Results 1 to 21 of 21

Thread: Is dark matter really anti gravity?

  1. #1
    Join Date
    Aug 2014
    Posts
    2

    Lightbulb Is dark matter really anti gravity?

    It's been rolling around my head lately and my theory makes complete sense when I think about it. Let's start from the beginning, the big bang. I believe that the big bang was created from a super massive black hole (in this same universe) getting so massive and full of energy, that it burst letting out all of the energy it was storing to create all of the space and matter that we know and see today. After the big bang, gravity pulls energy and matter together, but what is causing the universe to expand against the pull of gravity? We already know of matter verses anti matter and many other things that have opposite sides to them. Magnets have positive and negative poles that can attract or repel each other. The only term we have to describe the force causing the universe to expand is called dark energy (dark meaning: we don't understand it yet). I believe that if there is gravity, then there must be anti gravity as the natural opposite. Anti-gravity and gravity are repelling each other just like magnets do. This would cause the galaxies, gases, and all forms of energy and matter to expand and even accelerate away from each other if anti gravity was actually dark energy.

    Is there someone who can do the math on this? I am not a mathematician and cannot crunch the numbers to prove it. I'm not sure if this would help or hurt the theory of relativity.

    Does anyone else have any feedback for me on this theory?

  2. #2
    Join Date
    Jul 2006
    Location
    Peters Creek, Alaska
    Posts
    13,492
    dereklro,

    Welcome to the CosmoQuest forums. I've approved your post through the moderation queue as written but you should know that going forward, you may not advocate your against-the-mainstream (ATM) ideas in this particular forum. The Space/Astronomy Questions and Answers forum is where people get mainstream answers to their questions. You may not argue those answers on an ATM basis. We do have an ATM forum but it is reserved for the presentation and defense of ATM theories. It is not a speculative, collaborative, or developmental environment. If you haven't already done so, please read our rules and since you seem to have an interest in ATM, you should also see our advice on that topic. Both are linked in my signature line below. If you have questions or concerns, please report this post or send a private message to me or any moderator or admin.
    Forum Rules►  ◄FAQ►  ◄ATM Forum Advice►  ◄Conspiracy Advice
    Click http://cosmoquest.org/forum/images/buttons/report-40b.png to report a post (even this one) to the moderation team.


    Man is a tool-using animal. Nowhere do you find him without tools; without tools he is nothing, with tools he is all. Thomas Carlyle (1795-1881)

  3. #3
    Join Date
    Dec 2004
    Posts
    14,782
    Your speculations are pretty much identical to my own speculations
    thirty-five years ago. Of course that was before the acceleration of
    the cosmic expansion was discovered in 1998, and "dark energy"
    was hypothesized to account for it. I failed to predict acceleration
    of the expansion when I easily could have, even without an actual
    theory, because I wasn't imaginative enough to realize that it was
    a necessary consequence of the assumed conditions.

    Did you mean to say "dark energy" in the title, rather than "dark
    matter"? If so, a moderator can change the title, if you want.

    You ask if there is someone who "can do the math". Let me ask
    you what math you think needs to be done. Exactly what do you
    think needs to be calculated in order to advance your speculation
    from its current state to that of a theory?

    -- Jeff, in Minneapolis

  4. #4
    Join Date
    Jun 2008
    Posts
    4,692
    Quote Originally Posted by dereklro View Post
    It's been rolling around my head lately and my theory makes complete sense when I think about it. Let's start from the beginning, the big bang. I believe that the big bang was created from a super massive black hole (in this same universe) getting so massive and full of energy, that it burst letting out all of the energy it was storing to create all of the space and matter that we know and see today. After the big bang, gravity pulls energy and matter together, but what is causing the universe to expand against the pull of gravity? We already know of matter verses anti matter and many other things that have opposite sides to them. Magnets have positive and negative poles that can attract or repel each other. The only term we have to describe the force causing the universe to expand is called dark energy (dark meaning: we don't understand it yet). I believe that if there is gravity, then there must be anti gravity as the natural opposite. Anti-gravity and gravity are repelling each other just like magnets do. This would cause the galaxies, gases, and all forms of energy and matter to expand and even accelerate away from each other if anti gravity was actually dark energy.

    Is there someone who can do the math on this? I am not a mathematician and cannot crunch the numbers to prove it. I'm not sure if this would help or hurt the theory of relativity.

    Does anyone else have any feedback for me on this theory?
    First Welcome to QS!

    The best candidate for Dark Energy is the vacuum energy. Unlike gravity cosmic expansion is linear where gravity is an inverse square law. It is easy to think that matter and anti-matter are complete opposites but this isn't the case. Both have positive mass from the tests so far. There are also other quantum properties they share. We know of no known reason why gravity would suddenly become repulsive. We do speculate, with some good reasons, that GR might not hold in the first moments of early universe but until we figure out a quantum theory of gravity we might be at a loss.

    It is very human to think of things as balanced. But in nature we see some very basic things seem asymmetric and are just balanced all by them selves. At this point in time there doesn't seem to be any evidence for "anti-gravity" like most people would think of it. Nothing we know of has negative mass but the models don't exclude it. So we have a situation where models may not rule stuff out but observation's are lacking. The details are very technical but not beyond the average persons reach if they are willing to invest the time in it.

    So for my feedback, don't take this negatively or anything. Your idea is very pop-sci based. It seems very logical to our experience in general. But the universe has shown us that often things are often not very intuitive. Quantum Mechanics is a great example. Until people spend some time learning about it QM just sounds crazy. I'd encourage you to hang around. Ask questions. Find topics you are interested in and go with them. Your view of the universe will change but it will more closely match reality be less based on conventional gut feel.

  5. #5
    Join Date
    Jun 2008
    Posts
    4,692
    for some maths. Gravity is easily thought of as . This is the Newtonian formula for gravity and it works quite well for us
    Cosmic expansion is

    You can see that with gravity r is the distance between you and another object. You can see G, which is the gravitational constant, and M which is the mass. So gravity is dependent on Distance and the Mass of the 2 objects in question. Another thing to note is that since distance is squared and you divide by the result gravity falls off very quickly. This is what we call the inverse square law. Inverse, because we are dividing by the result, and square because distance is squared to get the correct result.

    Now with cosmic expansion we have v which is a recession velocity, which you can kind of think as force, H0 which is the Hubble constant and finally the D is the distance between the 2 points. So the velocity is just linear. Double the distance and you double the recession speed. Note that there is nothing there concerned with mass. Locally, like that other galaxies around the milky way, are close enough that the force of gravity is still large enough to dominate. A way to think of it is like the Milky way is falling towards the Andromeda galaxy, in actuality they are falling towards each other, due to the gravity based off of the first formula. Cosmic expansion is there constantly adding more space between them. But as long as the force of gravity is larger then the cosmic expansion the 2 keep getting closer and closer. Every moment they get closer v goes down, because there is less space being created between them because there is less distance, and g goes up because the distance between them gets less.

    For very distant object there is almost no gravitation, g≈0, effect between 2 object so you don't even need to factor that in. Likewise with close object v is so small that it really doesn't affect the answer. It is like me giving you 1 billion dollars then taking 1 cent away. You still, for all intensive purposes have a billion dollars. Most people wouldn't say "I've got $999,999,999.99" Likewise if you have a billion dollars and I give you 1 cent most people wouldn't factor that 1 cent into the description of their wealth.

  6. #6
    Join Date
    Aug 2003
    Location
    The Wild West
    Posts
    9,506
    Quote Originally Posted by Jeff Root View Post
    I failed to predict acceleration
    of the expansion when I easily could have, even without an actual
    theory, because I wasn't imaginative enough to realize that it was
    a necessary consequence of the assumed conditions.
    A necessary consequence? I'd say the assumed conditions in 1998, and even today, provide no explanation, mechanism, hint, or inkling that the expansion should be accelerating. How could it? This requires an additional force where no such force has any reason to exist. Even if there was such a force, it has to act on something. What would that be? A few scientists may have been playing around with a non-zero cosmological constant 20 years ago, but they were just doing experimental mathematics, seeing what this might imply about what we might detect.

    Of course, repeated observations indicate an acceleration. In this case, the observations have come well ahead of any explanatory theory, which is, in fact, still lacking.
    Everyone is entitled to his own opinion, but not his own facts.

  7. #7
    Join Date
    May 2005
    Location
    N.E.Ohio
    Posts
    22,006
    If there were a such thing as antigravity, wouldn't we need to have found a graviton first?
    And; if so, what would happen to a graviton/antigraviton collision?

  8. #8
    Join Date
    Oct 2009
    Location
    a long way away
    Posts
    10,993
    Quote Originally Posted by dereklro View Post
    I'm not sure if this would help or hurt the theory of relativity.
    I think the reason it is called dark "energy" is that it is easy to model the effect as an extra energy density term in the equations of GR (the cosmological constant). This has a negative pressure (rather than "negative gravity") and hence accelerates expansion.

    Of course, that doesn't get us any closer to knowing what it is.

  9. #9
    Join Date
    Dec 2004
    Posts
    14,782
    Quote Originally Posted by Cougar View Post
    Quote Originally Posted by Jeff Root View Post
    I failed to predict acceleration of the expansion when I
    easily could have, even without an actual theory, because
    I wasn't imaginative enough to realize that it was a
    necessary consequence of the assumed conditions.
    A necessary consequence? I'd say the assumed conditions
    in 1998, and even today, provide no explanation, mechanism,
    hint, or inkling that the expansion should be accelerating.
    How could it?
    Acceleration of the expansion is a necessary consequence
    of the assumptions -- or more accurately, guesses -- I made
    about what the actual conditions are. I guessed that there
    are equal amounts of ordinary matter and antimatter in the
    Universe, that they are distributed more-or-less evenly
    throughout the Universe (on very large scales), and that
    they are prevented from coming into contact with each other
    by their mutual gravitational repulsion. That repulsion could
    account for the rapid appearance of galaxy clusters, strings,
    and sheets, and the voids between. It might also account
    for the cosmic expansion itself. It didn't occur to me that it
    implied acceleration of the expansion. Bad mistake!

    The ALPHA experiment at CERN should determine within the
    next year or two whether this idea is very probably correct or
    certainly hogwash. It's going to be one or the other.

    -- Jeff, in Minneapolis

  10. #10
    Join Date
    Mar 2010
    Location
    United Kingdom
    Posts
    7,312
    The problem you always hit with this is that it predicts an excess of gamma rays from matter and antimatter meeting. Given the strength we see gravity to have there is simply no way I have ever seen successfully modelled to fine tune the matter/antimatter distribution to match the fairly smooth rate of expansion we see with the upper limit on gamma rays from galactic clusters colliding.

  11. #11
    Join Date
    Aug 2014
    Posts
    2
    Wow, thank you all for your answers! I love hearing explanations and theories from others. Your answers have given me lots to ponder now.

  12. #12
    Join Date
    Jun 2007
    Posts
    5,922
    Quote Originally Posted by Shaula View Post
    The problem you always hit with this is that it predicts an excess of gamma rays from matter and antimatter meeting. Given the strength we see gravity to have there is simply no way I have ever seen successfully modelled to fine tune the matter/antimatter distribution to match the fairly smooth rate of expansion we see with the upper limit on gamma rays from galactic clusters colliding.
    And the problem that gravitation is due to mass-energy, not matter, so a particle and antiparticle would behave differently gravitationally than the photons they annihilate into. And the problem that the photon is its own antiparticle, and so would be repelled by gravity half the time, producing effects clearly not seen in gravitational lensing.

  13. #13
    Join Date
    Mar 2010
    Location
    United Kingdom
    Posts
    7,312
    Quote Originally Posted by cjameshuff View Post
    And the problem that gravitation is due to mass-energy, not matter, so a particle and antiparticle would behave differently gravitationally than the photons they annihilate into. And the problem that the photon is its own antiparticle, and so would be repelled by gravity half the time, producing effects clearly not seen in gravitational lensing.
    Yeah, you have to posit that photons are not actually majorana and introduce the idea of a gravitational 'charge'. This complicates things a lot. I have a feeling I saw someone claim they could fix it by introducing structure to the stress energy tensor, but that is a very hazy memory and I think it was only for a very simple, almost toy, case.

  14. #14
    Join Date
    Oct 2009
    Location
    a long way away
    Posts
    10,993
    Quote Originally Posted by Jeff Root View Post
    I failed to predict acceleration
    of the expansion when I easily could have, even without an actual
    theory, because I wasn't imaginative enough to realize that it was
    a necessary consequence of the assumed conditions.
    But I assume that your model would have predicted that there had always been acceleration, rather than what is actually observed?

  15. #15
    Join Date
    Aug 2008
    Location
    Wellington, New Zealand
    Posts
    4,434
    Quote Originally Posted by dereklro View Post
    ... if anti gravity was actually dark energy.
    Since anti gravity does not exist as far as we know, it cannot be anything, dereklro .
    The gravitational interaction of antimatter has not yet been observed yet and so could act like anti-gravity. However the consensus is that this is not expected.
    Dark energy is not anti-gravity. The best candidate for dark energy is a positive cosmological constant (a cost of having spacetime or a "vacuum energy").

    Galaxies do not expand with the expansion of the universe - they are gravitationally bound like the Solar System: Why doesn't the Solar System expand if the whole Universe is expanding?

  16. #16
    Join Date
    Aug 2003
    Location
    The Wild West
    Posts
    9,506
    Quote Originally Posted by Jeff Root View Post
    ... I guessed that there
    are equal amounts of ordinary matter and antimatter in the
    Universe, that they are distributed more-or-less evenly
    throughout the Universe (on very large scales), and that
    they are prevented from coming into contact with each other
    by their mutual gravitational repulsion. That repulsion could
    account for the rapid appearance of galaxy clusters, strings,
    and sheets, and the voids between. It might also account
    for the cosmic expansion itself. It didn't occur to me that it
    implied acceleration of the expansion. Bad mistake!
    Well, I think you're wrong, but not ridiculous. Especially not ridiculous in what your guess claims to explain.

    But hasn't it been shown that both matter and antimatter are attracted by gravity, not repulsed, not to mention that opposites commonly attract?
    Everyone is entitled to his own opinion, but not his own facts.

  17. #17
    Join Date
    Aug 2008
    Location
    Wellington, New Zealand
    Posts
    4,434
    Quote Originally Posted by Jeff Root View Post
    I guessed that there
    are equal amounts of ordinary matter and antimatter ...
    There are other guesses from your assumptions:
    * That the equal amounts of ordinary matter and antimatter separate on large enough scales to essentially form separate universes at least observationally.
    * That the equal amounts of ordinary matter and antimatter generate equal amounts of gravitational attraction and repulsion thus no formation of "galaxy clusters, strings, and sheets".
    * That the equal amounts of ordinary matter and antimatter generate equal amounts of gravitational attraction and repulsion thus no galaxies being repulsed ("cosmic expansion") or its "implied acceleration".

    The mistake did not come there, Jeff Root. The mistake is that the evidence for the Big Bang is not just Hubble's Law. It is that which makes the idea, in your words, hogwash .

  18. #18
    Join Date
    Dec 2004
    Posts
    14,782
    Quote Originally Posted by Strange View Post
    But I assume that your model would have predicted that
    there had always been acceleration, rather than what is
    actually observed?
    Yes.

    A 2003 graph of the newly-discovered acceleration by Saul
    Perlmutter showed a range of possible evolutions of scale
    over time. I added my own line, in yellow. It was pointed
    out to me by a poster on Usenet that my curve fit the two
    earliest data points on the graph better than Perlmutter's.
    I hadn't noticed that when I drew it. Those data points
    have very wide error bars, though, similar to the graph
    Cougar just posted in the thread I started.

    http://www.freemars.org/jeff2/expansn1.png

    It results in a somewhat earlier date for the beginning of
    the Universe, which fit the belief at the time that the
    oldest globular clusters may be about 18 billion years old,
    and the puzzle of how large-scale structure appeared so
    quickly.

    -- Jeff, in Minneapolis

  19. #19
    Join Date
    Dec 2004
    Posts
    14,782
    Quote Originally Posted by Cougar View Post
    But hasn't it been shown that both matter and antimatter
    are attracted by gravity, not repulsed, ...
    Not yet. Should be sometime in the next year or two.
    I've been waiting for the experiment to be done for a
    long, long time.

    It is certanly known that antimatter has the same inertial
    mass as ordinary matter, but the gravitational effects are
    way, way harder to measure.

    General relativity implies that antimatter should have the
    same gravitational properties as ordinary matter, but GR
    was completed before antimatter was even hypothesized.
    Observations of antimatter or even the idea of antimatter
    had no input into Einstein's development of GR.

    -- Jeff, in Minneapolis

  20. #20
    Join Date
    Dec 2004
    Posts
    14,782
    Quote Originally Posted by Reality Check View Post
    * That the equal amounts of ordinary matter and antimatter
    generate equal amounts of gravitational attraction and repulsion
    thus no formation of "galaxy clusters, strings, and sheets".
    Could you describe this idea further? I think it is relevant to
    the original poster's interest. The fact that equal amounts of
    gravitational attraction and repulsion are generated shouldn't
    imply no formation of "galaxy clusters, strings, and sheets".
    Equal amounts of electric attraction and repulsion result in
    all sorts of smaller structures.

    -- Jeff, in Minneapolis

  21. #21
    Join Date
    Aug 2008
    Location
    Wellington, New Zealand
    Posts
    4,434
    Quote Originally Posted by Jeff Root View Post
    Could you describe this idea further?
    It is a guess, i.e. the same as yours - the overall gravitational effect cancels out so no "galaxy clusters, strings, and sheets" due to the gravitational attraction or repulsion.
    Actually galaxies, etc. are thought to be created because of fluctuations in density causing local in-falling of matter.

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
  •