Very clever to have that pie on hand. Otherwise we would never have grasped this so-called "three-fourths" concept.

Part of that pie represented itself o_O

I want that pie.

Wow everyone is so young! Just came across these channels recently, and wish I had found them earlier! Love everything you do!

Does dark matter have a dark periodic table?

Never thought a video of dark matter could make me hungry. Seriously the first three minutes i only heard pie, pie and pie.

Had a smoke before this and all I could think about was the pie

Astronomers have thought of that, but even if you add up all black holes, cold gas, brown dwarfs, etc, it just doesn't give you enough mass to account for dark matter.

just eat that pie already

Id like to see an update of this video where we get to see the ten years of progress from then until now.

That Pie is very distracting.

She really does have an impeccable speaking voice. I love listening to her explain things.

Where is it? Its dark you can't see it.... lol ...sounds so Monty Python the way he said it XD

My astrophysics professor always said that dark matter: "is a real bitch" lol

8 years later and I still think about that pie.

"What would happen if I drove my car into a big clump of dark matter?" This is what makes your videos relatable!

This video made me hungry. I'll tell you what. Since you're not using the dark energy, why don't I...dispose of it for you.

I love all of the Brady channels....absolutely fascinating.

Where can I find the recipe for dark matter chocolate pie? Or there is no way of knowing it? :)

Dr, Gray is absolutely endearing!

If it is gravitationally interacting with itself as well as normal matter, why isn't dark matter "lumpier" than is apparently observed? Normal matter is very lumpy. And as it apparently has mass, and there's about six times more of it than normal matter, why hasn't dark matter formed "dark black holes"? Or has it?

I thought the first slice was a third of the pie, but what do I know?

I'm not an astronomer, astronomy is for me just a hobby, but it makes me think of all these posibilities, and these videos help me understand all sort of things, and the real scientists that do the explainig part, they do it in a way that is easy for everyone to understand it all. So, thank you, Sixty Simbols :)

I love all of these guys, and they're all incredibly humble and intelligent people, but let's all take a minute to appreciate Brady Haran - not only for making these videos in the first place, but because though he remains behind the camera and out of the spotlight he proves himself to be as smart as any of the rest of them because he fearlessly and consistently asks the right questions. Thank you Brady, and all of the rest of you at Sixty Symbols/Numberphile. Keep up the wonderful work!!

I love the quote from time stamp 10:11 to 10:23.

Umm...that piece of dark matter looks delicious...

Great video! I must admit the moniker "dark" matter made me think of something like soot, but you make it clear that it difficult to detect - "elusive"! "They seek it here, they seek it there..." Pimpernelium?

In one version Membrane theory, dark matter is just gravity wells from normal matter in a nearby universe. I equate it to having each universe on a sheet of paper and drawing on them with a ball-point pen. The drawing in the paper is matter, and the indentations are the gravity wells. When you lay one "universe" page on top of the other and then draw "matter" onto the top one, you can see the "gravity well" indentation on the bottom page(our own universe). It makes sense to me.

i was just talking with a young lady teenager and she asked me what i was watching i showed here the screen grab of dr gray(i think thats her name?) i told her she was a cosmologist ,and she said ohhh she works with makeup.....priceless

So, basically, we're still stuck with an aether.

What makes me not repeating it repeatedly is the guaranty that I will repeat it as a whole!

I liked the unsophisticated thumbnail of the chocolate pie! The simplicity was in such contrast to the matter at hand... (any pun that could be derived from this was not intended).

Am I the only one who thinks that woman is breath takingly gorgeous?

Brady or someone from the Sixty Symbols team: I love your videos! I'm a high school science teacher in an American international school in China and you guys do a great job of making things visual and accessible for my students! Some of my students had really good questions about dark matter (very proud of them), and I was stumped! Does dark matter interact with black holes? Black holes collect mass around them because of their tremendously strong gravitational fields, so shouldn't we also see black holes becoming more massive several times faster than we can account for by monitoring their intake of "normal" matter?

I've a few suggestions what dark matter and dark energy are and i bet that people are already thinking about this: 1. broken gravity or free gravitons in spacetime. 2. particles too small to detect 3. psi phenomena emitted by nonliving and living things 4. spirit realm that exists in another dimension (i know people are smirking at this but options are still options)-ghosts sometimes interact with electromagnetism but are mostly not present in our universe.

8 years later I am still looking at the pie.

I see the Crips have started to diversify their activities.

Are your sure the dark matter isn't a combination of quarks that is neutral like 2 strange and 1 charm?

From what I understand, it's because the dark matter doesn't interact with itself or regular matter through electromagnetic forces. If you look at what happens in something like an accretion disk, the matter ends up colliding, which causes it to tend toward the center. With dark matter, it's more of an oscillation. You can see this effect easily if you look at the bullet cluster. The regular matter slows down from EM forces as well as gravity, while the dark matter just slows from gravity.

I loled so hard when she places the cake on the table after she cut it.

so dark matter is made of dark chocolate, that explains everything.

The biggest problem I have with the dark matter theory: Why doesn't the dark matter affect planetary systems? If there is dark matter permeating space all throughout a galaxy - enough to pull stars around at high velocities - why is it not affecting planetary orbits *at all*? Why can we completely explain the orbits of the planets with conventional theories? We only needed this idea of dark matter after observing the orbital motion of stars. Well after we had explained the orbits of the planets quite accurately. Why does dark matter seemingly only affect the orbits of stars? Perhaps this is explained within the theory, but I've never heard this question even asked.

That computing farm was neat. It's crazy to think that in a decade or two, all of that computing power will probably fit inside your phone in your pocket.

The energy potential of that pie is so large, that I can smell the chocolate even trough my screen!

the Kripps have a computing centre to simulate full universes of dark matter? wat..

That pie.

"... a vision of the universe that tells us, undeniably, how tiny and insignificant and how rare and beautiful we all are..."

Holding that pie near to ur mouth and not tempting to eat needs dedication from some other dimensions

I NEED THAT PIE! It looks.... NECESSARY!

Mmmmm... dark choc.. ehum.. matter :-)

I am not a physicist. When a gas cloud collapses, the atoms are spaced far enough apart to experience almost no friction. As they are drawn in to a common central area they are moved close enough to increase the probability of collision. These collisions transfer the kinetic energy from external (velocity) to internal (heat). If that didn't happen, then the particles would just rubber band backwards and forward. No collisions = no energy loss due to heat. 1/2

My guess is it probably does, but it has to interact with something we can detect in order for us to detect it. Think about 2 invisible people. If they silently shakes hands, we wouldn't be able to tell if they are in the room or not. But if one of them picks up an object (interacts with something that we can see/detect) we will know that the invisible person is there. Hope that's helpful/the kind of answer you were looking for.

What was the rest of the pie?

Physicists: The is no aether! Years later... Um, there is dark matter and dark energy, and...

I could listen to Dr Gray all day.

As far your question of how i would explain how a galaxy separated from the dark matter, my best guess would be that a majority of the matter in the galaxy had already been absorbed into a central black hole and that black hole didn't have a large enough sphere of gravity to maintain a hold on the dark matter around it. Some of the dark matter stuck with it as it gained velocity during a stellar collision, but a majority did not. That's just a guess, but it's better than your guess.

Sixty Symbols What if dark matter is a particle with absolute zero temperature? It does not react with other particles nor emit light because it cannot, but it still has gravity. You should measure dark matter at your laser cooler experiment. ^(Do I get a Nobels prize for this idea)

Blood's better step it up. The Crips already got super computers.

Dark matter is the darkness shield, like a curtain, the mechanical elves use to conceal themselves as they constantly work with their little space hammers to fine tune the universe and to tug on the strings connected to all the cosmic bodies.

The possibilities are endless. And its irony that prevails in these kind of cases. Everybody is looking up while they might be next to us..lol.

Dark matter is assumed to exist because our theories brake down when trying to explain how galaxies stay together without it. Could it not be that our theories are just wrong?

I found some dark matter in my toilet earlier... xD

wow this completely blows my mind, please keep us posted on this subject and also bring us up to speed with dark energy story, Thanks, David.

A theory should explain the interactions you observe with as few assumptions as possible. My theory (plasma-electric-universe) makes only two assumptions: 1. Protons and Electrons are objects which represent the elementary charge. 2. The electromagnetic interaction is based on the elementary charge, it's only one force. Neutrons decay to an electron and a proton, it is a composite of these two elementary charge particles. The EMI-Theory explains everything, redshift, galaxies, solar system etc.

We don't know if dark matter really exist, we only know that galaxies are rotating much faster than their mass should allow.

Nobody can see that dark matter, nor can detect, measure, prove, affect, etc. But at that the physicists know for sure and tell exactly how much space it occupies and gravity it has. How can one assert something about anything if one knows nothing about it at all? I wonder if the physicists ever were struck by the thought that their knowledge of the universe is near the absolute zero.

The "Vacuum Energy" effect of stiffness or hysteresis has an equivalent in water, in that warm moving water is "softer" and more yielding than cool still water, and the same applies to the atmosphere, ..and thixotropic fluids of any type and scale are a property of synchronization, which blends in with mass, gravity, momentum and large "objects" astronomically (?), inertially-gravitationally bound or "congealed". (Like chocolate pudding)

Cool stuff, good brain food.Dark matter sounds like skimming stones over water at the beach, but you can't see the stone. Each time it hits the water we see the ripples but never the stone. Cool.

Smart attractive female physicist/astronomer with chocolate pie talking about... er... I got a bit distracted 😥

Love this girl....unlike emancipated american whores she does not need to shout or take an aggressive stance to prove a point and garner attention. She is just smart and cute.

I feel that DM is leftover aftereffects of comprehensive dynamics placed on past conventional matter as humans understand it.The most difficult part in understanding it, is how DM's interreational status compares with standard matter as we know it.I feel that expressively this would be categorized as base weights measurements based in a comparative quantitative survey.

To answer the car collision question (assuming gravity is negligible) nothing would happen because dark matter has no charge, thus no electrons repelling each other and stopping one material from passing through another, which we perceive as a "collision"

why are they presenting this as a 'fact'?

My thought as always been, instead of dark matter to explain why galaxies are spinning strange, what if we delved deeper into gravity? What if there is more to the gravitational constant? What if it was not a constant at all, but a group of variables that we do not understand because in our solar system its the same variables, and its not until you go out further, that new variables are used? That's just what is floating in my head, but I hope it can get tested someday.

lol...you're right. And I would say they are "technically" air cooled, since none of the water cooling parts are on the electronic components. I would assume the "more parts, the more likely a break", or leak in this case. So they wouldn't "water cool". Just my opinion.

1 theory is that although dark matter can create a gravitational effect for regular matter, it may not attract other dark matter particles the same ways. Regardless stars run on the fission of atomic nuclei which not something shared by most particles know today.

I wish I were smart. So much of this stuff I can grasp at a conceptual level, but it eludes me. Especially the idea of general relativity. How time moves slower in other time frames, like a rocket speeding by is something I will never fully grasp. Like this dark matter thing. I just have to assume it to be true and move along with my life.

What we identify as dark matter shares many characteristics with neutrinos. One considerable difference, though, is that dark matter particles is predicted to be quite massive, but neutrinos barely have any mass at all. (The standard model predicts neutrinos being massless, but experiments have shown them to have a tiny mass.) Thus the the neutralino is instead offered as an explanation for dark matter. The problem here is that supersymmetry is having trouble showing itself at the LHC.

a physics professor from my university once argued passionate that a much better explaination for the observations that lead to the assumption that there is dark matter would be a quantum theory for gravitation. i cant remember the exact argument but he talked about how the additional gravity from the dark matter only seems to exist in these huge galactic scales of thousands of lightyears, influencing galaxy formation but beeing negligible on the scale of our solar system for example.

Neptune is pootling along very slowly!

Buddy asks excellent questions.

GOD DAMN!!! I come onto KZfaq to help me forget my chocolate cravings and run into this video!

The Astronomers and theoretical physicists seem by far the nicest people you speak with Brady.

This lady is super nice and an excellent speaker as well.

Anti-matter is essentially matter, but with opposite electrical charge. It thus fits in to the matter part of the pie. It probably isn't too far fetched to assume there exists anti-dark matter as well as well, but this would then fit into the dark matter part of the pie. The point of the pie is to show the total energy density of the universe, one can of course split the parts in to matter/antimatter, but it is essentially pointless, because they have the same traits.

I have one problem with the theory of dark matter existing while interacting with itself and with gravity. The problem is that it would, in the same way as with regular matter, converge in very small spaces and form dark matter back holes. Now if those existed we would be able to observe them in much the same way we observe black holes consisting of matter, and with the ratio of darkmatter to matter being so high you'd think they'd be more commonly observable, and also by conventional methods.

There is much more observation and interpretation necessary. But to give you an example for EM interactions. The Coulomb-Force is 10^36-times stronger than gravity, so even an infinitesimal small amount of EM forces overwhelms gravity. You can't see electric or magnetic fields, what you see are currents build out of real matter in plasma state. Electrons orbit, if a magnetic field is present. At the same time, these electrons generate a magnetic field. That's called electromagnetic induction.

If a dark matter unit is in line to come into contact with a conventional piece of matter, say an electron, something extraordinary happens. When it's within a plank length it disappears into a separate dimension or universe or what have you. It then reappears a planks length away on the other side. Since light behaves like a particle it does the same to photons. Hence its visual imperceptibility.

Thank you for all those wonderfull video's. I'm a teacher on high school in the Netherlands, so this is far from my daily work. But I love how it trains my brain. I started to get interested in these kind of video's, when I say a documentary on the Fermat theorem a few years ago. Now I ended up here. Sorry for my poor English. It is not my native language.

From what I understand, some/most Data Centers use a hybrid water-A/C cooling unit for their servers (basically a refrigeration unit cooling the water that's used to cool the air...i believe). But supercomputers are so advanced and different in such ways, I wouldn't have a clue to what would be best...like hot water?

The name of the lecture that explains why the sky is blue during the day and red at sunset is called For the Love of Physics - given at MIT.

so, yes, in our solar system for example, neptune is orbiting very slowly compared to mercury. and will keep orbiting slower than mercury even if the sun was 2x massive. the only way to speed up neptune is to add so much mass to it, to let him interact stronger with the sun. the problem here is not the sun and its mass, but neptune. small and distant.

"Pie-hungry" a special kind of hungry requiring it's own category.

Brady, we need an update on this video! The LHC might be able to elucidate the identity of Dark Matter and I'd like to hear the profs talk about it.

One of the reasons why I watch this video again and again is, beside it‘s great, this fuckin awesome lookin pie..

Having just watched 6 Dimensions, Extra Dimensions, and Dark Matter back-to-back, it seems an obvious suggestion that the anomalies we see in gravity distribution would be caused by something going on outside of our 4 observable time-space dimensions. Perhaps a video to explain how this compares to the hunt for exotic "dark matter" particles?

As far as I know, there aren't any holes remaining to be filled in the Periodic Table, anywhere up to the transuranic elements. Thus, the only *new* elements we could still discover are the super-heavy ones... However, these elements are extremely unstable, with very short half-lives. Obtaining them is only possible in the lab, and only for a limited time. There is a theory which claims that, beyond a certain super-heavy range of unstable elements, an "island" of stability may exist...

I just found an article about the possibility of the confirmation of Dark Matter by the particle collider on the International Space Station. Hopefully Brady does a video about it.

What I is that there are many different types of matter, all interacting with completely different forces, and dark matter is simply all the types of matter that aren't the same type of matter as us.

The more complex a system is, the higher the probability of something failing is. It's better to keep vital systems simple.