Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: acecharly on 24/02/2012 20:46:07
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If the velocity of an object relative to another produces a distortion in the time perceived then does that mean the the material at the equator is a different age to the material at the poles?
If I placed a stick in the ground at the equator it would travel approximately 24,000 miles in one day with a revolution of the Earth. If i also placed a stick in the ground 1 metre from the north or south pole it would only travel a few meters in a circle during the same 24 hour period meaning it must be travelling alot slower this must also be true for the depth also? i.e if you travelled halfway to the centre of the Earth your distance travelled in any 24 hour period would be less so does this mean every particle on Earth is expeiriencing time on a different scale to every other?
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Clocks accelerating around in circles run more slowly than nonaccelerated clocks moving parallel to the center of the circles. The acceleration at the equator is greater, so clocks on the equator run more slowly. However, the difference is too small to measure, even with the best atomic clocks. The effect is roughly proportional to the square of the relative speed, and satellites near the equator in low Earth orbit go around about 16 times faster than the ground below them; so the time dilation effect is about 256 times greater, which is barely measurable. It is necessary to make a correction for it in order for the GPS system to be accurate.
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Actually it makes lots of sense and some experiments could done to check the age of Earth at equator and at poles, even though the in lifetime of a human being the difference will be negligible but at life time of Earth or crust of the earth it would be big enough to test the difference.
This way we could at least have the latitudes of different crust at different time in history of the Earth, it should be done.
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Actually it makes lots of sense and some experiments could done to check the age of Earth at equator and at poles, even though the in lifetime of a human being the difference will be negligible but at life time of Earth or crust of the earth it would be big enough to test the difference.
This way we could at least have the latitudes of different crust at different time in history of the Earth, it should be done.
The most accurate way to estimate the age of rock is by measuring the quantity of elements that formed inside crystals by radioactive decay. The accuracy is something like 1%. If the crystal is a billion years old, the measurement error is millions of years, and the difference due to time dilation at the equator no more than a few hours in a billion years. So it is insignificant, and there's no way to measure it.
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Hmm yeah that is true, you can't detect few hours in few billion years.
Let me check with GR what I actually get, I'll get back to it.
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0.0001551% deviation from actual number of years.
Or 704154 years (in total earth life), which isn't small but seriously cannot be calculated or checked using atomic decay methods.
Yeah just leave it I guess.
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Mistake 7041.54 years
Forgot to divide by hundred ;D :P
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Mistake 7041.54 years
Forgot to divide by hundred ;D :P
Hey, what's an order of magnitude or two among friends? :)
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65.22 minutes in 80 years...
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These "ageing" problems depend on having systems with some form of clock in them. And also are only apparent to things when viewed at a distance. This is because time always flows perfectly normally local to an observer. Normal reasonably stable materials do not have clocks inside them and so any slight difference in time to an outside observer is not relevant. about the only significant natural case of time dilation being significant is the observation of mu mesons in cosmic ray showers because the normal life of these particles is not long enough to allow them to travel from their point of origin to the earth's surface. OK the GPS system has to correct for these time effects but this is man made and depends on precision clocks, orbits and the speed of light to measure location.
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I'm no good at tensor analysis, so I don't know how to solve this problem with GR, but I'm pretty sure that the time dilation for circular motion is less than for straight line motion. The relativistic gamma for straight line motion at the speed of the equator relative to the poles (http://www.wolframalpha.com/input/?i=relativistic+gamma+%281667.001+km%2Fhr%29) is 1.0000000000012. That's 1.2 parts per trillion, or 10.5 hours per billion years.
As I said, I think it would be less than that for circular motion.
By the way, those are present epoch years of 8766 hours. A billion years ago, there were fewer hours in a year.
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By the way, those are present epoch years of 8766 hours. A billion years ago, there were fewer hours in a year.
Shouldn't that be more hours? (assuming that previous epoch hours are still defined as day/24).
Rotation slowing due to tidal effects --> day lengthening --> shorter day (and hour) in previous epochs.
Orbital expansion or contraction affecting the year is surely smaller than this effect?
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Thanks to everyone for discussing my idea, having read through i can see the problems wth scale of literally a few hours difference over billions of years being impossible to detect.
How might this idea effect the rotation of galaxies?
I read somewhere that as a galaxy rotates the matter on the outside moves around the centre at a velocity similar to the mass near the centre unlike how the planets orbit the sun faster the closer to the sun that they are. Could time itself have something to do with not allowing this.
Just a thought (of which i have way too many) im probably barking up the wrong tree but any input would be nice
Cheers
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By the way, those are present epoch years of 8766 hours. A billion years ago, there were fewer hours in a year.
Shouldn't that be more hours? (assuming that previous epoch hours are still defined as day/24).
Rotation slowing due to tidal effects --> day lengthening --> shorter day (and hour) in previous epochs.
Orbital expansion or contraction affecting the year is surely smaller than this effect?
You're right, and I'm wrong. I was mistakenly assuming that the hour is defined as 86,400 seconds; in fact, the hour is defined as 1/24 of a mean tropical day. The length of the year in seconds is constant, and the length of the day in hours is constant, but the length of day in seconds is increasing. A billion years ago, the year had more days, and therefore more hours.
The present rate angular acceleration of Earth's rotation due to tidal friction is about .000023 s/year, or 23,000 sec/billion year. The rate of acceleration is slowing, but there's no way to know how fast it has slowed in the last billion years because tidal friction changes as ice ages come and go. We can say that a billion years ago the day was less than 63,000 seconds. Perhaps it was half of the present 86,400 seconds.
I should have given my result as 37,800 seconds, rather than 10.5 hours. That way, I wouldn't have to specify that I meant 10.5 of today's hours. At any rate, the difference is many orders of magnitude less than the margin of error in measuring the age of crystals.