APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep 17)

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APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep 17)

Postby APOD Robot » Tue Sep 17, 2013 4:10 am

Image Galaxy Cluster Abell 1689 Deflects Light

Explanation: It is one of the most massive objects in the visible universe. In this view from the Hubble Space Telescope's Advanced Camera for Surveys, Abell 1689 is seen to warp space as predicted by Einstein's theory of gravity -- deflecting light from individual galaxies which lie behind the cluster to produce multiple, curved images. The power of this enormous gravitational lens depends on its mass, but the visible matter, in the form of the cluster's yellowish galaxies, only accounts for about one percent of the mass needed to make the observed bluish arcing images of background galaxies. In fact, most of the gravitational mass required to warp space enough to explain this cosmic scale lensing is in the form of still mysterious dark matter. As the dominant source of Abell 1689's gravity, the dark matter's unseen presence is mapped out by the lensed arcs and distorted background galaxy images. Surprisingly, close inspection of the above image has revealed the presence of over 100,000 globular star clusters in the galaxy cluster.

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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby Boomer12k » Tue Sep 17, 2013 4:55 am

Ahhh....Curved Spacetime....awesome!

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SouthEastAsia

Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby SouthEastAsia » Tue Sep 17, 2013 5:48 am

Fascinating image...

My question would be: What came first... the mass cluster of Galaxies, or the mass cluster of Dark Mass?

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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby bystander » Tue Sep 17, 2013 5:59 am

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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby Ann » Tue Sep 17, 2013 6:45 am

SouthEastAsia wrote:Fascinating image...

My question would be: What came first... the mass cluster of Galaxies, or the mass cluster of Dark Mass?


Well, since dark matter is so much more abundant than ordinary matter, it seems very likely that the galaxy cluster grew around a strong local concentration of dark matter.

Abell 1689 is an interesting cluster, and it was fascinating to see the recent Hubble closeup of an amazing number of globular clusters in orbit around the central galaxy.

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workgazer

Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby workgazer » Tue Sep 17, 2013 8:15 am

Is that a ring galaxy just below center, or a distortion in the image?

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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby FLPhotoCatcher » Tue Sep 17, 2013 8:18 am

Einstein predicted warped images of distant objects in front of closer galaxies. But he did not know that there was dark matter, did he? Would you even see the warping if it were only 1% of what it is?

Einstein on left: Gravitational lensing minus dark matter. On right: What we actually see.

http://www.flickr.com/photos/mattmerritt/9782516856

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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby neufer » Tue Sep 17, 2013 11:56 am


http://www.khon2.com/2013/09/10/action- ... s-license/ wrote:
<<It is one of the most massive names in the entire U.S. :!:
Janice “Lokelani” Keihanaikukauakahihuliheekahaunaele's name is seen to warp space as predicted by Einstein's theory of gravity -- deflecting light from other individual drivers who stand patiently behind her in the DMV line.>>


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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby Beyond » Tue Sep 17, 2013 12:52 pm

I take it that the spelling on the drivers license is the correct spelling :?: Or did the drivers license just run out of room for the last 'e' :?: :lol2:
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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby tkc » Tue Sep 17, 2013 2:22 pm

All sorts of neat things in this picture. In the upper right corner there are two things that caught my eye.
1) What is going on with the red edge on spiral galaxy?
2) Are the two galaxies that are over lapping interacting or just in line of sight?

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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby donalgary » Tue Sep 17, 2013 2:24 pm

Can anyone tell me why the blue tint? If it's a blue shift, where does the energy come from? Are blue shifted spectral lines visible?

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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby BDanielMayfield » Tue Sep 17, 2013 2:25 pm

The main lensed galaxy in this image is blue, which I find supprising due to its extreme distance. How far away is both Abell 1689 and the blue galaxy behind it? It must be very blue indeed to still look blue after all the reddening that its light must have undergone.

Since we're being quite formal,

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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby biddie67 » Tue Sep 17, 2013 2:42 pm

Being the ol' country gal that I am, I can easily judge in my mind how tall a tree is ~or~ how far down the road a post is ~or~ approximately how many acres in a pasture BUT trying to grasp the enormity of space in that picture is mind-blowing (dark matter or whatever it is out there).

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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby Chris Peterson » Tue Sep 17, 2013 2:46 pm

BDanielMayfield wrote:The main lensed galaxy in this image is blue, which I find supprising due to its extreme distance.

This image was acquired through three infrared, one red, and one green filter, and the five channels were then mapped to red, green, and blue. Just because an astronomical image appears to be color, it is unwise to assume that color in any meaningful way represents the "true" color as our eyes would perceive things. This is especially true of images produced by the HST, which are almost never acquired through filters that allow for accurate color representations.

(In this case, the blue display channel consists of data collected through a wideband green filter, 475W, meaning the light is probably on the whitish side visually).
Chris

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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby geckzilla » Tue Sep 17, 2013 3:09 pm

Lensed galaxies seem to emit shorter wavelength light than their foreground galaxies, though. That's why they always end up in the blue channel. That confuses me as well.
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K1NS

Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby K1NS » Tue Sep 17, 2013 3:42 pm

If the main mass of galaxies is rotating and moving, I would think that the blue arcs produced by lensing might actually change, in a time scale we might be able to observe. Are there multiple versions of this image, taken at different time, that look slightly different?

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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby Ann » Tue Sep 17, 2013 3:45 pm

geckzilla wrote:Lensed galaxies seem to emit shorter wavelength light than their foreground galaxies, though. That's why they always end up in the blue channel. That confuses me as well.


Lensing galaxies are typically massive elliptical galaxies made up almost exclusively of cool yellow stars. Far-away galaxies are typically small and full of star formation, which means that they shine very brightly in the ultraviolet channel. Their ultraviolet light has since become redshifted into the blue channel due to the expansion of the universe. Presumably, the red light that these background galaxies also emit have been redshifted out of the optical wavelengths altogether.

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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby neufer » Tue Sep 17, 2013 3:58 pm

K1NS wrote:
If the main mass of galaxies is rotating and moving, I would think that the blue arcs produced by lensing might actually change, in a time scale we might be able to observe. Are there multiple versions of this image, taken at different time, that look slightly different?

Light echoes, relativistic particles and microlensing can be observed to move within our galaxy
but observing any motion outside our galaxy is out of the question.
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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby neufer » Tue Sep 17, 2013 4:00 pm

Ann wrote:
geckzilla wrote:
Lensed galaxies seem to emit shorter wavelength light than their foreground galaxies, though. That's why they always end up in the blue channel. That confuses me as well.

Lensing galaxies are typically massive elliptical galaxies made up almost exclusively of cool yellow stars. Far-away galaxies are typically small and full of star formation, which means that they shine very brightly in the ultraviolet channel. Their ultraviolet light has since become redshifted into the blue channel due to the expansion of the universe. Presumably, the red light that these background galaxies also emit have been redshifted out of the optical wavelengths altogether.

Read Chris's response above.
Art Neuendorffer

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Postby K1NS » Tue Sep 17, 2013 5:11 pm

neufer wrote:
K1NS wrote:
If the main mass of galaxies is rotating and moving, I would think that the blue arcs produced by lensing might actually change, in a time scale we might be able to observe. Are there multiple versions of this image, taken at different time, that look slightly different?

Light echoes, relativistic particles and microlensing can be observed to move within our galaxy
but observing any motion outside our galaxy is out of the question.


I'm not so sure. We would not be observing the motion of the distant galaxy, but the angular changes in the refracted image. The farther away you are, the easier it is to see small angular changes. (Hang a prism on a tree limb and walk away. The farther away you go, the easier it will be to see subtle color shifts due to rotation.)

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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby ErnieM » Tue Sep 17, 2013 5:15 pm

The power of this enormous gravitational lens depends on its mass, but the visible matter, in the form of the cluster's yellowish galaxies, only accounts for about one percent of the mass needed to make the observed bluish arcing images of background galaxies. In fact, most of the gravitational mass required to warp space enough to explain this cosmic scale lensing is in the form of still mysterious dark matter.

Is the 1:99 ratio of visible to dark matter true in all known clusters with evidence of background galaxy lensing? If so, then the mass from the visible galaxies is insignificant. I am very much interested in looking at a modified version of these pictures with only the arced background galaxies and the foreground galaxies filtered out.
So far, gravitational lensing is the only way we "see/infer" location of large mass of dark matter.
Using what we could learn from these modified versions, survey the universe and search for faint spots of gravitational lensing with little or no visible galaxies in the foreground.
There are more dark matter than visible galaxy clusters, so I expect we will find plenty of "lensing" large clusters of mostly or only dark matter.

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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby FloridaMike » Tue Sep 17, 2013 5:53 pm

wait, wait, wait... I haven’t had a drink of the cool aid...

Isn’t "dark matter" just something we made up to explain something we don’t understand?
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Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby geckzilla » Tue Sep 17, 2013 6:00 pm

FloridaMike wrote:wait, wait, wait... I haven’t had a drink of the cool aid...

Isn’t "dark matter" just something we made up to explain something we don’t understand?


You don't usually make fringe statements like this, so I'm going to give you the benefit of the doubt, here... while it's true that it's not yet well understood, it's still the best explanation for the discrepancy between the mass of observable and the mass required for gravitational lensing such as Abell 1689.
https://en.wikipedia.org/wiki/Dark_matter
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K1NS

Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby K1NS » Tue Sep 17, 2013 7:16 pm

geckzilla wrote:
FloridaMike wrote:wait, wait, wait... I haven’t had a drink of the cool aid...

Isn’t "dark matter" just something we made up to explain something we don’t understand?


You don't usually make fringe statements like this, so I'm going to give you the benefit of the doubt, here... while it's true that it's not yet well understood, it's still the best explanation for the discrepancy between the mass of observable and the mass required for gravitational lensing such as Abell 1689.
https://en.wikipedia.org/wiki/Dark_matter


Try a taste of this. http://www.popsci.com/science/article/2010-03/spinning-disc-could-test-modified-newtonian-physics-and-kill-dark-matter-explanation. You might find it more palatable than the Kool-Aid. :ssmile:

cindy4444

Re: APOD: Galaxy Cluster Abell 1689 Deflects Light (2013 Sep

Postby cindy4444 » Tue Sep 17, 2013 7:25 pm

I thought dark matter was distinguished from gravitational matter. IN FACT, I thought that was what defined it-that it does not respond to gravity. If dark matter does respond and produce gravity, then what is the difference between dark matter and the regular kind we know and love? Is it just that we can not see the dark matter and SO do not know what it is. Hence my real question, may be what is it that makes matter "matter".? Obviously matter is defferent from energy but is there a scientific definition that covers regular and dark matter? Really would appreciate an answer from someone who knows the science.


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