[MarkL]

And I would think that if it is too small to measure, if it does exist, how you would harness its power.

One of the problems is that the "source" of gravity is still a mystery. Sure, we know its properties, and that one of the properties of mass is gravity, but the source of gravity is one of the things that still puzzles physicists and scientists.

Something interesting is that it was GPS that proved a part of Einstein's theory of special relativity. The problem was that things on the earth kept shifting because their coordinates kept changing. GPS relies on very specific time-keeping. What was discovered was that time "runs" at a different rate in orbit than it does on the surface of the earth, and they realized that regular time updates needed to be made. And that's because gravity effects the rate at which time "runs."

Mark

[AFreeBird]

I thought that theory was put to the test before GPS. They synchronized two atomic clocks and sent one aloft in a high flying plane. When the plane landed they checked the clocks, and the one aloft was, or had been, running slower.

[DManA]

GPS doesn’t work unless you take relativity into account. Relativity was engineered into GPS from the beginning.

The fact that GPS works is a confirmation of relativity.

[21twelve]

“...but the source of gravity is one of the things that still puzzles physicists and scientists.”

As one who works with these basic properties, I too remind folks of this “mystery”. Electrical properties, electromagnetic fields, magnetic fields are fairly well understood. (Although still some mystery with the earth’s magnetic field.) But the one field that we ALL are VERY familiar with - gravity, we aren’t sure how it works! Although I suppose someone with a lot more brain power than I have perhaps “understands” it with regard to Einstein, bending of time and space, etc.

I think it is these “mysteries” that make life, and science interesting, and driving us to pursue those answers. It is a lot more fun when we don’t have all the answers.

[lafroste]

Something interesting is that it was GPS that proved a part of Einstein's theory of special relativity. The problem was that things on the earth kept shifting because their coordinates kept changing. GPS relies on very specific time-keeping. What was discovered was that time "runs" at a different rate in orbit than it does on the surface of the earth, and they realized that regular time updates needed to be made. And that's because gravity effects the rate at which time "runs."

Gravity does not affect the rate at which time runs. It's the opposite:gravity is caused by time fields. If you calculate the flow of time on the ground versus the flow of time at an altitude of 175 miles, you will note that time on the ground lags the flow of time at that altitude by about one second every 85 years, a very small differential.