 to scale.)
This giant map of invisible dark matter recorded in four directions by the Canada-France-Hawaii Telescope during each season of the year was released on January 9, 2012. The color inset shows the previous largest COSMOS dark matter map and the size of the full moon (as it would appear to the telescope) to scale.
Image: Van Waerbeke, Heymans, and CFHTLens collaboration.
AUSTIN, Texas — The hidden side of the universe is now a bit more illuminated thanks to the largest map yet of dark matter, the strange substance thought to inhabit much of space.
Scientists have created the largest scale rendering of dark matter across the universe, revealing a picture of the invisible stuff thought to represent 98 percent of all matter in the universe.
Dark matter has never been directly detected, but its presence is felt through its gravitational pull on normal matter. Scientists suspect dark matter is made of some exotic particle that doesn't interact with regular atoms.
"We know very little about the dark universe," said co-leader of the study, Catherine Heymans of the University of Edinburgh's School of Physics and Astronomy, during a press conference announcing the findings here at the 219th meeting of the American Astronomical Society."We don't know what the dark matter particle is. It's very widely believed that the final understanding of the dark universe is going to have to invoke some new physics."
The new map reveals the distribution of dark matter over a larger swath of space than ever before. It covers more than 1 billion light-years. One light-year is the distance light travels in a year, about 6 trillion miles (10 trillion kilometers). [See the new giant dark matter map]
Warping light
To trace invisible dark matter, the researchers searched for signs of its gravitational tug on other matter. They measured an effect called gravitational lensing, which occurs when gravity from a massive body bends space-time, causing light to travel along a curved path through space and appear distorted when it reaches Earth.
The scientists measured warped light from 10 million distant galaxies in four different regions of the sky, caused when those galaxies' light passed by large bundles of dark matter that bent its path.
"It is fascinating to be able to 'see' the dark matter using space-time distortion," another co-author of the study, Ludovic Van Waerbeke of the University of British Columbia, said in a statement. "It gives us privileged access to this mysterious mass in the universe which cannot be observed otherwise. Knowing how dark matter is distributed is the very first step towards understanding its nature and how it fits within our current knowledge of physics."
Scientists hope that by plotting out the distribution of dark matter throughout space, they will come closer to understanding what it is.
"By analyzing light from the distant universe, we can learn about what it has travelled through on its journey to reach us," Heymans said. "We hope that by mapping more dark matter than has been studied before, we are a step closer to understanding this material and its relationship with the galaxies in our universe."
A close match
The new maps represent the first direct evidence of dark matter on such large scales.
"What we see here is very similar to the simulation," Van Waerbeke said. "Dark matter is concentrated in lumps and the rest stretches in filaments."
The web of dark matter throughout the universe revealed by the map agreed well with predictions made by computer simulations based on scientists' best theory of dark matter.
See what we're tweeting about
62 Comments
Add CommentIf you are worried about spelling you probably should't be reading this. Everyone knows intellegent people don't get bogged down in this sort of stuff.
Reply | Report Abuse | Link to thisI think that just like "black holes", they are trying to make "dark matter" too complicated. If dark matter is everywhere, why are we scanning the far reaches of the Universe to find it...there should be a whole bunch of it in our backyard. If there is none in our backyard, then why not? Why would it only be in selected parts of the Universe? It must not be dangerous, if it was, we wouldn't been able to stay here for 4 billion years.
Reply | Report Abuse | Link to thisCould dark matter just be dead spots in the Universe where stars are not allowed to form because it is occupied by either negative or positive gravity; another invisible force? If that is the case, then that would explain how everything is being pulled back and forth and held in place.
Dark matter has a profound effect in our current knowledge of Physics. We are treading into a new dimension that will most likely change our current understanding of how the universe works.Humans were created with a burning desire to understand their world and how it works. I doubt we will ever completely know all of its secrets however its a quest that will never stop until we are no longer a viable species.
Reply | Report Abuse | Link to thisOh no; more reports from dark matter researchers...
Reply | Report Abuse | Link to thisThe article states: "The new maps represent the first direct evidence of dark matter on such large scales."
There is absolutely no direct evidence for the existence of dark matter - every bit of is is inferred based on rough estimates of of large scale gravitational factors.
From this article it seems that the subject study presumed that all instances of weak gravitational lensing are produced only by dark matter.
At the very least, the external gravitational fields of visible matter would certainly produce some weak gravitational lensing even if dark matter does not exist. The presence of dark matter is inferred by the discrepancy between the gravitational lensing effects inferred by statistical analysis of many background objects' apparent slight distortions and the estimated mass of observed visible matter, typically only roughly estimated from the apparent luminosity of foreground objects.
The article goes on: "The web of dark matter throughout the universe revealed by the map agreed well with predictions made by computer simulations based on scientists' best theory of dark matter."
I'd have expected that, based on these methods employing interdependent circular inferences, no other conclusion would be reached...
As for justifications of the presence of galactic dark matter, it was originally inferred erroneously by a discrepancy between the rotational characteristics of spiral galaxies' disks and astronomer's expectations based on Kepler's laws of planetary motion.
It has since been determined that the rotational characteristics of spiral galaxies can be described using Newtonian dynamics and universal law of gravitation, without dark matter or modified gravity. Please see: Feng & Gallo, (2011), “Modeling the Newtonian dynamics for rotation curve analysis of thin-disk galaxies”, http://www.raa-journal.org/raa/index.php/raa/article/view/858
While the self-gravitating disks of spiral galaxies do not behave as planetary orbital systems, more distant objects at the galactic periphery do independently orbit the Milky Way 'just like planets in the Solar system'. This observation conflicts with the presence of an enormous dark matter halo. Please also see: Bratek et al, (2011), "Keplerian Ensemble Approximation. The issue of motions of Galactic halo compact objects", http://arxiv.org/abs/1108.1629
Please also see a brief commentary including several other references: http://sciencewithoutfiction.com/uploads/JDwyer.PDF
Has anyone stepped back to look at this from a fresh perspective? Given the observations of the behavior of visible matter and energy at these large scales, can a theory be devised that explains it without invoking dark matter? Could General Relativity be incomplete or wrong? I know GR has been one of the most successful theories of all time and has proven accurate to a fantastic degree in a vast number of experiments but it still seems strange to posit a whole new type of matter that makes up the majority of the mass in the universe and cannot be directly observed just to explain anomalies in the observations of the motions of matter.
Reply | Report Abuse | Link to thisAlas, I don't have the mathematics to pursue an answer myself but I love to think about and discuss these topics.
You just missed my preceding comment (above). I (a layperson) and several dozen qualified physicists support the conclusion that the inferred presence of galactic dark matter was and is produced by invalid methods of evaluating the gravitational effects produced by large scale, compound objects.
Reply | Report Abuse | Link to thisIMO dark matter is likely not necessary anywhere in the universe, but certainly not to explain galactic rotation, and the gravitational approximation methods provided Newton and Einstein are perfectly adequate for most conditions when properly applied. Problems arise when simplified approximation methods are applied to large scale, complex aggregations of massive objects...
Indeed you are correct that dark matter may be all around us. This is the basis for several current dark matter detection experiments such as the Cryogenic Dark Matter Search I and II. If dark matter includes WIMPs (weakly interacting massive particles) they should be everywhere.
Reply | Report Abuse | Link to thisThere are other lines of evidence for dark matter besides "rough estimates of large scale gravitational factors". For example, calculates of Big Bang nucleosynthesis indicate that there may be non-baryonic matter. The Wilkinson Anistropy Probe satellite analysis of anistropies in the cosmic microwave background indicates that the universe consists of only 4% ordinary baryonic matter and approximately 23% cold dark matter. Moreover supersymmetry predicts the existence of supersymmetric partners of known elementary particles some of which may be good candidates for dark matter.
Reply | Report Abuse | Link to thisThere have been a number of alternative theories of gravity postulated as alternatives to general relativity, but none have survived stringent experimental testing, whereas GR has.
Reply | Report Abuse | Link to thisAs I stated, there is no direct evidence for the existence of dark matter (contradicting the statement made in the article) - all existing evidence is inferred by highly complex interpretations of observational data.
Reply | Report Abuse | Link to thisIMO, these additional lines of inferential evidence would not likely stand on their own as justifications for the existence of dark matter without the establishment of the perceived requirement for galactic dark matter in the 1970s and 1980s. I admit that these additional lines of evidence are derived from analyses so complex that challenging them would be exceedingly difficult for subject area experts and impossible for me. The erroneously inferred requirement for galactic dark matter is a much simpler issue.
Of course, despite long running, extensive and very expensive attempts to detect dark matter candidate particles, none have been found.
BTW, as I understand, the 'standard model' of cosmology justifies its approximations of parameter values for dark matter in the developing universe based on the estimates inferred for galaxies...
Reply | Report Abuse | Link to thisPeddling nonsense again. Don't waste your time on blogs. Submit your paper to a reputable physics journal. I'm sure it will be rejected. Btw, that Feng and Gallo paper was published in the Journal of Cosmology, which won the Pigasus Award for "publishing articles advancing scientifically unsupported ideas."
Reply | Report Abuse | Link to thisNo, but your objections are subjective and unfounded. The Feng & Gallo paper was published by the Institute of Physics (IOP) in the journal Research in Astronomy and Astrophysics. Other referenced papers are published in the Astrophysics Journal (ApJ).
Reply | Report Abuse | Link to thisAdmittedly, it's difficult if not impossible to get papers that directly criticize the methods used to infer dark matter as I do here. Perhaps there is some reviewer bias against against any effort to discredit a precept which has received so many research grants and upon which so many careers have been built over the decades. That doesn't make my arguments nonsensical - if you have specific, reasonable objections I will attempt to respond...
I just don't believe in "dark matter" as separate from normal matter. Maybe unobserved (so far) matter, but not matter outside known Standard Model particles. Find one or make one and prove its existence and the audience will be all ears. Lensing is a wonderful technique but does not at all prove matter beyond known forms.
Reply | Report Abuse | Link to thisI still think we are barking up the wrong tree if we expect to actually see Dark Matter. If it doesn't act at the electromagnetic level it probably does not have electron shells. Since most of what makes up the space of an atom is the electron cloud around a very small nucleus *something like a foot ball at the 50 yard line being a nucleus and the city of Dallas being the electron cloud, we can safely consider dark matter to be more point like in manifestation and since we know it reacts with gravity until we find something other than the geometry of space/time to represent gravity I would think of dark matter as something that we will never see in our life time but be able to see its affects right now.
Reply | Report Abuse | Link to thisI also think we are going to be deeply disappointed in our search for Higgs Bosons because again the only particles that require volume may be those that are bounded by electron fields. One of the more interesting points we have seen with atoms is that they behave somewhat like liquid drops which means they have some bounce to them.
What we are pretty sure of and this is important is that dark matter tends to cluster around galaxies and large objects. It would be very interesting to see what the boundaries are (at what point dark matter starts to become attracted to the object) I think we could learn a lot more about what it is and what else might be out there if we started with the idea we are not going to see something that does not require volume on our plane of the so-called m planes.
Just some thoughts to chew on late at night.
Whatever one thinks of the necessity or composition or physics of "Dark Matter", it's obviously transparent, not dark, and the nomenclature militates against credibility for the concept. Don't physicists know that? We can't "see" space or dark matter. What do they have in common? We see the effects of light distorted through space warped by gravity, more than accounted for by visible matter. So, why not a property of space? Matter via gravity warps spacetime. Why not spacetime exerts a force on matter? At least it's equivalent or inseparable, the effect of matter ( via gravity as a property of matter ) on spacetime is = the effect of spacetime ( via gravity as a property of spacetime or it's relationship to matter) on matter.
Reply | Report Abuse | Link to thisVery interesting. I think the more we get away from it has to take up space or have volume the closer we will get. What we are pretty sure of is that it clumps big time around regular matter but then again how can you tell what is in empty space. I like your thinking.
Reply | Report Abuse | Link to thisJames, it does not react with electromagnetic, strong or weak force as far as we can tell. It does interact with gravity and word is still not in if gravity is real or a geometry trick. But even if it was in front of you, it would have to react in one of the three mentioned forces for you to notice it. That is part of why neutrinos have been heavily pointed to but they fall short.
Reply | Report Abuse | Link to thisAlso keep in mind space/time speaking we are on the very lowest of the energy levels and at 30 frames per second we miss a lot of what is happening in the real universe. So listen harder, look slower and breathe. It may well be right in front of your face.
Also keep in mind about 24K light years away is a super massive black hole that is the center of the Milky Way. I do hope there are none too close and I hope Sirius doesn't get bitchy on us as a binary star. It is only 10 light years away and if it novas we will notice.
Reply | Report Abuse | Link to this"the only particles that require volume may be those that are bounded by electron fields."
Reply | Report Abuse | Link to thisUmmmm, go read up on how neutrons cause nuclear chain reactions or how fusion works or how neutron stars keep themselves from collapsing further.
Neutrons are about the size of a proton minus an electron and some energy. The weak force is what allows Protons to radiate to the Neutron, electron and the energy that makes things go boom. Relatively the neutron is still small back to the football as the nucleus and the city of Dallas being the Electron Cloud.
Reply | Report Abuse | Link to thisAlso to date there is no evidence that dark matter works with the weak force which would be required for your comment to hold water. But even if dark matter was the size of a neutron we are back to the volume issue. While the neutron is substantially bigger than the Plank length it is ruled by both the strong force (keeps the nucleus together and the weak force (allows the nuclear reaction both fusion and fission to work)) but it is very very tiny so your argument leaks volume.
My point is that if the dark matter is tied to just gravity it may be point like (probably bigger than the plank length but working under different forces (this drove Feynman nuts). But regarding volume at 235 footballs in an electron cloud the size of Dallas still makes the neutron snall and remember it had to be slowed way down to make the chain reaction work because the particles are so small.
I give you credit for that shot but it was not thought out. try thinking like Benoit and his Fractals with space something like an Escher painting which would allow us to rule out infinity (just gets in the way anyway) and may open the door to a universe that is truly a singularity that would fit with Hawking's description of M-Branes (you can see some of the forces but not all of the forces at one time) and Smolin's 'Life in the Cosmos' where black holes are actually big bangs in a multiverse.
What we are sure of is we have an ideal of what 2 to 4% of matter is, we know 24% of the rest is dark energy but we know that gravity is the only force we can tie to it and the other 70+% we call Dark Matter that at best resembles an event horizon. I would also call attention that we exist at the extreme low end of the energy levels (we are comfortable at about 470 degrees F above absolute zero, have smooth visualization at about 24 frames per second, just starting to realize that time/space is subjective and reality depends on location, velocity, trajectory and range of electromagnetic field lines.) If we were any more complicated our chance of making it to here, where we can ask some really interesting questions would have had about no chance in hell.
I do think Gravity and Geometry have some interesting relations that carry over to other things.
I have a few observations regarding your discussion with sault.
Reply | Report Abuse | Link to thisWhile general relativity describes the effects of gravitation in the geometric terms of dimensional spacetime coordinates, there is no real explanation for any physical effects produced by massive objects that impart the described changes to the geometry of spacetime.
Current cosmological assumptions are that ordinary matter constitutes 4.6% of the total mass-energy of the universe; dark matter 23% and dark energy 72%. I think you transposed the hypothesized dark constituents. It's incorrect to say that 'we are sure of' these things - as I mentioned previously, the roughly 5:1 ratio of universal dark matter to ordinary matter is largely justified by the perceived requirements for dark matter to compensate for the invalid gravitational evaluation of galaxies.
Back to sault's objection to your statement that "...the only particles that require volume may be those that are bounded by electron fields", in quantum therms particles' occupation of dimensional space is attributed to the Pauli Exclusion Principle and applies to electrons, protons neutrons, neutrinos and quarks. Please see:
http://en.wikipedia.org/wiki/Pauli_exclusion_principle
The section "Astrophysics and the Pauli principle" briefly describes how it applies to neutron stars (composed almost entirely of neutrons) as sault indicated. That neutron stars are prevented from further collapse indicates that that have minimum dimensional space occupancy requirements. Neutrons have no electromagnetic charge.
Neutrons are made of quarks and are affected by weak, strong and gravitational forces. You are correct on the dark matter/energy reversal my point was that we can only explain 2 to 4% of what we see and we make assumptions concerning volume or space being occupied by only one object at a time which quantum physics kicks in the balls pretty easily. My point is that what we can't explain or tie to only one of the 4 known forces may have different rules and also neutrons are very close in size to protons which again are very tiny when compared to an atom which is mostly empty space or electron cloud which ever you chose. It is the tension force that keeps things from passing through each other and regarding the exclusion principle I would say neutrinos more than make the exception there.
Reply | Report Abuse | Link to thisWhat I am trying to point out is that we assume volume and that may be a mistake. I believe that anything that has mass *dark matter included can be as small as the plank length and that is a hell of a lot smaller than an atom.
I also want people to think about how low on the energy spectrum we and regular matter exist. I am intrigue with neutron stars and would love to see how they warp the space and time in their area and am always amazed how something 10 miles across can rotate 2,000+ times per minute and the highest structure being somewhere around 2 inches.
But we have a fair understanding of neutrons and realize that they are affected by three of the known forces so far we can only tie gravity to both dark matter and dark energy and based on m theory and you know I hate string theory it is possible that certain types of m-branes will allow you to see other forces that have no business in our view of the universe. I think we over rate volume/space/time and gravity and still think Benoit passed away too early because I believe his weird fractal view of the Universe and Escher's collapsible space will expose a singularity when all is said and done. But I am not a physicist only a fool on the hill watching the world go by day after day. Or as I prefer I stopped playing the game and now I am watching the wheels go by.
Thanks for the catch it has been a while.
Me too, although I think those estimated constituents of universal mass-energy are highly suspect, Thanks!
Reply | Report Abuse | Link to thisProtons don't radiate to neutrons and electrons. They are stable to at least a lifetime of 10^31 years. Neutrons on the other hand do spontaneously decay to a proton, electron, and antineutrino via the weak force with a halflife of about 15 minutes.
Reply | Report Abuse | Link to thisI understand that proton decay has never been detected, although it has been hypothesized by some unification theories. Unbound, free neutrons are unstable, but neutrons bound by the strong force with protons to form atomic nuclei are, thankfully, stable.
Reply | Report Abuse | Link to thisAs I understand, during the core collapse of non-type Ia supernovae electrons and protons merge via inverse beta decay, producing neutrons and neutrinos. Neutron stability is also extended within the contracted spacetime of neutron stars' gravitational fields.
My mistake and good catch. That said as Jim remarked it has been tested and to date not likely but it is allowed. If dark energy is correct which it is way too early to have any absolute answers, everything would eventually decay including the atoms in your inquisitive head and this would include the decay of protons. I believe the estimated time is for all this to happen is 100s of trillions of years so I never loose sleep over it.
Reply | Report Abuse | Link to thisOne other problem that is more likely to be true is that as we continue to expand faster and faster the effect will be similar to being in a black hole on the other side of the event horizon. I think that is something that is a clue to what we are made of and it is fairly well established by the basic expansion of the universe not slowing down.
Events I wish I was here for but will miss:
1) the boiling of water off our planet as the sun begins to heat up in about 1 billion years.
2) the collision and actually the approach of Andromeda in about 2 billion years.
3) the sunrise provided we are not tossed out of the solar system in about 4.5 billion years as the sun goes through its red giant phase (I would just as soon miss the actual crispy part when it engulfs us)
4) Seeing Rigel A go super nova which is a possibility for all of us.
5) Another possibility and I am glad I live in Florida, the eruption of the super volcano at Yellowstone.
Mr. Darkness...is that you?
Reply | Report Abuse | Link to thisYahahahahahahahah now does anyone have a light, it is getting a little scary in here.
Reply | Report Abuse | Link to thisHope you enjoy Rationallylogicalaminalskeptics (LAN)
Reply | Report Abuse | Link to thisWe are Lost from the Woods
---------------------------
I’m not afraid of night
I created light
I’m not afraid of truth
I created false
I listen carefully
And react carefully
I will always be all right
I am not afraid of the light
I’m modern man
Improved, You don’t understand
I marvel at the success of man
I always buy the right brand
I’m space man I touch the stars
I’ve spread my crap near and far
I clone life
While I destroy life
My race makes DNA from your RNA
It matters naught as Earth Fades Away
I’m safe inside, just flip a switch
Waiting, waiting and waiting there must be a hitch
It was only a lightning storm
I’ll be fine by morn
The lights stayed out
As did the TV
With no cell phone I loose my grip of reality
My grip of 21st Century is not real anymore
My grip is gone the concrete cracks
People swarmed and they attacked,
People got mean while they lost all.
The first loss we saw was the rule of law
Even the mighty had fear in their heart
We have become lost from the woods
And it is getting dark
-----------------------
Yes it may be getting dark out there, but we are still here to discuss it.
My head will decay? Good Lord! Will it hurt?
Reply | Report Abuse | Link to this:)
I don't know are you planning on being here in 100 trillion years. You'd be quite old mister, with a lot of wrinkles and maybe not too sharp in the old head if you know what I mean.
Reply | Report Abuse | Link to thisOr as some historian once said about something he was writing about that he wasn't present for 'You had to be there to really understand it'.
:)
I am really counting on Benoit and Escher being right but no one took them seriously and I know Benoit is dead with Escher he may be more like his art.. I do know I studied infinity forever and found it boringly lacking in some necessary basics and like the ideal of a multiverse that is really just a singularity that gets to ask questions now and then. I am so glad we got a moon, magnetic shield, stabler orbit regarding inclination, less CO2 than our sister planet Venus (I do blame the collision that caused the moon for that one) and when the heavy metals were up for grab the earth got them and it gave us a core that rotates differently than the mantle and crust. I don't think you get a lot of all that to happen in the universe very often and then Elephants, dolphins and whales do not seem to need answers regarding purpose as much as we do being the weaker of the species.
I would hate to live on Europa where you would think the whole universe ends at the ice and would have the darndest time explaining gravitational tug that allows for life in a universe devoid of stars, planets or solid earth. And worse of all you would look like an Octopus or Squid if lucky enough to ponder such things.
Have a great day and look forward to more discussions. I think next to music it is the best part of being humans with politicians and preachers being the scariest.
If time and space is a function of energy according to E=mc2,dark energy is a unit of energy with no time and space. When we will go into a black hole at the end of the universe, the boundless energy will ressurrect all of us into a new dimension with past and future together.
Reply | Report Abuse | Link to thisThe Escher Factor....
Reply | Report Abuse | Link to thisGawd, the lack of an editor in the comments columns really detracts greatly from SciAm. There are loons and igroramuses galore writing their comments most especially on physics, astronomy, evolution and global warming but I am drawn like a moth to the light...well actually ..more like a fly drawn to smell of it perhaps!..It is a true sign that the U.S. where I suspect much of the commmentary originates has a basic lack of science education in its readership and considering that likely the Sci Am readership is a step above the Jerry Springer crowd, it does not bode well for its role as the second largest producer of research papers and patents. Note..second largest. At this rate reflected in the commentaries, it might be third or fourth down the road a few more years as other nations are doing a lot more to prepare their citizenry for a future of scientific mastery.
Reply | Report Abuse | Link to thisInaccurate measurements, rounding errors, bad computer programs, time shifted matter, time dilation and other can well account for the postulating of dark matter/energy. A small measurement error can become very large when multiplied to the scale of the entire universe.
Reply | Report Abuse | Link to thisIf we could just go back to the steady state and a flat earth the math would be much easier.
You complain yet you do not elaborate. If we are lacking please enlighten us poor Yanks with our lousy public schools and pro right leanings. Otherwise are you perhaps looking in the mirror because anything further than your nose has no merit?
Reply | Report Abuse | Link to thisI plead little knowledge beyond Dyson, Feynman, Bohr, Einstein, Smolin, Susskind, Manderbolt and a few other names but I was told they were pillars of science so again please stop following you nose and elaborate where your insults are aimed. I apologize if I don't eat from the troth of Greene or Hawking but I do read them also. I am very interested in your input and insight I can only learn by reading and sharing and I can only irritate by making comments such as yours.
I also notice you fear using your name. Reminds me of children hiding behind corners and throwing snow balls and then running. But you assume to have intelligence we are incapable of so I will await your responses and then I may understand your abusive language without any meat attached. Even what the fly is attracted to was food before fly perfume.
Reply | Report Abuse | Link to this"It's very widely believed that the final understanding of the dark universe is going to have to invoke some new physics."
Reply | Report Abuse | Link to thisSorry, but it ain't necessarily so (as Gershwin mused in his Porgy and Bess). What is sadly lacking here is a serious review of, and reflection on, hard data already gathered and reported in prestigious journals, but with an open mind sans blinkers. One shouldn't then be surprised to see that we only have to take that great step back to the old physics of classical Newtonian mechanics to comprehend this universe of our observation. The high-intensity nuclear activites at the centres of galaxies and associations thereof that force us to invoke supernatural entities, such as dark matter, dark energy and black holes, can now be safely jettisoned from (empirical) physics now dangerously cruising the science mainstream. |To make it short here, please access:
(1) www.sittampalam.net/TheSuperwind.htm
(2) www.sittampalam.net/PioneerAnomaly.htm
It's interesting to note that dark matter inside solar space was not speculated when the Physical Review D report in (2), above, was first published!
Thank you all.
I tend to agree with jtdwyer. Dark matter is not supposed to interact with baryonic matter, yet it is detected by its gravitational property to the effect of lensing light and distorting the shape of galaxies. If it can do this, then the lensing effect that was observed during the eclipse that confirmed Einstein’s theory would not have been possible as the gravity of the intervening dark matter would have played havoc with the light. Since it is stated that Dark Matter is far more abundant than the baryonic stuff, and it has gravity, why does its gravity fail to form dark suns and black holes, or would it form white holes?
Reply | Report Abuse | Link to thisOn the subject of dark matter, we seem to be at a stage similar to the pre-Copernican era; at the time elaborate explanations involving epicycles and mathematics were invented to explain a geocentric universe.
Shimagyoh
That's an interesting question about whether dark matter could form dark suns or black holes. I would think it could certainly form black holes since it is subject to gravitational attraction and has mass. Suns on the other hand imply a gravitationally bound collection of particles which is heated as it is compressed until the reactions of nuclear fusion start. Since dark matter doesn't form nuclei or interact via the weak, strong, or electromagnetic force, presumably it wouldn't participate in fusion reactions if heated and compressed, so there would be no "dark suns", just masses of dark matter not massive enough to form an event horizon.
Reply | Report Abuse | Link to thisOr not. :)
I don't think the validity of the gravitational lensing effect as a confirmed prediction of general relativity depends on the nature of the mass producing the lensing. It could be baryonic matter alone or baryonic matter plus dark matter. What counts is 1) there is enough mass to causing detectable bending of light; 2)there has to be a visible object (visible in any portion of the electromagnetic spectrum) which is being lensed by another visible object. If both the object being lensed and the lensing object were entirely composed of dark matter, then of course the phenomenon would be undetectable.
Reply | Report Abuse | Link to thisWow, bigbopper! What is the nature of dark matter’s gravity? Einstein’s idea that space is a malleable medium, that the presence of matter distorts it and this explains gravity and the lensing effect. There are other theories for gravity, but I doubt if any is sufficiently sound to finally discard this suggestion. Is dark matter’s gravity different?
Reply | Report Abuse | Link to thisShimagyoh
Maybe the planck length points in your theory are like virtual particle switches that turn on or off according to the wavelength of energy passing and the whole universe is like a mirror reflecting the unwinding of boundless energy.
Reply | Report Abuse | Link to thisGood point about the seemingly necessary but undetected impact that a 'cosmic web' of dark matter should have on our observations of distant objects. If intergalactic space contained such large web-like structures composed of dark matter there should be a very common distortion of EM emissions from distant objects.
Reply | Report Abuse | Link to thisThe magnification effect of gravitational lensing is produced by the smooth curvature of spacetime produced by regular configurations of matter - such as stars, and galaxies. Microlensing, commonly produced by individual stars within galaxies, can produce a mottled composite image effect by producing multiple images of a single background object. In both cases multiple distorted images can also be projected.
I strongly suspect that large areas of the irregular strands of intergalactic dark matter 'webbing' would produce irregular distortions of distant objects. As far as I know, nothing of that nature has been observed.
Regarding the accretion of dark matter objects, it was demonstrated in space not long ago that static electricity produced by physical interactions among ordinary matter likely contributes to its accretion into objects prior to any aggregation of mass capable of producing effective gravitation. Dark matter particles of course would not interact in this way.
Your're right, the classic example of contrived mathematical proofs is Ptolemy's geocentric model of the cosmos that could successfully predict the position of the planets in the sky. This established the Earth as the center of the universe, an idea that persisted for nearly 1,500 years. I often think of that when I consider how much of the current thinking in astrophysics and cosmology is essentially inferences based on inferences, ad nauseum. A house of cards?
Good thinking!
Another thought re. dark matter accretion - ordinary matter physically interacts, producing frictional heating that, in turn, increases the motion of particles and their interactions. BTW - If dark matter wasn't cold, how could it not at least emit thermal radiation?
Reply | Report Abuse | Link to thisWas just setting a point that illustrates how much more space is available for different forces and how volume is expressed. We need to be able to get of this box.
Reply | Report Abuse | Link to thisYou are Green Jello aha ... Photons only expresses one at am instant yet that takes to many photons keep watching.
Reply | Report Abuse | Link to thisI find sault a waste of time to even acknowledge. He tosses insults and derision, but when faced with facts, always disappears. This particular comment thread has been an interesting read. Thanks to all.
Reply | Report Abuse | Link to thisI submitted my comment today at ,12.00 Hrs GMT.
Reply | Report Abuse | Link to thisI received an Email from Scientific American that
my email adress is verified and correct.Please respond on
your decision.
The gravity that affects dark matter is the same gravity that affects baryonic matter. Another way of putting it is that the dark matter's mass affects spacetime in exactly the same way that baryonic matter's mass does.
Reply | Report Abuse | Link to thisI liked the SCIAM issue where they are starting to look at quantum as information. Susskind did a good job with his holographic look at the Universe and I believe that if you treat the particles as information with some being aggregates they would create mass on their own because of the time it takes to travel at light speed and send that much information. It also fits both relativity and quantum theories much better. But I still think we need to consider Fractal Space with boundaries some what like an Escher pictures.
Reply | Report Abuse | Link to thisI just think infinity doesn't make it in math or reality and that means we are in a singularity of some sort and Fractal particles fits that just right if it is bounded by Escher space.
"Dark matter has never been directly detected, but its presence is felt through its gravitational pull on normal matter."
Reply | Report Abuse | Link to thisWhat's the big difference between "detected" and "felt"? We don't really perceive matter of any kind, but only our consciousness of the impulse in the optic nerve caused by the light emitted or reflected from the body (or by feel etc.). At one time, asteroids were "dark matter", too dim to be detected without a good telescope. Is it possible that if we couldn't see asteroids, if maybe they had an outer coating of soot, that we might have eventually detected their mass gravitational effects on the solar system and thought them to be something other than normal matter?
How, exactly, do we measure lensing effects of gravitational bodies? Isn't it possible that at least a lot of dark matter is bits and pieces of all sizes of normal matter, floating undisturbed between planetary systems and between galaxies, not illuminated enough to see? Do we really know the true brightness of distant galaxies? Are there other wrong assumptions we're overlooking? Many such astronomical findings are based on long chains of assumptions, One wrong assumption invalidates the chain, therefore the statement.
The more mysterious, miraculous or magical something seems (such as also quantum physics), the more I suspect some information is being left out, or wrongly assumed.
"One billion light years" means little more to me than one light second. Give us something relatively comparable, such as the distances to the ten nearest galaxies.
You are right in that in the end it is all subjective but we do realize our visual limitations (very narrow band of the electromagnetic field) which is why we create machines that can perceive into the UV and IR area where we suspect EM ends based on energy. But you are also right that we are still missing information other wise how could this be fun.
Reply | Report Abuse | Link to thisBut I still wonder if attaching any size to dark matter makes sense because size or volume is really an area that is a reflection of tension energy between electron shells and Dark Matter may not have those which means it may be simply point like energy that interacts with gravity and perhaps other forces (back to your statement on quantum energy).
As far as measuring space at all after Einstein that became kind of the dog chasing his tail. We can make relative measurements and that is all and if we cannot agree on the speed of the observed object we cannot agree on it distance and that sounds like quantum issues doesn't it.
What is specifically inferred by interpretations of observations is that observed effects of gravitation exceed those expected to be produced by the approximated mass estimates for large scale, complex aggregations of massive objects.
Reply | Report Abuse | Link to thisThat derived discrepancy suggests to astrophysicists the presence of mass that is not included in their characterizations of observed aggregated masses.
The hypothesized dark matter is merely a proxy for mass effects exceeding astrophysicists' extrapolations of observational data.
As I understand, no gravitational effects have ever been identified that are attributed to the presence of dark matter alone, without the contribution of significant masses comprised of ordinary matter.
If the mass attributed to complex aggregations of ordinary matter is in any way underestimated, the observed gravitational effects attributed to dark matter could be produced by ordinary matter alone.
Jim,I still think that the dark matter issue is being looked at from the wrong direction but I would put money on it being there. We are able to account for 4% of matter that obeys the four fundamental forces of the standard model. We become lost if the observed object does not express itself electromagnetically, weak force or strong force but we see peculiar things that can be attributed to gravity.
Reply | Report Abuse | Link to thisFirst of all string theory may be on to something though not correctly when it uses the concept of Mbranes and the fact that certain branes are affected by different forces. I also hold that if there is no electron cloud then the concept of point like energy should be allowed because basically our electromagnetic universe is basically empty space and what we perceive as volume is actually surface tension of the electron clouds.
If dark matter does only interact with gravity then it would be logical that it would clump near massive objects such as galaxies and probably black holes. We also have seen galaxies that are basically dark and are very aware of objects that have IR characteristics yet are dark to our optical telescopes at our range of color.
I also think we need to keep in mind at how low on the energy level we exist. We are basically 472 degrees above absolute zero and visualize at about 32 frames per second meaning things that happen at lets say 1000 frames per second may be transparent or invisible to us.
There was some stop action work done on star fish and at our visualization rate they appear motionless but at stop action they are very active and in fact interactive. Yet I would think if I passed by them at a normal speed I would not even be visible in their frame of perception but if I would sit there for a while and then moved I would be a god like apparition.
What I am getting at is there may be going on that is beyond our perception for one reason or another.
The universe plays by its rules and if there are multiverses we will maybe get a glimpse but not a full view of the other side. Another thought experiment is lets assume you are an intelligent being on the moon Europa and your universe ends at the ice cap with borders and yet you may notice the effects of tidal forces from Jupiter. In that world how would you ever detect that there is an entire universe, multiverse or anything else except maybe Jupiter and a couple of its other moons.
Is the universe a sea of lazy neutrons?
Reply | Report Abuse | Link to thisHere are my comments:
I agree with James Davis in that the dark matter should be evident everywhere, and that it is not necessarily exotic as such. But what if our backyard has a set of conditions that excludes the presence of local dark matter?
A neutron, by itself, is not particularly stable. It decays into Hydrogen after a minute or so in all Earthbound experiments (the only type we can do). Nobody knows why the negative charge at the centre of a neutron gets so excited that it is flung out of the surrounding positive charge. That situation, given the behavior of electrical charges, should be very stable! What if it is the fact that the neutron is in a strong gravity well!
If dark matter was just lazy neutrons; hard to detect but exerting gravitational force on everything around it, that would explain why we can't find any in our "backyard".
We all know hydrogen well. It is the second most populous matter in the universe after the dark stuff! And it is the building block for stars.
Imagine gravity was the thing that caused a free neutron to decay so quickly here on a planetary surface, and imagine there was an abundance of free neutrons that we couldn't detect because they were not doing much. As a region of space became slightly more dense, neutrons might begin to decay in that area. They would clump together because of their own gravity and that would cause even more neutrons to decay.
Eventually, you would have a very clumpy universe much like the one we have. You would also have an enormouse resource of proto-matter from which to build new stars. Each of these would create and spew out heavier elements that would sometimes form planets.
It would all be very convenient, wouldn't it.
I don't know. I'm not a scientist!
Hi jtdwyer.
Reply | Report Abuse | Link to thisIn your last comment, you say if mass effects were, "...in any way underestimated". I say, "underestimated by a factor of 10 or twenty." That would be remarkable and would only be possible if we got a lot of other physics wrong.
No, I don't necessarily agree with David, who replied to your post, but I don't believe that dark matter just isn't there.
The parent article, if the methodology for measuring the dark matter density is valid, and I think it is, shows that light bends around masses that are not normal matter. A flaw in our basic physics would not account for this. It would only show the normal matter impacting on photons as they stream towards us so the map would show higher densities where galaxies are. That is definitely not the case!
Something else IS out there!
Hi James. I don't mean to be difficult but you say the existance of dark matter makes the model too complicated. Believe me, that is not necessarily true. We can't incorporate it in a viable model properly anyway, until we know what it is. We are only still talking about it's effects leading to that understansing.
Reply | Report Abuse | Link to thisThen... you go on to suggest that regions of negative gravity might be LESS COMPLICATED? C'mon!
You say in your reply to jtdwyer 'No, I don't necessarily agree with David, who replied to your post, but I don't believe that dark matter just isn't there.'
Reply | Report Abuse | Link to thisCould you please elaborate because from what I am saying is that if something does not require three of the 4 known forces (which may be an illusion based on geometry of space and reach of force) then the concept of electron clouds become unnecessary and may allow for point like energy. It may also follow other forces that we don't and therefore do not know how to measure at this time.
My point though is that it would make sense if the Dark Matter did react with gravity it would be natural to find it clumped around large gravitational areas such as galaxies, black holes and probably galactic gas clouds which can be light years in size.
But to simply say I don't agree with out elaborating leaves me with some dark thoughts.... I do not like string theory (I am more a fan of Smolin and loop quantum gravity and time being very subjective to the events that effect each other) but based on Hawking's description of Branes using forces that are local I think there is merit in that statement. I think we take to much of an egotistical view of the universe but that has always been the case and for some reason we keep getting smaller and smaller and much less significant as we dig deeper and deeper.
But the best description of an atom I have heard yet is the football is about the size of the nucleus and the city of Dallas is the size of the electron cloud. It reminds me of galaxies and the gravitational effects they have such as our expected collision with Andromeda in 2 billion years.
Anyway just elaborate a little so I can chew on it. I learn a lot from these discussions but always get lost when the comment is only 'I don't agree with so and so' without a follow up. Thanks.
Regarding your comment on the neutron decay that is old news in some respects but a good description of the weak force if I am not mistaking.
Hi jstokes!
Reply | Report Abuse | Link to thisAs I understand, the total mass of spiral galaxies is thought to be underestimated by factors varying from about 6 to 10, with the additional 'missing' mass provided by dark matter.
That missing mass that seems necessary to explain the observed rotational (orbital) velocity of objects at the periphery of spiral disks, presuming that they should diminish with radial distance as specified for discrete planets in Kepler's laws of planetary motion.
The attribution of mass effects producing 'observed' weak gravitational lensing is estimated by statistical analyses very slight distortions to thousands of background objects - minus the estimated aggregated mass of foreground objects (galaxies in galactic clusters). IMO, in all those complex estimations there is potential for error that may explain the mass attributed to dark matter.
The galactic mass attributed to dark matter to explain the rotation of spiral galaxies is clearly a simple matter of misapplying empirical planetary 'laws' to inappropriately distributed galactic masses.
As I explained in previous comments, these (potential) errors are not the results of flaws "in our basic physics" but simply the application of improper estimation methods.
I don't argue that no dark matter can exist in the universe, but I am skeptical since establishment of the justification of its existence (to explain galactic rotation) was invalid. I'm just not a dark matter believer.
Dark Matter and Dark Energy are two interconnected monstrous evidences to the periodical Multiverse existence, they realize DM gravity (attraction) and DE gravity (repulsion) between adjacent periodical dark Universes/Antiuniverses - physically equal - being from the same SM particles, but the nearest DM Universes electrostatically are isolated of us = pico-shifted in the 4-th dimension. The periodical (matter/antimatter) 3D-waveguided,global 4D-Multiverse concept looks as a 4D-mica-crystal: (see, please the e-Journal published paper in Berlin (Humboldt Univ. http://www2.hu-berlin.de/leibniz-sozietaet/journal/archive/13_12/01_gribov.pdf ).
Reply | Report Abuse | Link to thisIt explains:
(1) the interconnected nature of Dark Energy (DE) and Dark Matter (DM) & the flatness of our Universe/Multiverse & the accelerating expansion & the ?bubble? large-scale structure, with the estimated theoretical ratio DE/(DM + Ordinary Matter) ~74%/26%, that is very near to the recently done measurements. The DE&DM, etc data work as evidences for it);
(2) realizes massive-quantized ? elementary, hyper-periodical fermions / antifermions, with the string-like properties without singularities; the GR-like black holes also free of singularities;
(3) predicts antigravity in the future antihydrogen (or positronium) -gravity test (preparing in CERN and in the Mills lab -US);
(4) explains the Cooper-like (e-/e+) composite-ghost nature of the total supersymmetry (SUSY), providing zero (superfluid vacuum) energy density and its weightlessness;
(5) predicts natural absence of the hypothetical elementary SUSY sparticles (never detected at CERN);
(6) predicts absence of the ?elusive? Higgs bosons, naturally excluded by the holistic waveguided rest-mass creation mechanism (e.g. at CERN in the LEP experiments). These negative data are also revolutionary);
(7) predicts existence of plenty (physically equal, gravitationally interconnected) parallel, dark Universes, with enormous density of hyper-civilizations (placed proximally near 10 -100 light minutes in a R4-distance around via Milky Way galaxy)!