Linked Questions

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votes
1answer
511 views

A question about the physics involved in tracking satellites such as those used in the GPS system [duplicate]

I know that besides the effects of Newton's theory of Gravitation on the satellite's motion, one has to take account of the retardation of the satellite's clocks when compared to earth-fixed clocks. ...
6
votes
0answers
180 views

I don't see that general relativity is really needed for GPS to work correctly [duplicate]

From what I understand, GPS localization is based on the difference in the reception time from the time of emission of a signal from different GPS satellites whose positions are known. For this we ...
30
votes
3answers
3k views

Is there any current technology that depends upon a deep understanding of quarks?

I think the title about says it all. If someone asks me "What good is the Theory of General Relativity?" (or what did Einstein do that was so great, or whatever) My pat answer is, "You use GPS ...
6
votes
3answers
8k views

That 10km/day error predicted if GPS satellite clocks not corrected for relativity

Some authorities have stated publicly and without explanation that if the theories of Special and General Relativity were not taken into account in the design of the GPS (by building the satellite ...
4
votes
4answers
1k views

How do GPS devices work?

I have GPS in my phone but I have only a very rough idea of how it works. I have checked the Wikipedia article but that gone over my head (I can not understand that maths and other strange stuff there)...
5
votes
1answer
630 views

How are GPS corrected for special/general relativity?

I was looking for the equations that are used by the GPS receiver to calculate its position and time correction (bias). By looking at the Navigation Equations on Wikipedia, I don't see any account for ...
0
votes
4answers
182 views

Would GPS work in a (locally) newtonian universe?

Often, when there are question on why fundamental research makes sense or is neccesary, I've seen answers like "GPS is used everywhere today, and it wouldn't work without relativity". Of course, if ...
1
vote
2answers
408 views

How can I calculate time dilation between our clock, and clock in satellite? [duplicate]

We know satellite is moving , so there should be time dilation due to motion, also we know due to Earth's Gravitational field there should be time dilation, what should I do, just calculate both of ...
2
votes
1answer
484 views

Are the Schwarzschild metric and the Geodesic Equation relevant in the context of the Earth? [closed]

The geodesic equation used in general relativity is the following: $$ {\mathrm d^2 x^\mu \over \mathrm ds^2} =- \Gamma^\mu {}_{\alpha \beta}{\mathrm d x^\alpha \over\mathrm ds}{\mathrm d x^\beta \...
0
votes
3answers
223 views

Do relativistic phenomena affect communication with satellites?

Communication with satellites certainly requires knowing the speed of light. Beyond having that magic number, do relativistic phenomena affect communication with satellites? For example, would one ...
6
votes
3answers
349 views

Why do GPS satellites care about Earth clock at all? (relativity)

Many online resources make grandiose claims about how GPS would be useless without relativistic corrections. Specifically, they outline that satellite clocks runs slower by 7μs/day due to special ...
0
votes
2answers
505 views

Why would a modern smartphone not work if the theory of general relativity hadn't been discoverd? [closed]

My teacher told me that todays smartphones wouldn't work if the theory of relativity hadn't been discovered, but he didn't explained why.
2
votes
2answers
221 views

Schwarzschild metric: motivations and applications in physics

I have a mathematical background and I have just derived the expression of the Schwarzschild metric. Now I was wondering what were the motivations and applications in physics of this metric. Any info ...
2
votes
1answer
133 views

Is there any device/technology based on QFT in curved space?

General relativity has given us the GPS, and QFT has provided a big amount of useful technology, from medical treatments to advances in condensed matter. Can QFT in curved space lead to similar ...
3
votes
1answer
61 views

Why does time pass slow in an orbiting satellite relative to an observer on the ground?

I know that according special relativity, if an object travels at a very high constant velocity relative to an observer, the observer will see the object's clock running slow. I also know that ...

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