A Star Passing The Black Hole at The Centre of Our Galaxy Is About to Test Einstein's Theory

[Judi Lynn]

Astronomers have been waiting for years to watch this happen.

MICHELLE STARR 2 MAR 2018

In a few months, astronomers are going to be pointing their telescopes to Sagittarius A*, the supermassive black hole at the centre of our galaxy.

That's because it's going to be buzzed by a closely orbiting star - providing another context for testing Einstein's theory of general relativity.

The star is called S0-2, one of a class of stars known as S-stars (not to be confused with S-type stars) that closely orbit Sgr A*, which has an estimated mass of around 4.3 million Suns.

But S0-2 is special. It's one of two stars that zoom in closest to the black hole in its elliptical orbit, which means it's likely to show the effects of the black hole's gargantuan gravitational pull when it swings around once every 16 years.

More:
https://www.sciencealert.com/star-orbiting-milky-way-supermassive-black-hole-sagittarius-a-einstein-relativity

[Wwcd]

1. How interesting! Thanks

K & R
🌠

[Honeycombe8]

2. Wow. Amazing. I still can't quite grasp a black hole.

I mean, it exists, and it's something. It has mass. But it's invisible and doesn't seem to take up space. That's my understanding.

[radical noodle]

3. Thanks Judi Lynn!

I really appreciate so many interesting things you post. We don't tell you often enough.

[JohnnyRingo]

4. K&R for geek

I would think the star would be more than 17 light hours away from the black hole. It shouldn't last too many more passes if I understand my science fiction series correctly. That's four times the distance from the sun to Saturn, according to the article. The star can't add to it's existence if it accelerates to near light speed.

Incredible! Thanx for posting.

[Marcuse]

5. Looks like a larger scale version of the Mercury perihelion precession experiment 100 years ago.

[“As seen from Earth the precession of Mercury's orbit is measured to be 5600 seconds of arc per century (one second of arc=1/3600 degrees). Newton's equations, taking into account all the effects from the other planets (as well as a very slight deformation of the sun due to its rotation) and the fact that the Earth is not an inertial frame of reference, predicts a precession of 5557 seconds of arc per century. There is a discrepancy of 43 seconds of arc per century.

This discrepancy cannot be accounted for using Newton's formalism. Many ad-hoc fixes were devised (such as assuming there was a certain amount of dust between the Sun and Mercury) but none were consistent with other observations (for example, no evidence of dust was found when the region between Mercury and the Sun was carefully scrutinized). In contrast, Einstein was able to predict, without any adjustments whatsoever, that the orbit of Mercury should precess by an extra 43 seconds of arc per century should the General Theory of Relativity be correct.]http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html