Dark Matter Hinted at Again at Cresst Experiment

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Dark Matter Hinted at Again at Cresst Experiment

Posted by samzenpus on Wednesday September 7, 2011 @10:45AM from the look-what-we-found dept.

physburn writes "The BBC is reporting recent results from the Cresst dark matter search in Italy. Between 2009 and 2011, Cresst have seen 67 events, a 4 sigma detection of dark matter particles with a mass of either around 15 GeV or 25 GeV. The results are near those previous results from DAMA and Cogent. So has dark matter finally been found, and if so what is it?"

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Not yet. by Claws+Of+Doom · 2011-09-07 10:49 · Score: 4, Informative

4 sigma detection != (officially) found. You need 5 sigma for "discovery" status. The BBC have a good explanatory piece: http://www.bbc.co.uk/news/science-environment-14811580
1. Re:Not yet. by Claws+Of+Doom · 2011-09-07 10:53 · Score: 2, Informative
  
  I am an idiot.
2. Re:Not yet. by Anonymous Coward · 2011-09-07 11:41 · Score: 0, Informative
  
  I am an idiot.
  No. You had to get fancy with your "Frist Post" is all. If you kept it simple, "Ah! That's highly significant!"
  And when someone posted something that called you on it and asked what you mean by that. All you had to do was post, "Ah, Bach."
  That's all. And would've gotten at least a +3 out of it! (Mods always blow a point or two on the first comments that look intelligent which means your fist post may get a +5 something or another with a zillion comments calling you an idiot while your response [calling yourself an "idiot"] will be ignored)
3. Re:Not yet. by bigsexyjoe · 2011-09-07 11:46 · Score: 1
  
  True. Four sigma is only 99.993666% we need to wait for five sigma or 99.9999426697%
  
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4. Re:Not yet. by myrikhan · 2011-09-07 12:34 · Score: 2
  
  Will 8.9 sigma do? http://arxiv.org/PS_cache/arxiv/pdf/1002/1002.1028v1.pdf It's not that easy of course. DAMA/LIBRA, CoGEnT and now CRESS are getting hits while XENON100 isn't. I'm interested in how this will eventually turn out.
5. Re:Not yet. by sjames · 2011-09-07 12:53 · Score: 1
  
  She canna take much more Captain!
6. Re:Not yet. by dada21 · 2011-09-07 14:10 · Score: 1
  
  I spit out a solid half finger of good Scotch whisky at that.
  Haven't laughed this hard in weeks.
  Good work.
7. Re:Not yet. by Anonymous Coward · 2011-09-07 15:07 · Score: 0
  
  CmdrTaco, is that you?
Dark matter always seemed like a cop out. by AnonGCB · 2011-09-07 10:51 · Score: 2

Dark matter always seemed like a convenient hand wave, but I'm thrilled if there's some concrete evidence of it. I do love being wrong!

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1. Re:Dark matter always seemed like a cop out. by chill · 2011-09-07 10:59 · Score: 5, Funny
  
  I do love being wrong!
  You're married, aren't you? Sounds like for some time, too.
  
  --
  Learning HOW to think is more important than learning WHAT to think.
2. Re:Dark matter always seemed like a cop out. by Jello+B. · 2011-09-07 11:11 · Score: 2
  
  It's not a cop out.
  
  The correspondence of the two gravitational lens techniques to other dark matter measurements has convinced almost all astrophysicists that dark matter actually exists as a major component of the universe's composition.
3. Re:Dark matter always seemed like a cop out. by lgw · 2011-09-07 11:32 · Score: 2
  
  Dark matter was a convenient hand wave for the galaxy rotation problem, and just one of many hypotheses. But the the CMBR measurements also showed dark matter in the early universe, and in the same proportion predicted. That was as solid a confirmation as you ever get in cosmology.
  What's interesting now is what it's made of - all we know is there's no interaction with photons, and no frictional clumping as you'd see in normal matter (or at least not in the wide range of energies involved in galaxy formation).
  
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4. Re:Dark matter always seemed like a cop out. by Chris+Burke · 2011-09-07 11:51 · Score: 1
  
  What's interesting now is what it's made of - all we know is there's no interaction with photons, and no frictional clumping as you'd see in normal matter (or at least not in the wide range of energies involved in galaxy formation).
  Like neutrinos, only heavier. Perhaps the hypothetical neutralino. They only interact via the weak force and gravity, which would explain the apparent behavior. Or maybe something completely different, but then these detectors would probably not be able to find it at all, which would be a bummer.
  Man, it's so painful waiting for sufficient data to show up in real-time. These tantalizing but inconclusive hints are like torture! I can only imagine what it must be like for those actually doing the work -- or maybe actually doing the daily work makes it easier to bear and the years just slip by like on a big engineering project? I just wish I could fast-forward twenty years to when we have these problems solved! It feels like we're on the cusp of some great discoveries in physics.
  
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5. Re:Dark matter always seemed like a cop out. by ynotds · 2011-09-07 13:13 · Score: 1
  
  no interaction with photons, and no frictional clumping
  AFAIK this is one point not two as frictional clumping is mediated by photons, as at some point are all our observations. Not that I don't fully accept the evidence for dark matter, nor have any sympathy with DM deniers. From a history of science perspective, their kind have always been wrong.
  
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  -- Our systemic servants do not good masters make.
6. Re:Dark matter always seemed like a cop out. by DrJimbo · 2011-09-07 13:18 · Score: 1
  
  Dark matter always seemed like a convenient hand wave, [...]
  It might well seem that way, but I don't think it really is. In fact, it would be kind of strange if there was no dark matter because that would mean everything in the Universe glows. When you think about it a bit, you realize there's got to be a least some dark matter so the only question is: how much is there?
  ISTM the dark matter hypothesis is completely reasonable. If anything, it is more humble than arrogant because it's not assuming that the only things that exist are the things we can directly see. Sure, there would have to be a lot of it in order for it to be the primary cause of the effects it explains, but that too is totally reasonable. It is far less reasonable to assume that almost everything in the Universe emits substantial amounts of electromagnetic radiation.
  Given the evidence we have so far, I think the dark matter hypothesis is by far the most reasonable explanation. That doesn't mean it is right, but it is certainly not a convenient hand wave or a cop out.
  
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  -- Anais Nin
7. Re:Dark matter always seemed like a cop out. by rpresser · 2011-09-07 13:51 · Score: 1
  
  Probably not a neutralino. SUSY is mostly dead.
8. Re:Dark matter always seemed like a cop out. by user+flynn · 2011-09-07 14:18 · Score: 1
  
  What's interesting now is what it's made of - all we know is there's no interaction with photons, and no frictional clumping as you'd see in normal matter (or at least not in the wide range of energies involved in galaxy formation).
  
  It's 4 space dimension matter rather than 3 space dimension. Since 'our' 3 space dimension matter has nil (0.0) 4d space volume, there is basically zero % chance of interaction*. Likewise with other lower or higher dimensional matter.
  Additionally 4d photons don't interact directly with 3d matter, etc.etc.
  The interesting thing is that spacetime curvature still occurs... which explains the gravitational effects of different dimensional matter.
  * I can't recall the article, but a while ago someone was talking about how particles 'teleported' through a very thin "solid" sheet of matter because they had a small chance of being on the other side of the sheet of matter. Since a 2d slice of 3d spacetime has zero thickness (more or less infinitely smaller than the Planck length), the particle would be likely to be on either side of the 2d slice. Extend this up to a 4d/3d interaction...
  
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9. Re:Dark matter always seemed like a cop out. by mug+funky · 2011-09-07 15:18 · Score: 1
  
  i like to think of it as looking at a game of pool if you're sitting with your eye level aligned with the side of the table, and a whisky in your hand (that part is very important). the table is essentially reduced to 1 dimension instead of the 2 that are necessary to model it (excluding corner cases such as spin, and balls becoming airborne).
  when a shot is taken, balls appear to either collide and bounce, or pass through each other. far more pass through each other than collide, and it's nigh on impossible to predict which balls will bounce and which will not.
  stand up and it all makes sense.
10. Re:Dark matter always seemed like a cop out. by Chris+Burke · 2011-09-07 17:10 · Score: 1
  
  What happened to it?
  
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11. Re:Dark matter always seemed like a cop out. by Anonymous Coward · 2011-09-07 18:30 · Score: 0
  
  What if dark matter exists in 4 physical dimensions, detectable by its gravitational pull. How do truly find it?
12. Re:Dark matter always seemed like a cop out. by pushing-robot · 2011-09-07 18:32 · Score: 1
  
  In simple terms, it had its life sucked out by a machine and would take a miracle to come back now.
  
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  How can I believe you when you tell me what I don't want to hear?
13. Re:Dark matter always seemed like a cop out. by spiralx · 2011-09-07 22:06 · Score: 2
  
  It's not dead, initial results from the LHC are inconsistent with the simplest model of SUSY, but do not yet rule out other models which have higher energies for s-particles.
14. Re:Dark matter always seemed like a cop out. by Anonymous Coward · 2011-09-07 22:21 · Score: 0
  
  It may be, but it is the only really solid thing we have so far.
  There was an idea that it could be an effect of anti-matter on the galactic scale, and all those dark regions are filled with anti matter that is being hidden away due to refraction that may be happening too.
  We still don't know where all the anti matter went to, or the apparent asymmetry in mass we have now.
  But until we can get enough anti matter to experiment with it on larger scales to see if it is indeed reversed entirely (and is repelled by gravity, possibly), we are still stuck with 2 ideas that are equally messy, at best.
15. Re:Dark matter always seemed like a cop out. by jawtheshark · 2011-09-07 23:31 · Score: 1
  
  Enjoy
  
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16. Re:Dark matter always seemed like a cop out. by lgw · 2011-09-08 03:02 · Score: 1
  
  AFAIK this is one point not two as frictional clumping is mediated by photons,
  
  Frictional clumping in normal matter is about photons. There could be 17 additional fundamental forces that only interact with dark matter for all we know - but none of them can produce friction (exept perhaps at very low energy levels).
  
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17. Re:Dark matter always seemed like a cop out. by lgw · 2011-09-08 03:08 · Score: 1
  
  That doesn't hold up. If dark matter had friction (regardless of why), the dark matter in galaxies would tend to form disks - it doesn't. Also, in a 4-spatial-diminsion universe, there are no stable orbits, and no large scale structures like galaxies could form if gravity fell off as R^3.
  
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  Socialism: a lie told by totalitarians and believed by fools.
18. Re:Dark matter always seemed like a cop out. by Anonymous Coward · 2011-09-08 03:57 · Score: 0
  
  Hmm, so our universe may be just a mirage, a dance of light and shadow in a greater, DM universe?
19. Re:Dark matter always seemed like a cop out. by Chris+Burke · 2011-09-08 04:53 · Score: 1
  
  Dark matter does not appear to interact with itself any more than it does with normal matter. That's why in galactic collisions the dark matter of one galaxy will pass right through not just the dust clouds of the other galaxy, but its dark matter as well.
  
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20. Re:Dark matter always seemed like a cop out. by Anonymous Coward · 2011-09-08 07:28 · Score: 0
  
  http://theresonanceproject.org/shop/crossing-the-event-horizon
  ^^ this dvd is made by physicist Nassim Haramein. He explains that the equations to calculate the matter/energy in the universe are, according to him, fundamentally flawed because the consensus is to not factor in the massive torque that Nassim claims to be a natural part of the system.
  Natural as in, matter has gravity, matter also has a spin thus generates torque for the same reasons. So the dark matter/energy is what scientists use to explain this
and if so what is it? by FatLittleMonkey · 2011-09-07 10:58 · Score: 0

Spiders.

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1. Re:and if so what is it? by planimal · 2011-09-07 11:03 · Score: 0
  
  dinosaurs
2. Re:and if so what is it? by Anonymous Coward · 2011-09-07 11:06 · Score: 0
  
  turtles.
3. Re:and if so what is it? by V!NCENT · 2011-09-07 11:08 · Score: 1, Offtopic
  
  All the way down.
  
  --
  Here be signatures
4. Re:and if so what is it? by Anonymous Coward · 2011-09-07 12:02 · Score: 0
  
  Spiders.
  Mimic Octopus
  http://imgs.xkcd.com/comics/mimic_octopus.png
Don't bet your house on this result holding up by Xerxes314 · 2011-09-07 11:04 · Score: 4, Interesting

It's consistent with DAMA and Cogent in the sense that it's ruled out by those experiments at only a few sigma. It's "near" Cogent in the sense that 8 is "near" 25, and it's "near" DAMA in the sense that 35 is "near" 10; that is, it's not near at all. It's ruled out by Xenon by many orders of magnitude. My favorite theoretical model to explain these results is IDM (Italian Dark Matter), which consists of dark matter that only exists in Italy. Presumably similar particles are responsible for whatever makes Guinness taste better in Ireland.
1. Re:Don't bet your house on this result holding up by Pino+Grigio · 2011-09-07 11:29 · Score: 2
  
  If I had mod points..... IDM will be my acronym of the week.
2. Re:Don't bet your house on this result holding up by JamesP · 2011-09-07 12:33 · Score: 1
  
  So do you think Cogent should move to New Jersey??
  
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3. Re:Don't bet your house on this result holding up by Required+Snark · 2011-09-07 13:17 · Score: 1
  
  Italian Dark Matter. Do you mean Espresso?
  
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4. Re:Don't bet your house on this result holding up by Anonymous Coward · 2011-09-07 15:49 · Score: 0
  
  Woah. While I am as skeptic as you are, the three experiments agree at around "12" in your funny units (or lack thereof). Read carefully.
5. Re:Don't bet your house on this result holding up by Anonymous Coward · 2011-09-07 15:51 · Score: 1
  
  From your own link, Cresst's 'M2' preferred mass region ranges from 9 to about 13 GeV, which is indeed 'near' both Cogent's 8 and Dama's 10.
  At first glance it may look like this is ruled out by Xenon, but there is a lot of debate about the validity of Xenon's results in this low mass region, and just a small shift would make Cresst's results perfectly consistent with Xenon's.
  Of course the Cresst signal could still disappear, but with three independent experiments claiming evidence in such a small region, this is one of the most intriguing results in a long time.
Great introductions to dark matter by overshoot · 2011-09-07 11:23 · Score: 3, Informative

Starts with a Bang is an astrophysics professor's coverage of dark matter and what we know about it (including why we believe it makes up most of the matter in the universe.)

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How I ruined Guiness for a friend: by conspirator23 · 2011-09-07 11:35 · Score: 1

(paraphrasing here, this was almost 20 years ago)
Friend: "Look at this! It's Guiness! Real. Live. Irish. Guiness! And I got it.... at the [insert early 90's supermarket chain here]."
Me: "Oh I've heard of that stuff. Is it really all that special?"
Friend: "What? Philistine! Look at this stuff. It's blacker than your soul. You could eat this for lunch. Many Irish do. It takes your girly American lager out back and beats it with a 2x4. Look, even the can has this automagical thingy inside it to reproduce the legendary foamy head of a real draft Guiness. This is as close as you're going to get to Ireland without a passport. Here, try some." (Friend pours small amount in a glass, jealously hoarding the rest of his six-pack)
Me: (taking a slow sip) "Hmm... yeah. That is different. Not as bitter. But... hmm... it kinda reminds me of soy sauce."
Friend: "WHAT?!?!?! You're crazy."
Me: "No. Seriously. Check it out."
Friend: (takes his own slow sip). "..."
(Former) Friend: "DAMN YOU!"
1. Re:How I ruined Guiness for a friend: by Anonymous Coward · 2011-09-07 11:59 · Score: 0
  
  I don't get it...
2. Re:How I ruined Guiness for a friend: by Anonymous Coward · 2011-09-07 12:56 · Score: 0
  
  This is actually an interesting example of a phenomenon that where you are not aware of something, you will not notice it, but as soon as someone points "it" out to you, you will and there is no going back; every time you experience it, you will now notice it no matter how hard you try not to.
  Apparently Guinness tastes like soy sauce - I don't drink piss-warm "beer" so I wouldn't know.
3. Re:How I ruined Guiness for a friend: by Anonymous Coward · 2011-09-07 13:05 · Score: 1
  
  Whoever told you guinness is supposed to be warm ...lied to you. It's served moderately chilled normally, and you can also ask for it "extra cold", at least in Ireland, officially served at 3.5ÂC. Also, Guinness doesn't taste like any soy sauce I've ever tasted *anyway*.
4. Re:How I ruined Guiness for a friend: by bughunter · 2011-09-07 13:29 · Score: 2
  
  Guinness tastes like soy sauce - I don't drink piss-warm "beer" so I wouldn't know.
  Murphy's is better, is commonly available in the US, and also has the widget. Young's Double Chocolate Stout is even better than that. Rasputin's Imperial Stout is also not hard to find, and far better than Guinness. Australian Sheaf Stout is like heaven compared to any of those. But beware: Foster's makes a disappointing knockoff of the style and appears to have some kind of exclusive US distribution arrangement; I haven't seen a bottle of Tooth's Sheaf Stout in nearly 25 years.
  The only thing that Guinness has going for it compared to other Stouts is its near ubiquity and a large marketing budget. It's the Bleedin' Watney's Red Barrel of stouts.
  Oh, and also, either your piss is 40 or you let your beer get too warm.
  
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5. Re:How I ruined Guiness for a friend: by mug+funky · 2011-09-07 15:34 · Score: 1
  
  guinness and soy are both quite umami tastes.
  in australia we'd say it tastes like vegemite, and we'd all rejoice and drink it all down.
6. Re:How I ruined Guiness for a friend: by Patch86 · 2011-09-07 19:40 · Score: 1
  
  Apparently Guinness tastes like soy sauce - I don't drink piss-warm "beer" so I wouldn't know.
  You're lucky, then, that Guiness is served at as cold as 3.5C (unfortunately, for those of us who do like piss-warm beer).
7. Re:How I ruined Guiness for a friend: by Chris+Burke · 2011-09-08 04:50 · Score: 1
  
  guinness and soy are both quite umami tastes.
  Yeah. Saying Guinness tastes like Soy because both are "savory" is like saying potato chips taste like beef jerky because they're both salty.
  
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  The enemies of Democracy are
lots of these experiments running by bcrowell · 2011-09-07 11:54 · Score: 2

There are lots of experiments of this type running right now. This team, CRESST-II, has announced that they have more events than can be explained by their background. However, that's not really the most convincing evidence you could ask for, since the background could have been underestimated. A more convincing thing to see is that some of the experiments are reporting signals that are modulated by the expected amount on a yearly basis by the earth's motion relative to the frame of the cosmic microwave background. Here is a paper that includes a survey of the the results as of June. There are some apparent contradictions between some groups' positive results and others' negative results.

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1. Re:lots of these experiments running by Spinalcold · 2011-09-07 16:03 · Score: 1
  
  Most the the dark matter experiments are looking for WIMPs, not Axions, those, no my knowledge have been left behind by low energy detectors. I could very likely be wrong, I extrapolate far too much from documentaries, hehe. However, a yearly rotation will have no effect in comparison to the CMB, which comes from all directions at more or less the same direction; it's VERY uniform. So I highly doubt a 30km/s rotation around our sun will impact our interaction with the CMB when our relative motion to it around the center of the milky way seams to be 390 KM/s. (pulling the numbers from a book I have by Henning Gentz called Nothingness, which is 12 years old now)
2. Re:lots of these experiments running by Anonymous Coward · 2011-09-08 02:37 · Score: 0
  
  I'm not sure exactly what you're trying to say here. But our observation of the CMB is definitely affected by the Earth's motion around the Sun and the Sun's around the galaxy, as well as the galaxy's own motion. These cause the CMB to be doppler shifted, leading to the largest CMB anisotropy by far: The CMB dipole. The dipole is useful because it allows us to measure our velocity with respect to the average of the universe. But since it is caused by our motion, and is not intrinsic to the CMB itself, it is usually subtracted. So maps you have seen with small fluctuations more or less uniformly spread over the sky have had the huge monopole (overall temperature, approximately 2.7 K) and dipole (temperature gradient over the sky, approximately 3.4 mK) leaving the ~0.5 uK primary anisotropies.
3. Re:lots of these experiments running by bcrowell · 2011-09-08 07:24 · Score: 1
  
  So I highly doubt a 30km/s rotation around our sun will impact our interaction with the CMB when our relative motion to it around the center of the milky way seams to be 390 KM/s.
  You're right, it isn't the velocity relative to the CMB that's relevant, it's basically the velocity relative to the galactic halo. The dark matter particles they claim to be detecting would be gravitationally bound to the galaxy. I think the rest of what I wrote is correct. Check out the link I gave in the GP post, and also this paper http://arxiv.org/abs/1011.3076 , where they predicted the yearly modulation before they started the experiment. They measure a yearly modulation of about 16%, and that is apparently consistent with theory.
  
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Haters gonna hate. by Anonymous Coward · 2011-09-07 14:10 · Score: 0

...nor have any sympathy with DM deniers. From a history of science perspective, their kind have always been wrong.
Yeah. I know what you mean, but have faith! Those stupid deniers that didn't believe in luminiferous aether, phlogiston, epicycles, geocentrism, and the flat earth were certainly eventually given their proper, ignominious place in history. Now, please excuse me while I go burn in effigy that great heretic, William of Ockham.
1. Re:Haters gonna hate. by thrich81 · 2011-09-07 15:17 · Score: 1
  
  Were there any real deniers of luminiferous aether or was everyone (who cared) shocked when a supposedly routine experiment cast doubt on its existence?
2. Re:Haters gonna hate. by ceoyoyo · 2011-09-07 16:07 · Score: 1
  
  I hate to tell you, but modern physics has luminiferous aether deeply entrenched in it via BOTH relativity and quantum mechanics. Relativity calls it "the fabric of spacetime." QM calls it "vacuum."
3. Re:Haters gonna hate. by Anonymous Coward · 2011-09-07 16:34 · Score: 1
  
  The original concept of luminiferous aether was a medium requisite for the propagation of lightwaves. I hate to tell you, but Einstein completely debunked it via special relativity. Of course, Einstein allowed for a concept of "relativistic aether", but it is nothing like the original luminiferous aether theory claimed and only shares the concept the presence of physical properties of space. In that sense, "aether" was a regrettable choice of term on his part.
  If you wish to mentally substitute "an invisible medium that suffuses the vacuum and is requisite for the propagation of light" for "luminiferous aether" in the comment above, then by all means go ahead.
4. Re:Haters gonna hate. by blue+trane · 2011-09-07 18:39 · Score: 1
  
  But what if light works something like this https://hekla.ipgp.fr/IMG/pdf/Couder-Fort_PRL_2006.pdf ?
5. Re:Haters gonna hate. by hawkinspeter · 2011-09-07 20:10 · Score: 1
  
  I hate to tell you, but modern physics does not have luminiferous aether in it whatsoever.
  
  It's not even difficult to completely disprove aether by running an experiment to measure the speed of light and see if it various according to the direction of the earth's movement "through the aether". If light propagates using aether, then it's speed won't be constant.
  
  I bet you think that phlogiston is still used in physics as well.
  
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6. Re:Haters gonna hate. by angel'o'sphere · 2011-09-08 00:09 · Score: 2
  
  You are mistaken. Your parent is right. The concept of aether is indeed comming back as Gedankenexperiement or as an analogy. If you had read your parents post till the end you had seen "space time" or "fabric of space time" or "vacuum" as modern variations of the same aether concepts our for fathers had. Why don't you google? You should find many modern publications that "use" the word aether ... but not in the old classical sense.
  
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7. Re:Haters gonna hate. by lgw · 2011-09-08 02:58 · Score: 1
  
  It's not even difficult to completely disprove aether by running an experiment to measure the speed of light and see if it various according to the direction of the earth's movement "through the aether". If light propagates using aether, then it's speed won't be constant.
  Amusingly, the gravity wave detectors are basically the same as the Michelson Morley apparatus, and the opposite result is expected. But of course we won't call these "aether waves" when we find them- that's so 19th century!
  
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8. Re:Haters gonna hate. by ceoyoyo · 2011-09-08 02:58 · Score: 1
  
  "I bet you think that phlogiston is still used in physics as well."
  Sure. Phlogiston was believed to be a substance that was released when things burned or rusted (i.e. oxidized). The matter that was left afterward was believed to be in it's "base" state. If you extend the concept a little and postulate that phlogiston is released in any exothermic chemical reaction (oxidization being the most common and easily observable), you have... chemical energy. Extend it a little bit more to include all reactions and you have the general concept of energy.
  Yes, we have different words for the concepts of phlogiston and aether, and our understanding of them is much more sophisticated, but the concepts are still there, and never really went away.
  Aether for example, was postulated as an all pervading but unobserved substance through which electromagnetic waves propagated. It was HYPOTHESIZED that electromagnetic waves propagating through aether should show differences in velocity depending on whether they were propagating parallel or perpendicular to the Earth's movement through the aether. That turned out not to be the case.
  Then Einstein came along and explained, with special relativity, that the speed of light is always constant to a non-accelerating observer and space and time distort to accommodate. Wait... space and time distort? Hm... interesting.
  A little later came general relativity, with the concepts of distortions in the fabric of spacetime better fleshed out. And voila, you have aether, except now it's relativistic aether. Kind of like how you had Newton's laws, and then Newton's laws with relativistic terms added.
  The hypothesis of CLASSICAL aether was disproven by the Michealson-Morely experiment, not the more general concept of aether.
  By the way, note that the Micahelson-Morely experiment was conducted on planet Earth, in the fresh (basement) air (picture: http://e-ducation.net/scientists/Michelson_Morley_intf.gif). Wait, air? So the light was actually propagating through AIR? But if M-M proves there is no such thing as aether then shouldn't it have also proved there is no such thing as air?
  Physics is mostly a story about refinements and ever more sophisticated understanding, not complete replacement of concepts. Aether and phlogiston are both examples of that. But, as the subject says, haters gonna hate. And Slashdot seems to have a lot of hate for aether for some reason.
9. Re:Haters gonna hate. by hawkinspeter · 2011-09-08 03:29 · Score: 1
  
  I was referring to "luminiferous aether" which would be the medium that transmits light (if it were true). You seem to be referring to spacetime fabric as aether which would make light the equivalent of gravity waves (i.e. spacetime would be the gravitational aether that transmits gravity waves).
  
  Aether is used as a concept, but unfortunately, too many people confuse it with the old useless theory of luminiferous aether - yourself included.
  
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10. Re:Haters gonna hate. by hawkinspeter · 2011-09-08 03:35 · Score: 1
  
  I replied to someone else who was confusing luminiferous aether with a concept of aether. Luminiferous aether is completely useless as a theory as you'd have to fit in so many workarounds to get it to work, whereas General Relativity fits the data so much more easily.
  
  I don't see how you can equate phlogiston with energy as they had the entire concept of combustion the wrong way round. They believed that phlogiston was a substance inside objects that got released during combustion. This in no way explains how substances become more massive when they are oxidised, nor how oxygen is depleted from the air. I think you are playing with semantics to try to shoe-horn phlogiston into physics when it's simply incorrect.
  
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11. Re:Haters gonna hate. by ceoyoyo · 2011-09-08 04:07 · Score: 1
  
  If you mean specifically classical Lorentzian luminiferous aether, then yes, it doesn't work. But the basic idea of a universal, all pervading "substance" is consistent with both relativity and QM. Given special relativistic properties, the concept of a medium though which electromagnetic disturbances propagate is essentially the same as the EM field from EM field theory.
  Yes, phlogiston is a little more of a stretch, but you issued a challenge. However, my interpretation of phlogiston is completely compatible with combustion, so long as you add in oxygen. Phlogiston (energy) IS a "substance" that is released from objects during oxidization, or any other exothermic reaction. Once you compensate for the masses of ALL the reactants, you can even measure it's mass! Does that mean the ancients' explanation of phlogiston was correct and based on some mystical/alien knowledge? Of course not. But it was a valid explanation of the observations they had and, beefed up a bit, is not that different than what we believe today. Ditto, and more so, with aether.
  The general ideas of aether and phlogiston are not "simply incorrect" they are incorrect in some of their details. The general concepts, with appropriated extended details, are accepted as valid today. No, I'm not playing with semantics. Einstein himself hung onto the idea of aether until the 30s, probably because he liked the idea of a medium through which electromagnetism propagates, similar to the spacetime through which he saw gravity propagating. Einstein would probably have been very happy calling the the fields of electromagnetic field theory "aether."
  I think you need to realize that the history of science isn't quite as black and white as you'd like to think, and pre-1930s scientists weren't quite the fools Slashdotters like to paint them as (except Tesla, Slashdot loves Tesla).
12. Re:Haters gonna hate. by Chris+Burke · 2011-09-08 04:43 · Score: 1
  
  Amusingly, the gravity wave detectors are basically the same as the Michelson Morley apparatus, and the opposite result is expected. But of course we won't call these "aether waves" when we find them- that's so 19th century!
  Well of course, because the phenomenon and thus expected experimental results are completely different. The gravitational potential of the detector relative to the earth will be constant, ergo there would be no distortion based on the earth's movement -- consistent with the Michelson/Morely experimental results -- whereas you would expect a difference if there was a light-propagation medium through which the earth was moving.
  It's the same reason why when they detect minute changes due to seismic vibrations, they don't call those aether waves either. :P
  
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13. Re:Haters gonna hate. by ceoyoyo · 2011-09-08 05:42 · Score: 1
  
  Let's try it another way. The idea of luminiferous aether suggested an experiment to try and find the "aether wind." If you work out the speed of light propagating in a medium through which Earth is also moving, using Newton's equations you find that you should observe a difference in speed depending on the direction the light is travelling. Michaelson and Morely (and others) looked for that difference and didn't find it.
  However, if you calculate the speed of light using special relativity instead of Newtonian mechanics, you get no difference. Which is what the experiments showed. The Michaelson-Morely experiment is NOT a test of the existence of aether, it's a test of Newtonian mechanics. Note that special relativity is generally interpreted with the concept of space-time, which is a medium through which all things travel, including light, and the medium deforms and affects that movement, which is why light bends in gravitational fields (another famous test of relativity). So what you're left with at the end of the experiment is special relativity replacing Newtonian mechanics and an expanded concept of aether.
  Perhaps you're the one playing semantic games and artificially restricting your definition of "luminiferous aether" to a particular formulation of the hypothesis that specifically involved Newtonian mechanics? If you read about the time you'll find that there were all sorts of different hypotheses about the aether, with different properties, and more continued to be proposed and tested after the Michaelson-Morely experiment. In fact, the scorn for aether seems to be mostly revisionist history, particularly here on Slashdot and among other armchair scientists, particularly those who ridicule the concept of dark matter. Remember, the context of this thread is dark matter. Your argument that luminiferous aether is analogous to claiming that the concept of dark matter is ridiculous because the MACHO hypothesis didn't work out.
14. Re:Haters gonna hate. by Anonymous Coward · 2011-09-08 07:38 · Score: 0
  
  I was referring to "luminiferous aether" which would be the medium that transmits light
  Ah, but so was the post you were responding to. Relativity expands on (or reintroduces) that concept by assuming that light follows a minimum path along the spacetime curve. That effectively makes spacetime "the medium that transmits light", doesn't it?
15. Re:Haters gonna hate. by lgw · 2011-09-08 10:06 · Score: 1
  
  Imagine if the 19th century test equipent had been accurate enough to find gravity waves - don't you think Michelson and Morley would have seen that as evidence of something aetheric going on? How confusing would that have been.
  Ultimately, there is a light-propagating medium through which the Earth is moving - call it the vacuum, the "fabric of space time", or whatever - which can be distorted by the passage of objects, and which does act like a series of potential wells.
  The nature of this medium is IMO one of the big remaining mysteries - what is actually happening down there at Plank-length scales? Is the medium continous, or a scattering of allowed loci? Does it change over time (i.e., is the medium something, or just some place)? It is observer-invariant? If we knew, we might have a workable theory of quantum gravity.
  
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16. Re:Haters gonna hate. by angel'o'sphere · 2011-09-08 11:54 · Score: 1
  
  Myself certainly not included, insult to injustice, sigh.
  
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17. Re:Haters gonna hate. by Chris+Burke · 2011-09-08 13:03 · Score: 1
  
  Imagine if the 19th century test equipent had been accurate enough to find gravity waves - don't you think Michelson and Morley would have seen that as evidence of something aetheric going on? How confusing would that have been.
  Maybe, but they would have realised that it was very different than the theorised medium of the luminiferous aether. They expected a consistent difference between the arm of their device parallel to the motion of the earth versus the one perpendicular, showing the effect of the earth's motion through the medium. Transient effects not aligned with or related to the earth's motion would have indicated that their theory needed to be entirely re-worked.
  Saying ultimate light propagates through the medium of space-time is true in one sense, but only metaphorically similar to the type of 'medium' that the aether theory was intended to supply. The same sense in which matter is the medium for sound waves -- some kind of stuff that exists in space so that the wave can travel through space. Space is what everything including the medium travels through, but the aether was light's medium, not everything's.
  These two senses of 'medium' produce different experimental predictions. So "the medium for light is space-time" is the answer equivalent to what they would have called "light doesn't require a medium of its own, it can exist in empty space itself just like matter". Luminiferous aether is what you get if you believe that isn't the case.
  The ultimate nature of space-time is a huge mystery, to be sure.
  I'm just saying, whatever it is, it's nothing like the aether -- we know this much from experiment. Yes, they are in some ways analogous. That's not a reason to call it "luminiferous aether" when the whole point of how we got to here is that it isn't. And so the snark was unwarranted. "So 19th century" is no problem for the things from the 19th century that weren't wrong.
  
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18. Re:Haters gonna hate. by lgw · 2011-09-09 02:30 · Score: 1
  
  , but the aether was light's medium, not everything's.
  But that's just it - that's the underpinning of modern physics right there - it's no that there's not an aether, it's that as goes light so goes the universe.
  Amd this is /. - all snark is warrented, elsewise what would we read?
  
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19. Re:Haters gonna hate. by Chris+Burke · 2011-09-09 04:52 · Score: 2
  
  But that's just it - that's the underpinning of modern physics right there - it's no that there's not an aether, it's that as goes light so goes the universe.
  Not, that's not just it. The underpinning of modern physics is that there is no privileged reference frame, when the whole point of the aether was that it was such a frame. That frame -- the aether -- does not exist. That's the first major distinction between "modern" and the prior physics in which the aether was hypothesised. It is inherently contradictory to talk about modern physics and then say "it's not that there's not an aether" because it is an inherent consequence of the true underpinning of modern physics that there isn't.
  So calling space-time the luminiferous aether is completely stupid and and categorically wrong.
  That's why nobody does. Hard to believe, I know.
  
  Amd this is /. - all snark is warrented, elsewise what would we read?
  You're so right; what would people do if they had to be snarky and make sense?
  
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I have proof of dark matter by shelterpaw · 2011-09-07 16:36 · Score: 1

I consistently see it every night after a drinking binge.
New unit by hackertourist · 2011-09-07 19:48 · Score: 1

The abstract talks about "730 kg days". Huh?
1. Re:New unit by Anonymous Coward · 2011-09-08 00:30 · Score: 0
  
  730 kg days is the amount of data you get by observing 730 kg of detector for 1 day, or 1 kg for 730 days, or something in between.
Something's just not making sense ... by Anonymous Coward · 2011-09-08 00:26 · Score: 0

If the search for dark matter is supported by the need to know the nature of the unseen matter that accounts for 75% of the mass of the univers, observing that visible matter alone can not possibly account for the mass needed to hold galaxies together, how can WIMPS (which essentially do NOT interact with matter as we know it) possibly be the 'missing mass' ??? We seem to be offering an explanation for galactic structure, an explanation that is based on particles that do not affect galactic structure ..
Or is it thought that the 'mass effect' of WIMPS (infinitesimal as it is) , to be equivalent in effect to THREE times the 'mass effects' of the observable matter, must be incredibly more than merely what is represented by '75% of the mass of the universe' .. ie, WIMPS must exist, by present theory, in quantities immensely more in number than the equivalent total of observable particles that do represent 25% of the universe.
There is something crazy about this ... ... at least to this non-physicist.
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