Astounding conclusion is now virtually inescapable: Black Hole at the center of the Milky Way
Sam Wormley
http://antwrp.gsfc.nasa.gov/apod/ap051023.html
Explanation: At the center of our Milky Way Galaxy lies a black hole
with over 2 million times the mass of the Sun. Once a controversial
claim, this astounding conclusion is now virtually inescapable and
based on observations of stars orbiting very near the galactic center.
Using one of the Paranal Observatory's very large telescopes and a
sophisticated infrared camera, astronomers patiently followed the orbit
of a particular star, designated S2, as it came within about 17
light-hours of the center of the Milky Way (about 3 times the radius of
Pluto's orbit). Their results convincingly show that S2 is moving under
the influence of the enormous gravity of an unseen object that must be
extremely compact -- a supermassive black hole. This deep near-infrared
image shows the crowded inner 2 light-years of the Milky Way with the
exact position of the galactic center indicated by arrows. The ability
to track stars so close to the galactic center can accurately measure
the black hole's mass and perhaps even provide an unprecedented test of
Einstein's theory of gravity as astronomers watch a star orbit a
supermassive black hole.
Eric Gisse
I wonder if 17 light hours within somewhere between 1.5 and 3 million
solar masses is considered a strong field or not.
Nick
there is a black hole at the center of EVERY galaxy.
This supercompact object is the extreme of gravity.
But there are no black holes. The extreme of gravity
is only a Dark Hole.
I can prove there are no "black" holes.
Mitch Raemsch
mme...@cars3.uchicago.edu
with 3 million solar masses you get a field 2-300 times this of the
Sun at Earth orbit, 20-30 time this of the Sun at Mercury's orbit.
Perhaps not dramatic but should be noticeable.
Mati Meron | "When you argue with a fool,
me...@cars.uchicago.edu | chances are he is doing just the same"
Llanzlan Klazmon
@o13g2000cwo.googlegroups.com:
> This is not new information. It has been believed that
> there is a black hole at the center of EVERY galaxy.
>
> This supercompact object is the extreme of gravity.
> But there are no black holes. The extreme of gravity
> is only a Dark Hole.
A rose by any other name?
Klazmon.
Llanzlan Klazmon
@attbi_s71:
More recent observations by the VLBA show the object fits within half the
diameter of the Earth's orbit. I.e the 4 million solar masses lie within an
object less than one au in diameter:
http://www.nrao.edu/pr/2005/sagastar/
Klazmon.
Ron Baker, Pluralitas!
"Sam Wormley" <swor...@mchsi.com> wrote in message
news:Xidcf.532234$_o.173911@attbi_s71...
Interesting.
It makes me wonder if this is more or less a coincidence
or if black holes are seeds for universes.
I also wonder how precisely we can determine
the center of the galaxy.
(And it seems interesting that the center is not
obscured by intervening stars and other matter.)
Interesting.
--
rb
Sam Wormley
Longer wavelengths better penetrate gas and dust.
Ron Baker, Pluralitas!
"Ron Baker, Pluralitas!" <sto...@bellsouth.net.pa> wrote in message
news:4Qecf.4657$Hs....@tornado.socal.rr.com...
<snip>
> It makes me wonder if this is more or less a coincidence
> or if black holes are seeds for universes.
I meant 'galaxies', not 'universes'.
--
rb
CWatters
"Llanzlan Klazmon" <Kla...@llurdiaxorb.govt> wrote in message
news:Xns9709AD576F8D4Kl...@203.97.37.6...
> More recent observations by the VLBA show the object fits within half the
> diameter of the Earth's orbit. I.e the 4 million solar masses lie within
an
> object less than one au in diameter:
>
> http://www.nrao.edu/pr/2005/sagastar/
>
> Klazmon.
When they say a BH would "produce a distinctive 'shadow' " do they mean the
star is orbiting the BH in the same plane as we are? In other words are they
looking for the BH to eclipse the star?
Do we know how long it takes to orbit the BH or is that unknown?
Happy Hippy
'Black Holes' at the center of galaxies are the same as
nuclei at the center of atoms.
John
Galaxy Model for the Atom
(Quasars are the same as photons.)
http://users.accesscomm.ca/john/
Ian Parker
the Milky Way. The next question is about aggregation in the early
Universe. Did supermassive black holes come first with gas and dust
subsequently condensing round the BH? Or did black holes and galaxies
form at the same time?
Dr Photon
>At the Center of the Milky Way
> http://antwrp.gsfc.nasa.gov/apod/ap051023.html
[snip]
on their linked page
http://www.eso.org/outreach/press-rel/pr-2002/pr-17-02.html
it says
"The solid curve is the best-fitting elliptical orbit - one of the foci
is at the position of SgrA* ."
However, looking at their picture
http://www.eso.org/outreach/press-rel/pr-2002/phot-23c-02-normal.jpg
it doesn't seem to be. The foci should be along the major axis
somewhere, surely, even if the ellipse is tilted wrt our line of sight.
And if it's experimental error, then their "17 light hour" claim is
suspect, so what gives?
br
Ben Rudiak-Gould
> When they say a BH would "produce a distinctive 'shadow' " do they mean the
> star is orbiting the BH in the same plane as we are? In other words are they
> looking for the BH to eclipse the star?
Interestingly enough, it's not possible for a black hole to eclipse
anything. In the Schwarzschild geometry, there's a null geodesic between any
two points outside the event horizon, so you can see any object outside the
event horizon from any vantage point. If a large black hole passed in front
of the sun, the sun would appear to flow around it on either side. It may be
that this distortion is what they're looking for.
A neat paper which illustrates this is hep-th/9409089 (see page 6).
-- Ben
Happy Hippy
Do chickens come first and then eggs?
What time are you referring to? The
beginning of? ROTFL
John
Galaxy Model for the Atom
Michael J. Strickland
This mass could be accounted for by an object with an average density equal
to our sun occupying a radius approximately equal to that of Venus's orbit.
If its radius were slightly larger, it would not have to be a black hole.
--
---------------------------------------------------------------
Michael J. Strickland
Quality Services quali...@att.net
703-560-7380
---------------------------------------------------------------
Eric Gisse
If we can see the star being 'ecclipsed', for my lack of a better word,
could we perhaps tell if the hole is static or rotating? A rotating
black hole has to give a few effects at that range, I would assume.
>
> -- Ben
Sam Wormley
>
> If we can see the star being 'ecclipsed', for my lack of a better word,
> could we perhaps tell if the hole is static or rotating? A rotating
> black hole has to give a few effects at that range, I would assume.
>
Evidence for Frame Dragging Black Holes
http://antwrp.gsfc.nasa.gov/apod/ap971107.html
GRO J1655-40: Evidence for a Spinning Black Hole
http://antwrp.gsfc.nasa.gov/apod/ap041226.html
Llanzlan Klazmon
news:1131572826.9...@g43g2000cwa.googlegroups.com:
The "shadow" mentioned in the article I referenced has nothing to do with
the black hole eclipsing a star. Sam's article referred to a star being
tracked in its' orbit around Sgr A - closest approach 17 light hours. The
VLBA article I posted which mentions detecting the black hole's "shadow" is
talking about microwave radio emissions from gas orbiting Sgr A at less
than one au or eight light minutes. They don't explain what they mean by
this shadow effect they hope to detect using the yet to be completed ALMA
array.
Klazmon.
carlip...@physics.ucdavis.edu
[...]
> The "shadow" mentioned in the article I referenced has nothing to do with
> the black hole eclipsing a star. Sam's article referred to a star being
> tracked in its' orbit around Sgr A - closest approach 17 light hours. The
> VLBA article I posted which mentions detecting the black hole's "shadow" is
> talking about microwave radio emissions from gas orbiting Sgr A at less
> than one au or eight light minutes. They don't explain what they mean by
> this shadow effect they hope to detect using the yet to be completed ALMA
> array.
Look at http://www.mpifr-bonn.mpg.de/staff/hfalcke/bh/sld1.html for a
more detailed explanation of the "shadow."
Steve Carlip
Eric Gisse
That is the best overview of Sgr A* I have seen yet. Fascinating!
>
> Steve Carlip
Ian Parker
self gravitating. The BH is only about 0.5% of total galactic mass.
Could you have galaxies without BHs? On a first consideration of
gravity the answer would be yes. However observation tells us
otherwise.
Why are there no galaxies without BHs?
Is a BH a vital part of condensation?
Is a galaxy stable without a BH? Here numerical simulations would help
us.
Can a galaxy stably form without a BH?
These are really the questions that should be asked.
Llanzlan Klazmon
news:dku98u$mur$1...@skeeter.ucdavis.edu:
Thanks Steve. A very informative site.
Klazmon.
john_r...@sagitta-ps.com
Hey, no - You were most likely correct the first time!
Looking at the image at http://antwrp.gsfc.nasa.gov/apod/ap051023.html
I wonder if the arrows shouldn't be moved at tad "south west" to the
centre
of the obvious looking ring of light spots (stars?).
Might be just coincidendal alignment of stars, but do you notice also a
line
of light sources, extending again "south westerly" and apparently
increasing
in size the further from the centre of the ring?
Happy Hippy
A galaxy is a *structure*.
An organized structure.
It is not a blob of stars that glommed together.
Stars have a lifetime.
They are born, radiate, grow old and die.
That's like saying a human is a bunch of
cells that gravitated together.
John
hanson
news:4374bfea$1...@news.accesscomm.ca...
> Ian Parker wrote:
>> A Galaxy is NOT an atom. It is a collection of stars and dust which is
>> self gravitating. The BH is only about 0.5% of total galactic mass.
>> Could you have galaxies without BHs? On a first consideration of
>> gravity the answer would be yes. However observation tells us
>> otherwise.
>> Why are there no galaxies without BHs?
>> Is a BH a vital part of condensation?
>> Is a galaxy stable without a BH? Here numerical simulations would help us.
>> Can a galaxy stably form without a BH?
>> These are really the questions that should be asked.
>>
> A galaxy is a *structure*.
> An organized structure.
> It is not a blob of stars that glommed together.
> Stars have a lifetime.
> They are born, radiate, grow old and die.
> That's like saying a human is a bunch of
> cells that gravitated together.
> John
>
:::: A galaxy is a *structure* ... and so is an atom or molecule etc.
:::: An organized structure ... and so is an atom or molecule etc.
:::: It is not a blob of stars that glommed together... neither is an atom
:::: Stars have a lifetime ... and so does an atom or molecule etc.
:::: They are born, radiate, grow old and die ... and so does an atom..
:::: That's like saying a human is a bunch of
:::: cells that gravitated together.... and they do....
There is self-similarity in nature... in/over all realms... delimited by
scaling laws and domained numerically by N_A. Nature is discrete.
See, hear, smell, feel and touch it. Then classify it with your mind.
ahahahaha.... ahahahanson
Sam Wormley
> That's like saying a human is a bunch of
> cells that gravitated together.
>
> John
Not gravitated, but held together by electromagnetism.
Jeff_Relf
Hi Ha_Ha_Hanson, Happy_Hippy and Ian_Parker,
Although glaxies, rats and photons all look purposful and discrete to us,
it's merely notional... not physical.
Likewise, randomness and freedom are notional.
Glomming_On, i.e. consumption, only ever happens in the Short_Term,
in the Long_Term everything simply dissipates.
Births and deaths are notional, and mostly the product of outside forces.
If all variables could be known, and nothing was notionally random,
then it'd be clear that nature is composed of 5 _Spatial_ dimensions,
Space_Time_Entropy... where entropy, like time, is static and parochial.
It's just that, at the level of rats and photons,
the complexity is simply far too great to readily see it.
Happy Hippy
> :::: An organized structure ... and so is an atom or molecule etc.
> :::: It is not a blob of stars that glommed together... neither is an atom
> :::: Stars have a lifetime ... and so does an atom or molecule etc.
are regenerated by that Black Hole into charged plasma that becomes
more stars. The Black Hole (protons and neutrons) remains an entity
tremendously longer than its ever-regenerating stars.
> :::: They are born, radiate, grow old and die ... and so does an atom..
which it is a part falls into the galactic center. It's electron(s)
by that time have regenerated themselves zillions of times.
(It could, however, be unlucky enough to encounter a man-made
atom-smasher.)
> :::: That's like saying a human is a bunch of
> :::: cells that gravitated together.... and they do....
> There is self-similarity in nature... in/over all realms... delimited by
> scaling laws and domained numerically by N_A. Nature is discrete.
> See, hear, smell, feel and touch it. Then classify it with your mind.
> ahahahaha.... ahahahanson
>
>
>