Is it just me, or, doesn't it seem intuitive, that Super Massive Black
Holes create H2 from light...?  This could be the memory in the
light/mater equation, hmmm...

Well- exactly why would that be so? You say it's intuitive. But you
need more than intuition to cough up some hard numbers. Do a
calculation.

It is intuitive, if it is spinning at close to the speed of light,
that should counter the gravity, and explain the event horizon
paradox...  Just call me crazy...

Hmmm. What is the event horizon paradox you mention?

"event horizon paradox" - Newton would have loved Black Holes, the
more it eats the weaker it's gravity.  At least, that is what has been
reported...

"event horizon paradox" - Newton would have loved Black Holes, the
more it eats the weaker it's gravity.  At least, that is what has been
reported...

   That's not a paradox. The more massive the black hole, the larger
is its Swartzchild radius, and thus the greater the event horizon's
distance from the mass center. What's dropping off is the acceleration
due to gravity at the event horizon, which is entirely consistent even
with Newtonian gravity:

F = GMm/r^2

   The escape velocity at the horizon remains infinitesimally larger
than c, and the total gravitational flux through the event horizon
indeed grows with the hole's mass. This is not a mystery.

You don't actually expect me to buy that: "The escape velocity at the
horizon remains infinitesimally larger than c", unless, the speed of
light is infinitesimally smaller than c...   and which part of the
word "CONSTANT" don't I understand...?   TIA

>You don't actually expect me to buy that: "The escape velocity at the
horizon remains infinitesimally larger than c"

I thought it *was* C, but that's a side issue - the escape velocity is
just a value calculated from the mass and the diameter of the body in
question, and isn't limited by C.  Actually travelling at the escape
velocity is a completely different matter!

>Newton would have loved Black Holes, the more it eats the weaker it's gravity.

No, the weaker the tidal forces, as per QED100's explanation.  

Ian G.

The escape velocity *at* the horizon cannot be pecisely c, otherwise
light would be able to escape at that radius. It has to be greater
than c in order for it to be literally a black hole. So there's a
radius at which escape velocity is c, and anything closer is within
the event horizon, trapped.

Can we say with certainty yet that Super Missives have a fixed size
limit from which they radiate...?   -or-   Am I all wet here too...?

Well, in general relativity there's no size limit. Mass can fall in
without limit and the event horizon just keeps getting larger. As for
the Hawking radiation just barely above the horizon, the larger the
hole, the less powerfully it radiates. But there's no known limit at
which it stops radiating. It just keeps getting less luminous with
size.

With this in mind, it becomes evident that when a hole gets to some
critical size, its own Hawking radiation will be at equilibrium with
the ambient radiation falling into it from space. Hawking radiation
carries away mass, making the hole smaller. If this is offset by the
influx of background rdaiation, the mass of the hole can be
maintained. If the hole is massive enough, it'll actually recieve more
radiation than it emits, and so will grow steadily on that diet alone.

>The escape velocity *at* the horizon cannot be pecisely c, otherwise
light would be able to escape at that radius.

Is that true for a relativistic model of a black hole? The geometry
inside a black hole is completely different from the outside - for a
photon trying to escape, the event horizon's receding at c so it can
never be crossed.

Ian G.

OK, Can we agree that the target is C, and the event horizon
oscillates around C, with extraordinary events can occurring with each
oscillation...?

Don't forget that the event horizon is not a pleasant place to be. In
fact isn't there a rule that information itself is destroyed at the
limit, and once your past the event horizon your going to hit it
sooner or later. (At least unless you spaceship has a particularly
powerful hyperdrive.)
Actually I have a problem with the event horizon in a way - doesn?t
gravity itself only travel at the speed of light? - oh dear.

To iang-ga,

   Yes, you're right. As I understand it, spacetime within the hole
changes from 3 spacelike/1 timelike to 1 spacelike/3 timelike, so that
escaping the event horizon becomes equivalent to traveling
unambiguously backward through time. (Or, as you say, the horizon is
receding at c.)

   But still, a photon obviously may escape from the neighborhood of a
gravitating mass as close as the radius at which escape velocity
exactly equals c. (Though it'll be increasingly redshifted the closer
to that distance from which it starts.) Anything closer is trapped.
But GR is a continuum theory, and in context the difference between an
escape velocity of c and "just barely" more than c carries some
ambiguity. So I say that escape velocity exactly at the event horizon
must be "infinitesimally" greater than c.

I would even venture to say that the oscillation occurs between two
states: "Galaxy formation" and "Quasar"...

BTW, is the Milky Way eating the Andromeda galaxy, -or- vise versa...?

> But still, a photon obviously may escape from the neighborhood of a
gravitating mass as close as the radius at which escape velocity
exactly equals c.

Sorry, but I have to go back to the event horizon receding at c.  The
photon's moving at the same velocity, so it stays at the event horizon
- it isn't captured in the sense that it enters the black hole, but it
doesn't escape either.

I was talking to an astronomer this evening, about something
completely different, and she came out with the comment "If common
sense tells you one thing and the maths tells you something completely
different, go with the maths!"

Ian G.

"I would even venture to say that the oscillation occurs between two
states: "Galaxy formation" and "Quasar"..."

   I'm not quite sure what you mean by an event horizon oscillating
around c. But one thing is known, that quasars are all quite distant.
This means that there are no quasars in the modern observable
universe. The predominant view among astronomers right now is that
quasars were a phase in the typical evolution of a galaxy.

"BTW, is the Milky Way eating the Andromeda galaxy, -or- vise versa...?"

   Well, it's not necessarily that one is eating the other. They're
just a pair of massive bodies interacting gravitationally. It's like
the question of the difference between a planet & a moon. There's no
important difference; A so-called planet & its moon are just two
gravitating masses. For example, our moon doesn't orbit while Earth
resides fixated at the center. Both Earth and the Moon orbit their
mutual mass center, which is defined by the relative contributions of
the two bodies. In fact, the Moon orbits partially Earth's mass,
partially its own mass. And the same is true for Earth.

   And so the Milky Way & Andromeda are just gravitating toward each
other, and they may eventually meet at their mutual mass center. They
will eat each other: cosmic 69. >:)

Hydrogen is not created directly in or on a black hole or a Super
Massive Black Hole.