speed of light ever accelerating in a paradox of relativity to avoid faster than light speeds.
I don't really relish being the one to "defend" UA because I believe the it is wrong, but not for the reasons raised.
Special Relativity would mean that whatever the velocity of earth relative to an inertial frame of reference (one not accelerating) it would make no difference to us. This would be the same for 99.99% c, 99.9999% c or however close you like to make it.
Now under UA,
the earth, it's inhabitants, everything on esrth and all celestial objects are subject to the same acceleration (
g) - but some "magic" holds the celestial objects up there.
If you drop a rock (or jump off a cliff) the rock is initially travelling at the velocity of the earth, but is no longer accelerating.
So the earth accelerates towards the rock at
g.
But from the point of view of someone on earth, it simply appears as though the rock is accelerating downwards at
g.
I do find serious weaknesses in UA, but superficially it models gravity fairly well, but
- It does not explain the observed variations in g.
- It offers no explanation for tides. Celestial gravitation is suggested. I cannot see how it can explain the observe link between tides and the sun and moon, especially the fact that most, but not all places get two tides per day.
It should be pointed out that the observed variations of
g with latitude and altitude formed a big part in the research of Robert Hooke and Isaac Newton that lead to the formulation of Newton's Theory of Gravitation.
Now as to the lack of variation of gravity with altitude under UA affecting flight, even at an altitude is say 20 km,
gravity is reduced by only 0.6%, not enough to have a dramatic effect. The FES also
suggests that
Celestial Gravitation accounts for tides and other gravimetric anomalies across the Earth's plane.
There an interesting point that no flat earther will take seriously. This is as a result of
time dilation.If there is any part of the universe that is not accelerating, ie an
inertial reference frame, either that
inertial reference frame is an unimaginable age (and I mean an unimaginable times 13 billion years) or the earth as we know it is not more than a few hundred years old.
In
About this accelerating Flat Earth idea « Reply #13 on: September 27, 2016, 02:59:28 PM » I presented my ideas on this.
A couple of results from this were
If the earth were to start accelerating at 9.8 m/s2 13.6 billion years ago by now, due to time slowing down on the accelerating earth (that is Time Dilation) only 45.5 years would have elapsed on earth! I would love some "expert" to peruse these figures!
and
If you are a Douglas Adams fan, then 42 has a special significance, so if the "Inertial Reference Frame" outside earth were 2.46753105 billion years old[2] then the earth accelerating at 9.8 m/s2 would have experienced only 42 years!
Anyone here older than 42 years - er, I am, a lot!
These were presented a bit light heartedly but I would love someone far more expert in relativity offer an opinion.
But, the bottom line on UA, from my point of view is that it models gravity quite well, but has serious deficiencies.