Page 1 of 3 123 LastLast
Results 1 to 10 of 28
  1. #1
    Klaatu's Avatar
    Klaatu Guest

    Default Dark Matter & Dark Energy Two Aspects of the Same Thing?



    Dark Matter & Dark Energy Two Aspects of the Same Thing?
    http://exploration.vanderbilt.edu/ne..._k_essence.htm

  2. #2
    John Carruthers's Avatar
    John Carruthers Guest

    Default Dark Matter & Dark Energy Two Aspects of the Same Thing?

    >Dark Matter & Dark Energy Two Aspects of the Same Thing?<

    Like dark e=dark m* (not c)^2 ??
    jc


    --
    http://mysite.wanadoo-members.co.uk/jc_atm/



    ---
    Outgoing mail is certified Virus Free.
    Checked by AVG anti-virus system (http://www.grisoft.com).
    Version: 6.0.716 / Virus Database: 472 - Release Date: 05/07/2004



  3. #3
    Wfoley2's Avatar
    Wfoley2 Guest

    Default Dark Matter & Dark Energy Two Aspects of the Same Thing?

    >Dark Matter & Dark Energy Two Aspects of the Same Thing?

    Yes - B.S. with large helping of circular reasoning.
    Clear, Dark, Steady Skies!
    (And considerate neighbors!!!)



  4. #4
    Sam Wormley's Avatar
    Sam Wormley Guest

    Default Dark Matter & Dark Energy Two Aspects of the Same Thing?

    Klaatu wrote:


    Dark Matter and Dark Energy are totally different phenomena--related in any
    way will eventually be understood... what they have in common is the both
    user the word "dark" and that they are poorly understood.

    Assuming you sincerely want to learn the difference, see below.

    Particle Dark Matter: Evidence, Candidates and Constraints
    http://arxiv.org/abs/hep-ph/0404175

    The Dark Matter Mystery
    http://map.gsfc.nasa.gov/m_uni/uni_101matter.html

    Dark Energy
    http://physicsweb.org/article/world/17/5/7

    What is the Ultimate Fate of the Universe?
    http://map.gsfc.nasa.gov/m_uni/uni_101fate.html

    Ref: http://map.gsfc.nasa.gov/m_mm/mr_limits.html

    The data places new constraints on the Dark Energy. It seems more
    like a "cosmological constant" than a negative-pressure energy field
    called "quintessence". But quintessence is not ruled out.

    Fast moving neutrinos do not play any major role in the evolution of
    structure in the universe. They would have prevented the early
    clumping of gas in the universe, delaying the emergence of the first
    stars, in conflict with the new WMAP data.

    Empty Model Flat Dark Energy Model Closed Dark Energy Model
    http://www.astro.ucla.edu/~wright/DL-diff-vs-z.ps

  5. #5
    Wfoley2's Avatar
    Wfoley2 Guest

    Default Dark Matter & Dark Energy Two Aspects of the Same Thing?

    But both are still B.S.
    Clear, Dark, Steady Skies!
    (And considerate neighbors!!!)



  6. #6
    Brian Tung's Avatar
    Brian Tung Guest

    Default Dark Matter & Dark Energy Two Aspects of the Same Thing?

    Bill Foley wrote:

    Ahh, and your evidence for this opinion would be...?

    Perhaps you're put off by the fact that we don't know what they *are*,
    only what they do. In that case, Brownian motion was BS in 1900, double
    refraction was BS in 1800, and precession was BS in 1650.

    Of course, there is some ad hockery in the values of the parameters--we
    don't know why they should have the values they appear to--but not as
    much as you imply. They are not, as some people like to suggest, fictions
    invented in order to avoid making amendments to Einstein's precious
    general relativity--they *are* the amendments to general relativity.
    That they still fit within its framework gives us confidence that we are
    observing the phenomena with reasonable fidelity, even if we haven't the
    slightest clue as to what they are.

    But please, feel free to insist they are BS. Don't let me stop you.

    Brian Tung <brian@isi.edu>
    The Astronomy Corner at http://astro.isi.edu/
    Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
    The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
    My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

  7. #7
    scurry's Avatar
    scurry Guest

    Default Dark Matter & Dark Energy Two Aspects of the Same Thing?

    Wfoley2 wrote:


    Alright then Dr. Hawking. Where'd the bull come from? Hmm?

    In response to the O.P. No they're not the same thing. Dark matter
    sucks, and Dark Energy blows.
    ;-)

    Shawn

  8. #8
    starman's Avatar
    starman Guest

    Default Dark Matter & Dark Energy Two Aspects of the Same Thing?

    Brian Tung wrote:

    There are some reputable theorists who are open to the possibility that
    dark matter and energy don't really exist. They say it could be a
    manifestation of gravity that we haven't discovered. Einstein was close
    on gravity but maybe he didn't get it all.


    -----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
    http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
    -----== Over 100,000 Newsgroups - 19 Different Servers! =-----

  9. #9
    Harald Lang's Avatar
    Harald Lang Guest

    Default Dark Matter & Dark Energy Two Aspects of the Same Thing?


    I don't fully agree with this. There has always been a
    cosmological constant[1] lambda in GR (the General Relativity
    model), only that its value has been unknown, so it isn't an
    *amendment* of GR; it has always been part of the model. Einstein
    first thought that it had a non-zero value, since a value of zero
    was inconsistent with a static universe, which he thought was the
    case. When he got to know that universe is not static, he
    changed his mind, and thought that lambda=0. And cosmologists
    have considered lambda=zero to be the most "natural" value.

    But there is also a constant G in the model---the
    gravitational constant---which is non-zero. We know that from
    experience, but if we hadn't any experience of gravitation, we
    would probably have thought that G=0 would be the most "natural"
    value.

    Now it turns out that lambda=0.73 (or close to that.) I
    don't see that this is any more mysterious than the fact that G
    in non-zero. We have no "explanation" why G is non-zero, we are
    just *used to* the fact. All we can do with laws of nature is
    that we can describe them consistently in a model, and get used
    to them; we don't *understand* any of them. We might *understand*
    why content may settle somewhat during transportation, but only
    *conditional* on the physical laws (or rather, the model we use to
    describe them.) It helps us getting used to the laws of physics,
    but it doesn't explain them.

    As for dark matter, it is another ..er.. matter entirely. It
    is truly mysterious. In order for the GR model to fit data, there
    must be much more matter[2] than we can see. Either there is, or
    GR is out of whack.

    Cheers -- Harald

    ------
    [1] Assuming that "dark energy" is the cosmological constant.
    This means that the density of the "energy" remains constant as
    universe expands (in contrast with matter.)

    [2] Matter has the property that volume*density remains constant
    as universe expands.
    ------


    Brian Tung wrote:

  10. #10
    Brian Tung's Avatar
    Brian Tung Guest

    Default Dark Matter & Dark Energy Two Aspects of the Same Thing?

    Harald Lang wrote:

    I don't fully disagree with you.


    Isn't that only because the gravitational binding is much stronger than
    the general expansion of the universe?

    Brian Tung <brian@isi.edu>
    The Astronomy Corner at http://astro.isi.edu/
    Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
    The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
    My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

 

 
Page 1 of 3 123 LastLast

Similar Threads

  1. Dark Energy & Dark Matter
    By Amona in forum Astrophysics Forum
    Replies: 10
    Last Post: 05-21-2010, 06:54 PM
  2. Unravelling the Dark Matter - Dark Energy Paradigm
    By Surfer in forum UK Astronomy Forum
    Replies: 0
    Last Post: 03-28-2009, 02:06 PM
  3. Replies: 36
    Last Post: 10-16-2005, 03:13 AM
  4. Dark Matter and Dark Energy: One and the Same?
    By LenderBroker in forum Amateur Astronomy Forum
    Replies: 2
    Last Post: 07-14-2004, 12:45 AM
  5. Dark Matter/Dark Energy
    By fbug in forum General Astronomy Forum
    Replies: 3
    Last Post: 05-21-2004, 04:05 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBulletin® Version 4.2.0
Powered by vBulletin®
All times are GMT. The time now is 01:31 AM.