# Gravitational Time Dilation

Excessive contemplation works in mysterious ways, I didn’t wake up pondering gravitational time dilation. Placing blame squarely on GPS strikes me as a reasonable explanation. I brought it on myself – putting a monotone tyrant in charge before first coffee rubbed sleep from my eyes, obviously explains an inexplicable need to understand Einstein’s theory of relativity. With each directive – turn left, right, merge – absolute faith in GPS freed my mind to concentrate on time and space.

We think of GPS as an absolute tool, one linking position of our device with that of some imagined all seeing eye. Few of us realize GPS constantly recalculates and adjusts readings based on Einstein’s theory of special relativity. If left unchecked, navigational errors of 10 km per day would quickly topple getting from point A to B.

Einstein’s theory of relativity describes the effect of gravity on space and time. Time is relative to mass and proximity of gravitational pull – speeding up as it moves further away. Time passes at different rates according to gravitational potential. Space-time depends on proximity to forces of gravity.

GPS satellites orbit 20,000 Km above, with gravitational forces four times weaker than Earth. Science proves Einstein knew what he was talking about – satellite clocks tick 38 microseconds faster a day than clocks on our planet. I urge you to read the link below. It explains gravitational time dilution – I’m still digesting my first dip in the relativity pond.

http://www.physicscentral.com/explore/writers/will.cfm

## 8 thoughts on “Gravitational Time Dilation”

1. Pierre Lagacé says:

Interesting article.

2. I remember the first time I heard that people living at sea-level are younger than people living at high elevations given this same effect of gravity ~ the world of physics is definitely stranger than fiction.

3. Einstein’s general relativity is possibly the most extraordinary and certainly one of the most beautiful theories ever developed. His insight that he should study the relationship between space and time as an alternative to studying gravity is as basic as it is copernican. Gravity is after all the same as acceleration (his postulate) which is a feature of space and time.

Einstein struggled with the maths of tensors which underpin this theory. These seemingly simple things that are the big brother of vectors have eluded me for years and earlier this year I took the trouble to read a textbook about them. What happened to me is what happened to Einstein: at some point you see the reality behind the very abstract concept. Big time aha. It changes the way you see the world.

But Einstein had neither a textbook nor any example of this sort of theory. He only had is gut feel and the ability to think through complex physical and mathematical constructions whilst reclining in an easy chair.

Although I went to school some 75 years after Einstein published general relativity, as a subject it was still only taught to physics majors. I deeply wish that the ideas behind the theory were to be taught at primary schools. It wll help to develop a society of people that understand that the universe isn’t a static sky with stars hanging around, carefully put their by a creator, but more like a whirl pool of time and space and gravity that is as dynamic and violent as the wildest storms at the roughest seas, when viewed from a very long time scale.

Gravity is very hard to measure but were getting there. I expect that in the next 20-50 years huge progress will be made in observing gravitational waves and the developed of new theories of cosmic as well as the quantum dynamics. The most amazing part is that virtually all of that is already “hidden” in Eistein’s equations. How extraordinary!

– Oops my response is longer than your post!

• Your response is the reason I pondered time dilation in the first place. You put a smile on my face 🙂

• And on mine. I recentkly read Walter Isaacson’s biography of Einstein. He was just a man of his time but somehow the stars were reunited to give him the character, circumstances and brain to do what he did. I can’t properly describe the extraordinaress of what he managed to conceive but it sits well with Bach’s Brandenburg Concertoes, van Gogh’s Starry Night and Graeme Greene’s Our Man in Havanna. Still smiling!

• Is it true Einstein “rested” with an apple in his hand and woke refreshed when it fell to the ground?

• It may have been. I’m told that this is a trick to avoid getting into a real sleep and stay conscious even though the body is deeply relaxed. I haven’t tried it yet…