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2019-05-23 21:57:14 UTC

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s***@gmail.com

2019-05-23 21:57:14 UTC

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Arindam Banerjee

2019-05-23 23:49:57 UTC

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PermalinkHere's a physics problem for you -- at what altitude does a gps satellite not need an offset atomic clock?

What always happens is that light travels at c+V, never c. However it may appear to travel at c when the Earth is taken to be at rest, while in fact the Earth moves.

GPS equations work as the Earth is taken to be at rest EFFECTIVELY with all the universe going around it in a warped manner.

That is what the Michelson Morley results clearly show. If the Earth is moving, then to get the null results the speed of light must vary with the speed of the apparatus on the Earth going through space. If the Earth is really not moving, but supposed to be as per the equations, then the null results are explained with the constancy of the speed of light, invariant of its origin velocity.

A bit of detail - as the Earth is moving, as soon as a wavefront of light is released from the source, it has to go an extra distance to reach its distance, which is more, or less, than the distance measured in the apparatus depending upon direction of light throw. If the light throw is in the direction of the Earth's motion, then by the time the light reaches the destination point, the destination point will have moved by a little amount. The light thus actually has to travel a longer distance than what is measured out. Similarly, when the light returns from the destination point to the source, it will move against the direction of Earth's motion. In this case the destination point will come nearer to the wavefront of the light. So the actual distance that is travelled, in the second case, will be shorter than that measured out by the scale.

This very important fact has been totally neglected in the analysis, so far. I pointed this out back in 2005, that this huge but subtle bungle had taken place in the analysis of the MMI experiment.

The position of stars throughout the year changes, showing that the Earth moves around the Sun - that the Earth moves as per Galileo, is not stuck in the same spot as Aristotle would have it and his adoring Christian following for centuries.

As the Earth moves, relativity notions are wrong. Nevertheless, if it is supposed to be still, then relativity equations are useful for explaining the mathemetics involved in GPS.

Cheers,

Arindam Banerjee

Sergeio

2019-05-24 01:51:22 UTC

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PermalinkHere's a physics problem for you -- at what altitude does a gps satellite not need an offset atomic clock?

Libor Striz

1970-01-01 00:00:00 UTC

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PermalinkHere's a physics problem for you -- at what altitude does a gps satellite not need an offset atomic clock?

The zero net time dilation,

when gravitational and kinematic effects cancel each other,

is at an orbit with radius approximately 10000 km wrt Earth centre.

https://en.wikipedia.org/wiki/Gravitational_time_dilation?wprov=sfla1

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Sergeio

2019-05-24 03:21:25 UTC

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PermalinkHere's a physics problem for you -- at what altitude does a gps satellite not need an offset atomic clock?

The zero net time dilation,

when gravitational and kinematic effects cancel each other,

is at an orbit with radius approximately 10000 km wrt Earth centre.

https://en.wikipedia.org/wiki/Gravitational_time_dilation?wprov=sfla1

Orbit_times.png: P. Fraundorf Derivative work: Spotsaurian (talk) -

Orbit_times.png

The speedy motion of a satellite in space slows down its clocks relative

to ours on earth, while its distance out of the earth's gravitational

well makes satellite clocks go a bit faster. Thus shuttle pilots age

less than a couch potato at the south pole, while geosynchronous

orbiters (as well as interstellar dust particles) age more rapidly. This

also means that the surface of the earth may be more than a year older

than the earth's center, assuming that both were formed at the same

time. Although the resulting errors in satellite timing are measured in

nanoseconds, lightspeed is 30 centimeters (1 foot) per nanosecond so

that the combined effects can result in GPS errors as large as 15 meters

if not taken into account.

from the little graph;shows the 10k foot

https://upload.wikimedia.org/wikipedia/commons/3/36/Orbit_times.svg

p***@gmail.com

2019-05-24 05:25:00 UTC

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PermalinkHere's a physics problem for you -- at what altitude does a gps satellite not need an offset atomic clock?

it all depends about

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s***@gmail.com

2019-05-30 13:40:12 UTC

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PermalinkHere's a physics problem for you -- at what altitude does a gps satellite not need an offset atomic clock?

For more detail see: http://www.livingreviews.org/lrr-2003-1

Edward Prochak

2019-05-30 17:08:53 UTC

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PermalinkHere's a physics problem for you -- at what altitude does a gps satellite not need an offset atomic clock?

For more detail see: http://www.livingreviews.org/lrr-2003-1

Allen deviation, then seeing it used in this article. COOL!

Ed

Sergeio

2019-05-30 18:39:05 UTC

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PermalinkHere's a physics problem for you -- at what altitude does a gps satellite not need an offset atomic clock?

For more detail see: http://www.livingreviews.org/lrr-2003-1

Allen deviation, then seeing it used in this article. COOL!

Ed

I had a set of books the Canadians did on error analysis of GPS,

complicated stuff, (had all the math)

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