Time dilation at the pyramids?

Gary L

A Friend recently suggested to me over pints that a study showed time dilation in a clock next to one of the pyramids relative to one some distance away. Over enough time, does a great pyramid have enough mass to explain this or is it hogwash?

mikhail

Recently, some folks measured the time dialation between clocks with 1m vertical distance between them. That's pretty much the cutting edge of what we can detect.
http://www.sciencemag.org/cgi/content/abstract/329/5999/1630

Now, the decrease in accelleration due to gravity due to a 1m height difference at the surface of the earth is:
((G M / r^2) - (G M / (r + 1)^2))/(G M / r^2), where M is the mass of the earth, G is the gravitational constant and r is the radius of the earth. Working it out, it comes to about 0.00003%.

Taking the weight of the Great Pyramid at Giza to be 6 million tons, I get its gravitational effect at a distance of 100m (remember, it's not a point mass, so you can't get within a metre or anything like it of its centre of gravity and still feel anything like the lumped effect) to be a bit under 0.04% of gravity. So, yeah, it's plausible that with very, very accurate clocks, you could see a really tiny distortion.

A Primal Nut

Gary L wrote: »

A Friend recently suggested to me over pints that a study showed time dilation in a clock next to one of the pyramids relative to one some distance away. Over enough time, does a great pyramid have enough mass to explain this or is it hogwash?

I assume he got this from the Stephen Hawking documentary on "Time Travel." I think its on youtube (or used to be). The difference is tiny but in theory its true. I'm not sure if a study has been carried out at the pyramids though; but as far as I know it has been proven is other ways that time is slower around large objects.

Capt'n Midnight

the time dilation effect is far less than the gravitational effect, neither would be observable without very sensitive instruments

also we are at the bottom of a gravity well, so if you stand at the top of a pyramid you would be further the centre of the earth so your clock would run faster , I don't know if this effect would offset the slowing down of your clock by the gravitational effect of the pyramid

To give an idea of the effect GPS satellites run at 10.229 999 995 453 Mhz instead of 10.23 Mhz and most of that is because of the speed rather than the gravitational effect.

mikhail

Capt'n Midnight wrote: »

the time dilation effect is far less than the gravitational effect

My apple is also far less than 5 o'clock. One of those is a force, the other is a change to the rate at which time is progressing. Calling them both "effects" doesn't mean you can meaningfully compare them.

also we are at the bottom of a gravity well, so if you stand at the top of a pyramid you would be further the centre of the earth so your clock would run faster , I don't know if this effect would offset the slowing down of your clock by the gravitational effect of the pyramid

Yes, it would. I gave numbers above. If you disagree with them, disagree with them. Don't make vague hand-waving statements about something which has already been quantified.

To give an idea of the effect GPS satellites run at 10.229 999 995 453 Mhz instead of 10.23 Mhz and most of that is because of the speed rather than the gravitational effect.

The paper I quoted above gives an example of the scale of the problem:

For example, if two identical clocks are separated vertically by 1 km near the surface of Earth, the higher clock emits about three more second-ticks than the lower one in a million years.

They give more numbers and cite various experimental results. I'd suggest their introduction as a good starting point.