“The discrepancy between what was expected and what has been observed has grown over the years, and we’re straining harder and harder to fill the gap.” –Jeremiah P. Ostriker

When it comes to the structure of the Universe — forming the galaxies, clusters, and Universe as we see it — the normal matter we know of simply isn’t enough. Given our best-understood laws of physics, including Einstein’s general relativity, what we see of galaxies and the Universe in general simply doesn’t match up to our predictions.

Image credit: NASA, ESA and the HST Frontier Fields team (STScI).

Image credit: NASA, ESA and the HST Frontier Fields team (STScI).

The simplest solution, arguably, is to just add a new ingredient: a new form of matter, a dark matter if you will. But a counterargument is that we’ve got the laws of gravity wrong, and that no new matter is necessary. There’s only one way to settle an argument like this: with data, evidence and the full suite of observations at our disposal.

Image credit: NASA, ESA and the HST Frontier Fields team (STScI).

Image credit: NASA, ESA and the HST Frontier Fields team (STScI).

Do that, and one option goes down in flames on five different accounts. Find out more on today’s Throwback Thursday!

Comments

  1. #1 Alan L.
    October 23, 2015

    From Etan’s post:

    It’s still a mystery why MOND is more successful on galaxy-scales, but until it can provide an explanation for all the other observed phenomena, it’s only a phantasm of a theory.

    Mostly wrong, partly (apparently) right (MOND) = Wrong.

    Partly wrong, mostly right (current consensus on IDM) also = Wrong.

    They are both Wrong.

    What kind of tweak – or new ingredient to the new ingredient – would be needed to make the strongest IDM theory 100% consistent with all observations?

    Is it a minor tweak or would it be necessary to re-examine all existing scientific doctrines concerning the cause of the gravitational force from the ground up?

    (To forestall a predictable objection, calculations derived from general relativity theory are 100% right. The existence of IDM is also 100% right).

  2. #2 Vladimir Grujic
    October 23, 2015

    And maybe up to the total mass of baryonic matter is”captured” in the black holes hence not observable but the gravitational effect still exist

  3. #3 Al
    October 23, 2015

    Let us assume that the gravitational constant is not constant but varies with distance.

    And it may vary in this manner:

    1. at the quantum level, it is zero
    2. at the solar vicinity it is one
    3. at the galactic level it is, say 1.2, or a value to be determined
    4. at the intergalactic level it is, say -.1, or a value to be determined.

    Locally at each point in the universe it is 1. So any observations of activity locally, no matter the distance from the observer, will always yield 1.

    Since the gravitational constant in the arms of a galaxy would be greater than 1, wouldn’t the movement of the matter in that location w/r to the center be consistent with more mass?

    It seems to me that such a curve describing the gravitational constant might be similar to a decaying sine wave.

    Whaddia think?

  4. #4 Wow
    October 23, 2015

    “And maybe up to the total mass of baryonic matter is”captured” in the black holes ”

    No, this fails because to be enough mass to account for the imbalance, there would be so many that we would see them in the occlusion and gravitational lensing of distant stars and galaxies.

    We don’t see anywhere near the amount of that necessary for black holes to be the MACHO candidate.

    Ethan did a post on this a couple of years back.

  5. #5 Wow
    October 23, 2015

    Al, why is it partitioned like this? How does the universe “know” what is quantum scale, and what is solar scale? Especially if many suns have no planets therefore no solar system to be a scale to?

    Quantum mechanics devolve down to the classical mechanics answer at the classical scales with no region of change over, it becomes closer and ever closer to the same answer in QM as was found and codified in classical mechanics.

    The “quantum scale” is only where there’s enough of a difference for it to be meaningfully different for the measurements being take or system to be observed.

    There’s no actual size where it changes over from QM to CM. It’s just where the CM calculations are much simpler and are close enough to the QM result that the difference is not worth considering.

  6. #6 Stanley Durham
    October 25, 2015

    Historically, this has been called the “missing mass problem.”

    The “problem” being the observation that galaxies and clusters aren’t in sustained orbits; they’re flying apart and can’t be billions of years old.

    Dark matter is a fudge factor that was carefully added to give just the right mass so that we could picture galaxies and clusters as being in sustained orbits.

    The most important point in the article is; “…dark matter; it still isn’t as good at explaining the rotation of individual galaxies …”

    In other words, dark matter fails to solve the missing mass problem. That’s the whole reason the fudge factor was added to the theory!

    The observational proof that the fudge factor fails to solve the missing mass problem, falsifies the ‘Lambda Cold Dark Matter’ model.

    Why must we assume that 80% of the universe’s mass is missing?

    Is there any chance that what we see, is actually what we see?

    The actual observation is that galaxies and clusters are dispersing, and can’t be billions of years old. Why are we assuming that observation is false?

    How is it mathematically possible to add 80% more mass to objects zillions of light years apart? At what time frame is the mass added?

    Are new galaxies and clusters formed with the missing mass problem in tow?

  7. #7 Marshall Eubanks
    Clifton, Virginia, USA
    October 25, 2015

    Can you provide links to the papers behind this? For example, is that quote from Norbert Wex in print? Where? His recent review doesn’t even mention MOND or TeVeS: http://arxiv.org/pdf/1402.5594v1.pdf

    I am not doubting you, but I would like to see the original papers.

  8. #8 Torbjörn Larsson
    October 25, 2015

    Mind that this is perhaps no longer true: “It’s still a mystery why MOND is more successful on galaxy-scales”.

    LambdaCDM is now likely the most successful theory on galaxy-scales. Turns out that when you make more detailed galaxy simulations, supernova outflows (as seen in our own Milky Way) removes the central cusp in precisely the way it is observed.

    I assume that if alternative DM models have been tuned to follow the MOND relation, they no longer do as well as LambdaCDM does (i.e. best): see Fig 2 & 3 of http://astrobites.org/2015/06/12/the-labor-of-outflows-against-dark-matter-halo/ . (I also assume that if someone likes MOND better, they will check with against the new simulations and tell us if it still is more successful.)

  9. #9 Wow
    October 25, 2015

    “Historically, this has been called the “missing mass problem.””

    Yes, that is correct.

    It is also no longer called the “missing mass problem”, since we have several possible solutions, and it’s a good idea to describe the solutions, rather than leave it named after the problem, when it comes to working out what may be going on.

    “Why must we assume that 80% of the universe’s mass is missing?”

    Because that’s what it looks like is going on. And thinking it’s missing is addressing the historical name of the problem, not the current name of the problem. You may wish to catch up.

    “Is there any chance that what we see, is actually what we see? ”

    Well, pretty near 100% what we see is what we see. However, what is there isn’t necessarily comprised solely of what we see and nothing else.

    “The actual observation is that galaxies and clusters are dispersing, and can’t be billions of years old. Why are we assuming that observation is false?”

    Well, the actual observation doesn’t indicate they can’t be billions of years old. Hence we think the idea that it can’t be billions of years old is false because it’s not correct.

    “How is it mathematically possible to add 80% more mass to objects zillions of light years apart?”

    Mathematically, very easy. Just multiply every mass by a factor of 1.8.

    ” At what time frame is the mass added?”

    Never. It was always there.

    “Are new galaxies and clusters formed with the missing mass problem in tow?”

    Only in the same way as they’re formed with the visible mass ALSO in tow.

    You know, its mass is the mass we can see and the mass that isn’t visible, and neither are in tow, because they ARE the galaxy.

  10. #10 Wow
    October 25, 2015

    “The most important point in the article is; “…dark matter; it still isn’t as good at explaining the rotation of individual galaxies …”

    In other words, dark matter fails to solve the missing mass problem. ”

    No it doesn’t. The “missing mass” problem is that the rotation of the galaxies, produced by the mass interior to the orbit of a star around a galaxy, is faster than it ought to be given the visible mass total. If there were more mass that we can’t see (and therefore “Missing from the total of visible matter”), then the rotation curves will be fine.

    “That’s the whole reason the fudge factor was added to the theory!”

    Why do you claim it is a fudge factor, rather than one indicated by evidence, since the value is taken from observations?

    I believe you’re taking the idea that “it’s wrong” as being inerrantly true and then figuring out what rewording of what has been said that “proves” your assertion to be correct.

    “Directed reasoning”.

  11. #11 Wow
    October 25, 2015

    Think of it this way. If it were purely a fudge factor,wouldn’t it have been fudged so it fit better?

  12. #12 Stanley Durham
    October 25, 2015

    Torbjörn Larsson; Mind that this is perhaps no longer true: “It’s still a mystery why MOND is more successful on galaxy-scales”.

    MOND modifies the laws of physics specifically to fix the missing mass problem. ((The “Missing Mass Problem” in Astronomy and the Need for a Modified Law of Gravity)) ((http://arxiv.org/abs/1401.5904))

    It’s not surprising that MOND would appear to fix the rotations, that’s what it was designed to do. It’s also not surprising that “Modified Law of Gravity” causes MOND to fail at everything else, as the article points out.

    Torbjörn Larsson; LambdaCDM is now likely the most successful theory on galaxy-scales.

    A falsified theory can’t be termed “successful” at anything, it’s just false.

    ((…astronomical observations obtained during the last decade indicate that dark matter cannot explain the kinematics of galaxies…2014))((http://arxiv.org/abs/1401.5904))

    Actual observation, galaxies and clusters are flying apart. (((Ambartsumian, .. they are disintegrating…))((http://ned.ipac.caltech.edu/level5/Biviano2/Biviano4_2.html))

    The fudge factor, dark matter, was added to the Big Bang, to solve the missing mass problem.

    ((The standard approach to this “missing mass problem” has been the postulate of “dark matter”…))((http://arxiv.org/abs/1401.5904))

    The fudge factor has been falsified; dark matter fails at solving the missing mass problem.

    ((it offers no specific insight into the original galaxy rotation problem))((https://en.m.wikipedia.org/wiki/Bullet_Cluster))

    With the failure of dark matter, we’re left stuck with empirical science, the observation that galaxies and clusters are flying apart and can’t be billions of years old.

    Galaxies and clusters flying apart, falsifies the Big Bang.

    The LambdaCDM is a fudge factor theory, named after its fudge factors; Lambda = dark energy, CDM = cold dark matter.

    A “fudge factor” is the scientific term for something added to the theory to change observation to match the theory.

    Both dark matter and dark energy are listed as examples of “fudge factor.” ((https://en.m.wikipedia.org/wiki/Fudge_factor))

    ((This may indicate that the prevailing cosmological model is insufficient to describe the mass discrepancy on galaxy scales, or that its predictions about the shape of the universe are incorrect.))((https://en.m.wikipedia.org/wiki/Bullet_Cluster))

  13. #13 Stanley Durham
    October 25, 2015

    Wow; “Think of it this way. If it were purely a fudge factor,wouldn’t it have been fudged so it fit better?”

    – Lambda-CDM (aka Big Bang) is a fudge factor theory

    – it’s named after its fudge factors

    – Lambda = dark energy

    – CDM = cold dark matter

    A “fudge factor” is used to change observation to match the theory.

    Dark energy, dark matter and inflation, are listed as examples of “fudge factor.” ((https://en.m.wikipedia.org/wiki/Fudge_factor))

    If you’re not comfortable with the scientific term, “fudge factor”, you could use another cosmological term “tooth fairy.”

    ((Cosmologists have another saying they like to cite: “You get to invoke the tooth fairy only once,” meaning dark matter, “but now we have to invoke the tooth fairy twice,” meaning dark energy.))((http://www.nytimes.com/2007/03/11/magazine/11dark.t.html))

  14. #14 Stanley Durham
    October 25, 2015

    Wow: It is also no longer called the “missing mass problem”

    Still is, 2014; ((The “Missing Mass Problem” in Astronomy and the Need for a Modified Law of Gravity))((http://arxiv.org/abs/1401.5904))

    Wow: Because that’s what it looks like is going on.

    You got it backwards.

    A “fudge factor” is something that’s added to a theory to change observation, “what it looks like”, to match the theory.

    Dark matter is listed as an example of a “fudge factor.” ((https://en.m.wikipedia.org/wiki/Fudge_factor))

    Wow: “Well, the actual observation doesn’t indicate they can’t be billions of years old”

    ((Ambartsumian, the large velocity dispersions of clusters indicate they have positive total energy … they are disintegrating))((http://ned.ipac.caltech.edu/level5/Biviano2/Biviano4_2.html))

    If they’re “disintegrating”, they can’t be billions of years old.

    Wow: “Just multiply every mass by a factor of 1.8.”

    You’re forgetting about time-space. That’d be adding mass to objects zillions of light years apart, according to BB time.

    That changes the entire kinematics of the universe at different points in time.

    Me: ”At what time frame is the mass added?”

    Wow: “Never. It was always there.”

    Guess it’s time to move on … have a nice day!

  15. #15 Wow
    October 25, 2015

    “MOND modifies the laws of physics specifically to fix the missing mass problem.”

    And doesn’t manage to do it. It does worse than DM. And isn’t that really an admission that MOND is a fudge factor?

    “– Lambda-CDM (aka Big Bang) is a fudge factor theory”

    Just like MOND, then.

    “– it’s named after its fudge factors”

    Just like gravity is named after ITS fudge factor!

    – gravitational force

    “A “fudge factor” is used to change observation to match the theory.”

    Just like MOND, then.

    “Dark energy, dark matter and inflation, are listed as examples of “fudge factor.” ”

    Really?

    And, no, sorry, linking to Wikipedia isn’t really sufficient here for such a grand claim against mainstream science.

    “If you’re not comfortable with the scientific term, “fudge factor”, you could use another cosmological term “tooth fairy.””

    Why would that be any better? It’s just as much a load of bollocks misrepresentation of reality as the other term you used.

    “Cosmologists have another saying they like to cite: “You get to invoke the tooth fairy only once,” meaning dark matter”

    No. We don’t.

    “Actual observation, galaxies and clusters are flying apart.”

    Yeah, we know. It’s called “inflation”. and it’s why we know that the universe “started” 13-15 Billion years ago.

    Quite what you think you’re proving with this statement is anyone’s guess.

    And I really do mean anyone. Even you.

  16. #16 Wow
    October 25, 2015

    “Galaxies and clusters flying apart, falsifies the Big Bang.”

    Odd.

    Since everyone else who has a working brainstem knows it was the actual reason for it being the front-runner and beating out the other theories.

  17. #17 Wow
    October 25, 2015

    “the observation that galaxies and clusters are flying apart and can’t be billions of years old.”

    And again, why do you make this asinine claim?

    The observation that galaxies and clusters are flying apart indicate that they CAN be billions of years old.

  18. #18 Stanley Durham
    October 25, 2015

    Wow: Just like gravity is named after ITS fudge factor!

    Can’t bluff your way through everything.

    adios…

  19. #19 Wow
    October 26, 2015

    Yes, you admit it is not possible for you to bluff your way through everything. Especially the load of codswallop you were mouthing off with.

    Bye bye, then. Try a crank site. You may get better mileage there.

  20. #20 PATRICK DENNIS
    October 26, 2015

    Stanley, not every fudge factor is a load of fudge: consider, for instance, neutrinos and the planet Neptune.

  21. #21 Joe the carpenter
    FL
    October 29, 2015

    Not being any type of scientist, I would say there has to be a mysterious mass called dark matter. As we know the defination of a wave is a disturbance that transfers energy through a mediun of interacting particles. Ocean waves, sound waves. What medium is a radio wave carried in space? Are they oscellationg in the dark matter or a void? And how can nothing oscellate? Help me on this? All I think of is interdimentional material which is in front of our face but unseen.

New comments have been disabled.