Superfact 23: Global Positioning Systems or GPS uses Special Relativity and General Relativity to guide you to your destination. In fact, GPS systems would be rendered useless without the Theories of Relativity.
Did you use Einstein’s Theories of Relativity to get to the grocery store today?
The theories of relativity may seem strange and impractical, something you only use for astrophysics, black holes, cosmology and extreme velocities. They feature strange concepts such as time dilation, the stretching and bending of space, events simultaneous to some are not to others, the universal constancy of the speed of light in vacuum, the energy and mass equivalency, etc.
Therefore, it is a bit surprising that without the theories of relativity the GPS app on your phone would not be able to guide you to the grocery store. That’s why I call it a super fact.
GPS and Time Dilation
GPS is a satellite-based radio navigation system that provides location information and time anywhere on Earth. The fact that the information is provided by satellites that orbit earth at high speeds and high above earth’s surface makes General Relativity and Special Relativity necessary.
The GPS system needs to calculate precisely the time it takes for signals to travel from the satellites to a receiver on Earth for it to work. GPS satellites travel at high speeds causing a large enough time dilation that has to be accounted for. In addition, they orbit earth high above earth’s surface where earth’s gravitational field is weaker than on earth’s surface. Clocks run faster in weaker gravitational fields due to gravitational time dilation, so you must correct that as well.
If you ignore relativity, you will accumulate a discrepancy of six miles in one day. You are not going to find the grocery store that way, unless you use the old-fashioned method of reading a map. In a sense, if your GPS device finds the grocery store for you, you have proven Einstein right.
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Newstrade
Such an interesting fact 💙🌹💙
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Thank you so much Luisa
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You’re welcome! 🙏❣️🙏
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Argh I so remember the days of Map Reading Thomas.. no phones either, You just jumped in the car Map in hand and off we went… Not even a thought of what to do if you broke down.. But then cars back then, we mostly could fix at the side of the road, Not like today all Electric with gadgets etc ..
I must admit though Thomas, the GPS is very handy, and it has helped us navigate our way around very often…
Thank you Thomas for your informative post.. Glad to be back again among WP and friends… Crafting now all finished that is important….
I wish you and your family a Wonderful Christmas Thomas… And have a Peaceful Happy Healthy 2025 and beyond….
Much love Sue xx ❤
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Thank you so much Sue for your kind words and greetings. Yes back in the day when we used maps we did not need relativity to find the grocery store and thinking about it, we are using quantum physics too. The electronics in the phones can be understood only with quantum physics. I wish you and your family a wonderful Christmas too and a very Happy New Year and a wonderful and peaceful 2025.
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That’s fascinating. My brain cannot get beyond the train in the station paradox. I think that begets the image of Chaos in my head!
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Yes the train in the station paradox, which is very similar to the barn door paradox, which I have among my 160 suggestions for super facts, except I need to find a way to formulate it as such. Maybe what obviously seems like a contradiction is not. It is resolved by non-simultaneuity.
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Lulu: “Einstein wins again!”
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Ha ha you are right Lulu.
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I didn’t know this, Thomas. Great information.
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Yes I think it is an interesting fact that is easy to miss. Thank you Robbie.
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👍
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