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  Black Hole Star

the post:

Star hurtling around a giant black hole proves Einstein right again

At the centre of the Milky Way, Einstein's laws rule. Measurements of light from a star that orbits close to our galaxy's central supermassive black hole cannot be explained by classical views of gravity and instead require Einstein's general relativity.

my comment:

We are accepting another orbit that does not conform to Kepler's third law of planetary motion, with its relationship between an elliptical orbit axis and its duration.

S0–102 is a star that is located very close to the centre of the Milky Way, near the radio source Sagittarius A*, orbiting it with an orbital period of 11.5 years. As of 2012 it is the star with the shortest known period orbiting the black hole at the centre of the Milky Way. This beat the record of 15 years previously set by S0–2.

The orbits:
S0-102 axis = 260 AU, duration = 11.5 yr
S0-2 axis 970 AU, duration 15.56 yr

With Kepler's third law and those orbit diameters:

S0-102 axis = 260 AU, calculated duration about 4000 yr
S0-2 axis 970 AU, calculated duration about 30300 yr

By applying:
'general relativistic effects due to gravitational redshift '
the much shorter observed period can be accepted resulting in such an extreme orbital velocity.

Obviously we cannot wait 4000 yr to verify one complete orbit for S0-102. The orbit duration for that diameter was measured at 11.5 yr.

Obviously we did not wait 30300 yr to verify one complete orbit for S0-2.
S0-2 is known to have a difficult ellipse:

It is believed that there are thousands of stars, as well as dark stellar remnants (stellar black holes, neutron stars, white dwarfs) distributed in the volume through which S2 moves.'

We are trying to use Newton and Kepler to calculate the black hole's mass but the orbit parameters do not conform. This is an odd mix of old physics and new physics.

Our Sun is known to not follow an ellipse; its orbit is disturbed by a few billion stars. The stars around the Milky Way core are being monitored to find a valid ellipse.
In this case we are accepting one that is not valid and using relativity to excuse it.

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