Pair Of Stars Orbiting Each Other Become A Black Hole Due To High Rpm

[rafeh1]

Assume a pair of stars in orbit with each other.  If the stars orbital rpm spin is fast enough such that they are orbital speed is close to c their combined mass will increase due to special relativity and go over the black hole limit becoming a disc whose mass is a function of its rotational speed.  so after certain rpm the observer would see the stars light vanish as the two body system crosses the black hole limit. 

 

then if they are brushed by a third gravitational object whose gravity causes a reduction in the rpm of the two body star such that the rpm dips below the black hole limit the stars will become visible again.

 

same though experiment can be run if the two bodies are them selves blackholes. their combined 2 body rotation if large enough and enough rpm  then becomes a third black hole but it too can appear and disappear depending on rotation speeds.  If the rotation speed is reduced then they are 2 black holes if rotation speed is increased then it becomes one large black hole.

 

 

Edited March 9, 2016 by rafeh1

[rafeh1]

so as a thought experiment we can have black holes which transition in and out of black hole status.

second thought experiment input and extract energy via gravitional pull and push

[CraigD]

Welcome to hypography, rafeh! :) Please feel free to start a topic in the introductions forum to tell us something about yourself.

 

Assume a pair of stars in orbit with each other. If the stars orbital rpm spin is fast enough such that they are orbital speed is close to c their combined mass will increase due to special relativity and go over the black hole limit becoming a disc whose mass is a function of its rotational speed. so after certain rpm the observer would see the stars light vanish as the two body system crosses the black hole limit.

There’s a cool, fairly easy to mathematically describe, reason this can’t happen.

 

Using classical gravity, calculate the mass(es) and radii of the orbits r needed for 2 bodies to approach the speed of light (it’s easiest, but not required, to assume they have equal mass and circular orbits). Then calculate their Schwarzschild radii r_s.

 

You’ll discover r = r_s.

 

A body with a center-to-surface radius r_p smaller than its r_s is a black hole, so to be a star, the r_b must exceed its r_s. But to orbit one another, r_b must be less than r. It’s impossible for both of these to be true.

Edited March 10, 2016 by CraigD
Fixed broken hyperlink

[rafeh1]

Welcome to hypography, rafeh! :) Please feel free to start a topic in the introductions forum to tell us something about yourself.

 

There’s a cool, fairly easy to mathematically describe, reason this can’t happen.

 

Using classical gravity, calculate the mass(es) and radii of the orbits r needed for 2 bodies to approach the speed of light (it’s easiest, but not required, to assume they have equal mass and circular orbits). Then calculate their Schwarzschild radii r_s.

 

You’ll discover r = r_s.

 

A body with a center-to-surface radius r_p smaller than its r_s is a black hole, so to be a star, the r_b must exceed its r_s. But to orbit one another, r_b must be less than r. It’s impossible for both of these to be true.

 

what if the two body are themselves black holes would if in high rpm orbit with each other become a super black hole?

[CraigD]

what if the two body are themselves black holes would if in high rpm orbit with each other become a super black hole?

The math around this question is beyond my meager skill, but drawing from actual observation, I think the answer is something between “no” and “yes, but not how you’re imagining.”

 

In a purely universe that obeyed the classical mechanics’ laws of motion and Special Relativity, but not those of General Relativity, 2 black holes could, with some very elaborate mechanics, be able to form a very tight orbit such that their mass dilation was substantial enough to increase their masses, and thus the size of their event horizons (r_s) noticeably. But our universe doesn’t appear to work that way. It also follows General Relativity.

 

General Relativity gives the results where orbiting bodies radiate energy in the form of gravitational waves. This results in binary black holes them following a “black hole inspiral” (the best description I could find of this is this 2011 Physics Today article by Thomas Baumgarte and Stuart Shapiro).

 

So the BBH can’t form stable orbits with orbital speeds a substantial fraction of the speed of light, because they emit (huge amounts – see the Physics Today article) of gravitational radiation and spiral into one another to form a single, “ringing” black hole.

[rafeh1]

The math around this question is beyond my meager skill, but drawing from actual observation, I think the answer is something between “no” and “yes, but not how you’re imagining.”

 

In a purely universe that obeyed the classical mechanics’ laws of motion and Special Relativity, but not those of General Relativity, 2 black holes could, with some very elaborate mechanics, be able to form a very tight orbit such that their mass dilation was substantial enough to increase their masses, and thus the size of their event horizons (r_s) noticeably. But our universe doesn’t appear to work that way. It also follows General Relativity.

 

General Relativity gives the results where orbiting bodies radiate energy in the form of gravitational waves. This results in binary black holes them following a “black hole inspiral” (the best description I could find of this is this 2011 Physics Today article by Thomas Baumgarte and Stuart Shapiro).

 

So the BBH can’t form stable orbits with orbital speeds a substantial fraction of the speed of light, because they emit (huge amounts – see the Physics Today article) of gravitational radiation and spiral into one another to form a single, “ringing” black hole.

 

If two BH are in orbit with each other their effective even horizon will become oval to each other as they get closer the two event horizons almost touch. any addition mas thrown in with the right angles will increase the momentum of the two body system. Since conservation of momentum is still valid the additional mass will increase both speed and mass causing the two body event horizon to join together.

 

Similarly if additional mass hits at an angle and causes a slow down in the rotation speed then the combined event horizon will split back into two separate ones.

[CraigD]

If two BH are in orbit with each other their effective even horizon will become oval to each other as they get closer the two event horizons almost touch. any addition mas thrown in with the right angles will increase the momentum of the two body system. Since conservation of momentum is still valid the additional mass will increase both speed and mass causing the two body event horizon to join together.

 

Similarly if additional mass hits at an angle and causes a slow down in the rotation speed then the combined event horizon will split back into two separate ones.

As I’ve said before, the math of this is over my head, but based on the sources in my last post, I think your claim is wrong. Unlike the classical orbital mechanics useful for plotting the courses of planets and spacecraft, close encounters of black holes and similarly massive objects are dominated by General Relativitistic effects, which predict that the systems lose kinetic energy due to gravitational radiation in a way roughly analogous to bodies moving in high-friction medium. Close black hole orbits are impossible, collisions and mergers in such cases inevitable.

[Kyrpto]

Never.  The orbiting stars will only increase in relativistic mass.  Rest mass is what counts.