The Great Attractor

[umpa_lumpa]

What is this great attractor? What is it made of? Where is it?

 

[harmonicaman]

This is a great topical question because the recent meeting of the American Astronomical Society, in Washington, DC, had a presentation of new discoveries regarding "The Great Attactor". <br /><br />Background:<br /><br />Our Milky Way galaxy, along with our Local Group, is speeding through space at about 14⁸ miles per hour (1.4 million miles per hour) in the general direction of the constellation Centaurus. <br /><br />This mass migration includes the Virgo Cluster, the Hydra--Centaurus Supercluster, and other groups and clusters. It is as if a great river of galaxies (including our own) is flowing with a swift current toward Centaurus. <br /><br />Calculations indicate that about 10¹⁶ solar masses concentrated 65 Mpc away in the direction of Centaurus would account for this. This mass concentration has been dubbed the Great Attractor and some astronomers believe that the Great Attractor may be centered on the rich cluster known as Abell 3627.<br /><br />Detailed investigation of that region of the sky have previously found 10 times too little visible matter to account for this flow implying a dominant gravitational role for unseen or Dark Matter. <br /><br />Thus, the Great Attractor is certainly there (because we see its gravitational influence), but the major portion of the mass that must be there cannot be seen in our telescopes. <br /><br />One reason that we cannot see this mass is because it is a direction of the sky that is blocked from view by gas and dust in our own Milky Way. Our own galaxy blocks our view of about 25 percent of the rest of the cosmos.<br /><br />New findings:<br /><br />Now University of Hawaii astronomers Dale Kocevski, Harald Eberling, and R. Brent Tully, along with UH alumnus Chris Mullis, have seen through the galaxy looking at X-rays that pass through space dust the way they pass through human flesh. <br /><br />Kocevski announced their work at the American Astronomical Society in Washington, D.C.<br /><br />What they found was

 

[dougum3882]

I had an idea about dark matter which I got from the line about 10^16 solar masses and it's link to dark matter being in that region. Supermassive blackholes, like the ones theorized to be at the center of galaxies, can be on the order of 10^10 solar masses or so (about a billion solar masses)? Well, 10^16 solar masses would be like a million supermassive blackholes. What if there was a blackhole so massive that it was 10^16 solar masses or one million supermassive blackholes? Light certainly wouldn't be able to escape from it, so it would be dark (like all other black holes). But if there existed a blackhole so massive, I would think it could swallow much more of its surroundings than even a supermassive blackhole could; maybe even be able to swallow a small enough galaxy. So my theory (which is about 15 minutes old) is that maybe dark matter, whose mass and gravitational effects can be detected, could be blackholes that are so massive that they have swallowed all of their surroundings (including the rest of the galaxy which they originally might have anchored and maybe any other objects that passed too near to them). Because they are blackholes, you wouldn't be able to see them directly and without any surroundings, you wouldn't be able to use any of the indirect methods currently used to detect blackholes (like looking at the speed of stars orbiting a blackhole). All that would be there is a heck of a lot of gravity without any visible signs of what is causing it. Is this plausible?

 

[umpa_lumpa]

Couldn't this "Great Attractor" be just a large black hole? We have a large black hole in our galaxie, why couldn't a glalaxie have died from their large black hole and and been left in the middle of nowhere... leaving what we know as "The Great Attractor"?<br /><br /><br />Justin

 

[harmonicaman]

<i>"Couldn't this "Great Attractor" be just a large black hole?"</i><br /><br />This is exactly the question that was bothering cosmologists! If the "Great Attractor" was a single super-massive black hole in a very large galaxy, it implied an impossible amount of mass (dark matter) in one place.<br /><br />Since recent observations show that the "Great Attractor" is really several groups of widely dispersed clusters of galaxies; it appears that nothing unusual is taking place and dark matter theories are not in jeopardy.<br /><br /><i>"...why couldn't a glalaxie have died from their large black hole and been left in the middle of nowhere..."</i><br /><br />The universe isn't old enough for this to happen yet, give it another 10²⁰ years and the galaxies will start dying!

 

[newtonian]

harmonicaman - Excellent post on the updated findings on the Great Attractor.<br /><br />I have been quoting what is now apparently a little outdated Scientific American articles.<br /><br />Yes, I was aware ot the centering on abell 3627.<br /><br />What's new to me is mutltiple Attractors influencing the direction of travel<br /><br />Does this then mean the river in space bends somewhat?<br /><br />How would this effect calculations of arrival of Milky Way to the center of Gravity of the Great Attractor?<br /><br />Here, btw,. is a simple overview of the older data:<br /><br />"Margaret Geller, John Huchra, and others at the Harvard-Smithsonian Center for Astrophysics have found what they call a great wall of galaxies some 500 million light-years in length across the northern sky. Another group of astronomers, who became known as the Seven Samurai, have found evidence of a different cosmic conglomeration, which they call the Great Attractor, located near the southern constellations of Hydra and Centaurus. Astronomers Marc Postman and Tod Lauer believe something even bigger must lie beyond the constellation Orion, causing hundreds of galaxies, including ours, to stream in that direction like rafts on a sort of “river in space.”"- "Awake!," 1/22/96, p. 5.<br /><br />The discovery of vast structures in space may force scientists to reevaluate their theories. One such structure, referred to as “the great wall,” is described as an immense, flat expanse of galaxies spread out over a thousand million light-years. Another structure is termed “the great attractor” because it is pulling so many galaxies, including our own, toward itself. The New York Times notes that such structures, which “are not simply galaxies or clusters of them, but huge ‘continents of galaxies,’” confirm theories that “the basic objects in the universe are far larger and more complicated than astronomers had imagined.” One astrophysicist told the Times that many theorists were hoping that the great attractor would