beecee Posted March 28, 2018 Posted March 28, 2018 (edited) https://phys.org/news/2018-03-dark-galaxy.html Dark matter 'missing' in a galaxy far, far away: March 28, 2018, Gemini Observatory Galaxies and dark matter go hand in hand; you typically don't find one without the other. So when researchers uncovered a galaxy, known as NGC1052-DF2, that is almost completely devoid of the stuff, they were shocked. "Finding a galaxy without dark matter is unexpected because this invisible, mysterious substance is the most dominant aspect of any galaxy," said lead author Pieter van Dokkum of Yale University. "For decades, we thought that galaxies start their lives as blobs of dark matter. After that everything else happens: gas falls into the dark matter halos, the gas turns into stars, they slowly build up, then you end up with galaxies like the Milky Way. NGC1052-DF2 challenges the standard ideas of how we think galaxies form." Read more at: https://phys.org/news/2018-03-dark-galaxy.html#jCp <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I find this article quite interesting to say the least. Questions I am asking, is as follows....[1] I see this as paradoxically firm evidence supporting the DM concept and up there with the Bullet cluster observation. But is it reason for revising the 24% accepted content that is thought to make up the universe? [2] It says that it is thought that galaxies start their lives as blobs of DM...I was not really aware of this, and my question is why not galaxies starting their lives as blobs of normal baryonic matter? [3] My third question arises from the following extract from the article, "To peer even deeper into this unique galaxy, the team used the Gemini Multi Object Spectrograph (GMOS) to capture detailed images of NGC1052-DF2, assess its structure, and confirm that the galaxy had no signs of interactions with other galaxies". Wouldn't this observation and data support my contention/question at [2]? that is, this being what one would term as a "pristine" galaxy in its early formation era, could mean that galaxies forms from conglomerations of baryonic matter, that later attracts the dispersed DM...afterall our knowledge of this DM, tells us it only interacts gravitationally. The paper for this article at nature.com/articles/doi:10.1038/nature25676 is not opening for me and says "cannot be found" Edited March 28, 2018 by beecee
et pet Posted March 30, 2018 Posted March 30, 2018 (edited) On 3/28/2018 at 3:29 PM, beecee said: <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I find this article quite interesting to say the least. Questions I am asking, is as follows....[1] I see this as paradoxically firm evidence supporting the DM concept and up there with the Bullet cluster observation. But is it reason for revising the 24% accepted content that is thought to make up the universe? [2] It says that it is thought that galaxies start their lives as blobs of DM...I was not really aware of this, and my question is why not galaxies starting their lives as blobs of normal baryonic matter? [3] My third question arises from the following extract from the article, "To peer even deeper into this unique galaxy, the team used the Gemini Multi Object Spectrograph (GMOS) to capture detailed images of NGC1052-DF2, assess its structure, and confirm that the galaxy had no signs of interactions with other galaxies". Wouldn't this observation and data support my contention/question at [2]? that is, this being what one would term as a "pristine" galaxy in its early formation era, could mean that galaxies forms from conglomerations of baryonic matter, that later attracts the dispersed DM...afterall our knowledge of this DM, tells us it only interacts gravitationally. The paper for this article at nature.com/articles/doi:10.1038/nature25676 is not opening for me and says "cannot be found" 1.) your Post seems to be your own Personal Subjective Speculation of a "contention/question" or Hypothetical Theory that goes Against the Mainstream "thought that galaxies start their lives as blobs of DM." - Is it your speculation, proposal, theory or contention for "galaxies starting their lives as blobs of normal baryonic matter"? 2.) An actual working Link to the nature.com article (Abstract) "A galaxy lacking dark matter" : https://www.nature.com/articles/nature25767 - Mentions in Scientific Articles, Blogs, etc of "A galaxy lacking dark matter" : https://www.nature.com/articles/nature25767/metrics 3.) At the bottom of the Article/Page you Linked in your Post : https://phys.org/news/2018-03-dark-galaxy.html , under Related Stories is an article Titled "Scientists discover a 'dark' Milky Way: Massive galaxy consists almost entirely of dark matter". Link : https://phys.org/news/2016-08-scientists-dark-milky-massive-galaxy.html#nRlv 4.) After reading "Scientists discover a 'dark' Milky Way: Massive galaxy consists almost entirely of dark matter", at the Link, how does that information affect your speculation, proposal, theory or contention for "galaxies starting their lives as blobs of normal baryonic matter"? Of Note : Both of these discoveries were the result of Observations and Data amassed from the the Gemini North and W. M. Keck Observatories, both on Maunakea, Hawai'i Edited March 30, 2018 by et pet correction -2
Strange Posted March 30, 2018 Posted March 30, 2018 On 28/03/2018 at 9:29 PM, beecee said: [1] I see this as paradoxically firm evidence supporting the DM concept and up there with the Bullet cluster observation. But is it reason for revising the 24% accepted content that is thought to make up the universe? I haven't read all the details yet, but I'm not sure why it would be better evidence for dark matter. I can't see that a few galaxies without dark would make much difference to the average amount; I guess it would be down there in the noise. Although I suppose it is good evidence against some/most "modified gravity" theories. On 28/03/2018 at 9:29 PM, beecee said: The paper for this article at nature.com/articles/doi:10.1038/nature25676 is not opening for me and says "cannot be found" The link is: https://www.nature.com/articles/nature25767 Also available on Arxiv: https://arxiv.org/abs/1803.10237 2 hours ago, et pet said: Is it your speculation, proposal, theory or contention for "galaxies starting their lives as blobs of normal baryonic matter"? I think you will find it was a question, not a "speculation, proposal, theory or contention". I don't know the answer. Do you? Another article discussing it here: https://www.universetoday.com/138911/hubble-finds-galaxy-almost-no-dark-matter/ This hints at why dark matter [usually] seeds the formation of galaxies. I remember reading some time ago about simulations of how the large scale structure of the universe forms. I don't remember the details, but I think that the structure formation was lead by dark matter and then formed a "framework" that attracted baryonic matter to the same structure. Not sure why it is that way round though ...
beecee Posted March 30, 2018 Author Posted March 30, 2018 (edited) 3 hours ago, et pet said: 1.) your Post seems to be your own Personal Subjective Speculation of a "contention/question" or Hypothetical Theory that goes Against the Mainstream "thought that galaxies start their lives as blobs of DM." - Is it your speculation, proposal, theory or contention for "galaxies starting their lives as blobs of normal baryonic matter"? Hmmmm, not real sure how you can interpret this as personal speculation when I specifically asked as a question. Quote [2] It says that it is thought that galaxies start their lives as blobs of DM...I was not really aware of this, and my question is why not galaxies starting their lives as blobs of normal baryonic matter? and touched on in my third question...... Quote [3] My third question arises from the following extract from the article, "To peer even deeper into this unique galaxy, the team used the Gemini Multi Object Spectrograph (GMOS) to capture detailed images of NGC1052-DF2, assess its structure, and confirm that the galaxy had no signs of interactions with other galaxies". Wouldn't this observation and data support my contention/question at [2]? that is, this being what one would term as a "pristine" galaxy in its early formation era, could mean that galaxies forms from conglomerations of baryonic matter, that later attracts the dispersed DM...afterall our knowledge of this DM, tells us it only interacts gravitationally. I certainly accept the "mainstream view" and it clears up my mistaken assumption expressed and highlighted at question [2] The question though still stands. 1 hour ago, Strange said: The link is: https://www.nature.com/articles/nature25767 Also available on Arxiv: https://arxiv.org/abs/1803.10237 Thanks muchly Strange.... Quote I think you will find it was a question, not a "speculation, proposal, theory or contention". I don't know the answer. Do you? Perhaps he will answer it in his next post? Edited March 30, 2018 by beecee
Strange Posted March 30, 2018 Posted March 30, 2018 24 minutes ago, beecee said: Perhaps he will answer it in his next post? Not holding my breath.
beecee Posted March 30, 2018 Author Posted March 30, 2018 4 hours ago, et pet said: 2.) An 4.) After reading "Scientists discover a 'dark' Milky Way: Massive galaxy consists almost entirely of dark matter", at the Link, how does that information affect your speculation, proposal, theory or contention for "galaxies starting their lives as blobs of normal baryonic matter"? It tells me that according to observational evidence so far, we have some galaxies cosnsisting almost entirely of DM, and some with next to no DM at all. My question therefor still stands, thus..... Quote It says that it is thought that galaxies start their lives as blobs of DM...I was not really aware of this, and my question is why not galaxies starting their lives as blobs of normal baryonic matter? Does that clear it up for you? In fact with galaxies with virtually no DM now observed, it appears my doubt, speculation, proposal, theory or contention [as you describe] is well founded. 3 hours ago, Strange said: Another article discussing it here: https://www.universetoday.com/138911/hubble-finds-galaxy-almost-no-dark-matter/ This hints at why dark matter [usually] seeds the formation of galaxies. I remember reading some time ago about simulations of how the large scale structure of the universe forms. I don't remember the details, but I think that the structure formation was lead by dark matter and then formed a "framework" that attracted baryonic matter to the same structure. Not sure why it is that way round though ... An extract from your link says, Quote "Based on data from Hubble, the team was able to determined its distance – 65 million light-years from the Solar System – as well as its size and brightness. In addition, the team discovered that NGC 1052-DF52 is larger than the Milky Way but contains about 250 times fewer stars, which makes it an ultra diffuse galaxy". Which sort of adds another layer of mystery to galactic formation. also from your link.... Quote “Dark matter is conventionally believed to be an integral part of all galaxies — the glue that holds them together and the underlying scaffolding upon which they are built… There is no theory that predicts these types of galaxies — how you actually go about forming one of these things is completely unknown.” Which along with the fact that DM makes up around 25% of the content of the universe against the 5% baryonic matter, sort of explains the "glue that holds them together aspect" and finally in summing from your link..... Quote "However, these theories do not explain how the galaxy formed. To address this, the team is analyzing images that Hubble took of 23 other ultra-diffuse galaxies for more dark-matter deficient galaxies. Already, they have found three that appear to be similar to NGC 1052-DF2, which could indicate that dark-matter deficient galaxies could be a relatively common occurrence. If these latest findings demonstrate anything, it is that the Universe is like an onion. Just when you think you have it figured out, you peal back an additional layer and find a whole new set of mysteries. They also demonstrate that after 28 years of faithful service, the Hubble Space Telescope is still capable of teaching us new things. Good thing too, seeing as the launch of its successor has been delayed until 2020!" Which again justifies my querie and shows that while we know much about galactic formation, there is still much more to learn.
et pet Posted March 31, 2018 Posted March 31, 2018 5 hours ago, Strange said: I think you will find it was a question, not a "speculation, proposal, theory or contention". I don't know the answer. Do you? I am fairly certain that beecee clearly stated in the Post : "Wouldn't this observation and data support my contention/question at [2]? that is, this being what one would term as a "pristine" galaxy in its early formation era, could mean that galaxies forms from conglomerations of baryonic matter, that later attracts the dispersed DM...afterall our knowledge of this DM, tells us it only interacts gravitationally." Note that beecee did not end that statement with a "question mark (?)", but rather a period (.). My understanding of the definition of the word "contention", is 1.) - a strong disagreement, or 2.) - an emphatic assertion utilized in an argument. : https://www.collinsdictionary.com/us/dictionary/english/contention , https://www.macmillandictionary.com/us/dictionary/american/contention or https://www.merriam-webster.com/dictionary/contention so, on to..." I don't know the answer. Do you?" No, Strange, I do not "know the answer". -1
beecee Posted March 31, 2018 Author Posted March 31, 2018 (edited) 46 minutes ago, et pet said: I am fairly certain that beecee clearly stated in the Post : "Wouldn't this observation and data support my contention/question at [2]? that is, this being what one would term as a "pristine" galaxy in its early formation era, could mean that galaxies forms from conglomerations of baryonic matter, that later attracts the dispersed DM...afterall our knowledge of this DM, tells us it only interacts gravitationally." Note that beecee did not end that statement with a "question mark (?)", but rather a period (.). My understanding of the definition of the word "contention", is 1.) - a strong disagreement, or 2.) - an emphatic assertion utilized in an argument. : https://www.collinsdictionary.com/us/dictionary/english/contention , https://www.macmillandictionary.com/us/dictionary/american/contention or https://www.merriam-webster.com/dictionary/contention so, on to..." I don't know the answer. Do you?" No, Strange, I do not "know the answer". On 3/29/2018 at 6:29 AM, beecee said: I find this article quite interesting to say the least. Questions I am asking, is as follows....[1] I see this as paradoxically firm evidence supporting the DM concept and up there with the Bullet cluster observation. But is it reason for revising the 24% accepted content that is thought to make up the universe? [2] It says that it is thought that galaxies start their lives as blobs of DM...I was not really aware of this, and my question is why not galaxies starting their lives as blobs of normal baryonic matter? [3] My third question arises from the following extract from the article, "To peer even deeper into this unique galaxy, the team used the Gemini Multi Object Spectrograph (GMOS) to capture detailed images of NGC1052-DF2, assess its structure, and confirm that the galaxy had no signs of interactions with other galaxies". Wouldn't this observation and data support my contention/question at [2]? that is, this being what one would term as a "pristine" galaxy in its early formation era, could mean that galaxies forms from conglomerations of baryonic matter, that later attracts the dispersed DM...afterall our knowledge of this DM, tells us it only interacts gravitationally. The paper for this article at nature.com/articles/doi:10.1038/nature25676 is not opening for me and says "cannot be found" Obviously whatever you are trying to claim is full of holes my friend. You do recognise the question marks? three of them...The "statement" after [2]? was simply a clarification on the question. "But of course I welcome you to put whatever it is you are claiming to the mods and admins...I'll stand and/or fall on that judgement...as will you of course. Quote Strange, I do not "know the answer". That's OK, that's why I asked the question. ps: You do though sound like a long lost friend of mine on another forum. I just need to remind you that the nonsense that this long lost friend of mine got away with there, will not be tolerated here. Take it easy! Edited March 31, 2018 by beecee
et pet Posted March 31, 2018 Posted March 31, 2018 4 hours ago, beecee said: Hmmmm, not real sure how you can interpret this as personal speculation when I specifically asked as a question. and touched on in my third question...... I certainly accept the "mainstream view" and it clears up my mistaken assumption expressed and highlighted at question [2] The question though still stands. Thanks muchly Strange.... Perhaps he will answer it in his next post? To repeat my response to Strange, in case you did not read it : beecee, I am fairly certain that you clearly stated in your Post, in your "third question......" : "Wouldn't this observation and data support my contention/question at [2]? that is, this being what one would term as a "pristine" galaxy in its early formation era, could mean that galaxies forms from conglomerations of baryonic matter, that later attracts the dispersed DM...afterall our knowledge of this DM, tells us it only interacts gravitationally." Note beecee, that you did not end that statement with a "question mark (?)", but rather a period (.). My understanding of the definition of the word "contention", is 1.) - a strong disagreement, or 2.) - an emphatic assertion utilized in an argument. : https://www.collinsdictionary.com/us/dictionary/english/contention , https://www.macmillandictionary.com/us/dictionary/american/contention or https://www.merriam-webster.com/dictionary/contention in reference to : "Perhaps he will answer it in his next post?" I posed that question to you, beecee. It is NOT for me to answer. It is for you to answer, if you choose to. Is it your contention for "galaxies starting their lives as blobs of normal baryonic matter"? -2
beecee Posted March 31, 2018 Author Posted March 31, 2018 5 minutes ago, et pet said: To repeat my response to Strange, in case you did not read it : et pet, you can repeat your response as much as you like ...It doesn't work that way here. I asked three questions as is positively shown and recognised by genuine members without any axe to grind. Whatever nonsense and pedant you wish to pursue I'll leave for others to counter and/or moderate on. Quote I posed that question to you, beecee. It is NOT for me to answer. It is for you to answer, if you choose to. Is it your contention for "galaxies starting their lives as blobs of normal baryonic matter"? That wasn't my question...my question/s was... "[2] It says that it is thought that galaxies start their lives as blobs of DM...I was not really aware of this, and my question is why not galaxies starting their lives as blobs of normal baryonic matter? [3] My third question arises from the following extract from the article, "To peer even deeper into this unique galaxy, the team used the Gemini Multi Object Spectrograph (GMOS) to capture detailed images of NGC1052-DF2, assess its structure, and confirm that the galaxy had no signs of interactions with other galaxies". Wouldn't this observation and data support my contention/question at [2]? that is, this being what one would term as a "pristine" galaxy in its early formation era, could mean that galaxies forms from conglomerations of baryonic matter, that later attracts the dispersed DM...afterall our knowledge of this DM, tells us it only interacts gravitationally".
et pet Posted March 31, 2018 Posted March 31, 2018 56 minutes ago, beecee said: Obviously whatever you are trying to claim is full of holes my friend. You do recognise the question marks? three of them...The "statement" after [2]? was simply a clarification on the question. "But of course I welcome you to put whatever it is you are claiming to the mods and admins...I'll stand and/or fall on that judgement...as will you of course. That's OK, that's why I asked the question. ps: You do though sound like a long lost friend of mine on another forum. I just need to remind you that the nonsense that this long lost friend of mine got away with there, will not be tolerated here. Take it easy! I am NOT trying to claim anything. I am simply asking, Is it your contention for "galaxies starting their lives as blobs of normal baryonic matter"? It appears that you have chosen not to answer that question. - in reference to : "ps: You do though sound like a long lost friend of mine on another forum. I just need to remind you that the nonsense that this long lost friend of mine got away with there, will not be tolerated here. Take it easy! " What? How does that have anything to do with : "More evidence for Dark Matter:"?
beecee Posted March 31, 2018 Author Posted March 31, 2018 (edited) 16 minutes ago, et pet said: I am NOT trying to claim anything. That's nice. Quote I am simply asking, Is it your contention for "galaxies starting their lives as blobs of normal baryonic matter"? It appears that you have chosen not to answer that question. I have asked the question/s [three of them] and suggested another possibility with regards to one of them...and Strange has answered to the best of his ability and knowledge as usual. Quote in reference to : "ps: You do though sound like a long lost friend of mine on another forum. I just need to remind you that the nonsense that this long lost friend of mine got away with there, will not be tolerated here. Take it easy! " What? How does that have anything to do with : "More evidence for Dark Matter:"? Nothing of course...Just pointing out an observation. Yes this is more evidence for DM, based on the ability to observe where it does not exist as opposed to where it does exist, based of course on galactic rotational curves. Quote The team's results demonstrate that dark matter is separable from galaxies. "This discovery shows that dark matter is real - it has its own separate existence apart from other components of galaxies," said van Dokkum. Read more at: https://phys.org/news/2018-03-dark-galaxy.html#jCp Edited March 31, 2018 by beecee
et pet Posted March 31, 2018 Posted March 31, 2018 (edited) 1.) I was not, and I am still not, aware that Dark Matter has ever been directly observed. 2.) I evidently was, and still am, completely mistaken that I read the word "contention" in beecee's First Post. 3.) It seems that I am Not one of this forums "genuine members without any axe to grind". So, I must therefore extend my sincerest apologies to beecee, Strange and any other person(s) that has read this discussion. I am sorry that I am currently not aware that Scientists have indeed been able to observe where Dark Matter does not exist, nor of their ability to observe where Dark Matter does exist. Please forgive my ignorance that Dark Matter has been directly observed. I am sorry that I mistakenly claimed that beecee used the word "contention" in his first post. I can only hope that my extreme contrition may someday allow me to become one of this forums "genuine members without any axe to grind". Again, I extend my deepest apologies to beecee, Strange and any other reader(s) of my Postings. Edited March 31, 2018 by et pet clarification ? -2
beecee Posted March 31, 2018 Author Posted March 31, 2018 (edited) 49 minutes ago, et pet said: 1.) I was not, and I am still not, aware that Dark Matter has ever been directly observed. I said, "Yes this is more evidence for DM, based on the ability to observe where it does not exist as opposed to where it does exist, based of course on galactic rotational curves." I did not say "directly observed" That's simply another example of you misinterpreting/taking out of context/or deliberately being obtuse and misleading. Other evidence for DM of course was the bullet cluster observation, and of course gravitational lensing of distant galaxies by intervening DM. Quote 2.) I evidently was, and still am, completely mistaken that I read the word "contention" in beecee's First Post. I said "Wouldn't this observation and data support my contention/question at [2]?" that is, this being what one would term as a "pristine" galaxy in its early formation era, could mean that galaxies forms from conglomerations of baryonic matter, that later attracts the dispersed DM...afterall our knowledge of this DM, tells us it only interacts gravitationally. More light was thrown on that possibility by Strange and his link here... Quote Another article discussing it here: https://www.universetoday.com/138911/hubble-finds-galaxy-almost-no-dark-matter/ This hints at why dark matter [usually] seeds the formation of galaxies. I remember reading some time ago about simulations of how the large scale structure of the universe forms. I don't remember the details, but I think that the structure formation was lead by dark matter and then formed a "framework" that attracted baryonic matter to the same structure. Not sure why it is that way round though .. . Quote 3.) It seems that I am Not one of this forums "genuine members without any axe to grind". Your rather childish and misinterpreted pedant about what I said and what I obviously mean, certainly leads me to that conclusion. Quote I am sorry that I am currently not aware that Scientists have indeed been able to observe where Dark Matter does not exist, nor of their ability to observe where Dark Matter does exist. DM by definition means not baryonic, but as I have informed you, we do have observational evidence of its existence, in some/most galaxies, and as I detailed in the OP, observational evidence where it does not exist in other galaxies, based on their rotational curves or angular momentum.. Quote Please forgive my ignorance that Dark Matter has been directly observed. I said, "Yes this is more evidence for DM, based on the ability to observe where it does not exist as opposed to where it does exist, based of course on galactic rotational curves." I did not say "directly observed" That's simply another example of you misinterpreting/taking out of context/or deliberately being obtuse and misleading. Quote I am sorry that I mistakenly claimed that beecee used the word "contention" in his first post. I can only hope that my extreme contrition may someday allow me to become one of this forums "genuine members without any axe to grind". Again, I extend my deepest apologies to beecee, Strange and any other reader(s) of my Postings. I wish I could believe that. But time will tell. Edited March 31, 2018 by beecee
Strange Posted March 31, 2018 Posted March 31, 2018 57 minutes ago, et pet said: I am sorry that I am currently not aware that Scientists have indeed been able to observe where Dark Matter does not exist, nor of their ability to observe where Dark Matter does exist. As you are so woefully ill-informed about the current state of science, I'm not sure why you are pontificating in this thread. 1
swansont Posted March 31, 2018 Posted March 31, 2018 17 hours ago, et pet said: 1.) your Post seems to be your own Personal Subjective Speculation of a "contention/question" or Hypothetical Theory that goes Against the Mainstream "thought that galaxies start their lives as blobs of DM." - Is it your speculation, proposal, theory or contention for "galaxies starting their lives as blobs of normal baryonic matter"? ! Moderator Note If you think a post should be moved to speculation, you should report it to the staff, rather than take it upon yourself to enforce rule. The post links to the source material, and asks followup questions. It is not personal subjective speculation. Quote Note beecee, that you did not end that statement with a "question mark (?)", but rather a period (.). ! Moderator Note Try not to be obtuse And focus on the discussion at hand, rather than the people involved. 2
Strange Posted April 9, 2018 Posted April 9, 2018 On 30/03/2018 at 9:33 PM, Strange said: I haven't read all the details yet, but I'm not sure why it would be better evidence for dark matter. This article answer this question (and several others): http://astrobenne.blogspot.it/2018/04/the-galaxy-without-that-special.html Quote oddly a galaxy stripped of dark matter is solid proof that it exists: if it's stuff, it can be missing. If dark matter is really a different kind of gravity, one can't take it out of a galaxy, it's an inherent property. Overall summary seems to be that the conclusions in the original paper need more work.
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