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Galactic Traffic Patterns
eldavojohn writes "Using Hubble, researchers have noticed traffic patterns of stars within our own galaxy. From the article, 'Researchers analyzed 47 Tucanae, the second largest cluster in the Milky Way's galactic neighborhood, and determined the cluster sorts out stars according to their masses. Due to the associated gravitational pull, heavier stars slow down and sink to the cluster's core, while lighter stars pick up speed and zip out to the cluster's periphery.' There is speculation that these movements of stars — although tiny — can have significant implications and possibly result in mass segregation."
If this keeps up, the stars are gonna be marching on Washington, demanding their equal rights. I have a dream, that someday, all stars will be judged not be mass, but by the content of their cores.
Unknown host pong.
doesn't the summary defy conservation of energy? I thought they should speed up if they get closer and slow down if they get further away like an ice skater.
All this talk of galactic traffic, and not one mention of the hyperspace bypass.
Slashdot Burying Stories About Slashdot Media Owned
They ... keep ... going ... around ... in ... circles.
Funnypics
This is interesting. From my hopelessly and woefully inadequate understanding of celestial mechanics I would guess this must be due to the stars rotating around some huge mass in the centre, right? A black hole or similar? Without that in place wouldn't the stars interact with one another and eventually end up a horribly chaotic mess? The article doesn't say.
http://twitter.com/onion2k
It shows that this is also true for heavy masses, probably? Quite obvious, but you won't believe how much scientific work with obvious results is done (yes, bash me for that, Karl-Popper-fanboys).
A monkey is doing the real work for me.
How much money did they waste on THIS study? All they had to do is ask the Vogons, who have many reports on file concerning galactic traffic patterns (never mind that you have to file the requests at a planet 18 light years away, and that the files are located in cabinets in mynock-infested rooms).
Where were you when the voynix came?
Except in this case the rocks sink slow and the beachballs drop like a rock.
-Please don't take this comment seriously.
Better one (from my second prize ribbon-winning science fair project in 2nd grade): Why does a ship float and a potato sink?
When I saw the title, I thought this article was going to tell is when Adama and crew find Earth! Sucks to be hooked on a TV show. FRACK!
If you think about it a while you can see the problem - these stars are in orbit, so they should fall at all. Essentially, the stars are being sorted by mass when they should be just going around in circles...
while (sig==sig) sig=!sig;
This stuff rocks so hard, is has stars going around my head. That such light objects, are so heavy, shows the gravity of the whole thing, yet it makes music better than a gala xylophonic experience, and makes us realize that noone would have sold our system for anything else.
Have you read my journal today?
It's needed for Samantha Carter's stellar drift calculations.
Please, for the good of Humanity, vote Obama.
I hate when you're traveling down a spiral arm at 465m/s and you have to SLAM on the brakes because a bunch of systems have slowed down to a crawl to gawk at some dumbass who went nova. Geez, people, I've got sectors to see, and a job interview seven light-hours away!
So when will Battlestar Galactica reach Earth? Last I heard there were reports of battlestars and basestars zipping all over the commuter lane.
If heavy objects sink to the core, and lighter ones speed up, and go to the outer rim... do galaxies of galaxies behave the same way? And by that thinking, is the universe really expanding, or are we just moving towards the outer rim being a very large section of lighter galaxies (and we just appear to be expanding because behind us are heavier objects accelerating slower, stopped, or accelerating back into the core, and lighter objects are moving faster in front of us as we are all just moving on an outward spiral, thus giving the appearance of a universe that is spreading apart)?
And, if that's so, what would "THE core" be like. Hmmm, black hole not of one star but of entire galaxies?
Which begs the question, is there enough gravitational pull at a hypothetical core of all cores to hold the universe together like a giant counter weight on a pendulum, with fluctuations between expansions and collapses? (Never mind if 'Sha Ka Ree' is really there if it has the mass of 1 million Milky Ways, heh.)
IANA astronomer, astrophysicist, etc. Just curious because from what I read, as go moons, so go solar systems, so go galaxies, so goes the universe.
I8-D
Duh ! Potatoes aren't designed to sail about the place but ships are.
"The Daedalus [wikipedia.org] is coming back from Pegasus though"
No WAY! The Pegasus blowed up real good two weeks ago.
Where were you when the voynix came?
I guess pretty soon, we'll have to start bussing stars around to get an equal mix of heavy and light stars. Otherwise, the galactic central cores gonna be all fat, old stars griping about how they don't get cosmic incidents like they used to in the old days and all these young stars with their loud music and the dancing and the glavin. oh, hey!
"My God...it's full of trolls!"
To respond to a number of responses, this article is actually about globular clusters, not galaxies. Some globular clusters may have black holes at their cores, but others almost certainly do not (as I understand it). It is not neccessary that there be a huge mass in the center. When you have a large collection of objects close together they can act (very roughly) as if their combined mass were in the middle and they were orbiting that - this description is highly simplified, but it illustrates how a central mass is not needed. In response to another comment to the effect that this can only happen with two masses, it just gets more complicated as more masses are added (well, MUCH more complicated). And what's wrong with a "horribly chaotic mess," anyway? :)
> someday, all stars will be judged not be mass, but by the content of their cores
The content of a star's core is determined by its mass. Every star starts out with nothing but hydrogen and has to manufacture everything else. Larger stars burn hotter and can fuse heavier atoms. Some stars explode, spew out stellar matter, and become smaller stars, but this is really their own damn fault. So mass really is the main factor by which stars ought to be segregated. If you think it unfair, build your own universe.
Will someone please tell me which Dept. this article is from? Shouldn't it be from the don't-tailgate-Starbuck Dept. or something?
To reply to the previous comment, mass segregation should also occur in clusters of galaxies, especially the big rich clusters. Indeed, you often see supermassive elliptical galaxies in the center of clusters. The problem there is that the idea of equiparition of energy requires lots of 3-body gravitational interactions to equalize the energy of all the various objects. In globular clusters, this happens on short timescales (the timescale might be only 500 million years. :) ) In galactic clusters, you might only get one interaction every billion years so you have to wait a lot longer to see the results.
Rocks sink and beachballs float because of differing densities, not differing masses.
Here, we're looking at stars of different sizes and masses. There aren't some stars made mostly from silicates and iron oxides, while other stars are hollow plastic shells with slightly compressed air cores, or anything like that. A big red giant star may weigh 5x the mass of our sun, but be hundreds or thousands of times more voluminous, so the density as a whole object is actually much lower than a sun sized star.
Also, rocks sink in water. In a pool of mercury. both typical rocks and typical beachballs float. In vaccuum, near a gravitational source, everything that has mass is accelerated at the same rate, and densities really don't matter. Density affets falling objects if there's a drag, like there is falling through air. The space between stars is generally a near perfect vaccuum.
It's significant, because simple, standard physics explanations of sorting by density, type of material, or mass don't entirely explain this. Instead, there are probably other factors such as transfer of momentum between whole groups of stars, perhaps also to gas clouds or something, and maybe even modifying factors such as light pressure or angular momentum-linear momentum exchanges which are in turn affected by such unexpected things as the stars involved's relative surface areas or diameters.
The article talks about slingshot effects. Small stars can be slingshotted a lot faster by the same force that will only moderately accelerate large ones. This in turn means their orbit around the galactic core may even become a parabola or hyperbola, so that any given encounter sometimes becomes their last pass through the cluster. Larger stars get sped up and slowed down, but seldom by all that much, so they tend to keep returning to the cluster.
Sorting out which of these factors, and possibly others, are important and which are trivial is why the people studying this actually have to learn some math.
Who is John Cabal?
They are not racist. They are massist.
http://www.dieblinkenlights.com
Does this have any implications on the density of mass? When I think of things spinning around a center (e.g., the center of a galaxy), I think of a centrifuge. In a centrifuge, the matter is segregated by density (denser objects move to the outside). So, is it possible then to argue that the lighter stars (although lighter) are more dense than the heavier stars? I guess it depends on the magnitudes of the various forces. Everything is on such a scale that I can't even guess what forces are dominant; however, everything is happening on such a large time-scale that it's unclear to me if even non-dominant forces can play a significant role.
Actually, I don't believe you need a massive body at the center of the cluster to cause this to happen. Dynamical friction (due to the gravitational interactions between the stars) could have this effect, with small stars slingshotting off large stars, causing the large stars to loose energy.
Another reply pointed out that galaxies behind us are moving away as well. This can be looked at another way though. In order for this effect to happen on the largest scales of the universe, all galaxies must be gravitationally interacting. However, the distances involved are often too great to make such interactions significant. On smaller scales, such as clusters of galaxies, these gravitational interactions are significant, so it is concievable that something similar to what's in the article could occur.
I'm not sure this should come as much of a surprise, given that this has been predicted by dynamical theorey.
It's nice that it's been observed though.
Can't be any worse than the 405 in LA.
thegodmovie.com - watch it
The ship floats because it's a witch!
1) its not funny
2) and not true
3) and not sarcastic.
4) the last line of your post suggests that you are a karma hooker.
You just dont make sense.
Beachballs (light stars) get swong out, and rocks (heavy stars) *do* get sucked in.
Imagine a big roulette table without an outside border or obstacles inside.
Trow in a light ball, it will spin longer.
Trow in a heavy ball, it will drop sooner.
Use constant velocity to trow them in orbit, and not so hard that one or the other will touch the outside in their first orbit.
Hivemind harvest in progress..
Apparently in reading the last line of that post, you missed the point of the last line of that post.
Well, that's the obvious expectation if you consider only the interactions between each orbiting star and the center of mass of the galaxy; but their actual motion is a lot more complicated because the you've really got a bunch of non-uniformly distributed objects attracting each other, which is why (besides this effect), you get spiral arms, which aren't clumps of stars orbitting together, but, IIRC, compression waves that move at speeds different than those of the individual stars, with stars bunching up in them and then spreading out after they pass.
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