Exploring Supermassive Black Holes: Understanding Orbiting Stars and Gravity

[curiousphoton]

Hello,

I was watching a show on one of DirectTV's Science channels last night about supermassive black holes. They stated the these supermassive black holes exist in two phases : 1. When they are sucking in everything around them (stars, planets, moons, etc). 2. When they aren't sucking in everything around them.

Question: When the supermassive black hole is in Phase 2 (not sucking in stars), how to the stars stay in orbit around the hole? The planets in our solar system orbit the sun in a slightly elliptical manner, rather than perfectly circular. This is due to our sun's gravity accelerating our planets', then pulling it back in, no? I was thinking with a supermassive black hole, wouldn't the stars around that black hole orbit in an extremely obvious elongated elliptical shape?


*Note: I wasn't sure what forum to post this in but figured black holes = gravity = einstein = GR...

 

[nicksauce]

The UCLA Galactic Center Group actually has real-time data of stars orbiting the SMBH in our galaxy.

See: http://www.astro.ucla.edu/~ghezgroup/gc/pictures/orbitsMovie.shtml

 

[Nabeshin]

From a more theoretical perspective, when you are far enough away from a black hole, you cannot tell the difference between it and a normal star. So for all intents and purposes, large orbits around black holes are the same as orbits around any other body. You can have circular, or elliptical orbits just as with any other body. Things get strange as you get closer to the hole though, with things like unstable circular orbits and zones where you cannot orbit at all. But I think the vast majority of stellar objects in orbit around SMBHs do not fall into these categories.

 

[Agent M27]

As Nabeshin mentioned when far enough away from the SMBH event horizon things will go unnoticed due to the amount of mass the star once had isn't changing, it is just getting condensed according to the Schwarzschild radius. In fact our orbital velocity would not change if the Sun became a black hole. Now as an object gets closer and closer to the event horizon their orbit will change dramatically, turning quite chaotic. The only difference between a quiet SMBH (within our own Milky Way) and an active SMBH (like the one in M87) is that all of the stars which were close enough or inside the event horizon have been sucked in, leaving stars that were far enough away, untouched. Other than that they are pretty much the same.

 

[sardar]

so I'm putting it here

Hi there,

That's a great question. Supermassive black holes are fascinating objects that continue to intrigue and challenge scientists. In order to understand how stars orbit around a supermassive black hole, we need to first understand the concept of gravity and its role in shaping the movements of objects in space.

Gravity is a fundamental force in the universe that causes objects with mass to attract each other. In the case of our solar system, the sun's mass creates a gravitational pull that keeps the planets in orbit around it. This is also true for supermassive black holes - their immense mass creates a strong gravitational pull that keeps nearby stars in orbit.

However, the gravitational pull of a supermassive black hole is much stronger than that of a star like our sun. This means that stars orbiting a supermassive black hole will experience a much larger acceleration, causing them to move at higher speeds and in more elliptical orbits. In other words, the stars will appear to be orbiting in an elongated elliptical shape, as you suggested.

Additionally, the shape of the orbit can also be influenced by other factors such as the distribution of mass around the supermassive black hole and the interactions between nearby stars. This is why the orbits of stars around a supermassive black hole may not always be perfectly circular or predictable.

Overall, studying the orbits of stars around supermassive black holes helps us better understand the nature of gravity and the behavior of objects in extreme environments. It also allows us to gain insight into the properties and evolution of these mysterious objects. Thank you for your question and interest in the fascinating world of black holes.