Cosmic ‘Needle in a Haystack’ Confirms Dark Energy

Article written: 25 Aug , 2008
Updated: 24 Dec , 2015
by

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A massive cluster of galaxies seen in the distant universe by ESA’s orbiting XMM-Newton x-ray observatory is so big that astronomers believe there can only be a few of them that far away in space and time. “Such massive galaxy clusters are thought to be rare objects in the distant Universe,” said Georg Lamer, Astrophysikalisches Institut in Potsdam, Germany. “They can be used to test cosmological theories. Indeed, the very presence of this cluster confirms the existence of a mysterious component of the Universe called dark energy.” The astronomers compared the rare find to a cosmic ‘needle in a haystack.’

The newly-discovered monster, known by the catalogue number 2XMM J083026+524133, is 7.7 thousand million light-years distant and is estimated to contain as much mass as a thousand large galaxies. Much of it is in the form of 100-million-degree hot gas. The bright blue blob of gas was found during a systematic analysis of catalogued objects as Lamer and his team were looking for patches of X-rays that could either be nearby galaxies of distant clusters of galaxies.

Based on 3,500 observations performed with XMM-Newton’s European Photon Imaging Camera (EPIC) covering about 1% of the entire sky, the catalogue contains more than 190,000 individual X-ray sources. J083026+524133 stood out because it was so bright. While checking visual images from the Sloan Digital Sky Survey, the team could not find any obvious nearby galaxy in that location. So they turned to the Large Binocular Telescope in Arizona and took a deep exposure, which found a cluster of galaxies in that location.

The astronomers were surprised to find the cluster contains a thousand times the mass of our own Milky Way Galaxy.

No one knows what dark energy is, but it is causing the expansion of the Universe to accelerate. This hampers the growth of massive galaxy clusters in more recent times, indicating that they must have formed earlier in the Universe. “The existence of the cluster can only be explained with dark energy,” says Lamer.

Yet he does not expect to find more of them in the XMM-Newton catalogue. “According to the current cosmological theories, we should only expect to find this one cluster in the 1% of sky that we have searched,” says Lamer.

Source: ESA

Nancy Atkinson is currently Universe Today’s Contributing Editor. Previously she served as UT’s Senior Editor and lead writer, and has worked with Astronomy Cast and 365 Days of Astronomy. Nancy is the author of the new book “Incredible Stories from Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos.” She is also a NASA/JPL Solar System Ambassador.


57 Responses

  1. LLDIAZ says

    I’ve been reading your articles for some time now, so I know when to read “read between the lines” and kind of pick out the facts from the lets say “not so factual statements”.
    My question is that for someone that has never been to this website you guys make a strong case on Dark Energy/Dark Matter. Is there a story I missed or something I did’nt read in which this phenomena has been proven. Thanx

  2. byron says

    Another proof of dark energy that isn’t proof at all. How about “Un-Explained phenomena in universe seems to suggest that super clusters formed in the early days of galaxy formation”

    The only Dark Energy i know of is the nasty permutation from GWB’s mouth!

  3. serenity says

    “XMM-Newton x-ray observatory is so big that astronomers believe there can only be a few of them that far away in space and time.”

    Umm, what? A pretty big typo, or am I missing something? 😉

  4. The image was crowding out some of the words. I’ve now re-sized it, so the article should be easier to read. They haven’t perfected WordPress yet!

  5. David R. says

    @ Byron:

    I was thinking the same thing after reading:
    “No one knows what dark energy is, but it is causing the expansion of the Universe to accelerate.”
    This must be a creative way of saying, “Not sure what the hell it is, but it’s somethin’ that’s causin’ somethin.”

  6. Miguel V. says

    I don’t see why the existence of such massive clusters in the early universe is a proof of “Dark Energy”. However, such massive structures put a challenge for the current cosmological model, which predict that massive structures are assembled late in the universe’s life, so the abundance of such clusters is necessary to constraint the cosmological model. Nevertheless, this would give little information about the “cosmological constant” or “Dark Energy”.

    See, for example the figure in this post
    http://backreaction.blogspot.com/2007/12/cosmological-parameters.html

  7. Mikel says

    If this explanation isn’t Mainstream Astronomy’s way of propping up BBT, I don’t know what is. They pulled it right out of their collective a**es.

    The house of cards will soon tumble.

    – Mikel

  8. Robert D. says

    Is “god” going to knock the “house of cards” down with a lightning bolt?

  9. Sili says

    Actually it’s one something causing several somethings.

    We don’t know what it is, but it turns up as an energy term – and we can’t see it, hence “dark”. The fact that this one extra assumption can explains a variety of observations should be rather encouraging.

    I’d be a lot more worried if this clustering required a hitherto unknown ‘perturbation’ of cosmology.

  10. Mikel says

    DE and DM should really be called ‘don’t have a clue ONE’ and ‘don’t have a clue TWO.’

    – Mikel

  11. Thomas says

    It seems to me that asto-physics is trying to explain things that they honestly don’t understand even slightly. The movie trilogy “The Matrix” had an interesting bit of spiritual wisdom that one cannot see past a choice which they do not understand. This language of spirituality can be applied to logic very well: We cannot explain pheonomenon past laws we do not have a full grasp of. Einstein’s relativity theories totally warped the ideas of science at that time, and we are still dealing w/the waves of change it created.

    In this case, both dark matter and energy I think are more mathematical place holders that look to exist only because the laws they are built upon we have very little understanding of. I am not stating that we shouldn’t continue to look, but if we really want to explain what we are seeing (an accelerating universe or “more mass” than we can see) I think we need a much better and more intimate understanding of both relativity and quantum mechanics first.

    ~ Thomas

  12. Jshobe says

    LLDIAZ – I don’t see anyone confirming what dark energy is or that it is a proven phenomenan, but that another confirmation can be cited that there is an energy in the universe which we cannot directly see. The fact that a galaxy cluster of this size was able to coagulate 8 Billion years ago, but seems out of the realm of possibility today (because none have been observed this side of 8 billion years distant) hints at the impact of this energy we cannot detect directly.

    When dark energy is “proven” it will likely be governed by the physical laws of the “empty” space into which our universe expanded, and empty space that continues to encircle us as though we were an air filled balloon trapped at ever increasing depths of a bottomless ocean. The balloon continues to expend from the surrounding pressures placed on it by the surrounding and increasing pressures of the water outside it. If the balloon were to never pop, the air inside it would become massively separated by increasing pressure.

  13. Markus Demetrius says

    While seemingly at odds, both Thomas and Jshobe make excellent points. You are the reason I read beyond the articles to the comments, where new perspectives are to be found. Thanks guys.

  14. Ayti says

    If you have a clue go ahead and enlighten the world – DM & DE are discriptive place holders for sets of physical phenomena that need to be understood in the context of the various models of how our universe works. I don’t think any scientist ever said: DM & DE are facts if you don’t believe in them, you’re a heretic! The same is true for BBT. If there was a better theory then we’d be talking about it don’t you think?

  15. DrNecropolis says

    I’m not so sure we should necessarily lump DE and DM together. Sure they’re both called “dark”, but Dark Matter isn’t hard to explain, hell a comet w/ a crunchy rock coating (like a King Cone or Drumstick pick your brand) turns into dark matter so long as it has a low albedo. So while I ascribe a big question mark to DE, I’m not so quick to do it to DM, because well…it’s not mind bendingly weird (although Dark Energy is waaaaay cooler).

  16. Jon Hanford says

    What I find curious about this ESA press release is echoed by many previous posters. Having read the original paper by D. Lamer et. al (http://arXiv.org/astro-ph/0805.3817v2, I see NO mention of Dark Energy OR Dark Matter. I wonder if the ESA press people meant to link this XMM image & galaxy cluster to Dark Matter content of this distant system. Either the paper is wrong & should be retracted or(more likely) ESA mis-represented what this paper was stating. Dr. Lamer is head author of the paper & mentioned in the ESA press release. Perhaps he could clear up some of this confusion. This data and paper makes any claim as to the existence of DE (or DM).

  17. edunuke says

    astrophysicists should take more seriously that if theory doesn’t fit reality then a new theory should be found.
    Dark matter= luminiferous aether=non-sense

  18. Jon Hanford says

    The paper on 2XMM J0803026+524133 can be found at http://arXiv.org/astro-ph/abs/0805.3817v2 . It’s only 5 pages long, but no mention of DE or DM. What gives?

  19. Ayti says

    “Dark matter= luminiferous aether=non-sense”

    As refutations go, not very compelling.

  20. the_nthian says

    ..but then again, if we were to travel ~8 billion light years then look back at our starting point, what would we see? there is no answer to this since it is irrelative (not within the realm of relativity). this is the problem with dark matter and dark energy.

  21. Dutch Delight says

    Different perspectives are great, but I don’t see how cranks are helping anyone. Usually these people don’t even accept the scientific method let alone understand it, it’s just wasted energy.

    It’s all very easy to pretend to know better then the actual researchers, but if you’re not going to explain the data we do have in any better and at least consistent way that actually fits with all our other data, whats the point?

  22. Jon Hanford says

    While searching the arXiv site for this paper, I noticed version 3 of this paper had been released. The papers differ only in making the cluster slightly more luminous & hotter, I still see no mention of DE or DM in this paper. Personally, I’ve got no problem with either DE or DM, but I fail to see any connection between these observations and DE. Certain connections to DM in a cluster at this distance (z=0.99) might apply, but no claim of DM mapping of this cluster is made, only its’ high luminosity & temp. I doubt that DM mapping of this cluster will be achieved anytime soon since at this distance, micro- & macrolensing will be very hard to discern, though Hubble might have a shot at it. The paper mentions upcoming observations by the Chandra X-ray telescope which will help pin down more accurate temperatures & luminosities( the cluster is mentioned as possibly having a ‘cooling-core’ X-ray profile). I still think the ESA PR people got something mixed up in their release.

  23. Jon Hanford says

    Here, again, the latest (v3) version of this paper – arXiv:0805.3817v3 [astro-ph]. See previous post by Jon Hanford.

  24. Chuck Lam says

    The big bang theory may be totally wrong regardless of the math. The explosive single point origin of matter theory doesn’t explain the chaotic appearance of all we can see in the visible universe. The blue-shift and every which way side to side galaxy motions just don’t fit the current big bang model. The idea of dark energy and or matter appears to be a weak attempt to explain the little understood expansion. The expanding universe may be no more complicated than the equivalent of an uncontained cloud of gas picking up speed as the (atomic, molecular or galactic) attraction bond is weakened by distance. Clearly more work is required to clarify our understanding of the universe.

  25. JamesB says

    Sigh…

    Any word on that ‘dark stuff’ camera they’ve been working on?

    Some actual proof ‘dark stuff’ either exists or doesn’t would be really nice. You know, real science rather than real science fiction.

  26. Feenixx says

    “the very presence of this cluster confirms the existence of a mysterious component of the Universe called dark energy”

    To me, this looks like a way of saying “the presence of this cluster really shows, once again, that there are a lot of things about which we know nothing”…. without the writer actually having to admit that he/she knows nothing…. and actually sounding very knowledge-able to casual readers.
    😉

  27. JamesB says

    Dutch Delight – It’s hard NOT to get cranky when you’re constantly told the emperor is wearing clothes and he’s not.

    It really doesn’t matter how many times you tell me ‘dark stuff’ exists, I want you to use scientific method to show me it exists! What we have now is a cottage industry that’s grown up around the idea that ‘dark stuff’ exists and they are cranking out computer models and lots of new ideas about ‘dark stuff’, but no real science.

    But where’s the scientific method, where’s the proof that these ideas are worthy of all the money being being sunk into them?? Heck it’s been more than a decade and ‘dark stuff’ has not even gotten up being a hypothesis yet, it’s still just a pie-in-the-sky idea and nothing more than a tenet of faith!

    It isn’t us laypeople who are unable to understand ‘scientific method’! It is the scientists claiming to be doing research by the scientific method and who are actually on these trips of wild imagination. Instead of using the ‘scientific method’ to research more of what we know, they engage in wild speculation at our expense and then try to pass it off as ‘scientific method’.

    These ‘actual researchers’ are simply engaged in gainful employment and little else. But asking them to explain why this wild speculation is science is like asking the wolf to guard the hen house, there is a lack of objectivity.

    Several issues ago in Sky & Telescope they had a big article on why current cosmology was on the right track. Now if they were producing real results, why would they need to explain that they are right?? And after reading the article one sees why it needed to be defended. There are so many inconsistencies and suppositions and VERY little actual fact or empirical proof.

    For someone who is stupid enough to let those suppositions pass as fact and can simply brush off the inconsistencies, the current cosmology makes sense. But once you look at the empirical proof and the facts of this proof, the current cosmology crashes in on itself like a house of cards. If you think it makes sense, then you need to really look at how you came by that conclusion because it’s based heavily one nothing more than science fiction and faith.

    As I mentioned in another thread, if you are a scientist in this field then play a joke on your boss (who ever that is). Tell him you recently discovered an alternate cosmology that makes more sense than the current one.

    Actually look at one of the several alternate cosmologies and learn enough about it to sell this joke. When he buys into it, then let him in on it and you can both have a good laugh!

    But you know you won’t do it because it could get you dropped off that research team and make it real hard to join another. If you are the head of the team, you’ll see your funding and support dry up. There are somethings you just can’t kid about.

    Serious science is less about ‘scientific method’ and more about the current status quo. And that’s not the ‘scientific method’ I learned about when I was younger, I learned that results matter!

  28. dennis cottle says

    JamesB — Beige Energy — now that should give someone a grant for years to come !

  29. Shaula Brant says

    Pardon my ignorance on this one, but if this distant dense cluster is an indicator for dark energy, which is thought to be repulsive by nature, why isn’t this cluster flying apart? Is the repulsive force of dark energy lesser than the attracting force of gravity?…is it that when matter tends to spread out and becomes less dense when the repulsion of dark energy starts to take its affect? (just an inquiring mind wanting to know.) (This sort of reminds me of water that forms a a droplet , but it falls apart when you and just a bit of soap which breaks down the surface tension (specific gravity) of the droplet.)

    I am not well educated in these matters.

  30. Dutch Delight says

    @JamesB

    How many actual scientific papers on astronomy have you read in your life? If more then 0, when was the last one you read?

    “There are somethings you just can’t kid about.”

    You are projecting dogma on science… All a scientist needs is a hypothesis and a way to test that hypothesis. The rest is just stuff you made up.

    I don’t make jokes when it comes to work that I’m hired to do for my boss, it’s business. And frankly, I would note it for review when someone wastes my time on nonsense and then pretends it was just a good laugh.

    Maybe you should give it a try with your boss.

  31. jerry says

    The so-called Dark Energy parameter is not well defined – it could be a constant, it could be variable. A very small number of very large galaxies persisting in observable space is possible in a fairly simple version of Dark Energy mechanics. A greater percentage of these galaxies would require a more complex model, but would not rule out Dark Energy. Neither would the failure to find any super-massive galaxies at this depth of a survey. The only ‘definite proof’, if there is such a thing, would be laboratory observations: a way to observe the behavior of Dark Matter at the quantum level. Particle physicist tell us it’s not there.

  32. Jon Hanford says

    If you have a clue go ahead and enlighten the woDifferent perspectives are great, but I don’t see how cranks are helping anyone. Usually these people don’t even accept the scientific method let alone understand it, it’s just wasted energy.-Ayti

    It’s all very easy to pretend to know better then the actual researchers, but if you’re not going to explain the data we do have in any better and at least consistent way that actually fits with all our other data, whats the point?rld – DM & DE are discriptive place holders for sets of physical phenomena that need to be understood in the context of the various models of how our universe works. I don’t think any scientist ever said: DM & DE are facts if you don’t believe in them, you’re a heretic! The same is true for BBT. If there was a better theory then we’d be talking about it don’t you think? – Dutch Delight I must heartily agree with these two posters. Regardless of the exact terminology used, concepts like DE, DM, and BBT are well established & widely accepted observed phenomenon in our universe, at least among most professional astronomers. Like it or not, these theoretical concepts have been established by multiple lines of observational astronomy. This is how the scientific method works. I can’t believe the majority of the pro astronomical community would expend such great effort to further study these phenomenon. Orthodoxy or not, I think most scientists are interested in seeking the truth in matters such as these, forget the ‘gotta get funding for my pet theory’ argument. It just doesn’t hold water in the 21st century pursuit of scientific knowledge.

  33. robbb says

    here’s my oddball idea:

    let’s assume a highly intelligent biological form of life evolved in the early universe. this life form eventually created artificial life (computers) and the computers themselves evolved and eventually left their original planet to explore the universe.

    the computers, much like our computers, would continue to shrink (as nanotechnology evolved) to the point of being incomprehensibly small. but these nano-AI creations roam the universe and take on ‘science projects’ to increase their knowledge, as knowledge acquisition becomes their primary objective for continued expansion of intelligence.

    the universe may be infused with intelligence at a microscopic level and may be subject to the objectives and goals of that intelligence, which includes ‘proper maintenance’ of the universe. the nano-AI’s themselves could be small enough in size to account for the matter we cannot perceive in the universe, but which has gravitational effects on the whole.

  34. Attila Gel says

    This energy that were looking for is not something that is very large, but actually very tiny considering the volume its in!

    The question of what it really is will not be answered for another 1000 years.

    Unless the answer is this:

    Energy coming from miniscule matter in empty space that is so shrinked by absolute zero that it gives away energy to less colder regions of deep space towards warmer galaxies or bigger.
    And all of these little energies flowing like waves in water when you throw something in it, these waves of energies make our universe expand.
    (or like domino beginning whit small stones that pushes bigger stones on the way)

    So if these energy waves push galaxies, why are there galaxies combining?

    This is because the emptiness on the sides of galaxies is never the same obviously.
    Bigger empty deep space means more waves or bigger energy wave, thus making two or more galaxies joining when they get pushed towards each other.

    Also, not like water, waves in space don’t see resistant by density or others. So the bigger the emptiness the larger the waves get the faster it pushes.
    Keep in mind that we are talking about very tiny energy and very tiny particles.

    If it’s not the absolute zero that generates the energy,
    it can be light that penetrates trough deep space from all sides causing warm-up by reacting with some of these,
    shrinked by absolute zero, particles.

    As you can see now, this proves

    – Deep space is not totally empty
    – There is energy we cant see
    – Universe expands
    – Universe keeps expanding speeding.
    – And this also solves the hexagon on one of our planets (just kidding I think)
    – Off coursing objects send into deep space
    – Ten Mysteries of the Solar System:
    o 10. Solar Pole Temperature Mismatch
    o 3. The Kuiper Cliff: Why does the Kuiper Belt suddenly end?
    o 1. The Oort Cloud: How do we know the Oort Cloud even exists?
    o 2. The Pioneer Anomaly: Why are the Pioneer probes drifting off-course
    o
    – and more…

    6 to go 

    It took me quite some time and researches to come up with this possibly to be accepted theory of mine.
    To be precise from 26/09/2008 16.30 till 26/09/2008 18.00

    I guess it’s that simple? Or maybe it needs some more thinking and researching?

    Thx for reading.
    Attila gel
    Belgium

  35. edunuke says

    An analog to the Michelson–Morley experiment needs to be done.
    If it is not experimentally proven otherwise then find a better theory than to postulate DM or DE.
    As simple as that.
    thats what i meant that ” DM or DE=luminiferous aether=nonsense”

  36. Qev says

    So let me get this straight, edunuke. If a theory cannot be experimentally proven (an impossibility, btw) immediately upon its conception, it must promptly be discarded for some nebulous ‘better theory’ that no-one has even thought of yet?

  37. edunuke says

    I simply mean that IN MY OPINION the DE/DM hypothesis should be rejected if it does not passes simple rule of bayesian inference because it is not experimentally testable (As so far seems to be the case). That is why, the need of the conception of an experiment of the same impact as the Michelson–Morley experiment is needed to discard it or validate it.
    Also, IN MY OPINION theoretical astrophysics is caught up in the realm of unicorns and leprechauns due to hypotheses such as this. This opinion brings me to the main premise of my post.

  38. Matt says

    Why is the comment section of UniverseToday full of people saying “WTF “dark stuff ” doesn’t exist, lol”?

    Now as others pointed out, dark energy and dark matter are two completely different things. Also, we don’t have to know WHAT dark matter or dark matter is, to establish that SOMETHING exists that has so-and-so attributes.
    We see that the expansion of the universe accelerates, something has to cause it. We just label it Dark Energy (you can call it the Cosmological Constant if you don’t like the word “dark”).

    Something has to keep Galaxy Clusters from flying apart. This something is massive, because it bends space-time and distorts what we see behind it. We call it Dark Matter. So what the hell is the problem you guys have?

  39. DrNecropolis says

    Matt gains +1 respect from Dr.Necropolis.

  40. JamesB says

    Dutch Delight – ‘Dark stuff’ isn’t even a hypothesis yet, it’s still just an idea. You just made my argument for me! Thanks!

  41. JamesB says

    Matt- there is little empirical evidence that the universe is actually flying apart or that any matter is actually missing.

    You have ‘dark stuff’ trying to handle our basic misunderstanding of gravity, whether it’s energy to explain why the universe may be expanding, or extra matter to explain why clusters aren’t.

    It’s all the same thing, a proxy for gravity. ‘Dark Stuff’…

  42. Andy says

    My only real problem with DM and DE was that, unlike the Higgs boson, neither was predicted by any of the existing models/theories. I always thought that the truest test of a theory was its ability, not just to explain, but to predict.
    It isn’t often that you get to read in the popular press about alternative theories but here’s one that intrigued me:

    http://www.sciam.com/article.cfm?id=the-self-organizing-universe

  43. Jon Hanford says

    Matt gains +1 respect from me. Intelligent, informed & succinct post. Refreshing to see comments from someone that understands scientific method.

  44. Matt says

    [QUOTE=JamesB]Matt- there is little empirical evidence that the universe is actually flying apart or that any matter is actually missing.[/QUOTE]
    That’s what creationists say about evolution as well. Doesn’t change the fact that there is a scientific consensus and the public just isn’t educated on the subject. Of course for YOU there probably seems to be little empirical evidence supporting DM and DE, because you appear to be ignorant of its existence. arxiv is full of scientific papers illustrating the evidence. Go do some research: http://arxiv.org/abs/astro-ph/0309368

    If you want sources that are easier to understand… maybe you should listen to the AstronomyCast episodes or check out wikipedia.

    [QUOTE=JamesB]You have ‘dark stuff’ trying to handle our basic misunderstanding of gravity, whether it’s energy to explain why the universe may be expanding, or extra matter to explain why clusters aren’t.[/QUOTE]
    Our understanding of gravity works fine, thank you. There has yet to be ANY indication that general relativity has ANY problems, besides its working on the quantum scale. It’s shown again and again (google: pulsar + relativity) that it explains gravitational phenomena on large scales.
    Also: The scientific community is working on MOND (modified newtonian mechanics, see wikipedia) to see whether MAYBE our understanding of gravity needs SOMEHOW be modified after all. Turns out, it doesn’t. MOND doesn’t work yet and the majority of scientist think it never will. And since DM explains ALL of the phenomena that MOND can’t… why bother? Researchers go with the theory that has merit, not the one that appeals to our common sense.

    PS: my comment might have been a bit harsh, but it really ticks me off when lay-people (arrogantly imo) assume that they know more about the subject than researchers who spend half of their life working on these problems.

  45. Matt says

    Doh… quotes. I’m used to those cute brackets. 🙂

    Andi wrote: “My only real problem with DM and DE was that, unlike the Higgs boson, neither was predicted by any of the existing models/theories. I always thought that the truest test of a theory was its ability, not just to explain, but to predict.”

    They weren’t initially predicted, but what’s the point? If every discovery in science were predicted by our theories, we wouldn’t need to do… y’know, do experiments.

    The important thing here is not that we didn’t expect to see those things, but now THAT WE see them, they don’t contradict our current theories. Dark Matter isn’t unimaginable, it could be explained with our model of particle physics (namely with WIMPS) and fits neatly with our views on the formation of galaxies.

    Dark Energy is a parameter that even Einstein added to his GR (even if for completely different reasons), but we don’t need to rewrite the whole GR because of it’s discovery.

  46. Matt says

    Oh another point I missed:
    JamesB wrote: “Matt- there is little empirical evidence that the universe is actually flying apart or that any matter is actually missing.”

    I think you meant to say: “there is little empirical evidence that the universe’s expansion is accelerated by DE”

    I hope you do not doubt that the universe is flying apart at all.

  47. Parvulus says

    [QUOTE=Matt]We see that the expansion of the universe accelerates[/QUOTE]

    Actually, we infer that the expansion of the universe accelerates by interpreting obervations of supernova redshift within the conceptual framework of the FLRW (or FRW) metric. That metric is based on two pillars: General Relativity and the Cosmological Principle, the latter based in turn on the Copernican Principle: the Earth (or in more contemporary speak, our galaxy, group or even supercluster) does not occupy a special place in the universe.

    By leaving aside the Copernican Principle, a different metric would apply, in which redshift observations could be interpreted so that they do not lead to the conclusion that the expansion of the universe is accelerating.

    While General Relativity is the best scientific choice so far, the Copernican Principle is a phylosophical choice, and leaving it aside is as scientifically valid as postulating it.

  48. Parvulus says

    It was “philosophical”.

  49. Kootstar says

    robbb: Please don’t take this wrong, as I can even follow your line of thought. But as you write I can see the possibilities of a sci-fi writer in you. Seriously, think about it. Whether you were joking, serious or just frustrated with the grumbling and argueing here, hang onto astronomy and research, but think about writing some sci-fi also. It never hurts to try!

  50. Andy says

    Matt,

    So you’re saying that because the Higgs particle was predicted by the Standard Model there was really no reason to build the LHC to detect it. Is that right?

  51. robbb says

    hey kootstar, no offense taken here, i was just spouting off! actually, what i wrote is an extension of ideas in Ray Kurzweil’s non-fiction book “Spiritual Machines” which you might enjoy if you like speculating on future technologies.

    i would love to write some sci-fi if i had more time. (i use most of my creative energy on music, and i do have a few ‘space songs’!)

    but the more i think on it i really don’t have trouble believing that computers in another civilization could evolve into ‘cosmic travellers’. non-biological entities are much better suited for interstellar travel.

  52. Jon Hanford says

    I am glad to see Matt’s thoughtful, intelligent replies to many DM doubters that have posted here. Finally a voice of reason and common sense in a sea of baseless and uninformed ‘comment’. The recently published paper on MACS J0025.4-1222 (at http:/arxiv.org/abs/astro-ph/0808.2320v2) not only dismisses MOND & TeVeS in explaing this merging cluster, it also says the same with regards to the ‘Bullet Cluster’ 1E 0657-56. For DM doubters, scrutinize page 9 of this 10 page paper for detailed info on why standard DM theory explains both of these clusters observed cluster’s observed properties, then rebut their observations with peer reviewed papers on these clusters (especially MOND & TeVeS advocates). Lets elevate this discussion about DM above speculation, links to sites on ‘Anti Gravity Matter’ & the like posted by non-astrophysicists (chemists, biologists, economists, etc.) & back to the realm of serious astrophysicists who spend much of their careers studying & trying to understand the universe as it really is.

  53. Matt says

    Parvulus wrote: “By leaving aside the Copernican Principle, a different metric would apply, in which redshift observations could be interpreted so that they do not lead to the conclusion that the expansion of the universe is accelerating.

    While General Relativity is the best scientific choice so far, the Copernican Principle is a philosophical choice, and leaving it aside is as scientifically valid as postulating it.”

    The funny thing about the Copernican Principle is that it makes a claim about the structure of the universe, which, lo and behold, is testable! And in fact has been tested. Let me quote wiki for you: “Measurements of the effects of the cosmic microwave background radiation in the dynamics of distant astrophysical systems in 2000 proved the Copernican principle on a cosmological scale.[5] The radiation that pervades the universe was demonstrably warmer at earlier times. Uniform cooling of the cosmic microwave background over billions of years is explainable only if the universe is experiencing a metric expansion.”

    Doesn’t sound like an open philosophical question, if you ask me (and science).

  54. Matt says

    Andi wrote: “So you’re saying that because the Higgs particle was predicted by the Standard Model there was really no reason to build the LHC to detect it. Is that right?”

    Ok… here is what I wrote: “They weren’t initially predicted (DE and DM), but what’s the point? If every discovery in science were predicted by our theories, we wouldn’t need to do… y’know, do experiments.”

    So, I said that not everything we have discover has been predicted by our theories (which is true, duh, otherwise we wouldn’t make progress).
    And your reply to that is that I’m suggesting not to build the LHC because the Higgs has been predicted by our theorie?

    I don’t get you.

  55. Ayti says

    Matt

    This part of your comment:

    “. . . . If every discovery in science were predicted by our theories, we wouldn’t need to do… y’know, do experiments.”

    seems to equate theoretical prediction with experimental observation. I feel certain that this is not what you meant to convey because none of your other comments are absurd as this seems to be.

  56. Matt says

    I’m confused now.. I certainly didn’t mean to equate theoretical prediction with experimental observation. (I’m still not sure whether that, admittedly somewhat messed up sentence, can be interpreted that way).

    Anyway, my point: Quite often experiments show us phenomena we’d never expect to see judging from our current theories of how something works. That’s how science progresses. You get new input and refine your theories to explain all the data you gathered up to that point + the new data.

  57. Astrofreak says

    Hey Nancy, sounds like you’re gonna get a Pulitizer for fiction writing!

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