Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Us stuff

  1. May 15, 2004 #1

    wolram

    User Avatar
    Gold Member

    It seems that only 5% of the mass in the universe is
    us stuff, "baryonic", how does this percentage divide
    into black holes, neutron stars ,gas ,stars etc.
     
  2. jcsd
  3. May 15, 2004 #2

    Janitor

    User Avatar
    Science Advisor

    Off the top of my head, I would say that none of the mass of a black hole can be chalked up to baryonic matter (black holes being the one known violator of baryon-number conservation), whereas practically all of the mass of the other categories you listed can be attributed to its baryonic content. Maybe that's not the point of your question, though.
     
    Last edited: May 15, 2004
  4. May 15, 2004 #3

    jcsd

    User Avatar
    Science Advisor
    Gold Member

    Actually black holes fall under the catergory of baryonic matter. I'm not 100% sure why, but I think it's to do with the fact that they affect the relative abundance of elements.
     
  5. May 15, 2004 #4

    Janitor

    User Avatar
    Science Advisor

    Jcsd, I had not heard that, but you may well be right for all I know.

    What I had in mind was that a small black hole can evaporate due to Hawking radiation, and I am pretty sure that Hawking radiation puts out equal numbers of particles and antiparticles. That would mean that it is spraying out particles with net baryon number of zero, even though 99.9 percent of the matter that was used up to form the hole in the first place may have been baryonic, and 'ordinary' in the sense of not being antimatter made from antibaryons. It is hard for me to see how the Hawking black hole can be said to be made of baryons, by this reason. Am I somehow falling into a trap?
     
  6. May 15, 2004 #5

    jcsd

    User Avatar
    Science Advisor
    Gold Member

    Black holes are dfeunitely clawsifed as part of the baryonic mass of the universe of that I'm sure. I don' think it's necessarily to do with the fact that balck hole are formed mainly by the mass of baryons, but the fact that unlike non-baryonic mass they affect the relative abundances of different nuclei.
     
  7. May 15, 2004 #6

    marcus

    User Avatar
    Science Advisor
    Gold Member
    2015 Award
    Dearly Missed

    I agree, and I think light contributes some of that 5 percent.
    At least that is how I remember it.
    Can anyone confirm this?


    I think calling the 5 percent "baryonic" is just poor terminology.
    What they mean is "the mass we already knew about and could detect or estimate."
    And the roughly 20 percent they call "dark matter" is the part they decided they had to assume was there even tho they couldnt see it. They had to assume it to make things add up right and explain how clusters hold together
    and so on.

    This is makeshift temporary terminology. Someone will have to sort things out and label things better after more has been discovered about the 20 percent.
    They will invent clearer categories.

    For the time being "baryonic" works all right because the 5 percent *is*
    mostly baryonic matter----the small amount that is starlight and CMB and black holes only make up a modest fraction of it---even tho it is not entirely baryonic it can be thought of as the "mainly baryonic 5 percent that we understand".

    But this is what wolram is asking about!
    How does that 5 percent divide up? How much of it, for example, do the photons of the CMB represent?
    Is a breakdown on the web somewhere?
     
    Last edited: May 15, 2004
  8. May 15, 2004 #7
    Wolram, one can define the Universe as a 100% mass quantity if one knows what Mass actually is?..for instance in a Universe where there is no Dark-Matter, then one can model along the lines of knowing all of the visable Universe, and as a consequence the Universe would appear to be just a high luminous spectrum where-ever we gaze our eyes, there would be no Darkness in which to define a luminous function.

    Likewise, the ratio of 'Darkness to Lightness' is the backgound through which we gauge? all of the 'light' we see comes from Galaxies, which house the 100% of all positive matter in the Universe. What lies between Galaxies is the
    the Stuff we cannot see, and is currentl 99.9% Dark.

    The queston of :does a Photon have mass? seems very relevant when we take the context into the question of "in-between-Galaxies" absorption and emissions?

    The photon density of the Universe has decreased from a 100% value when there was(NO-DARK-MATTER) to one of about less that 5%, realistically it is the cosmic background radiation that is detected today. Now as the photon density as decreased with time, the aveage ENERGY of photons also decreased, the equations state(equation of state) that the Universe is in a Matter dominated phase, which leads us to the question you have posed:WHERE HAS ALL THE MATTER GONE?

    Now we can ask of baryons, if all the baryons exist within Galaxies, what exists in space between Galaxies? Quarks are the structure that make up baryons, they are made into bundles of positive matter energy two 1/3 positive bits and one 1/3 negative bit, so allt eh energy residing in Galaxies is seen as a ratio of positive charged matter PROTONS, "2 to 1" over negative charged matter.

    It is very likely that the structure that lay 'between' Galaxies is made from negative matter with a ratio of negative charged matter "2 to 1" over positive matter, ie 1/3, 1/3 negative bits and 1/3 positive bits.

    The mass in question now can be seen as having 'existence' or a pre-existence?..back to the photon density?..do photon absorption rates througout the Universe contribute to the 'mass of space inside our Universe'?

    Asked in another way, do photons add to the mass of the electron when atoms absorbs photons?

    The answer is that the space between Galaxies is made from a 2-dimensional Quark substructure, namely E-M non visable anti-proton flux, or a Electro-Magnetic-Vacuum, which has a Negative value in all relative means of detection/observations.

    The really interesting thing is that when the 'static' (electro-static) solutions are introduced to the E-M-V, they produce inertia, and this is where HIGGS force enters the arena.

    One really does have to understand that in one frame we have a baryonic positive set of equations and in another we have a symetric solution to early Universe evolving data?

    The trick is to do Relativity in a phase defined manner wherby the positive equations (Baryonic) all relate to Expansion, verified by observation, and the QCD solutions all reflect a Contracting of scalar Fields.

    I could show how the Quark=Proton and Antiquark=antiproton are Phase dependant, but this is already known, thus the cosmological ratio needs no further explination, but what needs asking now is:Do photons scatter off a Free Electron Condensate?
     
  9. May 15, 2004 #8
  10. May 16, 2004 #9

    wolram

    User Avatar
    Gold Member

  11. May 16, 2004 #10

    wolram

    User Avatar
    Gold Member

    OOPSS sorry OLIAS i missed last two posts, i will
    read them now.
     
  12. May 16, 2004 #11

    marcus

    User Avatar
    Science Advisor
    Gold Member
    2015 Award
    Dearly Missed

    I looked at it. I seems like a good source.
    I agree with that 4 percent. It is what I've seen consistently
    except where people are just want to give a rough idea
    and not "put too fine a point on it".

    the heidelberg guy (Mr. msb) said that as far as photons go
    there are 407 of them per cubic centimeter

    indeed! dont you like when a fellow is that certain of his data---to three decimal places, no less. :approve: I guess almost all of those 407 photons are in the cosmic microwave background.

    I think that is what he says on page 29 and also that's where he
    says what you picked out, that there are roughly a billion photons for each baryon.

    wolram congratulations on finding this, it doesnt completely answer your question but it is a step in the right direction and maybe more info will trickle in. I will keep an eye out for a breakdown on how that 4 percent is divided.

    Basically I think that mass-wise it is almost all baryons (almost all protons and neutrons in fact)
    because an electron weighs only 1/1836 of a proton IIRC
    and those CMB photons average something on the order of 10-4 eV
    so even a billion of them is roughlyspeaking only 105 eV

    but one proton (in energy) is worth just under a billion eV----- 109 eV

    so (this is just an orderofmagnitude calculation) those billion CMB photons that the heidelberg man is talking about are energywise worth only a tenthousandth as much as a proton----well, maybe a thousandth.

    I dont have anything precise handy about this but in a way they are right to call it "baryonic" because even tho it includes all familiar forms of mass-energy (protons, neutrons, electrons, photons.....) by far the great mass of it is the atomic nuclei: the protons and neutrons.

    over 99 percent, I'd guess, of the 4 percent we are talking about

    maybe you'll find something that proves my guess is off
     
  13. May 16, 2004 #12
    If you missed them first time around why bother, you need an exercise in Photon Density understanding, which is lacking from your original post.

    Read on and click next at the bottom of Baez pages:http://math.ucr.edu/home/baez/photon/odd-ques.htm#SECTION00050000000000000000

    This may help you focus a little :rolleyes:
     
  14. May 17, 2004 #13

    wolram

    User Avatar
    Gold Member

    If you missed them first time around why bother, you need an exercise in Photon Density understanding, which is lacking from your original post.
    -------------------------------------------------------------------------
    thanks for the url Olias, it takes me a while to assimilate some
    things.
     
  15. May 17, 2004 #14

    wolram

    User Avatar
    Gold Member

    indeed! dont you like when a fellow is that certain of his data---to three decimal places, no less. I guess almost all of those 407 photons are in the cosmic microwave background.
    --------------------------------------------------------------------------
    such accuracy is commendable, thanks for help Marcus.
     
  16. May 17, 2004 #15
    No Problem, you have the right level of questioning and everything should fall into place?..but as with some of the really abstract and 'new' line of theoretical thinking sometimes its good to get an overall perspective. The Baez link will hopefully inspire you to continue your quest.

    P.S the link follows the conversation of Baez and I believe a student of his(at that time?), keep hitting the next button after reading through each post(in your own time) there is a wealth of information in there.

    Thanks for the pdf link, this is another great source of infomation covering a wide amount of relevent data.
     
    Last edited: May 17, 2004
  17. May 17, 2004 #16
  18. May 18, 2004 #17

    wolram

    User Avatar
    Gold Member

    http://www.innerx.net/personal/tsmith/LARGEsmall.html

    The present scale of our Universe is about R(tnow) = 10^28 cm, so that its volume is now about 10^84 cm^3, and its baryon density is now about 10^77 protons / 10^84 cm^3 = 10^(-7) protons/cm^3 = 10^(-7-19-5) gm / cm^3 = 10^(-31) gm / cm^3 = roughly the baryonic mass density of our Universe.
     
  19. May 18, 2004 #18

    wolram

    User Avatar
    Gold Member

    origonaly posted by NERIED>
    Alpha does not vary with time - new study's stringent limits

    --------------------------------------------------------------------------------

    New Quasar Studies Keep Fundamental Constant Constant reports the work of a team of astronomers using the VLT in Chile.

    "To explain the Universe and to represent it mathematically, scientists rely on so-called fundamental constants or fixed numbers. The fundamental laws of physics, as we presently understand them, depend on about 25 such constants. Well-known examples are the gravitational constant, which defines the strength of the force acting between two bodies, such as the Earth and the Moon, and the speed of light.

    One of these constants is the so-called "fine structure constant", alpha = 1/137.03599958, a combination of electrical charge of the electron, the Planck constant and the speed of light. The fine structure constant describes how electromagnetic forces hold atoms together and the way light interacts with atoms."

    In summary, results from the ancient Oklo natural reactor show alpha is constant to within ~2 parts per 100 million over the past ~2 billion years; the VLT results ~0.6 parts per million over ~10 billion years.
     
  20. May 18, 2004 #19

    wolram

    User Avatar
    Gold Member

    Now im confused :uhh:
     
  21. May 21, 2004 #20

    wolram

    User Avatar
    Gold Member

    http://nedwww.ipac.caltech.edu/level5/March03/Freedman/Freedman2_3.html

    While we know more about the other one-third of the universe - the matter part - important questions remain. According to the current best census, the visible part of ordinary matter - that associated with stars - contributes only about 1% of the total. What we can see with telescopes is literally the tip of an enormous iceberg.
    ------------------------------------------------------------------------
    now the us stuff is down to 1%
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Us stuff
  1. More BH stuff (Replies: 0)

  2. Missing stuff (Replies: 97)

  3. Us in the center (Replies: 11)

Loading...