Catch up on stories from the past week (and beyond) at the Slashdot story archive


Forgot your password?
DEAL: For $25 - Add A Second Phone Number To Your Smartphone for life! Use promo code SLASHDOT25. Also, Slashdot's Facebook page has a chat bot now. Message it for stories and more. Check out the new SourceForge HTML5 internet speed test! ×
Space NASA Science

Hubble Telescope Maps Dark Matter in 3D 174

dido writes "The BBC reports that the Hubble Space Telescope has been used to make a map of the dark matter distribution of the universe, providing the best evidence of the role dark matter plays in the structure and evolution of the universe. From the article: 'According to one researcher, the findings provide "beautiful confirmation" of standard theories to explain how structures in the Universe evolved over billions of years.'"
This discussion has been archived. No new comments can be posted.

Hubble Telescope Maps Dark Matter in 3D

Comments Filter:
  • This is pretty cool. (Score:3, Interesting)

    by lordvalrole ( 886029 ) on Sunday January 07, 2007 @07:11PM (#17501648)
    I wonder what a 3d model of dark matter around a black hole would look like? Does it share the same properties as regular matter near a black hole?
  • Enlighten me (Score:4, Interesting)

    by Original Replica ( 908688 ) on Sunday January 07, 2007 @07:16PM (#17501684) Journal
    To those /.ers that know more of physics than I do, is Dark Matter supposed to be some actual particle, or is it a kind of natural gravitational topography? Everything I read ( quick google search/old copy of "Elegant Universe") about it seems to be rather vague and mysterious.
  • Re:Enlighten me (Score:3, Interesting)

    by marcosdumay ( 620877 ) <marcosdumay@gmaS ... com minus distro> on Sunday January 07, 2007 @08:18PM (#17502246) Homepage Journal
    Only if it interacts with light. Neutrinos, for example, don't glow (and don't absorb light either).
  • by pln2bz ( 449850 ) * on Sunday January 07, 2007 @11:30PM (#17503870)
    The real story of how we ended up with dark matter is not widely understood or accepted.

    Some time ago, a man named Hannes Alfven, who is today considered the father of plasma physics, founded the field of magnetohydrodynamics, which astrophysicists have been using to model plasma in the universe for several decades now. This field treats plasma as a fluid and assumes that currents cannot flow through the plasma because it treats plasma as an ideal conductor with no resistance. This is actually not *anything* like the way that plasma operates in the real world, and since plasma represents 99%+ of all observable matter within the universe, this massively incorrect assumption yields absurd results in astrophysics today. Plasma is in fact electrically conductive and its electrical properties interact with its mechanical motions, and vice-versa. If you've ever seen a novelty plasma globe, then you intuitively know that plasma is not like a fluid. You can tell by looking closely at a plasma globe that the plasma creates filaments and these filaments pair up and twist around one another. These twisting currents are called Birkeland Currents. As the current flow increases through them, they pinch together with increasing force and this pinching action can actually condense matter into a ball. This is a big deal because there is no good reason to believe that molecules will gravitationally collapse from a diffuse collection of matter in space; in fact, gases obviously expand in a vacuum. Contrary to the more popular beliefs propagated in astrophysics and the media today, the z-pinch effect is likely actually how planets and stars form. Astrophysicists don't understand this because of their earlier assumptions regarding plasma being a fluid with no currents. But we can see strong evidence of Birkeland Currents and Z-Pinches happening through our telescopes.

    The thing is, astrophysicists will see what they want to see through the telescope. All observations today are interpreted through mainstream concepts like stellar evolution and Big Bang theory. When an anomaly pops up, it can be a very simple matter to propose a "patch" for the theory to keep it going. Astrophysicists will invoke collisions, black holes, gravitational lensing or malformed electrical theory in order to explain away anomalies. But you will notice that anomalies are discovered nearly every week these days (especially with stellar evolution), and this is a problem because things like collisions should not actually be happening as often as they are being invoked to dismiss the anomalies.

    When Hannes Alfven received his nobel prize for plasma physics in the 70's, he recused himself from the field that he created (MHD) and warned astrophysicists to abandon it, and that the path they were taking would eventually dead-end. But they completely ignored him and continue to do so. So, now we have mysterious forces tugging on matter throughout the universe that we can't see. This is what we call dark matter. Dark energy is supposed to be matter that can gravitationally repel. Electrical forces can accomplish both of these feats without any mysterious matter. All you have to do is drop the earlier incorrect assumptions about plasma and accept that extremely diffuse plasma flows can and do exist. You will notice over time that the dark matter studies will reveal some details that correspond with the properties of electricity over plasma. For this particular article, it was noticed that the structure of the dark matter was in places filamentary. Filamentary structures are far easier to generate with electricity than with gravity. It was also mentioned that dark matter can exist in the absence of physical matter. This is to be expected with plasma because plasma can consist of just electrons and ions, or it can also be coexisting with or collecting dust.

    Some brave scientists and electrical engineers called Electric Universe Theorists are working on understanding the universe in terms of real plasma physics -- which makes p
  • Re:Enlighten me (Score:3, Interesting)

    by TMB ( 70166 ) on Monday January 08, 2007 @12:56AM (#17504430)
    Just one minor quibble:
    The problem that cold dark matter theorists have to deal with is that the extra-galactic dark matter can't just interact gravitationally, because gravity is too weak a force to produce structures in the short time the universe has been around. To clump in the manner observed, extra-galactic dark matter has to have some mechanism for losing energy. Otherwise two pieces of dark matter (or a piece of dark matter and a peice of ordinary matter) would just pass through each other. The dark matter would never be slowed down by anything, and so would never form clumps on any scale.
    Actually, gravity on its own is easily enough to produce the structure we see. The dark matter doesn't dissipate any energy to form clumps, it simply falls toward the overdense regions, which become even more overdense because of all the infalling dark matter, ad infinitum. Each individual dark matter particle may pass right through all the other dark matter particles and go out the other side, but as long as it's moving at less than the escape speed then it turns around and comes back, bouncing around inside the clump forever.

    In fact, one of the main problems now is that cold dark matter produces too many small clumps compared to the observations.

  • by Anonymous Coward on Monday January 08, 2007 @06:06AM (#17506036)
    Yes, there is, but we do not have a clue yet of what it is made of.
    Well, most of science has yet to agree what it is, but Randy Mills has a pretty solid theory backed by observations. []

    Mainstream says the 10% of the universe that is observable is 90% hyrogen, 9% helium, and 1% everything else. Mills says that the 90% unobservable universe is a lower-state hydrogen atom that he calls a "hydrino". The Mills theory explains the answers to some very old scientific questions, such as 'what happens to a photon upon absorption' and explains why the Sun's corona is so hot (>1,000,000 K) in spite of the fact that Sun's surface is so cool (6,000 K), and correctly predicted the accelerating expansion of the universe before it was observed (there was no big bang, just a sinusoidal expansion/contration where we are currently on the accelerating region of the curve).

    The foundation of Mills theory is that an electron is spherical shell, not a point. From this posit pretty much everything can be explained with 4 dimensions, Newtwon, Maxwell, and relativity - with no need for string theory, spooky interaction, uncertainty, or quantum mechanics.

"Only a brain-damaged operating system would support task switching and not make the simple next step of supporting multitasking." -- George McFry