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PatrickPowers
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From https://www.physicsforums.com/showthread.php?t=40391 in gravitational time dilation.
At the center of neutron star PSR J1614-2230 at 1.97 SM
mass of Sun 1.9891×10^30 kg
mass of PSR J1614-2230. 4 ×10^30
gravitational constant = 6.67300 × 10-11 m3 kg-1 s-2
radius(rough estimate) = 10000m
phi = - 3/2 * 6.67300 × 10-11 * 4 ×10^30 / 10000
phi = - 4 × 10^20 / 10000
phi = - 4 × 10^16
sqrt( 1 + 2phi/c^2 )
sqrt( 1 - 2 * 4 × 10^16 / (3^10^8)^2
sqrt( 1 - 8 / 9 )
sqrt( 1/9) = .33
so time runs perhaps three times as slowly at the center than in an area of weak gravity.I have read that the gravity of a neutron star owes more to its pressure than its mass. I don't know whether these figures take that into account.
DW said:That formula is only valid for the region exterior to the earth. Inside the Earth the corresponding formula would be
[tex]t = \frac{\tau}{\sqrt{1 + \frac{2\Phi}{c^2}}}[/tex]
[tex]\Phi = \frac{1}{2}\frac{GM_{tot}r^{2}}{R^{3}} - \frac{3}{2}\frac{GM_{tot}}{R}[/tex]
where [tex]M_{tot}[/tex] is the mass of the planet, R is its radius, r is the distance of the clock inside the Earth from the center with [tex]\tau[/tex] as its time and t is the time for a far remote clock. According to this gravitational time dilation is greatest at the center.
At the center of neutron star PSR J1614-2230 at 1.97 SM
mass of Sun 1.9891×10^30 kg
mass of PSR J1614-2230. 4 ×10^30
gravitational constant = 6.67300 × 10-11 m3 kg-1 s-2
radius(rough estimate) = 10000m
phi = - 3/2 * 6.67300 × 10-11 * 4 ×10^30 / 10000
phi = - 4 × 10^20 / 10000
phi = - 4 × 10^16
sqrt( 1 + 2phi/c^2 )
sqrt( 1 - 2 * 4 × 10^16 / (3^10^8)^2
sqrt( 1 - 8 / 9 )
sqrt( 1/9) = .33
so time runs perhaps three times as slowly at the center than in an area of weak gravity.I have read that the gravity of a neutron star owes more to its pressure than its mass. I don't know whether these figures take that into account.