Accretion Disc Same as a Spiral Galaxy??????

Dave I did not say same,but have some sameness. I think elliptical
galaxies are formed by two spiral galaxies merging. If it makes you feel
any better I read it. If a blackhole is in the center of every spiral
galaxy,and all blackholes that are devouring a star by creating an
accretion in space around them. I see a sameness and to me Jim's
pictures gave me this idea. I see lots of my ideas 25 years ago in books
I have read just recently. Dave why don't you wait,and read about it.
Thinking on your own is just as important than just reading.
Now if two spiral galaxies have completely merged with each other,my
thoughts are their cores might contain two blackholes revolving around
each other,and that means to me some elliptical galaxies have a double
core.(so where is the book to throw at me?) Bert

During a perfect moment of peace at Sun, 22 Jun 2003 13:30:25 -0400
(EDT), (G=EMC^2 Glazier) interrupted with:

Dave I did not say same,but have some sameness. I think elliptical
galaxies are formed by two spiral galaxies merging. If it makes you feel
any better I read it.

I've read many things over the years, many of them turned out to be
wrong or later evidence showed the idea was wrong. Lifes like that I
find.

But on the point, if Ellipticals are formed by Spiral mergers you
would expect to see,

1. More spirals then ellipticals in the young Universe
2. Large numbers of Spirals merging at some point. There are more
Ellipticals than Spirals on average IIRC.

I'm fairly confident the observational evidence is against this. What
is thought is that the massive Ellipticals in clusters (E0 types) are
formed by mergers very early on. But again, no observational evidence.

If a blackhole is in the center of every spiral
galaxy,and all blackholes that are devouring a star by creating an
accretion in space around them. I see a sameness and to me Jim's
pictures gave me this idea.

Ideas are good but it best to fully understand as many facts about the
idea as possible. If only to reject things that do not pass first
base.

I see lots of my ideas 25 years ago in books I have read just recently.

Must be nice for you reading up on Brahe and Kepler.

Dave why don't you wait,and read about it.

You seem to have inferred a lot about my character from very little
information about me. How was that?

Thinking on your own is just as important than just reading.

Couldn't agree more. But it helps to fully understand all that is
known about a subject before waxing lyrical about it. My experience is
that what people think are entirely new ideas have been debated and
mulled over before. To have a truly original idea you must first
become fully cognisant of all previous ideas, facts and data. That is
why reading around a topic is very important.

Now if two spiral galaxies have completely merged with each other,my
thoughts are their cores might contain two blackholes revolving around
each other,and that means to me some elliptical galaxies have a double
core.(so where is the book to throw at me?) Bert

I believe the Hubble recently imaged something similar in colliding
Spirals. But the survey that found all galaxies have central black
holes does not support the idea.

A spiral galaxy gets its disc shape revolving around a black hole. A
accretion disc gets its shape revolving around a blackhole. Bert

Bert posted:

A spiral galaxy gets its disc shape revolving around a black hole.

No Bert. A spiral galaxy gets its shape from the intital conditions of
its formation. The spiral form has NOTHING to do with a black hole
being in the middle (many galaxies don't have a central black hole).
The spiral arms are thought to be formed by density waves propagating
around the galaxy which enhance star formation as the wave moves through
the gas. You are confusing some bad artwork of the accretion disk with
the form of a spiral galaxy. Accretion disks don't look like spiral
galaxies or stuff flowing down the drain.

David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

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"David Knisely" wrote...
in message ...

Bert posted:

A spiral galaxy gets its disc shape revolving around a black hole.

No Bert. A spiral galaxy gets its shape from the intital conditions of
its formation. The spiral form has NOTHING to do with a black hole
being in the middle (many galaxies don't have a central black hole).
The spiral arms are thought to be formed by density waves propagating
around the galaxy which enhance star formation as the wave moves through
the gas. You are confusing some bad artwork of the accretion disk with
the form of a spiral galaxy. Accretion disks don't look like spiral
galaxies or stuff flowing down the drain.

David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 10th Annual NEBRASKA STAR PARTY *
* July 27-Aug. 1st, 2003, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

'Lo David --

I recently read that scientists are now fairly certain that most, and
possibly even all, galaxies have supermassive black holes at their
centers... even spherical and oddly shaped galaxies. I agree that
accretion disks are different beasts from spiral galaxies (our galaxy
is believed to have a tight accretion disk in addition to the billions
of stars spiraling around the central black hole), and yet the more i
think about it, the more sense it makes that supermassive black
holes would be galaxy hubs... and perhaps even bigger and bigger
"ultramassive" black holes are at the centers of galaxy clusters and
superclusters as well?

http://www.mpifr-bonn.mpg.de/div/the...etdisksbh.html

This link may also clarify the difference for Herb?

Also found this interesting tidbit while searching (it's from nearly two
years ago, so you may have already read about it)...

http://www.space.com/scienceastronom...le_010913.html

happy days and...
starry starry nights!

--
Kiss the girls and make them cry
Just like old Georgie Porgy--
In math base-2 brings Love to mind,
Base-10 stirs up an Orgy!

Paine Ellsworth

David K. wrote (responding to Bert):

You are confusing some bad artwork of
the accretion disk with the form of a
spiral galaxy. Accretion disks don't look
like spiral galaxies or stuff flowing down
the drain.

David, if you were to look at a Seyfert (active core) galaxy's central
engine up close, there would be some credance to the "stuff flowing down
the drain" pattern. As the inbound material from the accretion disk
approaches the BH, it must bifurcate into _two_ flows before riding 'up
and over' the central hump, then assume the form of two intake vortices
like 'bathtub drains' plunging head-on into the poles of the BH.
The essential bipolarity of every (spinning) BH has
been discussed a number of times here. A Seyfert galaxy has incandescent
superheating material falling in, giving a visual of the actual flow
pattern. A quasar in close-up would show a greatly ramped-up version of
the same bipolar flow as it was back in the fuel-rich early universe.
For some reason the mainstream suffers a block
concerning the essential biplarity of BHs and the fact that they _must_
be gravitically bipolar because of their very high spin rate.
Bipolar jets are sometimes seen associated with
certain massive objects in deep space. Their polar inflows have to be
superhot electric plasmas, each generating an enormous magnetic field as
it accelerates into the pole, setting up large-scale magnetohydrodynamic
(MHD) effects. Slower, lower-energy material in the infall is captured
and 'backfired' by the reverse-EMF (reverse-electromotive force) effect
(the same principle by which AC induction motors run). The backfired
material forms the familiar ejecta plumes or jets, seen shooting out on
the polar axis at relativistic speeds. If these bipolar jets aren't the
signature of bipolar accretion, I don't know what is.

oc

Hi there. You posted:

I recently read that scientists are now fairly certain that most, and
possibly even all, galaxies have supermassive black holes at their
centers... even spherical and oddly shaped galaxies.

No, many smaller galaxies (especially the irregulars) do not have
central supermassive black holes (and in the universe, a majority of
galaxies may be such dwarfs). There are undoubtedly black holes in all
galaxies, and big ones near the center of many large ones. Some
moderate to large galaxies clearly have them (ours has more than one in
the nuclear region around the galactic core and possibly one at the very
center), but others don't. Some ellipticals which formed from the
merger of two large galaxies may have two big black holes in orbits
around the eventual center, but may not have one at the precise center.
Having a black hole is not a requirement for a galaxy, and certainly is
not a requirement for a galaxy to be a spiral, which is where Bert seems
to be getting screwed up. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 10th Annual NEBRASKA STAR PARTY *
* July 27-Aug. 1st, 2003, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

David Knisely wrote:

No, many smaller galaxies (especially the irregulars) do not have
central supermassive black holes (and in the universe, a majority of
galaxies may be such dwarfs). There are undoubtedly black holes in all
galaxies, and big ones near the center of many large ones. Some
moderate to large galaxies clearly have them (ours has more than one in
the nuclear region around the galactic core and possibly one at the very
center), but others don't. Some ellipticals which formed from the
merger of two large galaxies may have two big black holes in orbits
around the eventual center, but may not have one at the precise center.
Having a black hole is not a requirement for a galaxy, and certainly is
not a requirement for a galaxy to be a spiral, which is where Bert seems
to be getting screwed up. Clear skies to you.

Note that while the Magellanic Clouds are irregular, and with little
if any central condensation or 'disc', they show traces of spiral
structure including a faint 'arm' connecting the two.

--Odysseus

Hi Painius Thank you. The link you posted had this to say that goes
with what I posted. "As one considers a galaxy as a giant accretion
disk. I think in every direction,and look for sameness. Bert

Hi David
You wrote,
The accretion disk doesn't really show
the 3-D "down the drain" effect depicted
in some bad TV science shows....

Yeah, I was just trying to point up that if the central engine were
examined in extreme close-up, the BH must be gravitically bipolar due to
its extreme spin rate- a fact that seems to be lost on the mainstream.
They continue to model BH accretion on a 'normal' stellar body's
accretion- i.e, a monopolar flow falling "onto" the object instead of a
bipolar flow going _into_ its poles. Twin, mirror-imaging "down the
drain" vortices _would_ be seen going into the BH's poles. This bipolar
flow, sgain, would be apparent only in extreme close-up of the central
BH.

And bipolar jets, whether powered by MHD effects and a reverse-EMF
"shear" I described or some other mechanism, are certainly the signature
of bipolar accretion.
The just-released story on the millisecond pulsar and
gravity waves shows the pulsar to have a high spin rate, though nowhere
near as high as a BH's would be. But is spin should be sufficient to
show the beginnings of gravitic bipolarity.

oc