The Dark Matter Mystery: Most Of The Universe Is Missing

A mystery exists! Galaxies do not seem to have enough mass for stars to orbit at their observed speeds. Galaxies should be flying apart, but they don't. Why not? Explore the surreal world of dark matter - one of the universe's greatest mysteries.

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This presentation is available to educators on DVD and comes complete with specially-crafted teacher notes.

The Mystery of Dark Matter Video Game

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In astronomy and cosmology, dark matter is a form of matter that is undetectable by its emitted electromagnetic radiation, but whose presence can be inferred from gravitational effects on visible matter and background radiation. According to present observations of structures larger than galaxies, as well as Big Bang cosmology, dark matter accounts for the vast majority of the mass in the observable universe.

Dark matter was postulated by Fritz Zwicky in 1934, to account for evidence of "missing mass" in the orbital velocities of galaxies in clusters. Subsequent to then, other observations have indicated the presence of dark matter in the universe, including the rotational speeds of galaxies, gravitational lensing of background objects by galaxy clusters such as the Bullet Cluster, and the temperature distribution of hot gas in galaxies and clusters of galaxies.

Dark matter plays a central role in state-of-the-art modeling of structure formation and galaxy evolution, and has measurable effects on the anisotropies observed in the cosmic microwave background. All these lines of evidence suggest that galaxies, clusters of galaxies, and the universe as a whole contain far more matter than that which interacts with electromagnetic radiation: the remainder is frequently called the "dark matter component," even though there is a small amount of baryonic dark matter. The largest part of dark matter, which does not interact with electromagnetic radiation, is not only "dark" but also, by definition, utterly transparent.

The vast majority of the dark matter in the universe is believed to be nonbaryonic, which means that it contains no atoms and that it does not interact with ordinary matter via electromagnetic forces. The nonbaryonic dark matter includes neutrinos, and possibly hypothetical entities such as axions, or supersymmetric particles. Unlike baryonic dark matter, nonbaryonic dark matter does not contribute to the formation of the elements in the early universe ("big bang nucleosynthesis") and so its presence is revealed only via its gravitational attraction. In addition, if the particles of which it is composed are supersymmetric, they can undergo annihilation interactions with themselves resulting in observable by-products such as photons and neutrinos ("indirect detection").

Nonbaryonic dark matter is classified in terms of the mass of the particle(s) that is assumed to make it up, and/or the typical velocity dispersion of those particles (since more massive particles move more slowly). There are three prominent hypotheses on nonbaryonic dark matter, called Hot Dark Matter (HDM), Warm Dark Matter (WDM), and Cold Dark Matter (CDM); some combination of these is also possible. The most widely discussed models for nonbaryonic dark matter are based on the Cold Dark Matter hypothesis, and the corresponding particle is most commonly assumed to be a neutralino. Hot dark matter might consist of (massive) neutrinos. Cold dark matter would lead to a "bottom-up" formation of structure in the universe while hot dark matter would result in a "top-down" formation scenario.

As important as dark matter is believed to be in the universe, direct evidence of its existence and a concrete understanding of its nature have remained elusive. Though the theory of dark matter remains the most widely accepted theory to explain the anomalies in observed galactic rotation, some alternative theories such as modified Newtonian dynamics and tensor-vector-scalar gravity have been proposed. None of these alternatives, however, has garnered equally widespread support in the scientific community.

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[mikeygordon]

The galaxy bend together by the vastness space of dark matter.And that is the cause of the explosion of the many types of the galaxies.

[Jason-gtkx]

My hypothesis that Dark Matter is not a weakly interactive massive particle (WIMP), but maybe is a deformation of space-time by which the curvature of space-time itself is the cause of the gravitational effect. The "dents" Verlinde talks about aren't slow motion effects, but rather fixed geodesics. Gravity is the consequence of the curvature of space-time when mass is present.  It may be possible that the structure of space-time itself could be warped without the presence of mass.  So, how did this warping occur?  We believe this warping of space-time occurred during the extreme conditions present during inflation. Space-time has been shown to react like a fabric by warping, twisting, and propagating independent of mass. These properties have been proven with observations of gravitational lensing, frame dragging, and now gravitational waves. Fabrics can be stretched, pressured, and/or heated to the point of deformation. Such extreme conditions were all present during inflation, so it is plausible that space-time’s elastic nature could have hit its yield point and permanently deformed. Therefore, if gravity is the consequence of the warping of space-time, and fabrics can be permanently deformed, then a deformation could create a gravitational effect independent of mass. Thus, the unidentified dark "matter" that seems to be so elusive to modern science may not be matter at all but merely warped deformities causing gravitational effects.  We have a prediction using gravitational lens mapping to prove Dark Matter isn’t a weakly interacting massive particle, but instead is a floating fixed pocket of warped geodesics in space-time geometry causing gravity wells.

[ariesdane]

The stipulation that dark matter exists is based on the fact that the orbital speed of stars are faster than what is expected based on a galaxy's calculated mass, but based on the examples given in this documentary there's a couple of things to be pointed out.

1. If each galactic center contains a super massive black hole, then who's to say that the brightness emitted by the galactic center plays nicely with the way it's mass is being calculated. I mean light generated by a black hole may be behave drastically differently based on how much material is feeding it - thus the mass of two different galaxies centers could be equal, but one could be brighter because it's consuming more material and ejecting more radiation.

2. Stars orbits the galactic center within the dusty spirals of a galaxy's arms. These galactic arms are massive, exert gravity, and are essentially side by side with other galactic arms. Isn't it possible that a galaxy's inner arms pull along outer arms due to gravity, turbulence, friction, etc at a higher speed than expected as compared to the formula used to calculate planetary orbit speed? I mean wouldn't individual planets have little to no impact of the orbiting speed of other planets where as galactic arms have a much more complex interaction - thus deserves a more complex formula to account for the # of arms, size, spacing, mass, etc?

3. If dark matter permeates all throughout a galaxy as indicated by the documentary (e.g. I'm getting bombarded with it now), then wouldn't the mass of our own solar system be drastically more than the sum of it's known visible parts? If so, is the orbital speed of our solar system's planets being skewed in the same way as the documentary states is being observed in the Andromeda galaxy's stars? And if not, then why would it behave differently in one scenario instead and not the other (e.g. would it not scale down)?

I'm not a physicist, but I did stay at a Holiday Inn last night, plus I have a Bachelors in Computer Science and Math so I'm not a total idiot (except for the bad joke). I'm just a little confused is all, so I'm asking a few questions with the hope that someone with more knowledge than me will respond to clarify.

[geezzerboy]

Galileo's Laws of Motion quantified the earth's gravity field. Newton took it further, and formulated his Universal Laws of Gravity. Universal. meaning the same in all times and places. Newton was working with our Solar System. By 1940 we knew we were in a galaxy, about 30, 000 LYs in diameter. By 1945 we knew M-31 was a galaxy like ours, Andromeda, 200, 000, 000 LYs away. And its light left it 200, 000, 000 years ago.

[geezzerboy]

The Hubble Deep Field photos of galaxies going out to the edge of the universe and apparently beyond. Maybe Newton's assumption that his laws were universal, the same in all times and places, is incorrect?

[HiAdrian]

@xCrowMagnuSx While it may account for considerable mass, it does not account for large areas of gravitational lensing.

It also doesn't explain the high rotation speed of the outer parts of galaxies, that wouldn't behave this way if the majority of the mass originated from a BH at the center with inverse square gravity falloff.

Something additional seems to be involved, hence the search for dark matter.

[CollinMaessen]

Dark matter is a hypothesis, not an actual theory, or an accepted part of a theory. Scientist are trying to figure out if it's a good explanation for what we are observing, and are trying to get verifiable evidence for it.

They will continue searching till they find something that gives a good explanation of what we are observing. And that explanation doesn't have to be dark matter, it can be something completely different (or some sort of 'dark matter' we haven't thought of yet).

[ccaptorchen]

@magnusalexa
lol.. both internet and computers are the product of science. military technology is also product of science. don't' fooled myself? says the "telepath" lol. the energy from atom splitting now powers a good % of Europe's citys, and also ended a world war. again.. what have you done to contribute to anything? if you are a telepth then take the James Randi challenge. its 1 million dollars for the taking.

[DX]

Cheers if you want to think that. I just fail to see any logical step from "invisible mass" and "love".

What you call "emotions" are abstract concepts that express relations between conscious living entities - that is these concepts describe a certain behaviour of complex systems of matter.

"Dark matter" on the other hand is most likely particles of some kind - concrete physical matter. Abstract concepts don't have weight.

[pfarabee]

Don't worry, Josh. I think it is extremely likely that the entirety of everything is not finite, but boundless and infinite. As such, there would be no "theory of everything" possible, because the infinite can have no qualities of it's own.

Our own cosmos, on the other hand, is looking to be smaller and smaller in relation to everything else that may exist, which I actually find exciting! :)

[DX]

Um.. well I think that's kind of over the top. I mean it's a strange idea to think of love as a particle (I'm firing my love at you, accelerate my love, my love gravitates towards you).

Air is also essential and invisible to the eye - just like UV and IR light or even atoms for that matter.

And it would be kind of a paradox because one would have to say that it's love (dark matter) that's pulling the universe apart..

[pfarabee]

One theory to account for the relative weakness of the force of gravity in relation to other basic forces is that gravitons are made of strings with their ends joined, and are thus not bound to our 3-dimensional space. These unbound gravitons then propegate into other dimensions.

The question then is: could those gravitons act upon matter encountered there? If so, what would that interaction look like, from the perspective of the other dimension?

[ccaptorchen]

@magnusalexa
again.. James Randi will test you if you qualify, its 1 million dollars reward, if you are "the most accomplished detective around" with your telepathic capability its easy money for you. you make the scientific test... what can be more easy, pass a test of your own design. as long as it proves ANY super natural ability. go on! what are you doing on youtube!!

[amandarandom]

My, martially educated, bet is on WIMPs, Weakly interaction massive particles; particles that only interact with gravity.

The problem is that NOT finding anything doesn't mean it doesn't exist, just that you can't find it, which is horribly frustration.

either that, or we've got something horribly wrong about our understanding of gravity.

[ccaptorchen]

@magnusalexa
one day people will realized supernatural is really just natural... and stop fooling themselves. again... I was asked what am I holding in my hands, you have yet to use your telepathy detective skills to answer. and you said people refuse to test you...

[exconguitar]

@infinitenight2093 Are we not seeing the interaction between Dark and Normal matter when we see the how it's effects thru gravitation as you stated? The interaction is observed in galaxies and galactic clusters.

[pfarabee]

Thank you, Collin! I feel better knowing that there are actual physicists suggesting the same thing I am! It seemed like a fairly logical and viable idea to me, glad to see there is real scientific merit to it! :)

[pfarabee]

A followup question: Could gravitons from those other dimensions come into our 3-dimensional space? If so, could they interact with matter here? And what would that interaction look like?

[resignator]

@trentcreek Do you think cosmologists somehow forgot to include super-massive black holes when calculating the mass of our universe?

Do super-massive black holes explain gravitational lensing observed by Hubble, Magellan, and Chandra?

Do super-massive black holes account for the uneven temperature distribution of the cosmic microwave background radiation?

Do they account for orbital velocities of galaxies in clusters?

[TheBinaryUniverse]

It seems to me that to create the idea of an invisible, non reflective, never before seen, yet massive substance that has to this day evaded our detection is nonsensical, especially as we have neglected to investigate simpler ways of explaining our observations. I stand by Newton and so do not support MOND. I also stand by our observations and therefore look to Newton and other areas of established science to explain them. Take a look at youtube videos on galactic rotation anomaly. KEN HUGHES