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Dark matters seems unlikely to succeed

  1. Jul 24, 2005 #1
    Gravity is not enough to consist a galaxy, some physicists put forward the dark matters theory. Although this theory seeming can solve this problem, I think it is unlike to succeed. Also I found some doubts on this problem.

    Many years, physicists are finding the dark matters but still have no breakthrough. And physicists still can not found its possibilities and existence.

    I have some doubts on the dark matters theory:

    1. If cosmos is occupied by the composition of dark matters, they may causing gravitational effects, they may be annexed by other heavenly bodies or self. But we have not found the sign.
    2. If the cosmos is filling full of the dark matters, then we see the image (lights) from other heavenly bodies that should be distorted when they meet the dark matters. But we can see the clear and normal image.

    I think that maybe there is another solution can solve this problem that better than the dark matters. Therefore I am doubtful on the existence of dark matters.
     
    Last edited: Jul 24, 2005
  2. jcsd
  3. Jul 24, 2005 #2
    Maybe my thought is not realy right. I expect other experts can give the viewpoints that is forceful.

    But I can not think out that my thought has any wrongs.

    I hope other people can give direction.
     
  4. Jul 24, 2005 #3

    EL

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    Dear yu_wing_sin

    1. ?? I'm not sure what you mean here. The dark matter is of course making influences through gravity. That's why dark matter is needed...
    What signs is it you expect us to see that we havn't?
    2. Non-baryonic dark matter (which is the form most of the dark matter must be in) hardly interacts with light. However, light can be gravitationally bended by dark matter, giving rise to so called gravitational lensing. This has been observed.
     
    Last edited: Jul 24, 2005
  5. Jul 24, 2005 #4
    --------------------------------------------------
    1: I don't know what you are saying, maybe you mistake my meaning. But I think you can know my meaning, only your mind is not very clear... I ever meet this situation, I also need time to understand the contents.

    2: I don't quite agree with you. When lights hit on the dark matters, they may cause refraction, also the proportion of dark matters according to the logical inference is very big, the effect should be very obvious. Also, although lights seems being curved by "unknown" matter, many peoples guess that is the evidence of dark matters, this is hard to judge absolute, it also can be curved by other kind of gravity.

    Without any doubt, my 2 hypothesis are the preventors of the absolute existence of dark matters.

    When I look back that physicists are no breakthrough on dark matters, I think that is it right? So I thought these doubts... We should make a clear brain, change our study route, that we can just have push of the knowledge. Maybe we always do the same wrong, we always can't awake from the silly works. My 2 hypothesis are worthwhile to notice.

    I appreciate to your valuable opinion.
     
    Last edited: Jul 24, 2005
  6. Jul 24, 2005 #5

    EL

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    I think you need to explain better what you ment then, it seems like I don't understand your english so well at all.

    Dark matter shouln't couse any noticeable amount of scattering of light, simply because dark matter and light hardly interact at all. That's why it's called "DARK matter". (OK there is probably a small part of the total amount of dark matter in the form of ordinary matter, like planets and dust, but that fraction is quite small since it's limited by nucleosynthesis and structure formation. Most of the dark matter must be non-baryonic, and may not interact with light.)

    What "kind" of gravity are you refering to?

    Well, it wasn't many years since the concept of "dark matter" was born. One of the most likely (in my and many others opinion) candidate for dark matter is some kind of supersymmetric particles. This will hopefully be detected when the LHC starts running at CERN (in about 2 years I think). Today we don't have enough powerful accelerators to produce those, and hence we havn't detected them yet.
     
  7. Jul 24, 2005 #6
     
    Last edited: Jul 24, 2005
  8. Jul 24, 2005 #7

    Chronos

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    Yu, consider this. Can galaxies form as early as the evidence suggests without dark matter? Rotation curves, and even cluster masses aside, that is one of the most difficult questions to answer. It's a big picture thing, and the big picture consistently supports the LCDM model. You can't take issue with the concept without taking issue with the evidence. And the evidence comes from many different directions. The dark matter conclusion was forced upon us, not conveniently snatched out of thin air. No other explanation fits - at least to date.
     
  9. Jul 25, 2005 #8
    Hahaha... Your saying is logical.
    Although dark matters seem that can solve the problem of expanding cosmos, I am doubtful whether it is possible to be proved... ... Also, here me saying the dark matters is quantum. Although I have a idea to replace dark matters, I have no enough assurance.
    And I still need to study more deeperly on this matter, there are many problems need to solve. And I feel it is impossible, my thought is very difficult to present clearly...
    Thanks for your opinion, it makes me has gain.

    I feel the density of dark matters is unable be very high, otherwise they will become heavenly bodies and has motion orbit. But this is not fit to the theory of expanding of cosmos. And if the density of dark matters is very low, then maybe they can't make function. This is the conflict of place. But my former doubts I think they are still worthwhile for me to notice.
     
  10. Jul 25, 2005 #9

    EL

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    Are you saying that dark matter can prevent light from passing by without interacting with it??? That's quite contradictory, don't you think?

    Wait a minute...we can see a lot of gravitational effects from dark matter, I mean the dark matter concept was invented to explain a lot of gravitational effects that could not be explained by the ordinary matter we could see.
    *The gravitation from dark matter can explain why galaxies rotate in the way they do.
    *The gravitation from dark matter is needed to explain the observed flatness of the universe.
    *Dark matter is needed to explain the observed fluctuations in the cosmic microwave background.
    *When large dense pieces of dark matter passes in the line of sight between us and a star, the star should appear lighter due to gravitational lensing. And this is observed all the time with telescopes!
    ...and that's just of few of the indications that dark matter exists.

    Of course we already know there is some dark matter in the form of neutrinos, and baryonic matter like planets and dust. But this form of matter cannot make up more than just a small fraction of the dark matter, since it's constrained by structure formation and light element abundance. Hence most of the dark matter need to be non-baryonic, and the calculated amount of neutrinos is not enough to account for this.
    As mensioned, supersymmetric particles is a good candidate for this. This kind of matter hardly interact with light at all, and that's why it cannot stop the light to reach us.

    You should not believe so much before you know the data.
    A lot of scientist is working on what the effects would be if the dark matter is some kind of supersymmetric particles. The problem is not that it would create phenomena that we should see but havn't. Instead the problem is that the predicted phenomena are so hard to observe it may not be possible with todays technology. For example I know people trying to calculate how dark matter would make a signature in gamma ray spectra from the galactic centre, and it's not a large effect at all. Maybe we will not solve the problem until LHC starts running, and maybe not even then in case the supersymmetric particles have too large mass.
     
    Last edited: Jul 25, 2005
  11. Jul 25, 2005 #10
    If one walks along on a sunny day,your form can cast a shadow. Where there was once Light, now becomes Dark, if one take a torch and shines it at a shadow, the Light appears whilst the Shadow Dissapears? According to your interpretations, do you think:

    A)When you cast a shadow, it influences your ability to move and cause's a Dragging effect opposite to your direction of motion, thus a longer shadow one cast's, the less ability you have to move due to the increased drag.

    B)When you cast a shadow, it is recomended that you carry a torch, by shining a light upon a shadow, one can reduce the drag-effect sufficiently enough to allow you to continue in the direction you are walking.
     
  12. Jul 25, 2005 #11
    Hahaha, EL, your view is worthwhile for us to notice. But I feel your some viewpoints seem not reliable, and some viewpoints are very reliable. Yes, dark matters are very important in many fields of theory, but it is not to represent that no other suitable solution is better than dark matters. Maybe dark matters can be proved the existence, I don't withstand it. But my 2 doubts still have not solve perfectly, mmm, it is very important for the fact of dark matters. MMM, I am very glad to hear your views, without doubts, dark matters have their meaning of existence in now theories, but I am doubtful on the discovering of dark matters, it is a bit of difficult to find it.

    But, and I can't imagine the monster Dark matters, how do them exist. Maybe my saying is not clear, but my decision and belief are not surely is. I think, if physicists still can't find the dark matters, they should change their thought and routes, or awake from the theory, just having the breakthrough.
     
  13. Jul 25, 2005 #12
    We have. The discontinuity of movement of stars around the centre of galaxy as we move outwards suggests hidden matter.The stars on the outerskirt of galaxy move faster than at the centre which is not so digestible.

    You are all confusing it up.When do you see an image being distorted? ..inside a black hole, watching outside?... probably you need to read more literature.

    http://www.space.com/scienceastronomy/dark_matter_021023.html
     
  14. Jul 25, 2005 #13

    EL

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    Who are "us"?

    So where am I not reliable?


    What is not solved then?

    Yes it is, but maybe we will in the next 10 years at least. Hopefully in 2-3 years.

    Monster dark matter??? What is that?

    But according to the theories of dark matter, we should not find it yet, since we do not have the technology. I can't see why dark matter sholdn't exist just because we havn't detected it yet.
    Wasn't the earth round before we discovered it?
     
  15. Jul 25, 2005 #14
    That is only an inference, we still have not observed its real existence. Also this is not enough to judge that it is the dark matters, there are many possibilities in it. Also, my stressed dark matters are not heavenly bodies, we are talking about the particles in space.
    We just stop from now, OK? Also, I suggest physicists to find the existence of dark matters, that is good for finding the truth.
    Arguments are always having, the most important is we can get the truth finally. Now to judge it, is to early. Maybe we will have breakthrough in future. And the dark matters this problem is not in my physical study scope, they should be handed over to you and the interesting physicists.
     
  16. Jul 25, 2005 #15

    Hahaha, other things I don't discuss.
    But you asked me why I said you some opinions are not reliable, I am pleasure to give possitive reply.
    Such as, you said that

    "supersymmetric particles is a good candidate for this. This kind of matter hardly interact with light at all, and that's why it cannot stop the light to reach us. "

    Your these sentences are equal to tell us, the lights can go through the supersymmetric particles. But how can lights go through? Does supersymmetric particles disappear, or lights have the supernatural phenomena can go through? They seem impossible. This is the conflict of the viewpoints. And so why I feel your viewpoints seem not reliable.

    Is my explain forceful? And I admit my saying is not very clear, but I tried the best to represent logically. I hope you can forgive me on this point.
     
  17. Jul 25, 2005 #16

    EL

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    Your problem is that you picture "particles" as classical solid speheres. It is wrong to picture the particle interactions as pool ball collisions. You need to study some physics before you take a stand about the dark matter.
    Learn som quantum mechanics, and then quantum field theory (but I must warn you, this will probably take some time).

    Yes, the supersymmetric candidates for dark matter hardly interact with light at all. That's why it is called "dark matter". This means that when light passes through, it will hardly be effected at all.
    Compare to the "neutrinos" which we know exist. Several millions of them passes through your body every second (okay I'm not sure about the correct order of magnitude, but it's however a huge amount) without interacting with any of the particles your body consists of. Why? Because neutrinos hardly interact with the matter in your body at all.

    I think you have got a lot of things wrong from the start, I suppose you have only read about "dark matter" in popular science books?

    It's nothing wrong with questioning things, but please make sure you know the subject before you start questioning the work of hundreds of scientists who all are probably a hundred times brighter and a hundred times more experienced than both you and me.
     
  18. Jul 25, 2005 #17
    I dont agree with your particle view of dark-matter.From your view of dark-matter , probably you are looking for physical evidence.'Just as the invisible wind can be inferredby a dancing leaf, dark matter is assumed to exist based on how stars andgalaxies behave'

    1.Actually dark-matter made its presence felt in outerskirts of galaxies by indicating towards the awkward motion of stars

    2. Dark-matter has been detected several times indirectly.Ofcourse nobody has seen it but the scientific community knows about its presence and it has been by far the only logical way to explain the shape of galaxies.Without it , the galaxies could have fly apart.

    3.X-rays from hot-gas cloud, which envelop some far-off galaxies also indicate presence of dark-matter.The peculiar thing here is that the hotgas cloud has different shape from the galaxy it surrounds ,which is only possible if there is some other matter besides the galaxy itself, which gives some extra 'air' to the gas-cloud.


    4. This might also help

    BJ
     
    Last edited: Jul 25, 2005
  19. Jul 25, 2005 #18
    Argue irrationally!

    ... ...
     
  20. Jul 25, 2005 #19

    EL

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    What is irrationally?
     
  21. Jul 25, 2005 #20

    EL

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