Hyperphysics: Hafel-Keating experiment

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In summary: HBASE/relativ/airtim.html#c5In summary, the conversation discusses the discrepancy between the approximation T0 = -TS made in the "Kinematic Time Shift Calculation" section and the other equations in the section. The conversation also mentions the use of SR (Special Relativity) and GR (General Relativity) to explain the concept of HK (Hafele-Keating) using the proper time \tau and the general Schwarzschild metric.
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Rasalhague
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http://hyperphysics.phy-astr.gsu.edu/HBASE/relativ/airtim.html#c5

I don't understand the approximation T0 = -TS that they make in the final step of the section "Kinematic Time Shift Calculation". From this, and the other equations in this section, I get

[tex]-T_0=T_0\left ( 1+\frac{R^2\omega^2}{2c^2} \right )[/tex]

[tex]-1=1+\frac{R^2\omega^2}{2c^2}[/tex]

[tex]c^2=\frac{R^2\omega^2}{-4}[/tex]

[tex]c=\pm \frac{R\omega}{2i}[/tex]

but how can this be when c is a constant positive real number, not dependent on the product of the rotation of the Earth with its radius? And

[tex]T_A=T_S-T_S\left ( \frac{2R\omega v+v^2}{2c^2} \right )[/tex]

[tex]T_0\left ( 1+\frac{R^2\omega^2}{2c^2} \right )=-T_S\left ( -1+ \frac{2R\omega v+v^2}{2c^2} \right )[/tex]

[tex]T_0\left ( 1+\frac{R^2\omega^2}{2c^2} \right )=T_0\left ( -1+ \frac{2R\omega v+v^2}{2c^2} \right )[/tex]

[tex]4c^2= 2R\omega v+v^2 - R^2\omega^2[/tex]

[tex]c=\frac{\sqrt{(R\omega+v)^2-2R^2\omega}}{2}[/tex]

which can't be right, since c doesn't depend on these arbitrary variables: radius of the earth, etc.
 
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Rasalhague said:
http://hyperphysics.phy-astr.gsu.edu/HBASE/relativ/airtim.html#c5

I don't understand the approximation T0 = -TS that they make in the final step of the section "Kinematic Time Shift Calculation". From this, and the other equations in this section, I get

[tex]-T_0=T_0\left ( 1+\frac{R^2\omega^2}{2c^2} \right )[/tex]

[tex]-1=1+\frac{R^2\omega^2}{2c^2}[/tex]

[tex]c^2=\frac{R^2\omega^2}{-4}[/tex]

[tex]c=\pm \frac{R\omega}{2i}[/tex]

but how can this be when c is a constant positive real number, not dependent on the product of the rotation of the Earth with its radius? And

[tex]T_A=T_S-T_S\left ( \frac{2R\omega v+v^2}{2c^2} \right )[/tex]

[tex]T_0\left ( 1+\frac{R^2\omega^2}{2c^2} \right )=-T_S\left ( -1+ \frac{2R\omega v+v^2}{2c^2} \right )[/tex]

[tex]T_0\left ( 1+\frac{R^2\omega^2}{2c^2} \right )=T_0\left ( -1+ \frac{2R\omega v+v^2}{2c^2} \right )[/tex]

[tex]4c^2= 2R\omega v+v^2 - R^2\omega^2[/tex]

[tex]c=\frac{\sqrt{(R\omega+v)^2-2R^2\omega}}{2}[/tex]

which can't be right, since c doesn't depend on these arbitrary variables: radius of the earth, etc.

HK is poorly explained using SR, a correct explanation requires GR. I am quite sure that I gave a GR-based explanation for HK somewhere in this forum. It is simply calculating the proper time [tex]\tau[/tex] by integrating the expression in coordinate time t. The expression can be derived straight from the general Schwarzschild metric setting:

[tex]dr=d\theta=0[/tex],
[tex]\frac{d\phi}{dt}=\omega +\frac{v_1}{R}[/tex]
[tex]\frac{d\phi}{dt}=\omega -\frac{v_2}{R}[/tex]

depending on the direction of plane motion
 
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FAQ: Hyperphysics: Hafel-Keating experiment

What is the Hafel-Keating experiment?

The Hafel-Keating experiment, also known as the Hafel-Keating gyro experiment, was a test conducted in 1971 by physicists Joseph Hafel and Richard Keating to test Einstein's theory of relativity. It involved placing two atomic clocks on aircrafts, one traveling eastward and one westward, and measuring the difference in time between them upon their return.

What was the purpose of the Hafel-Keating experiment?

The purpose of the Hafel-Keating experiment was to test the effects of time dilation, a phenomenon predicted by Einstein's theory of relativity. The experiment aimed to measure the difference in time between two atomic clocks traveling at different speeds and in different directions, and compare it to the predicted amount based on Einstein's theory.

What were the results of the Hafel-Keating experiment?

The results of the Hafel-Keating experiment were consistent with Einstein's theory of relativity. The eastward-traveling clock was found to have run slightly slower than the stationary clock, and the westward-traveling clock ran slightly faster. This confirmed the predicted effect of time dilation and provided evidence for the validity of Einstein's theory.

How did the Hafel-Keating experiment impact the scientific community?

The Hafel-Keating experiment was a significant milestone in the field of physics, as it provided strong evidence for Einstein's theory of relativity. It also helped to further our understanding of time dilation and the effects of high speeds on the passage of time. The experiment has been replicated and verified numerous times, solidifying its importance in the scientific community.

Can the Hafel-Keating experiment be applied to other areas of science?

While the Hafel-Keating experiment specifically tested the effects of time dilation, its findings have implications for other areas of science as well. The concept of time dilation is relevant in fields such as cosmology and astrophysics, where the effects of high speeds and gravity on time are crucial to understanding the behavior of the universe. Additionally, the experiment highlights the importance of testing and confirming scientific theories through experimentation.

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