Black whole theory is just black whole!

[vimto]

Universally accepted theory of a black hole is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull

Here is where I get confused about the nature of black hole.

1. If a Black hole is objects so massive that it stretched downward the fabric of the universe, then why do see a picture of black holes shooting jet stream from both ends? Does this mean these kind of black hole were so massive that they tear down the fabric of the universe?

2. Why some black holes are dormant while others are active? Shouldn’t the pull of gravity work indefinitely?

 

[MeteorWayne]

The jets are from material outsifde of the event horizon. Material forms a disk and has considerable angular momentum and is ejected by interaction with the magnetic fields.

When there is no nearby gas concentrations, there is not enough energy to be detected. When a large chunk of gas either by itself or from a ripped apart star or planet is nearby, it emits a lot of energy.

 

[CalliArcale]

1. What he said. ^ The jets are stuff that didn't get quite close enough to fall in, but close enough to get a really big gravity assist, or "slingshot". It's sorta like what NASA did with the Voyager probes, slingshotting them past Jupiter and Saturn to pick up speed, only on a much bigger scale.

The black holes won't tear the fabric of the universe; as I understand it, the "fabric of the universe" is really just a metaphor to describe the way that black holes warp space in their vicinity. The Earth actually warps space in exactly the same way -- it's not not anywhere near as dense, so it's not warped anywhere near as much.

2. The pull of gravity does indeed work indefinitely, but it follows the inverse square rule -- that is, the force is inversely proportional to the square of the distance between two objects. That basically means it decreases exponentially as you get further away. Those drawings of warped spacetime are actually showing precisely that -- the curve shows how strong gravity is.

So if you get far enough away from a black hole, you can't feel it. A dormant black hole is really just one that isn't "feeding" -- that is, no matter is falling into it, which means it's not going to be emitting any radiation for us to detect. Although light can't escape a black hole, radiation and even light can escape from just outside the event horizon. Stuff gets *really* hot as the black hole's gravity rips it apart, and when it glows, that's what astronomers call an active black hole. Once all the stuff close enough to be affected by the black hole has fallen in, it will stop producing radiation and will go dormant. If more stuff arrives, it could become active again quite easily.

 

[chebby]

Here a few interesting things I read recently in Stuart Clark's book called Deep Space:

There are two types of black holes: small ones that were created from exploding stars and supermassive blackholes in the center of each galaxy (possibly intermediate sizes also exist.) There is a supermassive black hole at the center of each galaxy. Not only the visible jets of matter can usually be seen, but also strong x-ray emissions are produced (which makes x-ray telespcopes very good at finding them.) The energy released in ejections of matter from BHs is huge, about 50% of matter is completely converted into energy, which is much more efficient than nuclear fusion. Sometimes the ejected jets of matter from black holes at galaxy centers coillide with ambient gas in intergalactic space and produce spectacular radio lobes, many times larger than the galaxy itself.

The scary thing to me about black holes, is that if there is no matter around, you can't really detect them. That means one could be slowly flying toward our solar system and we won't know until it's too late.

 

[kg]

....The scary thing to me about black holes, is that if there is no matter around, you can't really detect them. That means one could be slowly flying toward our solar system and we won't know until it's too late.

You can't see the actual black hole itself, however you can see light from distant objects magnified by the black hole. http://en.wikipedia.org/wiki/Gravity_lens#Simulation
There have been surveys done specifically to look for lensing events. In the search for dark matter, massive compact halo objects (MACHOs) were identified by micro lensing http://en.wikipedia.org/wiki/MACHO. The project was an attempt to determine how much "dark" matter was in the form of "normal" matter that doesn't emit much light, such as black holes, neutron stars, white dwarfs and planets.
The question is: Would a black hole bearing down on our solar system show up on this survey or any other?

 

[KickLaBuka]

What a mess you guys have dug yourselves into. Black holes don't have to be massive at all. All stars have neutron centers. And to answer your question about a "black hole" bearing down on us, it would be observed over long duration x-ray and radio wave exposures, because black holes are merely an electron flow. It's quite simple and this massiveness stuff really has to go.

 

[derekmcd]

What a mess you guys have dug yourselves into. Black holes don't have to be massive at all.

No one has made that claim other than the original poster in the form of a question.

All stars have neutron centers. And to answer your question about a "black hole" bearing down on us, it would be observed over long duration x-ray and radio wave exposures, because black holes are merely an electron flow. It's quite simple and this massiveness stuff really has to go.

Do you have any legitimate, scientific sources to back up these nonsensical claims?

 

[KickLaBuka]

Do you have any legitimate, scientific sources to back up these nonsensical claims?

First off, can you admit that black holes do not "require extreme mass density?" That "Black holes are borne of General Relativity and GR is the theory of gravity?" -Dr Rocket

Are you recanting those assertions made by your counterparts?

Secondly, think about the ionization energies of either Hydrogen or Helium. The temperature in the sun is too hot to have any electron "bounded" elements, so protons and neutrons must exist as ionized elements. Since H+ and He++ are what we are dealing with, neutrons must exist. It is logical to imply that the core is made of dielectric neutrons. I have legitimate sources for the nuclear reactions, although they are not needed here, because it is logical.

 

[derekmcd]

First off, can you admit that black holes do not "require extreme mass density?" That "Black holes are borne of General Relativity and GR is the theory of gravity?" -Dr Rocket

Are you recanting those assertions made by your counterparts?

No and no.

Your first question is not even related to your previous comments on "massiveness". DrRocket's assertion is quite accurate, though I don't understand why you dug it up and how it relates to any comments in this thread.

Secondly, think about the ionization energies of either Hydrogen or Helium. The temperature in the sun is too hot to have any electron "bounded" elements, so protons and neutrons must exist as ionized elements. Since H+ and He++ are what we are dealing with, neutrons must exist. It is logical to imply that the core is made of dielectric neutrons. I have legitimate sources for the nuclear reactions, although they are not needed here, because it is logical.

Again, do you have a legitimate, scientific source that claims the core of the Sun is made of neutrons. I'd like to understanding how you can make a "logical" leap from proton-proton chain reactions in the core of the Sun to the core of the Sun is made of neutrons.

 

[kg]

What a mess you guys have dug yourselves into. Black holes don't have to be massive at all. All stars have neutron centers. And to answer your question about a "black hole" bearing down on us, it would be observed over long duration x-ray and radio wave exposures, because black holes are merely an electron flow. It's quite simple and this massiveness stuff really has to go.

Your confusing me. What do you mean by "black holes are merely an electron flow"? We were talking about a black hole without an acretion disk around it. As I understand it it's the acretion disk that emits x-rays, not the black hole itself.

 

[yevaud]

Correct. In the absence of matter to accrete and form an accretion disc / polar jets (or another large mass to be affected), there is no way to detect it. There is nothing to show it's gravitational effects whatsoever.

 

[kg]

Correct. In the absence of matter to accrete and form an accretion disc / polar jets (or another large mass to be affected), there is no way to detect it. There is nothing to show it's gravitational effects whatsoever.

...unless it passes in front of another object and distorts the light coming from it as I mentiond in an earlier post on this thread. Of course it would be hard to spot if it was heading stright for our solar system. It wouldn't have much proper motion and would pass slowly in front of distant objects. If it was coming from a direction without many background stars it would definatly be in "stealth" mode.