Science Forums 2

[modest]

Originally Posted by Pluto

After reading hundreds of papers on the subject, you get this feeling If you know what I mean.

Feelings are what they are, but if you're making claims and refuting the claims of others then you need to throw some support and back up behind it. That inactive black holes can create jets without feeding or that mass can escape from inside a black hole... for example, seem like pretty strange claims to me. I'd be very curious to read any scientific literature making those same claims.

Originally Posted by Pluto

Galaxies go through an evolution of form. The mass and density of the centre Nucleon determines the form of the galaxy. Inactivity does not mean inactivity with respect with either the Nucleon or the galaxy.

“Inactivity” or “inactive galaxy” simply refers to galaxies which do not have AGN (active galactic nuclei). They are sometimes tersely called “normal galaxies” (as 99% of all observed galaxies have dormant nuclei), but are more properly called “quiescent galaxies”. The main characteristic that distinguishes active galaxies from quiescent galaxies is that the former has a source of intense luminosity in its nucleus and the latter does not. The scientific community is in good agreement that the majority of all (both active and quiescent) galaxies have supermassive black holes at their core.

Originally Posted by Pluto

As for the origin of the main jet. This comes from the centre of any compact object. Can anybody prove that, not yet.

Indeed, the source of an AGN is compact. A black hole (even a supermassive black hole) is easily considered compact. Its radius is given by,

or, in solar masses and astronomical distance units,

This makes the black hole at the center of the Milky Way just under a tenth of an A.U. in radius or a tenth of the distance from the sun to the earth.

Nevertheless, it appears Pluto is referring to a “compact object” such as Hoyle and Fowler proposed was responsible for the energy of AGN in 1963 (On the nature of strong radio sources). They took a step in the right direction claiming there was a single, compact, gravitational source causing quasars. It was, however, not a black hole they considered, but a star of about one billion solar masses (one billion times the mass of our sun). They remark in the paper “The concept of stellar-type objects with masses up to approximately 10^8 solar masses is of course strange...”, and indeed it is. But they correctly focus on one important characteristic of AGN—that the source of energy of an AGN is very small (as compared to something like a globular cluster). And also consider the possibility of accreting matter gravitationally as a source of energy.

As far as proving the source is compact (or small in size): When x-ray satellites were put in orbit in the 70’s it was found that quasars emitted strongly in x-ray wavelengths and the energy output varied in this wavelength by as much as a factor of two in as quickly as hours, minutes, or even seconds. This sets an upper limit to the size of the engine generating the quasar because it can only be altered as a whole on the timescale that light can travel from one side of the quasar to the other. This flux variability timescale does indeed demonstrate that AGN are generated in a very compact space.

Originally Posted by Pluto

Accretion is the main part, that most papers say creates the main jet.

Yes—where accretion means attracting and gaining mass gravitationally. The massive amounts of energy required of an AGN (including its jets and EMR output) needs an engine capable of delivering serious amounts of energy. The gravitational potential of a supermassive black hole is an hypothesis put forward in the mid 1960's. Observations have agreed with this hypothesis and helped explain the taxonomy of many different astronomical objects (Quasars, radio galaxies, Seyfert nuclei, Blazars, etc.) under one model (supermassive black holes). It really has explained a lot, but there's still a lot to learn about the exact mechanics involved.

Originally Posted by Pluto

The infall flow has not got the capacity to create jets that are able to reach speeds close to the speed of light,

Do you have a source for this?

A supermassive black hole is more efficient at converting mass into energy than more traditional stellar processes:

Since the early 1960s there was much speculation about how the observed luminosities could be produced within such a small region. Thermonuclear reactions, which have efficiencies of 0.7% at best (in the case of fusion of H into He), were quickly eliminated...

...Epsilon is the efficiency of conversion of mass into energy, and depends on the spin of the black hole, varying between 6% if the black hole is not spinning, and 42% if the black hole is maximally spinning.

http://arxiv.org/PS_cache/astro-ph/p.../0411247v1.pdf

In 1963, the specific calculations were originally done by Edwin Salpeter (who by the way, just died about a month ago)

Accretion of Interstellar Matter by Massive Objects - E Salpeter

This work (and a lot of subsequent work) shows that the extreme gravitational potential of a SMBH provides an energy source capable of driving AGN characteristics including relativistic jets.

The specific models of jets based on accretion have been verified (or at least supported) by recent observations,

The inner jet of an active galactic nucleus as revealed by a radio-to-big gamma-ray outburst

If you don’t have a subscription to Nature, you can read about the study in this Space.com article:

SPACE.com -- Powerful Black Hole Jet Explained

Or, you can request a PDF of the study from the head author, Alan Marscher, at his University web page (it’s the 4th one down):

Alan Marscher: Publications in Scientific Journals

Originally Posted by Pluto

not only that to give it magnetic properties that keep their straight direction for millions of years.

While the characteristics are more complicated than being straight (as Fripro's link above gets into), I understand what you mean, that the jet is always pointed in the same general direction. If the black hole is rotating though, I don't see why the jets would be pointed anywhere but perpendicular to the accretion disc.

Originally Posted by Pluto

As for matter been sucked in to black holes. I will give you information of the growth of compact bodies from Neutrons, to quarks composites and Nutrino ultra dense matter.

Matter being pulled into black holes isn’t the problem. The problem is claiming that matter that’s pulled into (inside) the black hole, is “then ejected” from it. Such a claim requires that matter be ejected from inside the black hole’s event horizon. This is impossible by the very definition of a black hole and all theory describing it.

A black hole is a region of space in which the gravitational field is so powerful that nothing, including electromagnetic radiation (e.g. visible light), can escape its pull after having fallen past its event horizon.

Black hole - Wikipedia, the free encyclopedia

Theorizing about compact, degenerate matter doesn’t change this. A body made of electron degenerate matter that is over the Chandrasekhar limit (~1.4 solar masses) will collapse. A body made of neutron degenerate matter over the Tolman-Oppenheimer-Volkoff limit (~2.5 solar masses) will collapse. We can then suppose some new degenerate matter, such as quark degenerate matter, preon degenerate matter, and string degenerate matter. We can suppose limits for each saying quark stars collapse at 30 solar masses and preon stars collapse at 60 solar masses. But, this line of thinking does not help matter escape a supermassive black hole. The black hole at the center of the Milky Way has 3.7 *million* solar masses. Even if it has some strange and exotic unknown degenerate matter inside it, its escape velocity will still be larger than the speed of light. In order for anything to escape it, it would need to go much, much faster than the speed of light which is not possible.

Jets therefore cannot originate from inside the black hole unless it is breaking some of the best known laws of physics. And, there’s no need to propose new laws of physics or breaking the laws of physics. The best theory of AGNs suggest that jets originate from the accretion discs collimated by magnetic field lines and ejected without ever crossing the event horizon and observations are tending to agree.

Originally Posted by Pluto

In actual fact they dance together, the driver is the ultra dense plasma (BH), the disc surrounding is probably a Neutron matrix and amongst other degenerate matter surrounding.

WE will never know because we will never be able to see within.

We’ll never be able to see in the event horizon of the black hole, but we can make observations of the accretion disc. X-ray spectroscopy (of iron, for example) has provided very good evidence of the accretion disc’s structure and relativistic nature not far (a few Schwarzschild radii) from the black hole.

Originally Posted by Pluto

So! the rule that nothing can escape from a black is in my opinion wrong.

If you agree that we cannot see in a black hole then you’ve come to a troublesome conclusion that light cannot escape a black hole but massive particles can (unless I've somehow misunderstood you). Such is not part of any recognizable physics of which I’m aware.

Originally Posted by Pluto

The ultra dense degenerate matter that forms the so called black hole is able to form the most powerful magnetic vortex to eject matter through it at close to the speed of light and because of the magnetic fields, the matter not to be affected by the extreme gravity of the so called black hole.

"Through it"? "not affected by gravity"? Is this a theory that you're aware of in the scientific community, or is this your idea?

~modest