Rare View of Black Hole

[Dryson]

A rare view of a black hole erupting.

http://www.space.com/29966-black-hole-bullseye-video.html

Rings of X-ray light flare and fade around an active black hole in a stunning new set of observations by NASA's Swift space telescope.

This is interesting

V404 Cygni's arousal on June 15 was likely caused by material falling into the black hole, part of a cycle that repeats every few decades, researchers said. The companion star is about 10 percent as massive as the black hole, and the behemoth pulls a stream of gas away from it over time. The cool gas can resist the black hole's pull, but when enough gas builds up and heats up, it's suddenly pulled into the center of the black hole, triggering a sudden outburst of X-rays.


The cool gas can resist the pull of the black hole.

Gas traveling slower than the speed of light has the ability to resist the pull of a black hole when light is not able to.

 

[Gov Kodos]

No, the gas is not resisting anything, it's just in orbit around the black hole and slowly spiraling into it.

 

[Crazy Eddie]

Surely I'm going to be accused of hobby horsing this, but I've always been bothered by the fact that astronomers identify objects as "black holes" despite the fact that they are obviously visible -- in V404's case, spectacularly so -- and merely ASSUME there is a black hole at the center of the extremely visible accretion disk because a set of theoretical models that have never been directly tested predict it should be there.

V404 Cygni could just as easily be a neutron star and still fit all of the known data about its characteristics. The only thing that would be inconsistent is the theoretical model for the formation of a singularity, but again, that model has never been tested or even verified and even astrophysicists generally concede that the model is incomplete at best.

 

[YellowSubmarine]

because a set of theoretical models that have never been directly tested predict it should be there

Not necessarily. The term black hole refers to whatever object is inside the event horizon. If it turns out it is not actually a black hole in respect to current understanding, then the word black hole will be changed to mean whatever's inside or to the event horizon itself. Besides, what's presently observed matches with what's predicted for a black hole and what's observed is pretty much black and pretty much a hole. I also want to call them bunnies, but nobody likes it.

 

[Crazy Eddie]

because a set of theoretical models that have never been directly tested predict it should be there

Not necessarily. The term black hole refers to whatever object is inside the event horizon. If it turns out it is not actually a black hole in respect to current understanding, then the word black hole will be changed to mean whatever's inside or to the event horizon itself. Besides, what's presently observed matches with what's predicted for a black hole and what's observed is pretty much black and pretty much a hole. I also want to call them bunnies, but nobody likes it.

That's just it: "Inside the event horizon" implies that there is an object at V404 whose physical radius is less than it's Schawrzchild radius. We don't actually know that to be the case. There are no direct observations of the event horizon, nor observational evidence supporting the conclusion that the object that formed the "black hole" necessarily MUST have collapsed below that crucial radius.

In other words "Pretty much black" is a prediction, not an observation. What we SEE from V404 Cygni is a lot of radiation and a lot of gravity coming from an object that the models predict is too small NOT to be a black hole, but that object is too far away and too small to be directly observed.

 

[aridas sofia]

Would it be more accurate to characterize a black hole as a "spherical void"?

I always liked the description given in TOS "Tommorow is Yesterday"- "black star".

 

[publiusr]

That and collapsar