15 Nov 12
1 edit
Just a thought: perhaps one day these clocks will get so accurate and precise that they would measure the minutely changing gravity made by someone or something as small as a person moving around in the area being scanned?
Is that degree of precision really possible or does the laws of physics indirectly put a limit on the possible degree of precision with the limit being less than that?
15 Nov 12
Originally posted by humyI don't think there is any limiting factor, just the accuracy of the clocks. They are getting clocks down to within one second for the age of the universe, you can't get much better than that! Those are still in the labs but they are coming.
Just a thought: perhaps one day these clocks will get so accurate and precise that they would measure the minutely changing gravity made by someone or something as small as a person moving around in the area being scanned?
Is that degree of precision really possible or does the laws of physics indirectly put a limit on the possible degree of precision with the limit being less than that?
- Joined
- 31 May 06
- Moves
- 1795
16 Nov 12
Originally posted by sonhouseThere is a difference between drift amount, and grain.
I don't think there is any limiting factor, just the accuracy of the clocks. They are getting clocks down to within one second for the age of the universe, you can't get much better than that! Those are still in the labs but they are coming.
To measure smaller and smaller effects due to GR you need finer and finer grain detectors.
You need clocks that have shorter and shorter ticks.
There is going to be (if quantum theory is correct) a fundamental limit on how short a tick can get.
You could have a clock loose only one second over the age of the universe with a 1 minute tick,
if that tick was precise enough.
It would however be useless for detecting fine gravitational structure.
16 Nov 12
Originally posted by googlefudgeThe best clocks now use light wave frequencies which is one reason they are so accurate. Each tick is in the attosecond range, not sure the exact number though.
There is a difference between drift amount, and grain.
To measure smaller and smaller effects due to GR you need finer and finer grain detectors.
You need clocks that have shorter and shorter ticks.
There is going to be (if quantum theory is correct) a fundamental limit on how short a tick can get.
You could have a clock loose only one se ...[text shortened]... k was precise enough.
It would however be useless for detecting fine gravitational structure.
The early atomic clocks had a tick rate of about 10 billion per second (cesium beam)
and hydrogen clocks. That is 100 picoseconds per tick. 10 Thz is in the low IR band and that comes out at 100 attoseconds per tick if you will, but the newest clocks use light a thousand times faster so the individual ticks are getting down to 1 E-18 seconds.
That should be accurate enough for some very detailed quantum experiments.
Maybe clocks a hundred years from now will use X ray frequencies, perhaps accurate to within one second in a trillion years, wouldn't that be incredible?