Andromeda's Origin Similar to That of Milky Way

telfrow · Feb 28, 2006

For the last decade, astronomers have thought that the Andromeda galaxy, our nearest galactic neighbor, was rather different from the Milky Way. But a group of researchers have determined that the two galaxies are probably quite similar in the way they evolved, at least over their first several billion years. In an upcoming issue of the Astrophysical Journal, Scott Chapman of the California Institute of Technology, Rodrigo Ibata of the Observatoire de Strasbourg, and their colleagues report that their detailed studies of the motions and metals of nearly 10,000 stars in Andromeda show that the galaxy's stellar halo is "metal-poor." In astronomical parlance, this means that the stars lying in the outer bounds of the galaxy are pretty much lacking in all the elements heavier than hydrogen. This is surprising, says Chapman, because one of the key differences thought to exist between Andromeda and the Milky Way was that the former's stellar halo was metal-rich and the latter's was metal-poor. If both galaxies are metal-poor, then they must have had very similar evolutions. "Probably, both galaxies got started within a half billion years of the Big Bang, and over the next three to four billion years, both were building up in the same way by protogalactic fragments containing smaller groups of stars falling into the two dark-matter haloes," Chapman explains. Link <div class="Discussion_UserSignature"> Made weak by time and fate, but strong in will to strive, to seek, to find and not to yeild. - Tennyson </div>

bonzelite · Feb 28, 2006

i pretty much followed and was fine until they said "dark matter haloes." excerpt: While no one yet knows what dark matter is made of, its existence is well established because of the mass that must exist in galaxies for their stars to orbit the galactic centers the way they do... ^^^dark matter's existence is not well established. that little comment is a way of sidestepping the subject of the heretofore unknown nature of gravity itself, ie, gravity is not really known as to what it is really about. so instead of examining the lack of gravity knowledge, they skip over it and remain fixated on dark matter to take the limelight off of their unknowing. they could say, more accurately "at this time we are still unaware of the reason behind the flat radial velocites observed in galaxies that apparently contradict our current models for gravitation." then i would have had a bit more enthusiasm for this article.

Saiph · Mar 1, 2006

Actually, there is a significant number of people in astronomy that lean towards the idea that our understanding of gravity is flawed. However, the work to date on that (MOND for instance) have failed to provide sufficient support via predictions and observations. So people are still working on that. Dark matter models however, have allowed researchers to accurately model and simulate various galaxy formations (barred spirals and merger rates), as well as adequately explaining the odd orbital velocities. So, dark matter has so far been a more accurate tool. Now, this could be because a) there is dark matter out there, with the properties assigned to it or b) the way dark matter is being applied is simulating the real mechanism, which is a gravitational basis. So we've really got a dichotomy in the field right now. Lots of people are seeing what can be done with dark matter models, some people are looking at gravity, and so far, nobody has anything really conclusive. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

bonzelite · Mar 1, 2006

]] b) the way dark matter is being applied is simulating the real mechanism, which is a gravitational basis. yes. they can apply anything they wish to compensate for the "lack of matter," and it will fulfill the "model." but it does not in any way necessarily reflect any bearing on reality. So we've really got a dichotomy in the field right now. there is a misrepresentation in the filed by yet continuing on with the idea of dark matter at all. they publish this material with the confidence that such a substance is actually there. when it is more than likely not there, as there is no evidence for it's existence.

Saiph · Mar 1, 2006

I'm not to familiar with the field, but there is evidence for it. First, we know what some dark matter is, but only about 15% of what's needed. Is that a major blow against the idea? Yeah, and one that's being looked at. People are searching for the rest, or finding ways of doing with less, or working around the idea of dark matter all together. The supporting evidence for darkmatter's existence is that the models work. By inclusion of dark matter in distribuitions that would produce the strange galactical orbital velocity distributions, we also get barred spiral galaxies, something we weren't able to simulate at all before using standard GR gravity. Now, that means either the dark matter is there, or the actual mechanism works in such a way as to make it apear there is dark matter. but you can't just chuck out the dark matter idea, and go with some underlying mechanism, because we don't know what that is, and when we try other things with dark matter, we also get suitable results. So, does the astronomy field know there's a problem? Oh yes. Do we have reservations about dark matter? Yep. So we look into the problem, which involves examining all the consequences of the dark matter idea, and working on alternatives. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

bonzelite · Mar 1, 2006

I'm not to familiar with the field, but there is evidence for it. there is evidence for a gravitational anomaly, to understate it, in galaxies. not for dark matter. dark matter is pure conjecture being passed off in the media as if it is nearly almost a slam-dunk, done deal. and this is a gross misrepresentation.

Saiph · Mar 1, 2006

Oh, I agree the media tends to overstate the issue. The media takes every single scientific report to be the end all, be all consensus of the scientific community. Rarely do they point out that each report is only one statement in a years long discussion of the subject. It's akin to how taking a single post in a thread here at SDC could easily give you some very strange conclusions. But if you look at the whole thread (or series of threads) you get a much better picture. Now, as to the validity of dark matter: I see no reason to actually discount it. Sure, there's no reason to say it's actually absolutely there, but it certainly looks like it. So the astronomers are running with the idea for a while, to see where it takes them. It may be wrong in the end (completely, partially, whatever) but science is also about figuring out the wrong answers to things, and more importantly why they are wrong. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

bonzelite · Mar 1, 2006

agreed.

robnissen · Mar 1, 2006

It seems to me that both "dark matter" and (even worse) "dark energy" are very problematic. But for the time being we are stuck with them, because we have no other models that explain the universe. I think we may be in the same position as 19th century physicists who had no idea how the sun was creating energy. They knew that even if the sun was pure carbon, it would have used up its energy source eons before life even began on earth. Now, I don't know if 19th century physicists referred to the unknown energy source for the sun as "dark energy," but that is basically what it was for them. Science did not just stop because they couldn't explain the sun's energy source. Likewise, science cannot stop merely because we can't currently explain dark energy and dark matter. We label both as "dark" to admit we don't know exactly what is going on, and we continue to learn. Hopefully, some day we will understand dark energy and dark matter as well as we now understand the sun's energy source.

Saiph · Mar 1, 2006

actually the "dark" label is to indicate that the mechanism isn't producing, or produced by, material giving off detectable amounts of light. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

bonzelite · Mar 1, 2006

actually the "dark" label is to indicate that the mechanism isn't producing, or produced by, material giving off detectable amounts of light. right, but as well, the dark matter and the energy are not detectable whatsoever by any means, as their existence is purely speculative and is incapable of being proven to even exist. as i said earlier, dark energy and matter are terms used to skirt the issue that modern "official" science does not really know what gravity is or how it really works. today, the gravitational models are assumed to be correct, so this is why they invent dark matter and energy to make the assumed models for gravitation remain "true." the reaity of the non-existence of dark matter or energy is downplayed, and, instead, purported to be things just "right around the corner of confirmation," when that, too, is absolutely inaccurate.

Saiph · Mar 1, 2006

bonz: that is certainly one way of looking at it. However no tweaks of gravitational models, or new gravitational systems have produced satisfactory results. So the work involving dark matter continues, as the posited presence of dark matter has provided accurate answers. Now, we may be getting the right answers, for the wrong reasons, but if so, that'll come to light sooner or later. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

bonzelite · Mar 1, 2006

Now, we may be getting the right answers, for the wrong reasons, but if so, that'll come to light sooner or later. again, agreed. ^^^above is a good thesis statement. if we go plugging in extra mass, matter, energy, to fulfill an incorrect, or, at best, incomplete model for gravity, then of course the results will be cofirmational and the model will work. but the results will still reflect inconsistencies in the model at it's very core, hence the need to fabricate more mass and energy to compensate for a potentially incorrect idea of gravity. and as you say, the nature of this mystery has yet to be determined.

Saiph · Mar 1, 2006

actually, it's a rather poor one. Lets see... The Astronomical Community explores the extent of the Dark Matter Models to find it's uses, limitations, and ultimate accuracy. That's a thesis statement. edit: limitates is not a word...oops. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

bonzelite · Mar 1, 2006

so far we've been sort of playing a safe gentleman's ping ponging of dark matter and it's validity with very little debate, as we sort of both agree on that it is indeterminant, with you being more apt to have enthusiasm for it's actual existence, and i having NONE. your thesis statement is worded in a way that bolsters it's possible existence as if it were real or may already be real: "...the extent of the Dark Matter Models to find it's uses, limitates, and ultimate accuracy. /i> you seem to give it an office, with a fax, phone, and address and company car by implying "it's uses, limits, and ultimate accuracy." when, really, it is useless. "dark matter is so far undetectable and incapable of being proven to exist --we may be derving results from it's assumed existence for the wrong reasons." that is a thesis statement.

Saiph · Mar 1, 2006

:::shrugs::: I think you're overstating the case against dark matter. If you'd like to take this discussion to another thread, where you present your case against Dark matter (i.e. why it's an unnecessary assumption, why it's undetectable, and why it can't be proven to exist) I'll chat with you there. As it is, I think we're bordering on a "hijacking" here, as we've diverged significantly from the thread topic. Now, mind you, this is one area I'll admit I'm a bit weak on. But I'm willing to spend some of my time slogging through references to learn about Dark matter beyond the classic supporting evidence of Galactic Radial Velocity graphs. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

bonzelite · Mar 1, 2006

this is typical of your behavior when a subject gets too hot under your collar. you cannot have any of it, so you call for another thread where you will be just as refuted. just as you were defeated in the entire NASA as military subject matter, and the subject matter here is EXACTLY on topic, by the way, as the thrust of the article, if you were to read it, places "dark matter haloes" front row centre. the readers and lurkers of this thread know good and well this to be true, and that your call for another thread is unnecessary. if anything, we're bordering on evasiveness from you, and, with your "control" status, you can say whatever you wish and it must be, then, validated. i am not validating your hijacking comment, nor the existence of dark matter haloes that are the thrust of the article. the content thus far is perfectly on track in dealing with the article, "Captain Saiph."

jatslo · Mar 1, 2006

**Dark Matter Halo**; and talking about dark matter is hyjacking, not to mention that these are empherical observations of *PHENOMENON* yet once again. Is it your job to bark at people openly, and/or draw attention, so that the moderators can act, if need be? Dark Matter Halo was mentioned in the article, which is one of telfrow's "Cut & Paste" jobs.

jatslo · Mar 1, 2006

RobNissen: "... Hopefully, some day we will understand dark energy and dark matter as well as we now understand the sun's energy source ..." That is an interesting comparison; however, you might be guilty of false premise at sometime in the future. For example, It may turn out that energy production on the Sun is *not* well understood, right? They change the star models frequently, right? Maybe comparing the *DARK* unknowns to fission, and/or fusion knowledge would strengthen your argument; do you think? Just a thought ...

CalliArcale · Mar 1, 2006

Actually, bonzelite, he's right. There's nothing wrong with brief tangents into related subjects, but if the related subject needs to be discussed in greater detail, it would be more appropriate to do so in another thread rather than co-opting an existing one. And there's no need to bring other threads into this one either. You're already discussing NASA's civilian status and military connections in another thread. (In which you did not acheive the victory you claim here. It is disingenuous to bring up other discussions where they are not remotely relevant and then claim victory when you know anyone trying to be productive cannot refute you without dragging the thread even further off topic.) <div class="Discussion_UserSignature"> "People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff." -- The Tenth Doctor, "Blink" </div>

bonzelite · Mar 1, 2006

the subject is on topic with dark matter, as that is a main pillar of the article. it discusses metal-rich, metal-poor galaxies, and dark matter. how is this discourse off topic? i never stated that "i achieved victory." now you are getting off topic and putting words in my mouth. i stated that saiph was refuted. and he was successfully refuted. as nasa is an entity of the military --period-- as this cannot be refuted. just as he is being refuted here by others, and you are defending him as he cannot make this stand by himself. for example, this is on topic --- /> dark matter haloes. my whole schtick has been talk of dark matter. and i am off topic in your view because Saiph is being refuted and you personally do not like it. and that has nothing to do with science whatsoever, but my posts do.

TheShadow · Mar 2, 2006

There was no reason to attack Saiph regarding his request to start another thread discussing dark matter. He made the suggestion, and you had the option of either accepting and starting a Dark Matter thread, or declining and continuing on with the discussion. Disrupting the thread by turning his request into a basis for personal attacks is not an option. If you disagree with the suggestion or request of another member, and you want to discuss it, it should be handled by PM or as a topic in Suggestions. Most of the problems we have had lately are directly related to members taking a comment made by someone else and using it to derail the thread into a discussion about that comment, instead of continuing to discuss the actual topic. This will not continue. I am posting this here only so that everyone will understand how the thread is off track and the reason for getting it back on. Start a thread on Dark Matter if you want to go into it in depth, or continue to discuss Dark Matter in context with the current discussion on Andromeda’s origin. Further discussions of whether a new thread should have been suggested, or whether or not Dark Matter is appropriate are concluded, at least on this thread. <div class="Discussion_UserSignature"> Who knows what evil lurks in the hearts of men, the Shadow knows. </div>

bonzelite · Mar 2, 2006

i was waiting for you, Shadow.

CalliArcale · Mar 2, 2006

<blockquote>In reply to:<hr />my whole schtick has been talk of dark matter.<hr /></blockquote> If dark matter is all you want to talk about, that's fine. But please do not disrupt other threads to do it. It is acceptable and quite reasonable to bring dark matter up in threads where it is relevant, such as this one. However, it should be confined to only where it relates to the topic of the thread, and should not digress into a discussion of dark matter which is completely independent of the topic of the thread. This is not a bias against dark matter discussions, as you seem to think. In fact, I find dark matter very interesting. Nor is this a bias in favor of Saiph or mainstream science. The same common courtesy applies no matter who is doing the talking and no matter what the subject is. Consider this: if colesakick started a thread about the Electric Universe and I were to hijack it into a discussion about good electrostatic discharge practises in the computer industry, that would not be appropriate, even though ESD is tangentially relevant to the EU, as it also is about static electricity. At best, it might warrant a brief mention, but not a full-scale digression. That would be very rude to colesakick and to any other members who had been trying to discuss the electric universe on its own merits. I will not tolerate any further digression in this thread. Let's get back on topic now, okay? If you want to discuss moderator actions, please do so in Suggestions. <div class="Discussion_UserSignature"> "People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff." -- The Tenth Doctor, "Blink" </div>

jatslo · Mar 2, 2006

Saiph: "... If you'd like to take this discussion to another thread, where you present your case against Dark matter (i.e. why it's an unnecessary assumption, why it's undetectable, and why it can't be proven to exist) I'll chat with you there ..." Dark matter is *empirical observation of phenomenon*, so where exactly should we talk about dark matter, if this point is space-time is, in fact, not the place? I *WILL* talk about alternatives to mainstream science, in which "Mainstream Science" is fallacy, and if any of you get political and/or religious, I *WILL* call you on it. [You = Moderators, Secret Police, Administrators, CIA, NSA, HLS, President Bush, etc...], and if any of you *ABUSE* your power, I will write *SPACE.COM ADMINISTRATION* a 1000-word executive summary, and build a case against you in a very compelling way. ..., So where do we battle, for a line has been drawn in the sands of time for all to see; minions from both camps are lining up on both sides for *ONE* decisive battle that will end this *MADNESS* once and for all. JUMPING FLAMING JACK-O-LANTERNS!!!!!!!!!!!!! WIN ONE FOR THE *MAXTHEKNIFE* PHENOMENA ...

Andromeda's Origin Similar to That of Milky Way

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