| |
Main
Date: 22 Aug 2006 03:05:20
From: Sam Wormley
Subject: Dark Matter Exposed?
|
Dark Matter Exposed?
http://sciencenow.sciencemag.org/cgi/content/full/2006/821/1
By Tom Siegfried
ScienceNOW Daily News
21 August 2006
A smoking bullet clinches the case for dark matter in galactic
clusters, NASA announced today. The cluster of galaxies designated
1E0657-56, known as the "bullet cluster" for its picturesque
bullet-shaped cloud of superhot gas, has provided astronomers with the
best evidence yet that intergalactic space is filled with the same
stuff that provides the gravity needed to hold the galaxies together.
Normal matter in galactic clusters consists mostly of stars and very
hot gas-- the gas between the galaxies, in fact, outweighs all the
stars. But the gas and stars together appear to be vastly outweighed
themselves by some mysterious form of unseen matter, composed of an as
yet unidentified species of particle (ScienceNOW, 7 February)
Previously, dark matter's existence had been inferred from its
gravitational effects on the motions of galaxies. But some scientists
suspected that odd galactic motions could be explained without the need
for dark matter if gravity's strength was merely altered on galactic
scales.
But such "modified" theories of gravity can't explain away the new
observations, report astronomer Douglas Clowe of the University of
Arizona in Tucson and colleagues. Images from NASA's Chandra X-ray
satellite indicate that the bullet cloud was formed by an explosive
collision between galactic clusters, with the shock wave dragging the
hot gas between the galaxies into its peculiar shape. The shock wave
would not have affected dark matter, which interacts only via gravity,
so the collision effectively separated the dark matter from the gas.
Images from the Hubble Space Telescope and other telescopes show that
the strength of the cluster's gravity no longer matches up with the hot
gas, indicating that a stronger gravitational source--the dark
matter--exists in the cluster. Those images show how the cluster's
gravity bends light and distorts the images of distant background
galaxies.
"For the first time, we're actually able to see dark and ordinary
matter separated in space. And this proves in a simple and direct way
that dark matter exists," said astrophysicist Maxim Markevitch, of the
Harvard-Smithsonian Center for Astrophysics, in Cambridge,
Massachusetts, at a NASA briefing. Markevitch is a member of the team
led by Clowe that will present its findings in an upcoming issue of
Astrophysical Journal Letters.
The data make the case "beyond a reasonable doubt" that galactic
clusters are held together by dark matter rather than a modified
gravity, says University of Chicago cosmologist Sean Carroll. "Evidence
[for dark matter] has been accumulating for a long time," Carroll says,
"and the great thing about this particular result is there are
pictures."
|
|
| |
Date: 21 Aug 2006 20:54:55
From: Ed
Subject: Re: Dark Matter Exposed?
|
But what the heck is Dark Matter & what is Dark Energy?
Isn't it interesting that just when we think we realize we know
most of what is going on in the Universe...a new discovery
appear and voila....
we realize we don't know anything!
|
| | |
Date: 22 Aug 2006 04:05:23
From: Chris L Peterson
Subject: Re: Dark Matter Exposed?
|
On 21 Aug 2006 20:54:55 -0700, "Ed" <ed1ward2@verizon.net > wrote:
>But what the heck is Dark Matter & what is Dark Energy?
>Isn't it interesting that just when we think we realize we know
>most of what is going on in the Universe...a new discovery
>appear and voila....
>
>we realize we don't know anything!
Wrong. We know _more_!
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
|
| | |
Date: 22 Aug 2006 03:58:28
From:
Subject: Re: Dark Matter Exposed?
|
In article <1156218895.845395.49910@i42g2000cwa.googlegroups.com >, "Ed" <ed1ward2@verizon.net> writes:
>
>But what the heck is Dark Matter & what is Dark Energy?
>Isn't it interesting that just when we think we realize we know
>most of what is going on in the Universe...a new discovery
>appear and voila....
>
>we realize we don't know anything!
>
No, just that we don't know everything. Is this a problem?
Mati Meron
|
| |
Date: 22 Aug 2006 11:26:07
From: Jan Panteltje
Subject: Re: Dark Matter Exposed?
|
On a sunny day (Tue, 22 Aug 2006 03:05:20 GMT) it happened Sam Wormley
<swormley1@mchsi.com > wrote in <QvuGg.146628$1i1.33705@attbi_s72>:
>Dark Matter Exposed?
>But such "modified" theories of gravity can't explain away the new
>observations,
Well, those, maybe not.
>The shock wave
>would not have affected dark matter, which interacts only via gravity,
>so the collision effectively separated the dark matter from the gas.
>Images from the Hubble Space Telescope and other telescopes show that
>the strength of the cluster's gravity no longer matches up with the hot
>gas, indicating that a stronger gravitational source--the dark
>matter--exists in the cluster. Those images show how the cluster's
>gravity bends light and distorts the images of distant background
>galaxies.
When we assume Le Saga model, or rather some variation thereof where
EM radiation travels as an 'effect' in the LS particles, we know that
in the 'cluster' there are less EM particles, and light moves slower
due to lower density.
Oops.
Treating dark matter is politically incorrect anyways, as it should
really have the same rights and obey the same laws as normal matter.
To avoid discrimination.
That theory will never make it.
LOL
|
| |
Date: 23 Aug 2006 01:51:43
From: Y.Porat
Subject: Re: Dark Matter Exposed?
|
Sam Wormley wrote:
> Dark Matter Exposed?
> http://sciencenow.sciencemag.org/cgi/content/full/2006/821/1
>
> By Tom Siegfried
> ScienceNOW Daily News
> 21 August 2006
>
> A smoking bullet clinches the case for dark matter in galactic
> clusters, NASA announced today. The cluster of galaxies designated
> 1E0657-56, known as the "bullet cluster" for its picturesque
> bullet-shaped cloud of superhot gas, has provided astronomers with the
> best evidence yet that intergalactic space is filled with the same
> stuff that provides the gravity needed to hold the galaxies together.
---------------------------
is matter not enough to hold matetr together??
it is an admitatnce that scince is far from knowoing what gravity realy
is !!
i wonder how is it that QM could not predict it and later solve it !!
(where is the 'almighty QM ??? )
----------------
>
> Normal matter in galactic clusters consists mostly of stars and very
> hot gas-- the gas between the galaxies, in fact, outweighs all the
> stars. But the gas and stars together appear to be vastly outweighed
> themselves by some mysterious form of unseen matter, composed of an as
> yet unidentified species of particle (ScienceNOW, 7 February)
----------------
i sugget the basic particle that moves anturally in a closed path
i called it The Circlon!!
it is needed not only for the gravity problem
it is needed for any attraction force !!
untill now sconce was cheating byposing that they explained any
attraction force
th esitruation is much worse than posed by pompous arrogant
mathematicians
that call themselves physicists .
------------------
> Previously, dark matter's existence had been inferred from its
> gravitational effects on the motions of galaxies. But some scientists
> suspected that odd galactic motions could be explained without the need
> for dark matter if gravity's strength was merely altered on galactic
> scales.
why should i tbe altered by galactic scales ??
the only excuse for it that can be acceptible that our data about
galaxies is not acurate enough.
that is in the quantitative aspect
the second posible aspect it that our lack of knowledge in the
qualitative aspect !!
------------
>
> But such "modified" theories of gravity can't explain away the new
> observations, report astronomer Douglas Clowe of the University of
> Arizona in Tucson and colleagues. Images from NASA's Chandra X-ray
> satellite indicate that the bullet cloud was formed by an explosive
> collision between galactic clusters, with the shock wave dragging the
> hot gas between the galaxies into its peculiar shape. The shock wave
> would not have affected dark matter, which interacts only via gravity,
> so the collision effectively separated the dark matter from the gas.
> Images from the Hubble Space Telescope and other telescopes show that
> the strength of the cluster's gravity no longer matches up with the hot
> gas, indicating that a stronger gravitational source--the dark
> matter--exists in the cluster. Those images show how the cluster's
> gravity bends light and distorts the images of distant background
> galaxies.
>
> "For the first time, we're actually able to see dark and ordinary
> matter separated in space. And this proves in a simple and direct way
> that dark matter exists," said astrophysicist Maxim Markevitch, of the
> Harvard-Smithsonian Center for Astrophysics, in Cambridge,
> Massachusetts, at a NASA briefing. Markevitch is a member of the team
> led by Clowe that will present its findings in an upcoming issue of
> Astrophysical Journal Letters.
>
> The data make the case "beyond a reasonable doubt" that galactic
> clusters are held together by dark matter rather than a modified
> gravity, says University of Chicago cosmologist Sean Carroll. "Evidence
> [for dark matter] has been accumulating for a long time," Carroll says,
> "and the great thing about this particular result is there are
> pictures."
---------------------------
fo r me
the Circlon is a wonderful candidate of being 'dark matter '
the basic aprticle that moves naturally in a closed Circle is
INEVITABLE !!!
it was guessed by me fo rordinary matter
now i find it fitting the above enigma as well
see the Circlon idea at the appendix of my site :
http://www.geocities.com/porat_y/mypage.html
you can see there how it can cause any attraction force
and be the reason that our matter is held together and does not explode
at once
to get lost at the endless universe !
ATB
Y.Porat
-----------------------------------
|
| |
Date: 23 Aug 2006 21:30:44
From: malibu
Subject: Re: Dark Matter Exposed? -- More on Dark Matter
|
Sam Wormley wrote:
> More on Dark Matter
> http://www.astro.ucla.edu/~wright/cosmolog.htm#News
>
> 21 Aug 2006 - NASA announced updated information about the "bullet
> cluster" 1E0657-56 today. Two clusters of galaxies have recently
> collided in this X-ray source.
Oh, who saw them collide?
Perhaps a larger cluster just split apart because
of some other reason?
A large % of what you are
saying is supposition, another bit is fantasy, and
the rest of these statements is wishful thinking-
I haven't figured out how much is deliberate
misinformation.
The only 'dark' in science these
days is the control from gov't and
others preventing real truths to be known.
Dark matter, black holes and blacker hearts.
John
|
| |
Date: 24 Aug 2006 03:51:35
From: Sam Wormley
Subject: Re: Dark Matter Exposed? -- More on Dark Matter
|
More on Dark Matter
http://www.astro.ucla.edu/~wright/cosmolog.htm#News
21 Aug 2006 - NASA announced updated information about the "bullet
cluster" 1E0657-56 today. Two clusters of galaxies have recently
collided in this X-ray source. This cluster is filled with hot gas so
X-ray observations by the Chandra X-ray Observatory show where the
ordinary matter is located. 90% of the ordinary matter (the "baryonic"
matter) is hot gas. The new results [Clowe et al., Bradac et al.] use
gravitational lensing of background galaxies to show where the sources
of gravity are located. The sources of gravity in the cluster are not
located where the ordinary matter is located, so this cluster is a
counter-example to MOND. All of this was known in 2003 but with less
precision. Sean Carroll has a nice post about this at Cosmic Variance,
http://cosmicvariance.com/ .
For the embedded links, see:
http://www.astro.ucla.edu/~wright/cosmolog.htm#News
|
| |
Date: 24 Aug 2006 01:11:07
From: Bless You
Subject: Re: Dark Matter Exposed? -- More on Dark Matter
|
just to remind you, this is a scientific issue to be demonstrated or not
- not an
issue of planets for an IAU to screw around with!
malibu wrote:
> Sam Wormley wrote:
> > More on Dark Matter
> > http://www.astro.ucla.edu/~wright/cosmolog.htm#News
> >
> > 21 Aug 2006 - NASA announced updated information about the "bullet
> > cluster" 1E0657-56 today. Two clusters of galaxies have recently
> > collided in this X-ray source.
>
> Oh, who saw them collide?
>
> Perhaps a larger cluster just split apart because
> of some other reason?
>
> A large % of what you are
> saying is supposition, another bit is fantasy, and
> the rest of these statements is wishful thinking-
> I haven't figured out how much is deliberate
> misinformation.
>
> The only 'dark' in science these
> days is the control from gov't and
> others preventing real truths to be known.
>
> Dark matter, black holes and blacker hearts.
>
> John
|
| |
Date: 25 Aug 2006 04:13:13
From: Sam Wormley
Subject: Re: Dark Matter Exposed? - PrePrints
|
Sam Wormley wrote:
> Dark Matter Exposed?
> http://sciencenow.sciencemag.org/cgi/content/full/2006/821/1
>
Astrophysics, abstract
http://arxiv.org/abs/astro-ph/0608407
From: Marusa Bradac [view email]
Date: Sat, 19 Aug 2006 17:51:03 GMT (119kb)
A direct empirical proof of the existence of dark matter
Authors: Douglas Clowe (1), Marusa Bradac (2), Anthony H. Gonzalez (3),
Maxim Markevitch (4), Scott W. Randall (4), Christine Jones (4), Dennis
Zaritsky (1) ((1) Steward Observatory, Tucson, (2) KIPAC, Stanford, (3)
Department of Astronomy, Gainesville, (4) CfA, Cambridge)
Comments: Accepted for publication in ApJL
We present new weak lensing observations of 1E0657-558 (z=0.296), a
unique cluster merger, that enable a direct detection of dark matter,
independent of assumptions regarding the nature of the gravitational
force law. Due to the collision of two clusters, the dissipationless
stellar component and the fluid-like X-ray emitting plasma are
spatially segregated. By using both wide-field ground based images and
HST/ACS images of the cluster cores, we create gravitational lensing
maps which show that the gravitational potential does not trace the
plasma distribution, the dominant baryonic mass component, but rather
approximately traces the distribution of galaxies. An 8-sigma
significance spatial offset of the center of the total mass from the
center of the baryonic mass peaks cannot be explained with an
alteration of the gravitational force law, and thus proves that the
majority of the matter in the system is unseen.
___________________________________
Astrophysics, abstract
http://arxiv.org/abs/astro-ph/0608408
From: Marusa Bradac [view email]
Date: Fri, 18 Aug 2006 20:06:48 GMT (373kb)
Strong and weak lensing united III: Measuring the mass distribution of
the merging galaxy cluster 1E0657-56
Authors: Marusa Bradac (1,2), Douglas Clowe (3), Anthony H. Gonzalez
(4), Phil Marshall (1), William Forman (5), Christine Jones (5), Maxim
Markevitch (5), Scott Randall (5), Tim Schrabback (2), Dennis Zaritsky
(3) ((1) KIPAC, Stanford, (2) AIfA, Bonn, (3) Steward Observatory,
Tucson, (4) Department of Astronomy, Gainesville, (5) CfA, Cambridge)
Comments: Accepted for publication in ApJ; Version with full-resolution
figures available at this http URL
The galaxy cluster 1E0657-56 (z = 0.296) is remarkably well-suited
for addressing outstanding issues in both galaxy evolution and
fundamental physics. We present a reconstruction of the mass
distribution from both strong and weak gravitational lensing data.
Multi-color, high-resolution HST ACS images allow detection of many
more arc candidates than were previously known, especially around the
subcluster. Using the known redshift of one of the multiply imaged
systems, we determine the remaining source redshifts using the
predictive power of the strong lens model. Combining this information
with shape measurements of "weakly" lensed sources, we derive a
high-resolution, absolutely-calibrated mass map, using no assumptions
regarding the physical properties of the underlying cluster potential.
This map provides the best available quantification of the total mass
of the central part of the cluster. We also confirm the result from
Clowe et al. (2004,2006a).
|
| | |
Date: 25 Aug 2006 05:01:48
From: Tommy Lee
Subject: Re: Dark Matter Exposed? - PrePrints
|
"Sam Wormley" <swormley1@mchsi.com > wrote in message
news:tNuHg.151856$1i1.60460@attbi_s72...
> Sam Wormley wrote:
>> Dark Matter Exposed?
>> http://sciencenow.sciencemag.org/cgi/content/full/2006/821/1
>>
>
>
> Astrophysics, abstract
> http://arxiv.org/abs/astro-ph/0608407
>
> From: Marusa Bradac [view email]
> Date: Sat, 19 Aug 2006 17:51:03 GMT (119kb)
>
> A direct empirical proof of the existence of dark matter
>
> Authors: Douglas Clowe (1), Marusa Bradac (2), Anthony H. Gonzalez (3),
> Maxim Markevitch (4), Scott W. Randall (4), Christine Jones (4), Dennis
> Zaritsky (1) ((1) Steward Observatory, Tucson, (2) KIPAC, Stanford, (3)
> Department of Astronomy, Gainesville, (4) CfA, Cambridge)
>
> Comments: Accepted for publication in ApJL
>
> We present new weak lensing observations of 1E0657-558 (z=0.296), a
> unique cluster merger, that enable a direct detection of dark matter,
> independent of assumptions regarding the nature of the gravitational
> force law. Due to the collision of two clusters, the dissipationless
> stellar component and the fluid-like X-ray emitting plasma are
> spatially segregated. By using both wide-field ground based images and
> HST/ACS images of the cluster cores, we create gravitational lensing
> maps which show that the gravitational potential does not trace the
> plasma distribution, the dominant baryonic mass component, but rather
> approximately traces the distribution of galaxies. An 8-sigma
> significance spatial offset of the center of the total mass from the
> center of the baryonic mass peaks cannot be explained with an
> alteration of the gravitational force law, and thus proves that the
> majority of the matter in the system is unseen.
>
Surely you don't have the absolute gaul to appear just like these real
astro-scientists...do ya?
|
| |
Date: 26 Aug 2006 04:23:49
From: Sam Wormley
Subject: Re: Dark Matter Exposed?
|
Sam Wormley wrote:
> Dark Matter Exposed?
> http://sciencenow.sciencemag.org/cgi/content/full/2006/821/1
>
[Astronomy]
Enlightened: Dark matter spotted after cosmic crash
In the aftermath of a cosmic crash between two galaxies, researchers
say they've detected invisible dark matter for the first time.
http://www.sciencenews.org/articles/20060826/fob1.asp
|
|
