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Ring Of Stars Found Around Milky Way
LoPingHo writes "Scientists have found a ring of stars around our galaxy that has previously been undetected due to the faintness of the stars. The article says that it only amounts to 1% of the galaxies mass, but if they are just now finding those, that means there could be even fainter ones there too. Could this be part of the elusive 'dark matter' talked about so much lately?"
Sounds like they've discovered a Kemplerer Rosette. :)
Isn't dark matter simply matter that doesn't emit light? If stars get formed by huge clouds of gas that eventually create so much heat and pressure that it starts a process of fusion, then its more than likely all this dark matter we are talking about is just that, dark matter, dirt, whatever you want to call it. It isn't anything significant other than it isn't radioactive, which is a good thing, IMO.
In the article: "If the ring turns out to be due to a satellite galaxy, it would mean that we are seeing the Milky Way cannibalizing a small galaxy and incorporating it into the galactic disk..." But what if it's the other way around?
Wouldn't that be like the researcher who, several years ago, proposed the theory that The Odyssey was not written by Homer the blind poet but was in fact written by a completely different blind poet named Homer?
I am disrespectful to dirt! Can you see that I am serious?!
Could this be part of the elusive 'dark matter' talked about so much lately?
.05% of the mass of dark matter.
Yes.
Most scientists believe that dark matter makes up 80 - 95% of the total gravitational mass of the galaxy, and probably the universe.
Dark matter is simply the term given to matter that we haven't observed yet, except indirectly through its gravitational effect.
This is certainly some portion of the dark matter. But I wouldn't say a significant part, or even a part really worth mentioning. While the dark matter is almost definitely comprised of several different sources, it seems certain to me that there is an entire class of gravitational objects that we have yet to observe, and this is the cause of the dark matter. Whether its dark stars, black holes, heavy neutrinos, or some even more strange and cosmic form of matter I don't know. It could be all of those and more.
Point being, if the dark matter within the Milky Way is only 80% of the mass of the galaxy, and not say 95% as some researchers suggest... this would make it 400% of the mass of the observed portion of the galaxy. These stars are, according to the article, 1% of the mass of the (previously) observed portion of the galaxy. Which makes them 0.25% of the mass of dark matter required to account for gravitational effects that are otherwise unexplained. If dark matter turns out to be a significantly larger percentage, such as 95%, then these stars only account for
For those who question the value of determining either the cause or the exact amount of dark matter in the universe, this debate is pivotal for determining the final fate of the universe. So far our calculations of the total mass of the universe, including the dark matter, are riding the knife-edge required to make the universe exactly stable. If there is a little more mass than this, then the current expansion of the universe will one day reverse, until the universe contracts back to a singularity. If there is a little less mass than this, then the current expansion of the universe will continue infinitely.
This is all according to current theory on the creation and eventual fate of the universe and is subject to change with brilliance, genius, and persperation.
I am disrespectful to dirt! Can you see that I am serious?!
Dark matter doesn't necessarily need to be completely invisible, just rather hard to detect. Its exact properties depend on the sort of dark matter candidate you are considering. The two general types of dark matter candidates are MACHOs- MAssive Compact Halo Objects, which are relatively large (but very small on a galactic scale), dim objects such as gas giant planets, brown dwarfs, and black holes. Many of these object emit faint radiation, but are completely washed out by brighter objects nearby, or are merely too dim and too far away. The major method for searching for MACHOs is gravitational microlensing- if a MACHO passes between us and a faraway star, its gravity should bend the star's light like a lens, making it appear temporarily brighter, with the intensity chance and duration being indicative of the mass and velocity of the MACHO. The other major candidate is that an invisible cloud of massive particles surrounds our galaxy. These particles would have to have a gravitational field (i.e., nonzero mass), but must be extremely nonreactive- dark matter seems to have effects on a galactic scale, but seems to be undetectable or nearly undetectable on earth. Some physicists think that no known particle meets this description, and are looking for WIMPs (Weakly Interacting Massive Particles) I believe these were named before the MACHOs, btw. As their name implies, they interact with normal matter very weakly- they can pass though many miles of solid matter (like the entire earth) and emerge unscathed. Detection efforts usually involve sensitive experiments carried out deep underground. There are other physicists who believe the dark matter has been located already- in the humble neutrino. Results from the Super Kamiokande neutrino detector strongly suggests that the neutrino, long believed to be massless, has a very small but finite mass. The exact mass is unknown, but should exist because neutrinos oscillate freely among its 3 varieties (electron, muon, and tau), which could only occur if the neutrino had a mass. This mass is very, very small- much smaller than that of an electron, even, but there are so many neutrinos that even a tiny mass would mean that neutrinos make up the vast majority of matter in the universe.
"FDA staff reviewers expressed concern about the number of patients who were left out of the study because they died."
For a long time, I've heard that some astronomers think the Milky Way is a barred spiral galaxy. It's of course very hard to tell looking out from within. This discovery would tend to vindicate that view. What they have detected is the ring of stars that form the faint spiral around the outer periphery. We live at the far end of one of the bars. Have a look at this photo of NGC5850 and you can see what I'm talking about. It's "ring" is a bit more prominent than ours though. Google has more.
So what do you think about the hypothesis that dark matter is the matter in an adjacent universe who's properties cause side affects in our own. This would imply that gravity is not constrained to one space-time, but also affects those universes around our own.
I can't help but think something like this, in combination with the theory that black holes in one universe are the points of origin for adjacent universes. I've heard it said before that most galaxies have a black hole at the center at the least?
That might account for both of your points, along with the observation that the universe is constantly expanding (matter continuously arriving through the black hole in another universe).
You are checking your backups, aren't you?
Others suggest alot of neutron stars spinning around out there, also not likely. We'd have noticed them, either by an inordinate amount of nearby pulsars, or simply from gravitational lensing. Same goes for dead hunks of carbon. To make up the missing mass, there would have to be many of these things. And with many of them, the chance of spotting several would be high.
The macho theory suggests there COULD be a *few* but *extremely* massive objects wandering around out there. Something like supermassive blackholes, or something else. If there were a few, and they emitted no light (likely), then they'd be easy to miss.
The other theory suggests that there is some kind of exotic matter which we haven't discovered yet that emits no known form of radiation, but may indeed generate gravity. This is also possible, as the newly discovered 'dark energy''s origins are also unknown. The confirmation of dark energy (which is recent) is what drives the expansion of the universe, and is indeed some kind of 'anti gravity'. Very interesting, but very strange. And we have no idea where the hell it comes from.
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Among the current theories that are more "exotic" then WIMPs (neutralino and friends) those that deal with the breakdown of the Newton law at large distances look like the most promising.. ;)
Many people do not realise that general relativity equation do have some fairly heavy assumptions - like requirement for the equations to be of no higher then second order. It may be possible to write a different theory that will lead to non-linear beahviour of acceleration for small forces. That would explain rotational curves (the most solid evidence for dark matter) without dark matter.
Nevertheless, WIMPs involve less new assumptions, at elast at this moment, so Brother Occam tells us it must be true..
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