# Speed of light error by scientists



## Peairtach (Feb 23, 2012)

Scientists did not break speed of light - it was a faulty wire - Telegraph


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## SRoper (Feb 23, 2012)

I think the question was always, "where was the error made?" Glad they found it.

To explain something from the article, GPS satellites transmit time data as well as location. Normally in a handheld unit the time is thrown out after resolving the unit's position, but researchers will use GPS to get a precise time value for their work (and often they'll throw out the position).


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## John Bunyan (Feb 23, 2012)

I would feel happier if it wasn't a mistake. Don't know why, but I enjoy paradigm changes and it would be nice to see one happening right now.Also poor Lorentz winning in his interpretation after some one hundred years would make a good story.


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## jwright82 (Feb 24, 2012)

SRoper said:


> I think the question was always, "where was the error made?" Glad they found it.
> 
> To explain something from the article, GPS satellites transmit time data as well as location. Normally in a handheld unit the time is thrown out after resolving the unit's position, but researchers will use GPS to get a precise time value for their work (and often they'll throw out the position).



Are you refering to the uncertianty principle? Is that why they keep one perspective and throw out the other?


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## SRoper (Feb 24, 2012)

jwright82 said:


> SRoper said:
> 
> 
> > I think the question was always, "where was the error made?" Glad they found it.
> ...



No, it is about what is useful information in different applications. If you are trying to go from point a to point b, you care about where you are but not about the time (at least not to the nanosecond precision that GPS gives you). If you are doing a critical experiment requiring precise clock synchronization, you care about time, but, presumably, you already know where you are. (I suppose there might be applications where you'd like to know both your position and your time.)

All four values (three for position and one for time) are required from four different satellites to resolve either your position or your time (or both). I'll explain what I mean in the case of wanting an accurate time value. Say you get a signal from satellite 1 that says it's position is x1,y1,z1 at time t1. That's great, but it doesn't tell you _your_ time because you don't know how far away you are from the satellite. You need to know your position because the signal didn't reach you instantly; it traveled to you at the speed of light. So you get signals from three other satellites to solve for both your position and your time. Then at the end, if you were only interested in getting an accurate time value, you ignore the position information that you resolved.


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## Pergamum (Feb 24, 2012)

Now if we can get scientists to re-examine evolution.


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## Rich Koster (Feb 24, 2012)

Pergamum said:


> Now if we can get scientists to re-examine evolution.



From the behavior of adolescents in out local school system, if I were not a believer, I might suggest that the process is reversing itself. Hey, if they believe they are merely animals, what's to stop them from behaving like them. OOPS! A little off topic. So ends my rant for the day


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## ZackF (Feb 29, 2012)

SRoper said:


> jwright82 said:
> 
> 
> > SRoper said:
> ...




There is also a correction made for time dilation due to the satellites' relative velocity.


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## SRoper (Mar 1, 2012)

I could be mistaken, but I believe that the correction is all done on the front end--it is built into the atomic clocks on the satellites. The clocks are designed to run slow to take into account the effects of special and general relativity.


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