Re: The most accurate clock ever

On Sat, Dec 22, 2018 at 2:36 AM Brent Meeker wrote: * > I'm not sure why you converted 9" to kilometers instead meters,* > Oh that's very easily explained. I was stupid. > *> but: 2(6.67e-11)112/0.2(9e16) = 8.3e-25* > Yes, I get 8.3*10^-25 too. And the square root of (1 - 8.3^10^-25) is

Re: The most accurate clock ever

On 12/21/2018 7:29 AM, John Clark wrote: On Thu, Dec 20, 2018 at 11:57 PM Brent Meeker > wrote: >> The mass of the Earth played no part in Cavendish's determination of G because he was measuring gravitational attraction in a direction that

Re: The most accurate clock ever

The leading term in time difference with radius is the g_{tt} component of the Schwarzschild metric g_{00}(r) = 1 - 2GM/rc^2 We have 2GM/c^2 = 0.0088m which is the Schwarzschild radius. From R to R' we can integrate this ∫g_{00}(r) dr = R' - R - 2GM/c^2 ln(R'/R). For R' = R + δr we

Re: The most accurate clock ever

On Thu, Dec 20, 2018 at 11:57 PM Brent Meeker wrote: >> The mass of the Earth played no part in Cavendish's determination of G >> because he was measuring gravitational attraction in a direction that >> was parallel to the Earth's surface. > > > * > But in comparing it to the clock precision you

Re: The most accurate clock ever

On 12/4/2018 5:35 PM, John Clark wrote: Brent Meeker wrote: > / finding the value of G depends on scaling the result by that ratio of masses (1.37e25 lbm/348 lbm). / The mass of the Earth played no part in Cavendish's determination of G because he was measuring gravitational

Re: The most accurate clock ever

Brent Meeker wrote: > * finding the value of G depends on scaling the result by that ratio of > masses (1.37e25 lbm/348 lbm). * > The mass of the Earth played no part in Cavendish's determination of G because he was measuring gravitational attraction in a direction that was parallel to the

Re: The most accurate clock ever

On 12/4/2018 6:28 AM, John Clark wrote:  Brent Meekerwrote: /> Neither does a cesium clock measure the change in strength of 2 large gravitational fields.  It measures the difference in gravitational potential. / Same thing, a gravitational field describes the gravitational

Re: The most accurate clock ever

Given the Earth has a liquid core, is there any chance that turbulence in the core would move the center of gravity around by some minute amount, but large enough to throw off measurements of such tiny differences? On Thu, Nov 29, 2018 at 9:29 AM John Clark wrote: > In yesterday's issue of the

Re: The most accurate clock ever

Brent Meeker wrote: *> Neither does a cesium clock measure the change in strength of 2 large > gravitational fields. It measures the difference in gravitational > potential. * Same thing, a gravitational field describes the gravitational potential at every point. *> **So I compared the

Re: The most accurate clock ever

On 12/3/2018 5:24 AM, John Clark wrote: On Sun, Dec 2, 2018 at 11:54 PM Brent Meeker > wrote: >>If you are on the Earth's surface and you raise a clock by one centimeter you've increased its distance from the earth's center by one part in

Re: The most accurate clock ever

On Sun, Dec 2, 2018 at 11:54 PM Brent Meeker wrote: >>If you are on the Earth's surface and you raise a clock by one centimeter >> you've increased its distance from the earth's center by one part in >> 637,000,000, it is now 1.16 times further away. The intensity of >> the gravitational

Re: The most accurate clock ever

On 12/2/2018 7:04 PM, John Clark wrote: On Sun, Dec 2, 2018 at 4:29 PM Brent Meeker > wrote: /> The Earth is 3.9e22 times heavier than Cavendishes cannon ball. / The mass of the earth is irrelevant because we're talking about measuring the difference in the

Re: The most accurate clock ever

On Sun, Dec 2, 2018 at 4:29 PM Brent Meeker wrote: > *> The Earth is 3.9e22 times heavier than Cavendishes cannon ball. * > The mass of the earth is irrelevant because we're talking about measuring the difference in the strength of gravity as distance increases not its absolute value. >> In

Re: The most accurate clock ever

On 12/2/2018 6:22 AM, John Clark wrote: On Sat, Dec 1, 2018 at 6:59 PM Brent Meeker > wrote: > /But an ocean wave many feet high would change the gravitational field less than would moving a centimeter relative to the Earth's center of mass./ Not so.

Re: The most accurate clock ever

On Sat, Dec 1, 2018 at 6:59 PM Brent Meeker wrote: > *But an ocean wave many feet high would change the gravitational field > less than would moving a centimeter relative to the Earth's center of mass.* Not so. In 1798 technology was good enough for Cavendish to measure the gravitational

Re: The most accurate clock ever

On 12/1/2018 7:06 AM, John Clark wrote: On Thu, Nov 29, 2018 at 6:34 PM Brent Meeker > wrote: >> good enough for jet fighters to automatically land on aircraft carriers without a pilot, even at night in a heavy fog in a bad storm with the

Re: The most accurate clock ever

On Thu, Nov 29, 2018 at 6:34 PM Brent Meeker wrote: >> good enough for jet fighters to automatically land on aircraft carriers >> without a pilot, even at night in a heavy fog in a bad storm with the deck >> tossing up and down. > > * > Unfortunately for that idea, the surface of the Earth,

Re: The most accurate clock ever

On 11/29/2018 6:28 AM, John Clark wrote: In yesterday's issue of the journal Nature Scientists at the National Institute of Standards and Technology (NIST) reported they have made a new type of clock that is the most accurate ever, it's called a Ytterbium Lattice Clock. It's about 100 times

The most accurate clock ever

In yesterday's issue of the journal Nature Scientists at the National Institute of Standards and Technology (NIST) reported they have made a new type of clock that is the most accurate ever, it's called a Ytterbium Lattice Clock. It's about 100 times better than any previous clock, if set at the