Mysterious gas cloud that was supposed to enter Milky Way centralblack hole turned out to be a couple of merging stars instead!

Yousuf Khan wrote...

We were supposed to see a big fireworks display when our quiet black hole turned itself into a mini-quasar once again for a brief period of time. Looks like that never happened, and now they figured out why. The gas cloud that was supposed to drop through the gullet of the black hole was not a gas cloud after all, it was a pair stars that have just recently merged with each other.

it seems that if stars merge, they inflate to a gigantic size before it settles down again. This star seems to be in the expansion phase.

Yousuf Khan

Mysterious G2 cloud near black hole identified
Astronomy.com http://www.astronomy.com/news/2014/1...ole-identified

The authors abstract says the object should have been disrupted as it neared periapase.
That is... it *should* have been disrupted *IF* there was a black hole. But it wasnt. So the
only possibility they can think of, that is consistent with the assumption of the existence of said
black hole...is to assume its a merged double star system. Of course they havent actually
seen the star or merged star system. All thats observable is whats previously been observed.
Which is a gaseous object orbiting the center.
So this doesnt prove there is a black hole at the center of our galaxy . All this proves
is that rather than admit the object didnt react as expected and not confirm the existence
of a black hole....The authors have proved they would rather make up the imaginary existence
of a merged double star system just to get them off the hook for erroneously predicting
the existence of a black hole.
Pseudoscience at its best as usual. This time courtesy of Keck.

On 11/11/2014 7:45 AM, sean wrote:
The authors abstract says the object should have been disrupted as it neared periapase.
That is... it *should* have been disrupted *IF* there was a black hole. But it wasnt. So the
only possibility they can think of, that is consistent with the assumption of the existence of said
black hole...is to assume its a merged double star system. Of course they havent actually
seen the star or merged star system. All thats observable is whats previously been observed.
Which is a gaseous object orbiting the center.
So this doesnt prove there is a black hole at the center of our galaxy . All this proves
is that rather than admit the object didnt react as expected and not confirm the existence
of a black hole....The authors have proved they would rather make up the imaginary existence
of a merged double star system just to get them off the hook for erroneously predicting
the existence of a black hole.
Pseudoscience at its best as usual. This time courtesy of Keck.

Whether or not the gas cloud was disrupted is not a proof against the
existence of a blackhole at the center of the Milky Way. Just the fact
that this object swung around the central object is proof that the
central object is a blackhole. What else could it be with that much mass
and that much speed?

Yousuf Khan

Yousuf Khan wrote...
Whether or not the gas cloud was disrupted is not a proof against the existence
of a blackhole at the center of the Milky Way. Just the fact that this object swung
around the central object is proof that the central object is a blackhole.

For starters I personally dont agree with the theoretical concept of a BH and
correctly predicted that there would be no fireworks.
What I was pointing out was that the prediction of a black hole tearing
apart the gas cloud *failed*, and the spin being put out now by Keck researchers
that somehow this failure to detect a black hole is proof positive that there is
a black hole at the center of the galaxy is ...pseudoscience. How can a theory
that fails in its predictions be deemed a success?
Their argument is that its not a gas cloud but a star shrouded by a gas cloud.
Nice idea but no proof is offered. The abstract admits its an assumption
not a confirmed observation.
Why cant a group of objects rapidly rotate around a common central point without
a black hole? I dont see any science that says this is impossible. There are rotating
pairs of stars that can do this trick without central black holes. Im sure you can
scale this rapid rotation up to groups of stars and gas without using central black
holes.
Dont forget that current theory on galaxy formation and rotation speeds
is a failure as it fails to model the observed rotation curves. The disc appears to
rotate too fast, because, when the calculations are made all the disc mass in the
calculation is erroneously assumed, for expedience, to be at the center of the disc.
Spread the mass more evenly around the disc and you get a model that does
match the observed rotation curves.

Dear sean:

On Thursday, November 13, 2014 7:29:49 AM UTC-7, sean wrote:
....
What I was pointing out was that the prediction of
a black hole tearing apart the gas cloud *failed*,

Well, comets are "torn apart", but manage to reform. And we cannot see all that well, that close in.

and the spin being put out now by Keck researchers
that somehow this failure to detect a black hole is
proof positive that there is a black hole at the
center of the galaxy is ...pseudoscience.

.... or just noise.

How can a theory that fails in its predictions be
deemed a success? Their argument is that its not
a gas cloud but a star shrouded by a gas cloud.
Nice idea but no proof is offered.

Cloud or star + cloud, still would be cloudy.

Why cant a group of objects rapidly rotate around
a common central point without a black hole?

The closest object in orbit gets within 980 AU, with a central mass of 4 million solar masses, and there are no surface emissions, such as we get form neutron stars.

I dont see any science that says this is impossible.

No star, or collections of stars, that massive, can be that small.

There are rotating pairs of stars that can do this
trick without central black holes. Im sure you can
scale this rapid rotation up to groups of stars and
gas without using central black holes.

Nope. Not and get nice elliptical orbits, unless the mass center is very concentrated.

Dont forget that current theory on galaxy formation
and rotation speeds is a failure as it fails to
model the observed rotation curves. The disc appears
to rotate too fast, because, when the calculations
are made all the disc mass in the calculation is
erroneously assumed, for expedience, to be at the
center of the disc.

False. The luminosity is assumed to be proportional to total luminous and non-luminous mass. We know the center is swept clear, and the central stars are light days away from each other... stellar wind and tidal effects will dispose of the photosphere of a normal star. Central stars will simply be brighter, and have less gas to absorb and "cool" the spectrum.

Spread the mass more evenly around the disc and
you get a model that does match the observed
rotation curves.

No, you really need more mass. What is more, sheet-distributed-mass does not produce 1/r^2 "attraction", necessary for elliptical, centrally-directed, orbits. Such as we observe in the Milky Way, around its central black hole.

I accept your position that you do not "believe" in black holes, and respect your assertion that failure of this model (the original article) is nothing to be crowed about. Just something else we need to learn about.

Until we get off the planet, and can go see, I guess it does not much matter...

David A. Smith

On Thursday, November 13, 2014 4:55:01 PM UTC, dlzc wrote:
Dear sean:

On Thursday, November 13, 2014 7:29:49 AM UTC-7, sean wrote:


I dont see any science that says this is impossible.

No star, or collections of stars, that massive, can be that small.

Its not clear what you refer to here. What is too small?
There are rotating pairs of stars that can do this
trick without central black holes. Im sure you can
scale this rapid rotation up to groups of stars and
gas without using central black holes.

Nope. Not and get nice elliptical orbits, unless the mass center is very concentrated.

Where is your evidence for groups of stars and gas rotating about a common
central axis not giving eliptical orbits? The only example I can think
of *is* the center of the galaxy . And seeing as there is no obvious sign
of a black hole shredding the gas cloud in question one can assume that the
central stars are orbitting about the center without a black hole. There is
no other example that contradicts this interpretation
Dont forget that current theory on galaxy formation
and rotation speeds is a failure as it fails to
model the observed rotation curves. The disc appears
to rotate too fast, because, when the calculations
are made all the disc mass in the calculation is
erroneously assumed, for expedience, to be at the
center of the disc.

False. The luminosity is assumed to be proportional to total luminous and non-luminous mass. We know the center is swept clear, and the central stars are light days away from each other... stellar wind and tidal effects will dispose of the photosphere of a normal star. Central stars will simply be brighter, and have less gas to absorb and "cool" the spectrum.

I was referring to the calculation using velocity, mass G etc.This assumes the mass to at the center of rotation. This calculation does not match that assumed
from luminosity that you refer to above. The problem is that the calculation for
rotation curves assumes , incorrectly ,that the mass of the disc is at the center of rotation. Like that used for the solar system. The difference with our
solar system is that for us it (m) is mostly in the sun.
Redo the calculation and assume mass is spread across the disc more
evenly and you get flat rotation curves. No need for black holes or dark matter.
Spread the mass more evenly around the disc and
you get a model that does match the observed
rotation curves.

No, you really need more mass. What is more, sheet-distributed-mass does not produce 1/r^2 "attraction", necessary for elliptical, centrally-directed, orbits. Such as we observe in the Milky Way, around its central black hole.

Where is your evidence for sheet distributed mass not giving the observed orbits
in galaxies? AS far as I can tell galaxies are the only example and they give
flat rotation curves, contrary to that predicted by luminosity methods.
Obviously the luminosity method is incorrect. Especially when you read that
its based on an "assumption" that most of the mass is in the central halo.
Assumption is not proof.
I accept your position that you do not "believe" in black holes, and respect your assertion that failure of this model (the original article) is nothing to be crowed about. Just something else we need to learn about.
I dont believe because I know there is no convincing evidence or neccessity for
Black holes. Whereas you believe in black holes even though there is no evidence
nor neccesity for them. Science is based on observation not assumption without evidence.

Dear Sean:

On Friday, November 14, 2014 4:22:20 AM UTC-7, sean wrote:
On Thursday, November 13, 2014 4:55:01 PM UTC, dlzc wrote:
Dear sean:

On Thursday, November 13, 2014 7:29:49 AM UTC-7, sean wrote:


I dont see any science that says this is impossible.

No star, or collections of stars, that massive,
can be that small.

Its not clear what you refer to here. What is too small?

The closest approach of "S2" is 980 AU. With millions of solar masses, not shredded, and on a non-chaotic orbit. Compressed, centralized mass is the only conclusion possible.

There are rotating pairs of stars that can do this
trick without central black holes. Im sure you can
scale this rapid rotation up to groups of stars and
gas without using central black holes.

Nope. Not and get nice elliptical orbits, unless
the mass center is very concentrated.

Where is your evidence for groups of stars and gas
rotating about a common central axis not giving
eliptical orbits? The only example I can think
of *is* the center of the galaxy.

If you remove "stars" and substitute "planets" or "moons", we are observing lots of them.

And seeing as there is no obvious sign of a black
hole shredding the gas cloud in question one can
assume that the central stars are orbitting about
the center without a black hole. There is no
other example that contradicts this interpretation

Sure there is. But I do not intend to convince you, just speak "over your shoulder" to posterity.

Dont forget that current theory on galaxy formation
and rotation speeds is a failure as it fails to
model the observed rotation curves. The disc appears
to rotate too fast, because, when the calculations
are made all the disc mass in the calculation is
erroneously assumed, for expedience, to be at the
center of the disc.

False. The luminosity is assumed to be proportional
to total luminous and non-luminous mass. We know
the center is swept clear, and the central stars
are light days away from each other... stellar wind
and tidal effects will dispose of the photosphere
of a normal star. Central stars will simply be
brighter, and have less gas to absorb and "cool" the
spectrum.

I was referring to the calculation using velocity,
mass G etc. This assumes the mass to at the center
of rotation.

Again, false. It only presume the mass is at a smaller "r" than the object in question. Since we are speaking across the disc of the galaxy now, and not "what is at the very center".

This calculation does not match that assumed from
luminosity that you refer to above. The problem
is that the calculation for rotation curves
assumes , incorrectly ,that the mass of the disc
is at the center of rotation.

Again, false. Keplerian dynamics, Newtonian dynamics, do not requires "at the center", just closer in.

Like that used for the solar system.

The Sun orbits the Sun-Jupiter barycenter. So again, NOT like the solar system.

The difference with our solar system is that
for us it (m) is mostly in the sun. Redo the
calculation and assume mass is spread across
the disc more evenly and you get flat
rotation curves.

We know more mass is needed. We know it is distributed. What we don't understand (for some reason) is why the mass is not as luminous as the center of a galaxy, per unit total mass.

No need for black holes or dark matter.

Dark just means "mystery". It includes:
- normal matter not represented by luminous matter like at the calibration region, and
- calibration errors, and
- exotic matter not yet seen, and not predicted by any Standard Model

Spread the mass more evenly around the disc and
you get a model that does match the observed
rotation curves.

No, you really need more mass. What is more,
sheet-distributed-mass does not produce 1/r^2
"attraction", necessary for elliptical,
centrally-directed, orbits. Such as we observe
in the Milky Way, around its central black hole.

Where is your evidence for sheet distributed
mass not giving the observed orbits in galaxies?

NOT "orbits in galaxies". IS for objects orbiting the center, like "S2". The subject of our discussion is still your disbelief of black holes, specifically the one purported to be at the center of the Milky Way.
http://www.mathpages.com/home/kmath530/kmath530.htm

AS far as I can tell galaxies are the only
example and they give flat rotation curves,
contrary to that predicted by luminosity methods.

Not arguing this. Trying to get back to the thread subject.

Obviously the luminosity method is incorrect.

.... at best.

Especially when you read that its based on an
"assumption" that most of the mass is in the
central halo.

False. Only "closer in".

Assumption is not proof.

Assertions of understanding, do in infer understanding.

I accept your position that you do not
"believe" in black holes, and respect your
assertion that failure of this model (the
original article) is nothing to be crowed
about. Just something else we need to learn
about.

I dont believe because I know there is no
convincing evidence or neccessity for
Black holes. Whereas you believe in black
holes even though there is no evidence
nor neccesity for them. Science is based on
observation not assumption without evidence.

I have challenged, I find the evidence, and I find it compelling.
http://en.wikipedia.org/wiki/Sagitta...ral_black_hole
.... elliptical orbits such as these cannot be met without a central mass, very concentrated.

David A. Smith

On 14/11/2014 6:22 AM, sean wrote:
On Thursday, November 13, 2014 4:55:01 PM UTC, dlzc wrote:
Dear sean:

On Thursday, November 13, 2014 7:29:49 AM UTC-7, sean wrote:


I dont see any science that says this is impossible.

No star, or collections of stars, that massive, can be that small.

Its not clear what you refer to here. What is too small?

He's referring to the central blackhole of course. The level of
concentrated mass at this point cannot be replicated by a large
collection of huge stars in that small amount of space. The central
blackhole has a mass of 4 million solar masses, and has a radius of only
17 solar radii.

There are rotating pairs of stars that can do this
trick without central black holes. Im sure you can
scale this rapid rotation up to groups of stars and
gas without using central black holes.

Nope. Not and get nice elliptical orbits, unless the mass center is very concentrated.

Where is your evidence for groups of stars and gas rotating about a common
central axis not giving eliptical orbits? The only example I can think
of *is* the center of the galaxy . And seeing as there is no obvious sign
of a black hole shredding the gas cloud in question one can assume that the
central stars are orbitting about the center without a black hole. There is
no other example that contradicts this interpretation

Galaxies and globular clusters are examples. Some globular clusters have
no central blackhole, therefore their individual component stars swarm
around a common center of mass, like a swarm of bees. Not quite chaotic,
but not smooth ellipses or circles either, more like twisted rubber-band
ellipses and what not. Then there are other globular clusters which do
have a central blackhole, and they have more ordered orbitals from their
stars.

Galaxy centers are like really huge globular clusters, and since they
might all have central blackholes, they have ordered orbitals there too.
We have not really discovered any galaxies without a central blackhole,
although there might be some, we can't rule that out. If we do discover
one without a central blackhole, then that would be an ideal opportunity
to study what the stars' orbital patterns look like, but it would have
to be a galaxy pretty close to us, because we won't be able to measure
the individual stars around it.

Yousuf Khan

Addendum: just as I spoke, looks like there is a candidate galaxy that
may not have any examples of galaxies without central blackholes, that
are nearby, it looks like I was wrong. We have M33, the Triangulum
galaxy, which is part of our Local Group of galaxies, may not have a
central blackhole. Anyway, it doesn't look like they've been able to do
an exhaustive study of the motion of its central stars yet.

M33: A Galaxy with No Supermassive Black Hole - Abstract - The
Astronomical Journal - IOPscience
http://iopscience.iop.org/1538-3881/122/5/2469/

On 13/11/2014 9:29 AM, sean wrote:
Yousuf Khan wrote...
Whether or not the gas cloud was disrupted is not a proof against the existence
of a blackhole at the center of the Milky Way. Just the fact that this object swung
around the central object is proof that the central object is a blackhole.

For starters I personally dont agree with the theoretical concept of a BH and
correctly predicted that there would be no fireworks.

It was a 50:50 guess and you know it. Whether or not there were
fireworks has nothing to do with what's at the center of the galaxy.
What's at the center of the galaxy is pretty well known, it was this
object G2 that was mysterious.

Dont forget that current theory on galaxy formation and rotation speeds
is a failure as it fails to model the observed rotation curves. The disc appears to
rotate too fast, because, when the calculations are made all the disc mass in the
calculation is erroneously assumed, for expedience, to be at the center of the disc.
Spread the mass more evenly around the disc and you get a model that does
match the observed rotation curves.

Again, galaxy rotation curves don't affect what's at the center of the
galaxy. Whether the rotation curves matched Newtonian gravity or not,
you would still need a blackhole at the center of the galaxy to anchor it.

Yousuf Khan

In article ,
sean writes:
Why cant a group of objects rapidly rotate around a common central
point without a black hole?

They can, but the center of the Milky Way has 4 million solar masses
within a radius of a few thousand astronomical units. If that's not
a black hole, it's something even weirder. A cluster of neutron
stars (as someone else suggested) would fit in the volume, but the
lifetime of such a cluster would be very short. Some objects would
be expelled, and orbits of the rest would decay very rapidly because
of gravitational radiation. Also, it's not obvious how such a
cluster could form in the first place. How could neutron stars have
been segregated from the rest of a stellar population?

... current theory on galaxy ... rotation speeds ...
all the disc mass in the calculation is erroneously assumed, for
expedience, to be at the center of the disc.

That's silly. Of course nobody assumes that. Perhaps some press
release used it for an illustration?

The simplest assumption is that mass follows the light distribution
(corrected from 2d to 3d), but a wide variety of other assumptions
have been tried.

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA

On Monday, 17 November 2014 22:26:59 UTC, Steve Willner wrote:
In article ,
sean writes:
Why cant a group of objects rapidly rotate around a common central
point without a black hole?

They can, but the center of the Milky Way has 4 million solar masses
within a radius of a few thousand astronomical units. If that's not
a black hole, it's something even weirder. A cluster of neutron
stars (as someone else suggested) would fit in the volume, but the
lifetime of such a cluster would be very short. Some objects would
be expelled, and orbits of the rest would decay very rapidly because
of gravitational radiation. Also, it's not obvious how such a
cluster could form in the first place. How could neutron stars have
been segregated from the rest of a stellar population?

This is what I was disputing. How do you know the center of the milky
way is 4 million solar masses? (I assume you are referring to sagitarius A*)
My understanding is that this is only an assumption based on rotation
speeds of the observable stars like S2 etc. Maybe the understanding of
what g forces are at work in galaxy cores are incorrect. For instance we
know from rotation curves that the assumption that most of the mass of the
disc is in the core ,assuming estimates based on illumination,... is incorrect.
Obviously the mass of the galaxy is spread much more evenly across the disc
then generally assumed. Maybe assumptions about rotation speeds in the core
are also incorrect. I don't see why one couldn't have the observed
rotational speeds near the center of the core without having to factor
in a Black Hole. We have no other precedence for core behaviour so
its odd we have to assume they behave like the solar system where most of the mass *is* at the center. And one of the points I made in previous posts was
that there are galaxy centers that astrophysists agree don't have black
holes (Yousof K cited one) , yet they are essentially disc galaxies with
cores. And as we cant see the rotational speeds of those cores one cant rule
out the possibility that these non BH galaxies also have stars rotating
at faster speeds at the center. Without a central black hole.

... current theory on galaxy ... rotation speeds ...
all the disc mass in the calculation is erroneously assumed, for
expedience, to be at the center of the disc.

That's silly. Of course nobody assumes that. Perhaps some press
release used it for an illustration?
v2 = (G M)/r
You are wrong. Its a general assumption implicit in the calculations.
Look at any of the calculations for rotational speeds, G,m, and radius.
Any of these formula Ive seen assume ALL the mass at the center. If you
disagree show me the part of the calculation that spreads M across the disc.

The simplest assumption is that mass follows the light distribution
(corrected from 2d to 3d), but a wide variety of other assumptions
have been tried.
Unfortunately the simplest assumption is erroneous. One only has to
look at observed galaxy rotation curves to see this is the case.
After all which method is best for calculating mass distribution in the solar
system. Looking at the brightness of the sun , or measuring orbital
speeds of planets?