Cosmology Views

Star Dancing Around Black Hole

the post:
just a link to  a story titled:
Astronomers saw a star dancing around a black hole. And it proves Einstein's theory was right

my comment:

 For many years astronomers have been seeking a star orbiting around the claimed black hole. If it is a valid Kepler ellipse then they seek to apply Kepler's 3rd law to calculate the MBH mass. This was done with S1 years ago to derive the silly mass of billions of solar masses. Unfortunately someone noticed S1 was not a valid ellipse; instead of the claimed period of 16 years, its claimed radius requires many thousands of years. The silly mass persists but astronomers seek another star to try again for this mass calculation.
Obviously S2 orbit is invalid as well because it is not closed as stated in the article.
Because astronomers have been watching for a few decades, so perhaps they gave up and came up with this 'rosette' orbit to bring up Einstein - which is obviously effective to get your story published.

as a follow-up to my previous comment:

From Wikipedia, not the story:

S2, also known as S0–2, is a star that is located close to the radio source Sagittarius A*, orbiting it with an orbital period of 16.0518 years, a semi-major axis of about 970 au.

(excerpt end)


S2 = 970 au, 16.052 y

Jupiter= 5.203au,  11.86 y
Saturn= 9.54au, 29.46y

With Kepler's 3rd law:

S2 = 970 au takes  about 30,200yr

S2= 16.0518 yr is for about 6.5au

the observed orbit parameters for S2 are not a valid Kepler ellipse.

I added another comment later:

These news stories never reveal the importance of this search for a star like S2 and the requirement for a valid ellipse.

With a valid ellipse, astronomers can use Newton's change to Kepler's 3rd law to calculate the number of solar masses at the core with a known mass in an orbiting star. The mass for S2 will be a guess. With electromagnetic forces in play this calculation might be debated.

Currently every black hole claimed to be in every galaxy is assigned a value of solar masses loosely based on the estimated number of stars in that galaxy. That assumption has no basis.

If the Milky Way core,  which is claimed to have a a SMBH for the roughly 300 billion stars in the galaxy, is observed to have an orbiting star then this will be a significant milestone for black hole advocates.

Until that star is found, there is no black hole in any galaxy with a justification for its claimed number of solar masses.

This is a basic problem for cosmologists of no evidence or no justification for any claims about a SMBH in every galaxy. Cosmologists hope this finding and calculation can save all their claims spanning  many years. Unfortunately for them, an orbit with a larger radius for its measurement requires a longer period like in thousands of years (like S2 needs).

One might expect rules to be broken about the orbit to achieve the calculation.

Every scientific claim requires evidence.