The "Great Attractor": What is the Milky Way Speeding Towards at 14 Million MPH?
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March 20, 2009

The "Great Attractor": What is the Milky Way Speeding Towards at 14 Million MPH?

Milky_way Astronomers have known for years that something seems to be pulling our Milky Way and tens of thousands of other galaxies toward itself at a breakneck 22 million kilometers (14 million miles) per hour. But they couldn’t pinpoint exactly what or where it is.

A huge volume of space that includes the Milky Way and super-clusters of galaxies is flowing towards a mysterious, gigantic unseen mass named mass astronomers have dubbed "The Great Attractor," some 250 million light years from our Solar System.

The Milky Way and Andromeda galaxies are the dominant structures in a galaxy cluster called the Local Group which is, in turn, an outlying member of the Virgo supercluster. Andromeda--about 2.2 million light-years from the Milky Way--is speeding toward our galaxy at 200,000 miles per hour.

This motion can only be accounted for by gravitational attraction, even though the mass that we can observe is not nearly great enough to exert that kind of pull. The only thing that could explain the movement of Andromeda is the gravitational pull of a lot of unseen mass--perhaps the equivalent of 10 Milky Way-size galaxies--lying between the two galaxies.

Meanwhile, our entire Local Group is hurtling toward the center of the Virgo cluster at one million miles per hour.

The Milky Way and its neighboring Andromeda galaxy, along with some 30 smaller ones, form what is known as the Local Group, which lies on the outskirts of a “super cluster”—a grouping of thousands of galaxies—known as Virgo, which is also pulled toward the Great Attractor. Based on the velocities at these scales, the unseen mass inhabiting the voids between the galaxies and clusters of galaxies amounts to perhaps 10 times more than the visible matter.

Even so, adding this invisible material to luminous matter brings the average mass density of the universe still to within only 10-30 percent of the critical density needed to "close" the universe. This phenomena suggests that the universe be "open." Cosmologists continue to debate this question, just as they are also trying to figure out the nature of the missing mass, or "dark matter."

It is believed that this dark matter dictates the structure of the Universe on the grandest of scales. Dark matter gravitationally attracts normal matter, and it is this normal matter that astronomers see forming long thin walls of super-galactic clusters.

Recent measurements with telescopes and space probes of the distribution of mass in M31 -the largest galaxy in the neighborhood of the Milky Way- and other galaxies led to the recognition that galaxies are filled with dark matter and have shown that a mysterious force—a dark energy—fills the vacuum of empty space, accelerating the universe's expansion.

Astronomers now recognize that the eventual fate of the universe is inextricably tied to the presence of dark energy and dark matter.The current standard model for cosmology describes a universe that is 70 percent dark energy, 25 percent dark matter, and only 5 percent normal matter.

We don't know what dark energy is, or why it exists. On the other hand, particle theory tells us that, at the microscopic level, even a perfect vacuum bubbles with quantum particles that are a natural source of dark energy. But a naïve calculation of the dark energy generated from the vacuum yields a value 10120 times larger than the amount we observe. Some unknown physical process is required to eliminate most, but not all, of the vacuum energy, leaving enough left to drive the accelerating expansion of the universe.

A new theory of particle physics is required to explain this physical process.

The universe as we see it contains only the stable relics and leftovers of the big bang: unstable particles have decayed away with time, and the perfect symmetries have been broken as the universe has cooled, but the structure of space remembers all the particles and forces we can no longer see around us.

Discovering what it is that makes up the heart of the Great Attractor -- will surely rank as one of the greatest discoveries in the history of science.

Recent findings suggest these motions are the result of gravitational forces from not one, but two things: the Great Attractor, and a conglomerate of galaxies far beyond it.

The location of the Great Attractor was finally determined in 1986 and lies at a distance of 250 million light years  from the Milky Way, in the direction of the Hydra and Centaurus constellations. That region of space is dominated by the Norma cluster, a massive cluster of galaxies, and contains a preponderance of large, old galaxies, many of which are colliding with their neighbors, and or radiating large amounts of radio waves.

Major concentration of galaxies lies beyond the Great Attractor, near the so-called Shapley Supercluster, 500 million light-years away—the most massive known super-cluster. Mapping X-ray luminous galaxy clusters in the Great Attractor region has shown that the pull our galaxy is experiencing is most likely due to both the nearby Great Attractor and these more distant structures.

In the 1987, a group of astronomers known as the "Seven Samurai," at Cal Tech  uncovered this coordinated motion of the Milky Way and our several million nearest galactic neighbors. They found that galaxies are very unevenly distributed in space, with galactic super-clusters separated by incredibly huge voids of visible ordinary matter. The place towards which we all appear headed was originally called the New Supergalactic Center or the Very Massive Object until one of the discoverers, Alan Dressler, decided they needed a more evocative name and came up with "The Great Attractor."

The motion of local galaxies indicated there was something massive out there that are pulling the Milky Way, the Andromeda Galaxy, and other nearby galaxies towards it. For a while, nobody could see what it was, because it lies behind the plane of our Galaxy --- that means the gas and dust in our Galaxy obscures the light from the Great Attractor, and it is outshone by the stars and other objects in our Galaxy.

The Great Attractor is a diffuse concentration of matter some 400 million light-years in size located around 250 million light-years away within the so-called "Centaurus Wall" of galaxies , about seven degrees off the plane of the Milky Way. X-ray observations with the ROSAT satellite then revealed that Abell 3627 is at the center of the Great Attractor. It lies in the so-called Zone of Avoidance, where the dust and stars of the Milky Way's disk obscures as much as a quarter of the Earth's visible sky.

Posted by Casey Kazan. Image credit: Wally Pacholtz

Related Galaxy posts:

"Beyond Einstein": Search for Dark Energy of the Universe
"42" -Hitchhiker's Guide to the Galaxy Foreshadows Actual Weight of Univers
1st 3-D Map of the Universe's Dark Matter
Cosmic Collision  Sheds Light on Mystery of Dark Matter
GAIA -Mapping the Family Tree of the Milky Way
New, Revised Hitchhiker's Guide to the Galaxy

http://www.solstation.com/x-objects/great
http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/990924a2.html
http://www.world-science.net/exclusives/060419_attractorfrm.html

Comments

Maybe the dark matter its only ordinary matter witch the light didn't reach us at the present time. After all when we observe the universe, in any direction, we only can look to the past. I believe that our local group is the past of the present of another part of the Universe. Maybe the "The Great Attractor"?

@Helder

Hmmm, I didn't think of dark matter in that sense and I am certainly no physicist but I think you're onto something there.

The above mentioned link in Galaxy's related posts is relevant because it notes that the captive Sagittarius galaxy which is being consumed by our Milky Way galaxy and is currently penetrating our galaxy exactly where we happen to be in our 240 million year orbit around our galaxy's center.....

"The shape of the Sagittarius debris trail shows us that the Milky Way's unseen dark matter is in a spherical distribution, a result that is quite unexpected," Weinberg said.”

check it out:
http://astsun.astro.virginia.edu/~mfs4n/sgr/sgr.time.mpg

Nice, the Milky Way totally ROCKS!
www.FireMe.To/udi

That 10120 figure in paragraph 11 should read 10^^120 (ten to the one-hundred-twentieth power).

Just a bit bigger than 10120 ;)

The answer seems so painfully obvious I'm surprised scientists and astrophysicists haven't already noticed.

Supersymmetry is the key.

Atoms have rings of electrons surrounding them.
This "center" and "ring" structure is apparent in many different scales, from atomic structures, to planets (see saturn, neptune, etc) to solar systems (our own for example) to galaxies.

I wouldn't be surprised to find that the milky way is a bit player in an incredibly vast disc of galaxies that forms a ring around this Great attractor which acts as the center.

"On the other hand, particle theory tells us that, at the microscopic level, even a perfect vacuum bubbles with quantum particles that are a natural source of dark energy. "

This sentence doesn't seem quite right to me.

The parts of this article you didn't cut and paste from Wikipedia are poorly written and I actually feel less informed on the subject after wading through your first 4-6 paragraphs. Also - you need a good copy editor!

Jesus dude, holy grammatical errors. Learn English or how to proof-read...

maybe dark matter is unrealized matter and it is what the protons, neutrons, and electrons are made of, and also what makes up photon partials. which would mean that a dark matter partial is too small to reflect light and therefore it appears dark.

Could Oprah Winfrey's ass be involved?

Gnocchi: I assume your referring to a classical atomic model with a nucleus and rings of electrons. It should be pointed out this is a relatively over-simplistic model and doesn't necessarily represent the structure of an actual atom where electrons behave rather erratically, not symmetrically as the classical model might suggest.

in reply to some of the posts above -

protons and neutrons are made up of quarks.
the idea that light hasn't reached us yet from the places we know dark matter to be is utterly ridiculous, for instance the milky way is only 100000 light years across, and the universe is 13.73 billion years old so...
it seems that because we've evolved in this kind of middle-world we've only evolved to observe the things that that we happen to interact with in a lifetime.
whatever dark matter and dark ebergy really is you will sadly never really know.

Dear Mr Cazan

I am a private person involved in a non-profit effort to divulgate scientific knowdlege among Spanish talking people.
As such, I have produced my own articles and, specially, I have translated (duly authorized) many more, from differente sources like Astronomy Magazine, Universe Today, Science NASA, etc.
May I translate this one and publish it in my blog, "El Atril del Orador"?.
If you agree, please let me know by sending a mail to the adressI added to this comment.
Reegards

your blog is nice . For more coverage submit your stories in indiha.com

That sounds like a respectable percentage of lightspeed we're moving at already.

John Dobson, on dark matter:

Helium Abundance
For the Big Bang models, the observed helium abundance is far too low unless most of the matter of the Universe involved in the fireball explosion was of such a nature that it could not be made into helium. It has therefore been suggested by some proponents of the Big Bang model that some 90% to 99% of the matter in the Universe is of such a nature that it responds only to gravity, and not to any of the other forces such as electricity and magnetism which might allow us to detect it. This "dark matter", as it is called, is thought to surround the visible galaxies, but not to reside within them. And the problem is, that if it responds only to gravity, why doesn't it all fall in?

Dark Matter
For a Steady State model, there is no problem about the dark matter being ordinary matter, because the visible galaxies could be expected to be surrounded by what I call "hovering layers" of ordinary matter blown out by the stellar winds. When a cluster of stars condenses from a cloud of gas, some 90% to 99% of the material in the cloud could be expected to be blown away by the stellar winds of the cluster. Since the diameters of these hovering layers may be five to ten times the diameters of the associated galaxies, their densities might be well below one percent of the densities of the associated galaxies. The detection of this material might be rendered problematical simply by its low density.

From: http://quanta-gaia.org/dobson/origins.html

**********
I believe Dobson also mentioned in his lectures that dark matter was the true form of matter ("the changeless, the infinite, the undivided") showing through into an apparitional universe:

"So if the "origin" of the Universe is apparitional, and if the nature of the apparition is seeing what we see as if in space and time, and if what's behind the apparition is the changeless, the infinite, the undivided, then the consequences of such an apparition would be that we would see the changeless as if changing, the infinite as if finite, and the undivided as if divided. But, because of the revealing power, we must have seen the changeless in the changing, and that is what I see as inertia; we must have seen the infinite in the finite, and that is what I see as the electrical charge of the minuscule particles; and we must have seen the undivided in the divided, and that is what I see as gravity. And thus far these consequences do correspond to what we see. And they also provide a possible explanation for gravity, electricity and inertia, which heretofore we have had to take for granted.

As I see it, the only reason the Universe is energetically wound up is because it is apparitional. (In an apparition, the underlying existence must show through.)"

(Ibid.)

Is this right?

1) The Great Attractor is 250 Million Miles Away
2) We are moving towards it at 14 Million Miles an Hour

So

3) We will begin to collide with it in only ~17.9 years?

Will we see this in our lifetimes?

not in our lifetime

[quote]


Is this right?

1) The Great Attractor is 250 Million Miles Away
2) We are moving towards it at 14 Million Miles an Hour

So

3) We will begin to collide with it in only ~17.9 years?

Will we see this in our lifetimes?

Posted by: Rick
[/quote]

Light travels many many miles in a year :-)

670,616,629mph according to google.

The actual speed of travel from the article is 200,000mph.

So we travel one light year towards the great attractor every 3353 hours ( or 139.71 days ), and we must do this 250 million times, we do 2.61 light years every year, so we will get there rather quick, in 95,627,514.83 years. I wouldn't worry about it, personally.

--The loon

edit that!

Just re-checked the article, it was 14,000,000 mph ( 200,000 was closure rate of something else, sorry ) - not to mention I did something backwards in the math & logic ( & violated the laws of physics ) - not bad :-)...

corrected math:

We need to travel 1.67541573_E_17 miles. At 14,000,000 mph, it will take:

498,970,706.1 days or 1,366,107.34 years.

Somewhat more to worry about

--The loon

I'm not sure if we'll ever reach the great attractor, because the universe is expanding. Andromeda is blue-shifted, so we definitely will reach it someday. But Wikipedia says The Great Attractor is red-shifted, just less red-shifted than everything else. So we may never actually reach it due to the expansion of space and eventual shrinking of our galaxy cluster's event horizon to just outside our cluster.

If you want to refer to dark energy and dark matter as a crutch- you are still too ambiguous. The astro-physicists must staple a scientific name to these speculative seen(or unseen) things.

Not sure when wikipedia became a reputable source, but whatever.

The grammar in this article makes it illegible.

Beyond that, what if dark matter was some form of real matter (inert or otherwise) but exerts specific properties on the space it resides in and surrounds to locally warp the region. We could in effect, have matter that moves "faster than the speed of light" from one perspective and is relatively stationary from another. It could be a remnant from long gone reactions or perhaps those we are to view in the future but are otherwise incomprehensible to the general forces (besides gravity) that we see.

With all of the quarky observations at the micro and macro scale, it would not surprise me to learn that the three-dimensions of physical space we observe are irrelevant and simply a byproduct of the (known?) universe trying not to collapse on itself. It could in fact be many objects of many dimensions occupying the same physical space... Thoughts?

Your calculation must be wrong again :)
there are only 12273 years left. this time try in metric system, it's better ;)


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