What is Dark Matter and Why Does it Matter?

In this public lecture, Fermilab physicist Dan Bauer explains what scientists know about dark matter, the mysterious, invisible stuff that accounts for most of the matter in the universe. After presenting evidence for the existence of dark matter, he describes some of the physics experiments that scientists build and operate to look for signals from dark matter particles. From going deep underground to operating equipment at temperatures close to absolute zero to operating the most powerful particle collider in the world, scientists are pushing technological boundaries in their quest to discover the building blocks of dark matter. This lecture was held at Fermilab in October 2018 as part of a worldwide series of events to celebrate Dark Matter Day.
For more information visit www.darkmatterday.org

[@anwarsroka9976]

Dear Dr. Bauer, I am not a scientist, nor do I have any kind of educational graduation, but I like to discuss and think about physical problems, trying to understand them and share my thoughts with other enthusiasts. I followed the conclusions made by the scientific community regarding DARK MATTER and your presentation to the subject, and I wanted to thank you for the excellent explanations. As far as I could follow your present conclusions it seem to be a dead end, and no one in the community knows, or has an idea how to proceed. The facts are: 1. The generated gravitational power is there 2. The NORMAL MATTER that we can see is not great enough to generate it, so there must be something complementary providing the gravitational power 3. The effect is there but we are not able to recognize the cause! Are we asking the right questions? 1. The first question could be “Why can we not see the cause” and not “where or what it might be” 2. Where is the missing MATTER, or when is the missing MATTER? 3. Did the BIG-BANG… originate MATTER, SPACE, and TIME, at exactly the same moment, or was there a distortion in time that caused a separation of the total amount of Matter, splitting it in “Normal MATTER in which we are imbedded” and “DARK MATTER which might be a few seconds or minutes ahead of us”? The TIME GAP seems to be constant That might also be the reason why we cannot see or detect it, but we realize the effect of its partial gravitation. By the way if the cause would be present in our time it might become quite crowded in our universe. 4. The amount of “DARK MATTER or FUTURE MATTER” is much bigger than our visible Matter, so also the gravitational forces must be much higher and will also have a great affect to TIME, so it might also be a great Existential benefit for us that only a partial amount of gravity reaches our TIME SECTION. I know, it sounds crazy, but I think it could be an amazing theory because gravitational forces in a singularity can also affect time. The BIG BANG was generated by a singularity. That is the theory in the community. Maybe someone can setup an equation.....

[@familyfarmsandfactories9870]

Dr. Bauer is an excellent teacher. His explanations of dark matter and the experiments to detect dark matter particles make it easy to understand. Thank you, Dr. Bauer.

[@guff9567]

Is he paying you?

[@petersuvara]

Finally, a lecture on dark matter that understandable and well structured, no crazy hype, just real relatable science backed by observable evidence. Well done!

[@petersuvara]

@Astute Cingulus why is it wrong?

[@Joaocruz30]

Wow! FINALLY A DISCUSSION about this subject! Greetings from Portugal and congratulations for your presentation. THANK you

[@daloshea6723]

Question If there is 5x more dark matter than regular matter, or 5 dark matter grams per every 1 normal matter gram - why is it that their existence doesn't mess with our local gravitational force calculations? Given that they are so abundant, and only affected by gravity; for every 1 gram of matter, there is supposedly 5 grams of more mass, so why is it that we never see the dark matter affect local gravitational fields, our solar system would be a lot more different?

[@tonib5899]

And if dark matter is everywhere in a truly darkened room wouldn’t a percentage of the total darkness be dark matter particles.

[@tonib5899]

I suppose the super CDms is a theoretical darkened room.

[@sirierieott5882]

Amazing how effective springs and tennis balls are at communicating the detection concept for mark matter detectors.

[@rameyzamora1018]

These advances in our conception of what the universe was, is and will be are fascinating. That clumping of dark matter also looks like the neurons of the brain of living things.

[@Coach.Chrisy]

It’s almost like matter of the dead or persay ghost matter

[@nachannachle2706]

This was such a delight of a talk: deep, structured and with lots of questions raised. Thank you FermiLab! :)

[@Jesusismykin]

You can't see the power of God, it is invisible it exists in the spiritual dimension. Revelation chapter one verse 10.

[@guff9567]

Sorry about the American accent and bumblingness

[@leuk2389]

I do not have any expertise or former knowledge in any of the related fields, I am so lost but the video was very interesting

[@MrBurghausen]

I hope you are ok.

[@modalmixture]

For a leading expert in a very unintuitive field, Dr Bauer is a remarkably good science communicator. I really appreciate how he is able to describe his experiments in a relatively sophisticated level of detail, showing actual data, while keeping it accessible and using intuitive physical models (the vibrating lattice, the light-up particle detectors) to illustrate some of the principles.

[@amreshyadav2758]

How serious is quantized interia, for explaning the apprent motion of stars in galaxies? It does explain annomlies of dynamics of galaxies.

[@bobbymah2682]

Great talk, I understand it so much better now. Thanks

[@duster0669]

Very good job. I am nothing buy an old man with a 2 year engineering degree. I took all science classes to fill my schedule while I caught up in math. All science classes start the same. They teach the student the basics. Being fairly well versed in the basics a person can understand the rules. The rules of math...and the rules of science. Our science is built on our observations, and nearly everything we can observe is right here on Earth. I love how this lecturer stressed how Dark Matter must be somewhere, or we don't really know the rules of science. That so clearly describes the evidence Dark Matter is somewhere I am for the first time fully convinced! It took this guy about 5 minutes to fully explain and prove Dark Matter. We have not one damn clue what Dark Matter is, but by taking very accurate measurements we can tell it is there. That is assuming EVERYTHING we see and can measure is wrong. I'm not ready to believe that prior sentence. Collectively we are pretty bright. We believe we know basic science real damn clearly. All of our engineering depends on our sharp people having their poop all in one sock!

[@TheSophisticatedFrog]

thank you for teaching us this.

[@andrewbartram7688]

A dark 'ether',hmm? That's a new one to me. Thanks Fermi lab.

[@inertia186]

I really like this answer he gave. The question was, I'm paraphrasing, that if dark matter only interacts with ordinary matter by gravitation, what are these experiments even looking for? 52:08. His answer was basically, that these experiments will rule out all other interactions. That's pretty exciting, to be able to say they've experimentally exclude everything but gravity.

[@1964metube]

Is it possible you did not take into account Thermodynamics in the calculations of Dark Energy and Dark Matter? If the binding Energie is taken in account, there must be a lot of energy inside galaxies due to the binding energy of the systems. I just ask that question because I miss this in your explanations.

[@lexzbuddy]

Dr Jamie Farnes' paper on this. Have a look, any thoughts?

[@prasannabhat8429]

This might be a dumb question, but. What if, in your experiment you are looking for a very small amount of heat dissipation due to dark matter interaction. However, how will you detect heat absorption by dark matter ? Is that even possible ? Or why is it always heat dissipation when dark matter collides with normal matter ?

[@nmagko]

Very nice. This open our minds up. Thank you.

[@4or871]

Combine: 1. cosmological constant in Dxy [m^-2] = lp^2/λ^4= lp^2 Nxy ^2 [m^2] [m^-4] 2. schrodinger solution 3. Planck E= h f= h Nxy 4. Nxy = number of superpositions per m^2= wave function frequency Result: dark matter = superpositions of the electron wich gives the electron extra weight Dxy [m^-2] = lp^2/λ^4= lp^2 Nxy^2 [m^2] [m^-4] Nxy = sqrt(Dxy / lp^2)= (Dxy / lp^2) ^0.5= [m^-1] [m^-1] = m^-2 Nxy = sqrt ( 10^-52 / 10^ -70) = 10^18 ^0.5 = 10^9 Schrodinger solution: Nxy^2 h^2 / ( 8 m L^2) = h Nxy 8 m L^2 h Nxy = Nxy^2 h^2 m = Nxy^2 h^2 /( 8 L^2 h Nxy) m = Nxy h 0.125 L^-2 m= 10^9 10-34 = 10^-25 ( all superpositions). 1 particle = 0.331 10^-25 / ( 0.4 10^9) = 0.828 10^-34 kg = 46 eV If you count only the positive wave function amplitudes: n = 10^4.5 then 1 particle = 0.331 10^-25 / ( 0.4 10^4.5) = 0.828 10^-30kg 5.6 10^35= 10^5 ev = 0.5 Mev Superposition (recoherence) of electron causes dark matter and expansion of the universe? And vacuum catastrophe solved: m= 10^9 10-34 = 10^-25 ( all superpositions). E= m c^2= 10^-25 10^16= 10^-9 J m^-3 Im curious for youre reaction

[@MbardGem]

Oh wow! Whole lecture about dark matter

[@siobhanc777]

Bob Sawyer is a long time friend of mine! I didn't know he wrote a book he's always drunk!? Wow congrats, bobbert!! (He likes that name)

[@shivamg_sk]

Nice talk, want more !

[@FreshBeatles]

Great lecturer, the whole thing was an experience to watch.

[@l.l.9806]

Do you need to watch it? I'm just listening to it..

[@gravityzack]

Does dark matter have entropy? If there is 5 times more dark matter than regular matter, is there more entropy in dark matter than regular matter?

[@TheStephaneAdam]

... Probably...? It's an excellent question but it's hard to tell as we don't know what Dark Matter is. Or if it's actually "matter" in the first place. It's infuriating, scientist KNOW the standard model is wrong on a fundamental level but all test thus far have shown it to be incredibly accurate.

[@World--Citizen]

@@TheStephaneAdam If its also expanding... it should have entropy in that way?

[@shayneoneill1506]

Sure. Most likely. But as the video says, we just don' know what it is yet, so definitive answers are not gonna be a thing for while yet until we figure this out.

[@robietonie8695]

Great audio!

[@peteraltonmertz4439]

The problem I am seeing here is that movement of some Bose-Einstein condensates does not always translate into heat, in some cases it becomes vibrations. If you are using supercooled detectors, viewing crystals, then it is possible that the crystals are vibrating and not increasing in temperature. If an interacting particle "Hits" another interacting particle then energy is exchanged and heat is created. A non-interacting particle might only create a vibration in the crystal structure. That would be next to impossible to detect with the methods you are using. Helium 4, however, creates a very distinct whistling noise when a barrier with microscopic holes is placed in the middle of a pool, in which vibrations would be far easier to detect. Let us say we use Muon decay, in which a large amount of mass is lost. Now using that method, one could create a container in front of your muon to the neutrino generator and one in your mine in Montana and then see if the container produces a distinct hum while the neutrino creator is turned on. The essential concept is that what you are trying to detect is the gravitational tug or quantum lensing effect on the Helium 4 and not an interaction with it. This, of course, will prove nothing. However, it might provide you with another angle to detect particles that do not normally interact with matter. And if the initial proof of concept experiment works, then you can develop it further. If not then it isn't that big of a waste of resources. The University of Berkely has done extensive research on this subject, you might want to call them a see if that is feasible... www.berkeley.edu/news/media/releases/2005/01/27_helium4.shtml

[@KafshakTashtak]

Question (related to the question at 50:35), when he shows the formation of the cosmic web from dark matter only, what is pulling dark matter into those specific points? I mean something has to slow down the DM particles so that they collect in a point of space, otherwise, they should just orbit the centre of the mass of the system. What is slowing them down? Is it the curvature of the space caused by the dark matter's collections, or is it due to their gravitational waves taking their energy away from them? I can't think of any other phenomenon.

[@MsSomeonenew]

Dark matter only interacts with gravity(so far as we can tell at the moment). And critical to know we are looking at a very tiny slice of time, that matter isn't collected in a point of space, it is moving around.

[@Lady8D]

I'm not very far into this talk right now but I'm in the middle of a fairly crappy allergic reaction¹ today and thus, not feeling my best - which is _only_ the least bit relevant because I may not be able to sit through the whole lecture as attentively as I'd like and I don't wanna pass up the opportunity to ask a question I've had for quite some time now. I hope you'll forgive me if it's covered in the lecture. 1) How has it been determined that dark matter doesn't interact at all with the electromagnetic force? 2) For quite some time now I've had a thought that I'm positive must have already been considered and ruled out but so far I've not been able to find anything that would suggest so, though I'm not the most skilled at this so that may not mean much. I'm hoping someone here will help me understand why/how this idea has already been ruled out - please don't jump to conclusions and consider the whole of my thought rather than addressing only one part, my terminology isn't always spot on: • We are missing a lot of anti-matter and as I understand it anti-matter is the opposite of regular matter in every measurable way, correct? • We are looking for dark matter because there seems to be far more gravitational pull in most galaxies than can be accounted for using ordinary matter, correct? • Last I heard, it'd been observed that anti-matter was also repulsive/anti-gravity, does the latest research still support this? • Is it possible that either anti-matter or something that has a repulsive/anti-gravitational force could be responsible for both dark matter and dark energy? • Meaning rather than forming planets and stars and such the anti-matter (or whatever else it could be, if anything) particles repel not only regular matter but also each other - therefore, never clumping together enough for us to see at a distance nor getting close enough to see near us, though we can see it's effects. • Considering it was theorized we should have 50/50 matter/anti-matter and aren't sure why we don't, if we consider that for every particle of normal matter in the universe there is a particle of AM pushing the other particles away, would it then be possible that they are what lies between the galaxies pushing against one another as well as against the nearby galaxies, providing the needed gravity just in the opposite direction? • When one plays with magnets it's always *_far_* easier to pull the attracted sides apart than to push the repellent sides together; would gravity/anti-gravity exhibit this same sort of phenomenon? • This would also explain why our space probes (the names of which have just slipped my mind, sorry!) experienced an unexplained deceleration as they neared the edge of our solar system. • I'm aware that current theories say that for some unknown reason more matter was made than anti-matter and that's why we have matter even though most M/AM annihilated each other, again for some unknown reason (as I've heard it explained, I apologise if this is incorrect), is it possible it didn't annihilate but instead "filled in the gaps" between matter, so to speak? This is already far too long, I've spent the last few years thinking this out and trying to find reasons to rule it out (especially the anti-gravity part) but so far have been unable to do so on my own, though I'm not quite educated enough to really know what I'm doing and am hoping to get the input of someone that is. Thanks in advance! ¹ By fairly crappy I mean not life threatening but full body rash, feeling all around yuck. Been here before, I'll be fine =)

[@celiaosborne3801]

I like this Prof., he can teach me, many thanks for such clear presentation

[@Anaurodama]

!Excellent presentation!

[@samo4003]

Fascinating. Certainly one of the best presentations I've seen.

[@tlew1588]

In the Bullet Cluster model. Do the dark matter clusters interact with each other?

[@vanessacherche6393]

Thanks for posting! Always interested on this elusive subject. The greater our area of knowledge, the greater our circumference of our ignorance. Which is ok, keeps it interesting :)

[@REIwAlexY]

Even though I'm sure there's a reason for why things were written the way they were isn't "too energetic and too little mass" not possible? Or is energetic being used in some other meaning here besides "having lots of energy" aka mass?

[@WhosSenGaming]

Oleksandr YAREMA yeah didn’t make sense to me either

[@rubberbites619]

Neutrino carries lots of speed and has near zero mass. Most of dark matter observed seem to be quite stagnant, while the neutrinos are frequently traveling at near the speed of light. The total mass of neutrino per theory prediction isn't even close to the total mass of dark matter. So, yes, neutrinos are too "energetic" and have too little mass.

[@nihlify]

Think of light.

[@williambeck5678]

Imagine what you would see if one cast a deck of cards in the air. An observer would see only 1/3 of the cards at any one instant when each card is face-on while those same cards would be invisible to any observers looking from the sides or from the up and down positions. Imagine the basic building blocks of all matter as being flat discrete plates of quantum energy fields acting in a similar manner to the cards.. When flipping rapidly, but randomly, only 1/3 of total matter would be present in each of 3 dimensions. 2/3 of total matter in the universe would disappear as dark matter as viewed from each dimension. Now if all the fields were flipping at the same rate in a vacuum this would only allow light waves to travel at a fixed rate because the vibration of each field would propagate light only during that time when in one dimension it being cancelled out while in the other dimensions. The flipping of fields would also not allow the universe to be heated to an infinite degree, as observed because again the effects of heating would occur 1/3 of the time. As the fields flip between dimension, for a brief instant the fields would be invisible to all the dimensions and this being extradimensional would have no time whereas the 3 dimensions would be locked to the same time and held together (causing gravity) which is represented by each field being held thru time by separate quantum coupling in each dimension by far away other fields in other matter. Thanks for reading.This is my humble theory.

[@Kitsudote]

These sounding detectors are amazing. They literally play the cosmic symphony.

[@martin36369]

The expansion of space-time, doesn’t appear to include that occupied by Galaxies etc, so between the negative curvature of the gravity wells of Galaxies are positive space-time curvatures, which may have the effect of increasing the gravity of those gravity wells, just as differentials in atmospheric pressures do.

[@walterbishop3668]

Please correct me if I'm wrong: Dan said that we can see the Einstein ring even in places without any matter. Right?

[@GlynWilliams1950]

Great talk but please use metric units, Centigrade and Kelvin, not Fahrenheit. A fridge will produce temperatures down to is -18°C (-0.4f) to -20°C (-4f) in the freezer.

[@danielbergman1984]

Outstanding! (Y)

[@kevincorvus3298]

Regarding "dark forces" and other things on the dark matter side of an extended standard model, can we make any inferences based on the observations we've made about how dark matter behaves during galaxy collisions? I would think we could model a dark matter cloud collision with a super computer (with the assumption that it doesn't interact at all with itself or "normal" matter except through gravity), compare to what we actually observe using gravitational lensing, and see if there are any discrepancies that might point to dark forces. Anyhow, thanks for the video- very informative and interesting!

[@xiperivera2946]

Yyyyyyyyyyyyyyyyyyyyyyyyyypop pup

[@kirillbeckmann]

Always wondered how they predict thoretical mass in the distant universes. Keeping the expansion of the univers, black holes etc in mind, that should make it harder to do predictions shouldnt it? Also if DM formed in some cases the galaxies shouldnt it be sorta attached to the planets and stars, especially since large ones gravity should also pull DM to itsself? And if its the case shouldnt just calculating the expeccted weight of an object and its actually gravity give an insight of existing unvisible mass?

[@anmolpreet8959]

Bud for staters look out doppler effect

[@derekohachey]

Thanks it was a very good informational source

[@horus2779]

Dr Micheo talked about all dimensions being joined together at the start, but for some reason they seperated as time ? went on but we dont know why. The Indians past stories full of beings and talk about a different frequency. So over time as the universe started to settle so did the frequency of the universe change, This caused the dimensions to shift and seperate. All we got to do is find that key example - a big church bell is struck very hard causing the bell to vibrate very loudly, 4 minutes later it drops a few optives , 3.3 minutes later it drops a few more optives and the frequency starts getting lower..

[@nfto8922]

9:00 Looks like earth's composition.

[@whitenight941]

Yes you Are !

[@ryankeeling2406]

My question is thou and it's been bugging me if the universe ends due to dark matter push the universe further away and eventually nothing in space is left not even black holes and then the end of time then how did the universe even begin if originally space was empty and nothing was around ?

[@Brandon-wx2ty]

This is awesome

[@4or871]

Combine: 1. cosmological constant in Dx = lp^2/λ = lp^2 n. Then n = ( 10^-52 / 10^ 70) = 10^18 2. schrodinger solution 3. Planck E= h f= h n 4. n = number of superpositions per m^2 And you get dark matter = WIMP n^2 h^2 / ( 8 m L^2) = h n m = 0.3313 10^18 10^-34 = 0.3313 10^-16 kg ( all superpositions). 1 particle = 0.331 10^-16 / ( 0.4 10^18) = 0.828 10^-34 kg = 46 eV If you count only the positive wave function amplitudes: n = 10^9 then dark matter = WIMP m = 46 GeV

[@bubuandfreinkvideos]

Did 3 people just leave because of the joke?

[@costa_marco]

Correlation doesn't mean causation

[@gutspraygore]

@Rebelation N. Or maybe they just got there.

[@matthewburson2908]

@@costa_marco en.wikipedia.org/wiki/Correlation_does_not_imply_causation

[@UteChewb]

@@costa_marco , but it is required for causation. Necessary and sufficient conditions, read up about them.

[@alanmalcheski8882]

I'm here to make more jokes... what'd i miss?

[@jamesrick3524]

Dark matter is exactly what you first described and you can see it in the right conditions i would like to present a Lecture into dark matter and explain why it is important for the scientific community and present a live performance showing dark matter and it at work i discovered the reaction of dark matter by mistake. That changed my entire research and will change everything you thought you knew about the universe

[@Dra741]

And the search for the wimp, I'm amazed I'm so happy that Tech from Japan was brought to United States and I hope all the scientists and researchers that there they been amazing thing and thank God welcome to America, this is a gift from Japan

[@csabanagy8071]

I very much doubt it is the way to go. If it would be a particle it would have been found in LHC already. I think this phenomenon is more fundamental. Related to fields and space-time behavior in large scale. The big question how you define your local reality? How those realities are related to each other? Probably the moving mass has bigger effect on the local reality as anybody imagines.

[@quahntasy]

Can we have more talks like this please?

[@Jason-gt2kx]

My hypothesis that Dark Matter is not a WIMP, but maybe is a deformation of space-time by which the curvature of space-time ALONE is the cause of the gravitational effect. Gravity is the consequence of the curvature of space-time. It may be possible that the structure of space-time itself could be warped without the presence of mass. 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. DM could be a microscopic black hole with no mass at the center... Prediction: Spacetime's elastic property hits a yield point, so only that part of geodesic's "stretch marks" would remain after inflation stopped. These steep gravitational wells would not follow the inverse square law. I am looking for Observationalist to help test..

[@rubenmartinez2994]

Why? Because this is highly speculative stuff!

[@mrloop1530]

They are all over KZbin

[@davidhuntsinger128]

@@Jason-gt2kx hgopuu

[@davidhuntsinger128]

@@Jason-gt2kx kuhhuhht h hi u

[@EarthPoweredHippie]

How is dark matter a seed for galaxies if dark matter doesn't interact with regular matter? If dark matter doesn't interact then why I ask does it matter?

[@Gabeloveyou]

Best explanation 😊. Bravo!

[@marechuber818]

Once identified to be listed as an element its understanding will become ever more useful ! Imagine the possibilities !

[@rubberbites619]

All chemical reactions are caused by electromagnetic forces. Unfortunately, dark matter doesn't interact with them at all or only extremely weakly, that means any "dark atoms", if they even exist, is not going to have anything chemically interesting. Also, you won't be able to store them in any normal containers, and you definitely won't be able to see them. I'd say the chances are pretty slim, and if it ever happens, photons will be on the table way earlier.

[@MsSomeonenew]

Probably not an element, if it exists within the standard model at all it's probably a super elusive particle. We do know some types of neutrinos that fit the profile, however their mass is far too low to explain the whole phenomenon.

[@littlejolit]

I think it is strings of proto-matter of just protons and neutrons or their free quarks in weak or unstable densities and exist as 2d information that has not been 'volumized' and projected into 3d by the electron. I think the density of the nucleus is what attracts the electron with gravity and in relativity and it bends space a bit to create a 'projector' about which the electron orbits and with centrifugal force spun out projects the 3d volume out of the 2d information packet. I don't think it is charge that does the attracting. If anything the charge is what 'repels' it and holds it in orbits and turns it into volume. I would love to hear if I there are flaws in my theory. I also think our models for quarks aren't helpful and should be looked at as sets (quanta) of 1s and 0s and instead of up down. and the 1 and 0 for example could have + or - to add and subtract, much like our DNA. And the shape is probably more like a zipper in how the proton and neutron lock in together, and similar also to DNA, the syncopation of the 1s and 0s creating a lattice of tines that organize information and try combinations until there is stability and density enough in mass to attract an electron as they are significantly different in size and the gravity will capture it...like a fishing lure. If you want to test for it - I think you need to figure out how to take an image of 2d space without first making it 3d! A conundrum. Neutron Stars have Dark Matter cores, made of 2d neutron/proton densities and all the electron shells that typically volumize the space are shot out and separated from the core in the supernova creating it's own massive gravitational field as an electron shell around the 2d nucleus. So looking at them is probably the best way to study dark matter.

[@EyeDreamMellowDees]

does dark matter travel-vibrate faster than speed of light? is that why we can never see it, only "feel" it? (a blind person can never see light, but can feel it as heat)

[@renx81]

No, we cannot see it because it doesn't interact with electromagnetism (the force responsible for light). And as for heat - heat is just light in the infrared spectrum.

[@anttumurikka8728]

is dark matter need particle at all? It can be like gravity

[@mariusvanvuuren4299]

Why do they not consider the obvious provable mechanism as explanation for what they see rather than dreaming up exotic things like dark matter. Also I don't think Einstein actually ever explained the mechanism of gravity, thus we still do not understand gravity at all - we merely have a pretty good mathematical gravity model.

[@rubberbites619]

Dark matter is the most obvious and closest to provable theory to explain these phenomena. Any other theories that may be obvious to you are far more complicated, full of assumptions and hard to believe when you lay out the math and look at it in a scientific way. Also, Einstein's general relativity is the first valid theory that explained the mechanism of gravity - that gravity is the curvature of spacetime, and that free falling objects follow the geodesics on their paths.

[@minirock000]

Please provide the experiment that shows relativity to be incorrect. Can you show the maths as well? Also compare that experiment with the hundreds of others that show relativity to be correct and the ones that can only be done if relativity is correct. Newtonian is a pretty good model and that will get you to any planet in the solar system, if you want to know how much our star will bend light, you need relativity. They did think of everything before they "made something up". They added everything up in the galaxy and still wondered...he explained all that, you were not paying attention.

[@Dragrath1]

MOND or modified gravity theories have been an active area of research however one of the most basic predictions of nearly every MOND theory predicts that Gravitational waves should travel slower than the speed of light in order to replicate the observations of "dark matter" we see. The LIGO detection of a neutron star merger via gravitational waves and subsequent gamma Ray burst has however delivered a very hard blow to modified gravity as gravitational waves and light were detected as expected by general relativity implying gravitational waves travel at or at least very near to the speed of light which has highly constrained if not ruled out various modified gravity theories. GR has been extensively tested with physicists looking for any small deviation that could lead to anew better theory however within observational limits GR has perfectly passed every test which combined with the extremely strong indirect evidence of "Dark Matter" seems to point to an unknown substance being the most plausible explanation. Part of the reason this remains true despite a long history of non-detection is that there is no guarantee that a dark matter particle could ever be detected as dark matter needs only to interact gravitationally to match observations in which case we would never be able to detect it. Occrams Razor thus can't point away from dark matter particles as we can't ever prove there are no Dark Matter particles as infuriating as that might be. It is even plausible that dark matter may be the effects of matter in parallel universes interacting with our own which would leave no known mechanisms to ever detect or differentiate from dark matter that only interacts with gravity. So short of modified gravity finding alternate ways of producing a theory that matches observations of both light and gravitational waves or finding some theoretical particle or external proof of other universes the question as to what "Dark Matter" is may be fundamentally unanswerable. But Science on testing hypothesis based on observations and so expect scientists to look until they can rule as many possibilities out for a nondetection is as important as a detection according to the scientific method.

[@user9005]

Damn this was good. My understanding was completely lifted. Is dark matter the biggest mystery in the universe?

[@TheSundaysLive]

No, dark energy is.

[@derschmiddie]

Could it be, that Dark matter consists of particles with an Integral of phi² dt < 1 is you assume spacetime to be finite and dont integrate over infinity?

[@zoltankurti]

No

[@darwinlaluna3677]

Ok r u done measuring?

[@sorelymistaken1176]

How do you stop something that is "moving" in time?

[@BarryBBryson]

Is it possible that we don't understand gravity and that this is a set of interpretations to try to save our present understanding of it?

[@dionsilverman4195]

15:15 The dark matter determines the large-scale web-like structure of the universe that we observe. Would normal matter not produce that pattern? How would what we see be different if normal matter was left to clump by itself?

[@TheSundaysLive]

I'm afraid not, there isn't enough normale matter to create the structure we see in the universe. If there wasn't dark matter there probably wouldn't be galaxies or only very low densities galaxies.

[@michaelblacktree]

That was really informative. 👍

[@calebpoemoceah3087]

The week force gets stronger in the nucleus of a atoms as you add more energy. The most energy is found in dark matter.. so could dark matter have so much energy collected togather that now the nucleus of dark matter if it has one acts more like a gass. This would make its interactions with normal matter less, just like neutrinos being so small they miss a lot of time .

[@gr-xw3sp]

It is true that some models for DM predict peaks of DM at the center of galaxies, but those are mainly classical computational models that assume DM in galactic halos as a classical gas of point particles. But that's not the way DM exists: since DM does not interact with any radiation it never exists as localized point-like particle (like an electron sometimes is.) Quite the contrary, it only exists in states similar to a free wave under no potential. In fact the only potential that DM "feels" is the gravitation potential, so the DM particles in galactic halos are in a non-localized state similar to those of electrons around an atomic nucleus (but under gravitational potential Vg(r) instead of electrical, of course.) This link below shows publication of a quantum model for DM galactic halos which predicts their distributions being flat at the center of galaxies, as have been observed: @t

[@oriongurtner7293]

I feel like the question isn’t ‘where is the dark matter’ but ‘have we found it already but don’t know?’ And there are more neutrinos than can be inferred, as we can’t detect them properly, nor can we properly gauge the amounts that would be generated due to that, but you’re right, it’s not the neutrinos, though those are directly linked to it I’ll give you a hint ‘light is both a particle and a wave at a quantum level’, for a second clue try to imagine that this isn’t the only superpositional state that a given force could be in For the last hint, imagine the boson variants and electron variants and having a particular form of symmetry to each other, as if the basic construct of these two force carrying entities were inverse of each other

[@rubenanthonymartinez7034]

Wonderful, it proves that you can make a living out of possibilities, science based on futility!

[@tnekkc]

Shh! don't tell him. He wasted his life.

[@charllescarrrera625]

Just wondering is are shadow dark matter they say dark matter can just past trew any matter and it might be a just one of more dark matter particles

[@whtbobwntsbobget]

We're whalers on the MOON We carry a harpoon! But there ain't no whales So we tell tall tales And sing our whaling tunes!

[@4or871]

Combine: 1. cosmological constant 2. schrodinger solution 3. Planck E= h f= h n 4. n = number of superpositions And you get dark matter n^2 h^2 / ( 8 m L^2) = h n m = 0.3313 10^18 10^-34 = 0.3313 10^-16 kg ( all superpositions). 1 particle = 0.331 10^-16 / ( 0.4 10^18) = 0.828 10^-34 kg = 46 eV If you count only the positive wave function amplitudes: n = 10^9 then dark matter = WIMP m = 46 GeV

[@rkreike]

To understand why there must be more gravity in galaxies than could be explained by observable objects, F. Zwicky came up with dark matter, around 1933?. He predicted that there could exist something as neutronstars, later observations proved him right, and since then there have been observed many more objects in the universe that were previously unknown?

[@terrywallace5181]

Can there be dark matter black holes? i.e. dark black holes?

[@davidwilkie9551]

Mathematically, DM is the zero-infinity ground state of a selected "Gravitationally bound" volume of timing orbital spacing, aka Black-body Singularity, resonance-location(?).

[@joecaner]

It is a placeholder that balances our current theoretical accounting, AND It is gaping hole in our understanding of the nature of the universe. In other words, we do not know what or if it is.

[@ronaldsanchez1341]

i was taught these two equations in jhs; p=m/v and v=ma... then why can't you figure these into your question of why the universe is accelerating?

[@TheSophisticatedFrog]

i LOVE stodinging dark matter now just because of you. thank you. :)

[@r107560sl]

sadly, he can't prove jack shit!

[@thomas.02]

If gravity is not an inverse-square law but rather some inverse-[some higher degree polynomial?] law, would that explain the expansion of the universe and dark matter? More importantly, what kind of evidence would support this?

[@rubberbites619]

This would cause a lot of instability to planet orbits and we know for sure it isn't true. Subtler modifications of gravity theory, however, may explain dark matter and dark energy. These modifications are called Modified Newtonian Dynamics, or MOND. They are not mainstream, but they are from real physicists. If you are interested, there is a wikipedia page for it.

[@xxoopusiecatooxx]

Thomas Chow Pretty sure they have already experimented with that. It wouldn't explain shutting if it did. All it would produce is a mathematical equation explation, not a story on it's origin.

[@adriang.cornejo4800]

The paper where is described a solution of the rotational velocities observed in spiral galaxies, without using dark matter (but adding the Coriolis force in the rotating system, from the General Theory of Relativity), is the following (from 2020): article.sapub.org/10.5923.j.astronomy.20200902.01.html

[@timothykieper]

"Dark Matter" Or, The dog ate my homework.

[@Nothing_serious]

But does it energy?

[@showmewhyiamwrong]

Maybe the fact that we call it "Dark Matter' leads us down the wrong rabbit hole when looking for it. Essentially, as far as my limited knowledge takes me, we think that DM exists because of its observed effects on a given region of Space appear to be the same as what we would expect to see from Normal Matter and this may very well be a logically correct assumption, but maybe there is another path. What if Spacetime behaves the way we see it behave due to other influences of some process or processes arising when a localized region of Spacetime is subjected to a critical level of influence from say a certain amount of NM by itself or in conjunction with, or in the absence of, some critical level of NM as yet undetected which replicates what happens to Spacetime when NM is present Volume. You would be looking not for DM itself but for a correlation between the observed amount of NM and the inferred amount of DM on a given region of Space. So you take measurements and plot results one against the other. The thought behind this is that yes Space reacts to NM in a gravitational way but does it react gravitationally uniformly to NM on very large scale. I don't know maybe it does and maybe it doesn't. Since we know almost noting about the nature of Spacetime itself we are possibly missing a very important piece of the puzzle. What if Spacetime itself has a property equivalent to what we think of as Density and that Spacetime Density is influenced by the amount of NM in a given region of space in way which causes space to bend in an amount greater than would be expected from the amount of NM present or thought to be present in that region.

[@smartscience5305]

In which grade will learn about dark matter and dark energy ??? I am in the 7 th grade and I finished learning quantum physics and dark !matter and dark energy....

[@noelharrison902]

is the aether an archaic description of dark matter or is dark matter an archaic description of a higgs boson, lol, when did james maxwell postulate his theory? he most likley had a pencil a notepad and a sliderule, how much did the LHC cost?

[@samuelrodrigues2206]

scientists are neatly explaining how they can't explain it

[@alexkregel8915]

Dark matter could be astral matter. It would fit, mirrors normal matter, little interaction with normal matter most of the time, due to coexisting in the same space, and it is not detectable in the visible light spectrum. It would be relatively easy to prove this and make future expermtashion easier. If astral mater is dark mater than replace isolate the signals from projector and recreate.

[@alexkregel8915]

We also assume the speed of light is constant and therefore the speed of obsevable light is also constant. But light shown was in an arc or seen threw a lens. Therefore this throws off the calculation. Because distance/time gives you speed. And if light is affected by gravity and does not slow it down but only bends we assume that currently. And a black hole constitutes the center of that galaxy than their would be a larger bending of the light at the center than the outer edge. Therefore the speed discrepancy would be because the speed of purely obsevable light from point a to point b would not be a strait line at all times but a curb dependent on gravity.

[@sean007smith]

The only problem I have with comparing the rotations is the planets rotate around a central mass the sun. While the black hole is heavy not heavy enough for the stars to rotate around it. So in my mind the mechanics are different in a big way.

[@sean007smith]

Great lecture btw

[@elijahyousefcorachea6583]

Every question has matter in it

[@tresajessygeorge210]

THANK YOU ...!!!

[@williambeck5678]

Furthermore as each quantum field spins it creates a shell of magnetic energy. The resulting field would follow the field as it spins remaining immortal throughout all dimensions and tie all the dimensions to one time and gravity.

[@nancywoodellmccracken9136]

Dark matter is some form of matter, got it. I absorbs or reflects light but does not let light affect or something, what form are you talking about?

[@timmytim9054]

It was mentioned that radiowaves and gamma ways would be classified as dark matter but these frequencies come from stars.

[@aussietaipan8700]

Fully understand BH's and we will have the answer to DM and DE

[@royrasmussen9738]

Thanks

[@darwinlaluna3677]

Ok thanks have a wonderful day