What a great time in human history to be alive. Sometimes it's not the answers a generation comes up with, but the questions they ask that matter. Keep up the good work and don't fret the sound issues.
I’m so glad YT suggested one of your videos. You are instantly one of my favorite physics channels. Your presentation style is so natural and clear and balanced. It’s the right amount of simplification such that I can (mostly) understand the subject matter with enough scientific information that I actually learn something. Fantastic job.
😁😁😁 agreed. It makes me feel a lot better about stumbling over my words in love presentations to know that brilliant people do too! It’s sometimes hard to avoid comparing my raw output against the edited videos that get published on RUclips.
Even as a layman, I'm so intrigued by this channel and everything you cover. I may not understand it all on your level but it's still fascinating. I could watch this stuff all day.
@@Hailfire08 Is it compressible if you can't actually compress it, I was wondering. But I guess it gets pretty compressed orbiting a black hole. That's probably the only circumstance since the Big Bang, I'd imagine.
@@akizeta Well if you had some way of compacting it, it would be very easily compactible. So I guess a small black hole would do, since it'd pull the dark matter into its small but deep gravitational well...
Superfluid He is weird as fuck. There's video here on YT that shows different experiments with it. In some it acted like it was frictionless (0 viscosity) but in others it didn't. ruclips.net/video/sKOlfR5OcB4/видео.html
I'm an aspiring astrophysicist and plan on someday getting my degree in astrophysics, and i spend all my free time watching these videos because they are so informative! Thanks for providing such great information!!!
5 лет назад+89
So, the "Betteridge's law of headlines" also applies to peer-reviewed papers :D
Well my PhD title was something reminiscent of "combined mass transfer in a small scale plain piping system with a normal water bath". So no. (I have changed the actual title because you would be able to easily dox me if I said the real one).
Once i saw the title i just realized "Why'd i never think about that before". Thanks for making this video, was not the conclusion my gut reaction expected. I expected the majority of matter to compose the majority of matter that goes into black holes. But your explanation made it very clear why we shouldn't expect that to be the case. I hadn't known dark matter was collisionless, but that makes sense. If dark matter is made of multiple different types of particles is it possible some of them are collisional but just not what composes the majority?
Ummm, hate to break it to you but dark matter being "collisionless" is 100% pure speculation. It took her almost 13 minutes to finally say so, we really have no clue and these are not only pure guesses, but they are guesses on top of pure guesses extrapolated from pure guesses...
MrWildbill47 The gravitational lensing measurements of the galaxies colliding seemed like pretty strong indication that dark matter is collisionless. Is there some way to explain that result in which dark matter is collisional?
Dark matter is collisonless if it's matter. But confusingly the Term "Dark Matter and Dark Energy also include ideas where it's not matter or energy. So if Dark matter is some sort of effect gravity has on space time we are unaware of yet there would be no collisions.
Just found your channel; this video impressed me so much I instantly subscribed. I love how you make the tough stuff, the questions being asked in these papers, readily available and easily understood by those of us not in the loop! Looking forward to checking out more videos!
I just wonder, what if Dark Matter isn't particles at all? Nor even close in the dimensions of particle accelerators? Maybe it's some sort of gravitational waves that are locally intertwined or some other mass bearing phenomenon of spacetime or another field we don't yet understand?
Dark matter has always been one of those things that up until this point felt to me personally less like astronomy and more like (shudder...) astrology. But listening to your attempts to sort out and understand how something as yet still poorly understood as dark matter into a very practical and very real explanation as to how it would interact and behave in a much more understood and observed setting are absolutely fascinating for one. And more importantly for myself, allowed me to more firmly grasp the concept of dark matter as something actually real and observable, at least theoretically and to a limited point. But far more real for me than when I started watching this video. Well done! Thank you!
The answer to a question in a title/headline being no is called Betteridges law. It's intuitive when you think about it, neutrinos are also weakly interacting, don't form accretion disks, and likely have the same low probability of passing within the schwarzschild radius.
It makes very little difference, but for some reason i find it really pleasant to hear a british voice explaining science for a change. I seem to follow all the american science channels. Subscribed, and totally not biased.
@@RurikLoderr yeah I am aware of that, but that is why scientists are trying to detect dark matter, formulate alternative gravity theories or try to get rid of the neccesity for it. Anyhow, I am excited to see how this problem will be solved!
I like that you do a great job explaining complex topics in a way that is very easily follow. Also cool how you bring in studies by others. Interesting how your videos teach about the topic but also about the study behind the topics. Of course the outtakes are great as well 😄 Nice work! Subscribed!
Since we infer the existence of Dark matter by its gravitational interaction with normal matter, that would seem to imply that it would still feel the gravitational attraction of a black hole. Further if it can't loose it angular momentum via collisions and thus can't fall into a black hole, then would Dark matter pile up around a black holes due to being attracted gravitationally and but being unable to fall in?
How would the dark matter wind up in a low orbit like that to begin with though? I could imagine a stellar mass black hole capturing a clump, or cloud, or whatever of dark matter the same way a star would capture an asteroid, but what force could make that orbit shrink further from there?
M_Chupon I am not envisioning it piling up at the accretion disk but more on a larger scale. I was curious if overtime more and more dark matter would migrate toward the vicinity of a black hole due to gravitational attraction. If this was the case I wonder if on a larger scale the attraction due to dark matter and that due to the black hole would begin to function as one.
no. if you're collisionless, being attracted doesn't mean you stay there. you swoop in by whatever happenstance, then your enormous velocity gained makes you swoop off. we're so ingrained to think of attracted things going splot and losing their momentum we don't notice everyday "attraction" is two things, attraction + a lossy interaction that doesn't apply to dark matter
Add mass. Black holes don't care what they eat, all that matters is mass, spin, and charge. And the only thing that they do is they change the properties of the black hole by adding the properties of whatever went in - a charged object will make the black hole slightly charged, for example.
No, antimatter=opposite charge, same mass. So the "anti" just refers to charge. When a particle and its antiparticle "collide" they give off 2 times the particle's equivalent mass energy
Only in the VERY rare case that the particle/antiparticle pair are created at the event horizon under such conditions that one is inside the event horizon and one is outside. Simplified: The energy to make both particles is "borrowed" from the energy of the vacuum of space. Energy can be borrowed from the vacuum due to the uncertainty principle, where uncertainty of energy times uncertainty of time is equal to the modified Planck constant. Since the event horizon is preventing the particles from ever meeting up again and giving their energy back to the vacuum, the energy loan for both particles is paid for by the black hole (when this happens the "virtual" particles become "real"). Notice the black hole only gets to collect one particle's worth of energy back so it is at a net loss. This is Hawking radiation. Nothing inside the black hole ever escapes besides this type of energy bookkeeping.
Loved the video! Clear and to the point but without forgetting to quickly explain other stuff like gravitational lensing. And you're good to listen to as well.
This is the first video that I've found on this channel, but I already know this Dr. Becky is a great place to go for physics. The information is simple yet profound, the script is very natural, which makes me think that you know a lot about the subject you're explaining. Also, the ideas for the videos I've seen so far seem to be varied, thought-provoking and original. One thing: invest in a camera. I know you've probably got this often, but if you do invest in a camera, you'll be all set! I know that it will cost a lot, but I find that upgrading your kit will be a big step forward for this channel. I see a stellar future for this channel, good luck!!
I've actually thought of black holes growing from dark matter too, but i figure the professional scientists would have thought of that already. Does dark matter not collide with itself in a hypothetical dark matter accretion disk? For that matter, would there be dark matter "stars?" Just balls of dark matter that doesn't glow, but has an unexplained planetary system or system of gas and dust around it? Hard to detect for sure since its not something you could see in a telescope until it birthed a star of its own.
From what I understand, Dark Matter doesn't clump up the way regular matter does. Since it doesn't seem to interact with itself, it tends to stay in those Halos that Becky mentioned in the video. Also, if the hypothetical Dark Matter Star had enough gas and dust around it to form a planetary disk, the majority of that matter would probably condense down into the dark matter star and become a regular star.
@@NatalieNirian Ah okay so it doesn't self-interact either. Thanks! And yeah that was what my "birth a star" comment was referring to, because eventually the regular gas and matter itself would form a regular star, so when you finally see it it would just look like a regular star system.
Improved audio would have made this video much more enjoyable. I almost clicked off in the first 5 seconds based on poor audio alone. My curiosity of the title kept me here, but I assume most missed this interesting video. All other quality metrics are great! Subject, Editing, Camera. I look forward to the success of this channel and enjoying more content. ;) Edit: I just watched the last few seconds that you say your mic battery died.
Doesn't dark matter orbiting black hole lose energy via gravitational radiation or is this so slow process that it does not matter? If so, this does bring up interesting question. Which one happens faster: black hole evaporation via Hawking radiation or dark matter absorption due gravitational radiation?
I had the same thought. In the paper that suggested up to 10% of the mass could be dark, was this due to the dark matter bleeding off energy via gravitation waves, or how does even 10% end up dark? Or was this 10% just due to the "ideal" initial conditions?
Not just gravitational radiation. There is gravitational attraction between the flow of "frictionful" matter which emits its energy and frictionless dark matter which doesn't. They form a mechanical system which as a whole loses energy. As soon as there is difference in velocity of the two, the kinetic energy of faster flow will be drained by slower flow, and then it will be lost by friction in the slower flow. Admittedly, dark matter loses energy at slower rate though, but with steady influx of ordinary matter into accretion disk, amount of captured dark matter increases too. Vice versa, with great amount of accumulated dark matter orbiting the black hole, we will observe an incredible amount of energy radiated by collisions of ordinary matter, with it apparently losing very little of its kinetic energy, as it's energy is replenished through gravitational interaction from huge pool of dark matter orbiting the event horizon.
@@salec7592 ah thanks, that makes perfect sense. I had figured that gravitation waves would have far too little an affect to significantly effect the dark matter. But normal matter acting as a 'break' explains it.
Just a general comment, Dr. Becky...I really appreciate your videos, you explain things so well and it's exactly in the range of understanding that I look for in these subjects. Your qualitative and visual approach to describing cosmic phenomena is very clear. Keep up the awesome work. I also love the outtakes!
I asked a question along these lines several years ago, and the only one time I got an answer was by someone that totally misunderstood what I was asking. I have emailed physicists and commented on youtube videos, and no one ever came up with an answer, and as I don't know the physics really, I don't even know if I am just failing to understand. I titled my question "Stable Pulsar's disprove WIMP model of dark matter" Points: 1. WIMP's would travel far below the speed of light to be able to stay roughly connected through gravitational attraction to galaxies, anything traveling at the speed of light would not stay bound to anything other then inside a black hole, so there could be no dark matter halo. 2. We don't see neutron stars and or pulsar's that appear to gain mass and eventually collapse into a black hole on their own. 3. There are many paths for any given object in the presence of a strong enough gravitational field, and not traveling at the speed of light, a set of paths that will leed to capture of that object into orbit of the the strong gravitational field. 4. A portion of dark matter WIMP's that cross paths with a neutron star, even if they manage to not interact with the basically solid matter ball that it is, could end up in orbits, likely below the surface, of the neutron star. 5. No matter how non-interacting they are, they should over time build up in mass inside the star, eventually pushing it past the mass limit for a black hole. 6. And or conversely, they do interact enough, that the stars should gain heat and only ever get hotter and brighter the longer the exist, due to the interactions with the WIMP's
I barely understand a tenth of what you are saying, but I love the enthusiasm. What is your take on quantized inertia? (no dark matter at all, just a Hubble scale casimir effect)
@@lordgarion514 I would still like to hear what she has to say. There was an alternative explanation posited by Mordehai Milgrom. We have been looking for dark matter for ages and still haven't found direct evidence. en.wikipedia.org/wiki/Bullet_Cluster
@@hibiscus779 So what you're saying is so we need multiple theories instead of just one? And just so you know, it took about two and a half decades to find the neutrino from the time it was first theorized. Not to mention, the very beginnings of quantum mechanics go back to the mid-1800s, and we still aren't even close to having that all figured out. It's a little stupid to start talkin three or four theories instead of just one. Also, if you'd actually read that Wikipedia article you would have realized it said it doesn't get rid of the need for all dark matter. But then they go next level stupid and say they "expect" that to be ordinary matter we just haven't found yet. You should probably try thinking about this a little bit more.......
@@hibiscus779 Forgot to mention, in the bullet cluster the effects that we call dark matter only exist in the galaxies themselves. There is no effect of dark matter inside the gas cloud in between the galaxies even though there is more matter(and US gravity) inside the gas cloud then and either Galaxy on its own. Which means any explanation has to be able to turn the effect that we call Dark Matter on and off, even at the scale of entire galaxies. No one who talks about either MOND, or QI has ever explained how it turns off in a bigger Galaxy worth of matter, but on in a smaller Galaxy worth of matter.
@@lordgarion514 no. I mean, I would like to hear Becky talk about it :) I heard Anton Petrov's take on it and found it fascinating, but I believe he lacks Becky's credentials. ruclips.net/video/VYdebV9YlnI/видео.html
I think that it is because orbital mechanic- when you encounter dark matter it is accelerated to star, but it means that it will have huge speed near star and just fly away. In two bodies orbital mechanic you cannot change type of orbit (elliptic or hyperbolic) with just gravity. Orbits are symmetrical- if matter goes into sphere of influence with speed X it will leave SOI with speed X. Same way we do not have thousands of moons around Earth, because asteroids come and go. Or with Oumuamua.
Perhaps because of conservation of momentum? If they don't collide then there would be no momentum transfer thus the dark matter would probably just pass right through. Of course any dark matter particles that wander into something moving at velocities greater than the masses escape velocity could presumably be trapped in bound orbits of course dependent on what dark matter is.
Syriusz B As the black hole (or star for that matter) orbits the galaxy I think it's conceivable to capture dark matter into some sort of orbit with one of those backwards gravity assists? If that *is* possible the orbit would probably be very elliptical.
@@m_chupon5131 Yes, it is possible, but very unlikely so we do not have much of this. Not enough to see it at least (as gravitational disturbance, lensing would not work here I think). To capture something with gravity assist everything have to be just right. And black holes would be much likely to capture black matter and since it is very rare according to simulations, it is even rarer with regular solar systems.
It's kinda the other way around, everything is donuts. A black hole is just the side of a donut that is facing this Universe. At the singularity of a black hole spacetime turns inside out so the other side of the donut that we don't see, ie "inside" the black holes event horizon, those are the big bangs of other Universes. Consider that we can look 13 billion lightyears in any direction, but instead of a sphere 26 billion light years across, the edge of the visible universe is a single point 13 billion years ago, so this Universe is inside out too!
Wikipedia states that donuts have their origin in the beginning of the 19th century. The nearest black hole is 1120 light years from earth. Since donuts don't travel faster than light, black holes don't contain donuts. ...barring of course an infinite improbable scenario that a complete donut has spontaneously quantum tunneled into one.
Besides the answer "we don't really know" it seems the current papers are saying that we don't expect significant amounts of dark matter to be captured by black holes. The reason I hear in this video is that dark matter doesn't strongly interact with itself or with normal baryonic matter through the electromagnetic force. This weakly interactive behavior stops it from clumping like normal baryonic matter so it doesn't lose energy and fall into black holes, or stars, or planets. This is quite non-intuitive but if there is no electromagnetic interaction (friction) to slow things down, a piece of dark matter would travel right through a star or planet as if it weren't there. Gravity would speed up as it approached the center of mass and slow it down as it passed by until it was back to the initial speed it had before the interaction. Unless it were on a collision course with the event horizon (where it would be stuck in the black hole), it would follow a parabolic path around a black hole and continue on its merry way. This is why so little dark matter is captured in the black hole. Thank you so much for explaining this.
@@derlinclaire1778 yep... Scientists of today should take a cue from the great Richard Feynman here... Try and have a look at "Quantized Inertia" or "QI". Its a "so called" fringe theory. But it is a much better model than Dark matter. QI can even explain binaries that are very far apart. Dark matter cannot explain this.
What an odd way to admit you don't understand the math. for the record, the math is DESCRIPTIVE, not PRESCRIPTIVE. As such, it's not fiction, and isn't nonsense (unless you have something actually useful to enlighten us on). Buy a couple books mate.
It is, on its face, the dumbest model in current physics. It is the aether of our generation of science. Hopefully we can one day get rid of the model and replace it with something better, and translate things like this video to the new model.
Regardless of what you call it, there is a physical interaction in the universe that functions the same way as gravity. The "matter" part is speculative but since mass is what makes gravity it's a fairly natural title for the unknown agent responsible. Dark is simply an accurate descriptor that we don't directly perceive it visually. While we can speculate about its exact nature quite a lot, imagining it not existing would require contradicting more physical evidence than I'm personally comfortable with. YMMV.
We don't know if dark matter is a "thing", but we definitely know there is an extra source of mass in our galaxy which isn't accounted by the total mass of regular matter, given our understanding of gravity. That unknown source is called "dark matter". Because we cannot see or interact with it, but we know it's there, since we have observed that it exerts gravity on regular matter.
@@esdev92 Not just on matter but also light. You can view it indirectly when a region of apparently empty space causes gravitational lensing. When that happens we see Einstein Rings, almost like rainbows, from the defracted light. This might just be a "humans are visual creatures" thing but personally I find being able to see it, at least indirectly, to be the most persuasive evidence.
Very easy to understand explanation. Dark matter has to lose energy in order to be drawn in past the event horizon. I wonder though if there are quantum effects, such as virtual "particles" to where one virtual dark matter "particle" would be drawn into the hole while its entangled twin did not. Yes particle physicists hurry up why don't ya! I am now a new subscriber Dr. Becky. Thank you!!
@@thishandleistacken , lol, triggered fanboy is triggered. Neil De Grasse Tyson and wikipedia? seriously? The problem with stupid people is that they are too stupid to know how stupid they are.
Maybe dark matter and energy is/are other dimensions. We can't interact , but all that stuff is still there even though, it's not... What needs to happen, is a visit from Uncle Martin. To explain how to simply manipulate space time. it may just be a branch of physics that is yet to sprout. We can't seem to de linear ourselves or separate perception from thought. There are ways But it's a family show....
We have never measured any spatial or temporal dimension other than our 3+1. This is why the R^2 law is so common is physics, for electromagnetism and gravitation.
Speaking of dark matter, a good friend of mine is a physicist and he told me about the theory of quantized inertia, which, among other things, says we don't need dark matter to explain our observations. It's a pretty interesting idea, and I know it's just a fringe theory, but I'd like to hear your take on it if you think you could make a good video on the topic.
Damn, you got me thinking now. Colisionless matter... that only interacts through gravity. A whole new research venue, just like discovering where exactly the mass property lies. Astonishing, keep up the good work!
Hey, just wanted to tell you you're great, have a great way of explaining things followed by awesome animations unlike most space related channels out there who mostly borrow already overused animations from old documentaries :) Good luck!
Hi. Wow. What does it feel like to think so deeply? I mean "normal" people don't really think about this stuff, right? But I find this stuff fascinating. Thank you for sharing your finds. 👏👏👏🇿🇦🇿🇦
As soon as I read the title I was wondering, but I did not quite come up with the angular momentum barrier fast enough. Keep up the great content, don't let some fraction of the comment section get you, although quite a tough read at times...
Hi Dr. Becky. If you are up for some questions: (1) Does dark matter pull on other dark matter? (Or it only attracts matter? This might affect every simulation...) (2) What is the temperature at the center of a black hole? (Infinite? Or... zero... because nothing can move???) (3) Do we know the crushed diameter of everything subatomic particle - including photons? (Why can't we assume zero space in between and calculate the core diameter of a black hole from its known mass, based on the diameter of the calculated number of all of the subatomic particles it contains - making some assumptions course?) (4) Why does everyone believe a black hole can exit via a white hole through other dimensions? (If the mass of a black hole is known then it's all trapped in there - right? Being squished to somewhere else would reduce the measurable mass - right? (5) Can a "black hole made up entirely of photons really exist? (If not then why can't you "evaporate" a black hole made up of matter by throwing an equal amount of antimatter into it? (Yes - initially the photons would be trapped. But after enough matter - antimatter masses are all converted to photons, then the black hole no longer has sufficient mass to sustain a sufficiently strong gravitational field to hold itself together.) -- Thanks, and great work!!
Dr. Becky's channel is by far my current favorite! But the tiny plant looks so lonely :( Can I donate a bigger plant to keep it company? Maybe they will collide to form one BIG plant? A dark supermassive plant!! I think she needs a bigger stage set that is fitting of her brilliance!
Thank you for this wonderful explanation! I once had a very cool discussion about a very similar topic with a group of folks much more educated on Physics than me at a Science Getaway (with Dr. Phil Plait). While several folks there were physics PhDs, none were as tuned into this as you, so we were all just kinda speculating about the dark matter halo and whether it would ever get captured by black holes or other dense gravitational areas (stars, etc). We *guessed* that the lack of friction would mean the DM wouldn't slow down enough to get sucked in, so you might wind up with a slowly growing mass of orbiting DM. It was a wonderful midnight discussion with finger-drawings of potential DM orbits in all three dimensions on the table... I am super glad to know that we were at least in the realm of plausibility with you folks who actually know this stuff. I can't wait to hear more as we learn more.
Alot of physicists rather attribute 'Dark Matter' as Dark Gravity as far as I know. Since the only current way for us to oberve this phenomenon, is due to its gravity properties and the way Galaxies cluster. That being said, since Black holes have infinite density is it not possible that 'Dark Matter' increasing a size of the black Hole and only measurable by its gravitational pull, not so much matter being sucked in, but the gravitational properties of the 'Dark Gravity' being added to the black hole? Since the way we describe how 'heavy' a black hole is due to its equivalent gravity properties to mass, even though the Black holes gravity attraction is proportional to its radius, we cant say how heavy it actually is? Im an engineer, not a physicist, so I might be completely missing the ball here though.
I think the last few sentences sum up most of my astrophysics experience: "maybe/we don't know" lol I did my bachelor's thesis on the question if baryonic feedback can be sufficient to form cored dark matter density profiles in faint galaxies and you can guess the results
Dr Becky please have a part of your podcast when you answer questions. Unlike dark matter orbits of reflective matter experience drag and that would cause their orbits to decay and end up in black holes. However dark matter does get pushed away by matter either. Once any massive object comes into contact with dark matter it will hold on it and if the object falls into a black hold so will the dark matter.
Have been learning about superconductivity this week, and how you describe dark matter as collisionless reminds me of quantum fluid. There appears to be a new theory that the surface of black holes are actually surrounded by a superconducting plasma, and if the mechanism of accretion is collision then that would mean that the frictionless quantum fluid is never accreted. Feels like the pieces of the puzzle are only waiting to fall in place.
There's many pieces, since there's quite a number of possibilities as we don't have *any* idea what dark matter is made of - and perhaps not 'matter' at all! I were going to add the most outlandish tinfoil idea to give an example of that, but only came up with one that's outlandish but actually have been suggested - sorry about that. ;) And that idea is that we live in a brane, while there's another brane nearby in a higher dimension. The 'dark matter' we see the effect of, is actual normal matter in that other brane universe, the matter in that dimension accumulate close to our galaxies etc since gravity is the only force that can be transferred between the two brane dimensions. While we see that as 'dark matter' here - without any other effect and completely impossible to detect.
Dr. Becky. I have two questions: One reasonable and one wild, and I'd be flattered if you'd humor me by answering both. 1. Why isn't dark matter just referred to as "unexplained space-time curvature"?, and 2. Has anyone considered dark matter as being curvature caused by a large mass from *outside* our universe--i.e. a nearby parallel universe, and we assume gravitational waves can permeate beyond our four known dimensions and towards other parallel universes?
Last Friday at the Delaware Valley Astro Club, we heard a timely talk by Dr. Joseph Neilsen, Villanova University on Black Holes. Dr. Joe has degrees from Harvard & MIT, so he is top knotch. Our club meets close to the University who has added outstanding talent to its physics department. I shared your YT video with him. He's very young like you and demonstrates lots of enthusiasm also like Dr. Becky! 🤗
So glad you covered this topic. I had been thinking about this question a bit over the last few months, especially relating to supermassive black hole formation in the early universe. Whatever dark matter actually is, when it was first formed with the rest of the universe, and was incredibly dense, would it be possible that the densest areas of dark matter could have created supermassive black holes under their own gravity, while normal matter was being prevented by collapsing due to the intense heat it was subjected to?
What I think is much more interesting is that if a black hole can be at least partially made up of dark matter, then in theory it should be converted to energy via Hawking radiation. So in theory you could map out where the bigger clumps of dark matter are, carry along a portable black hole (assume that's possible for the moment), and convert it to energy via Hawking radiation. So in theory we have more energy than previously thought. This should also mean that once a black hole explodes it should convert not just regular matter but also all of the dark matter into energy (unless I'm mistaken which is distinctly possible.)
All of this was much above my head even though I find it fascinating but my hat's off to your taste in music. Keep expanding our understanding of reality and putting it out there in chunks us mere mortals can possibly understand :D
Has any progress been made about what dark matter isn't? It's an odd question, but since we don't what dark matter is, have any promising theories been ruled out?
There have been a lot of groups which have ruled out many things (like neutrinos and primordial black holes and newly hypothesized, prevalent black hole swarms), but others who have ruled them back in. When I go to conferences, however, people seem pretty prejudiced about what has been ruled out.
Nicely explained cheers. I guess there's still the possibility that dark matter behaves strangely in accretion disks but of course that's pure speculation.
What a great time in human history to be alive. Sometimes it's not the answers a generation comes up with, but the questions they ask that matter. Keep up the good work and don't fret the sound issues.
Brown nose she is talkin pure crap
@@johnnycarrion4754 and your PhD thesis was on ... what, exactly?
Well...
It always a great time to be alive🧐
I'm sure this has and will be said
throughout the ages
of space-time🥺
Maybe even🤔...
The Dark Ages🙄
I’m so glad YT suggested one of your videos. You are instantly one of my favorite physics channels. Your presentation style is so natural and clear and balanced. It’s the right amount of simplification such that I can (mostly) understand the subject matter with enough scientific information that I actually learn something. Fantastic job.
Wearing a Muse shirt while talking about supermassive black holes. Subtle.
Beat me to it.
I couldn't tell it was Muse but if I knew then I would say that's awesome. (I can see the word on her left shoulder now that I look closely).
believe whatever religion told you is barking mad ╭∩╮
chat.whatsapp.com/LT8eYjMxtza7uZ9tnqgZkf
I come for the science, but remain for the outtakes! Thanks for the knowledge!
She wants that motorbike
😁😁😁 agreed. It makes me feel a lot better about stumbling over my words in love presentations to know that brilliant people do too! It’s sometimes hard to avoid comparing my raw output against the edited videos that get published on RUclips.
Moron she is clawn bugger eater she is brain washing
Even as a layman, I'm so intrigued by this channel and everything you cover. I may not understand it all on your level but it's still fascinating. I could watch this stuff all day.
You are so good at explaining this information.. Love your channel!
As a physical chemist, "collisionless" matter sounds a lot like frictionless matter, such as a superfluid like liquid helium-4.
But a collisionless material is also nearly infinitely compressible.
@@Hailfire08 Is it compressible if you can't actually compress it, I was wondering. But I guess it gets pretty compressed orbiting a black hole. That's probably the only circumstance since the Big Bang, I'd imagine.
@@akizeta Well if you had some way of compacting it, it would be very easily compactible. So I guess a small black hole would do, since it'd pull the dark matter into its small but deep gravitational well...
Superfluid He is weird as fuck. There's video here on YT that shows different experiments with it. In some it acted like it was frictionless (0 viscosity) but in others it didn't. ruclips.net/video/sKOlfR5OcB4/видео.html
There are a lot of simulations and papers that try to deal with dark matter as or in essence as a superfluid. So keen observation on your part.
I'm an aspiring astrophysicist and plan on someday getting my degree in astrophysics, and i spend all my free time watching these videos because they are so informative! Thanks for providing such great information!!!
So, the "Betteridge's law of headlines" also applies to peer-reviewed papers :D
Yep. If the answer was yes, you would just say Black Holes Contain Dark Matter.
the question should be "does dark matter"?
Well my PhD title was something reminiscent of "combined mass transfer in a small scale plain piping system with a normal water bath".
So no.
(I have changed the actual title because you would be able to easily dox me if I said the real one).
Once i saw the title i just realized "Why'd i never think about that before". Thanks for making this video, was not the conclusion my gut reaction expected. I expected the majority of matter to compose the majority of matter that goes into black holes. But your explanation made it very clear why we shouldn't expect that to be the case.
I hadn't known dark matter was collisionless, but that makes sense. If dark matter is made of multiple different types of particles is it possible some of them are collisional but just not what composes the majority?
Ummm, hate to break it to you but dark matter being "collisionless" is 100% pure speculation. It took her almost 13 minutes to finally say so, we really have no clue and these are not only pure guesses, but they are guesses on top of pure guesses extrapolated from pure guesses...
MrWildbill47
The gravitational lensing measurements of the galaxies colliding seemed like pretty strong indication that dark matter is collisionless. Is there some way to explain that result in which dark matter is collisional?
Dark matter is collisonless if it's matter. But confusingly the Term "Dark Matter and Dark Energy also include ideas where it's not matter or energy. So if Dark matter is some sort of effect gravity has on space time we are unaware of yet there would be no collisions.
Just found your channel; this video impressed me so much I instantly subscribed. I love how you make the tough stuff, the questions being asked in these papers, readily available and easily understood by those of us not in the loop! Looking forward to checking out more videos!
Sound quality aside, this is one of the best videos of yours that I've seen! Thank you.
Ive literally wondered this! Thanks Dr. Becky!
Yes partical physicists, hurry up why don't ya! Nice shirt too.
I thought it was a Pokemon shirt...
Yeah, she looks like, more rested in this one to me. Shirt is nice!
Starlight! Muse!
I just wonder, what if Dark Matter isn't particles at all? Nor even close in the dimensions of particle accelerators? Maybe it's some sort of gravitational waves that are locally intertwined or some other mass bearing phenomenon of spacetime or another field we don't yet understand?
Yeah! It's like they don't even want the Nobel Prize that would come with it!
I've been wondering this question for 10 years and it's the 1st time I see an video about it.
Thank you Dr becky. So smart and intelligent and yet you seem so friendly and approachable. People we might have found the perfect science educator!
Muse shirt wins the internet today.
Anyone know where I can get one ? Looks a bit like a Jack Kirby design. Any info would be appreciated...
Awesome job on the lighting and white balance! Also MUSE FTW!
She's still purple and muse suck. Other than that you are spot on!
Dark matter has always been one of those things that up until this point felt to me personally less like astronomy and more like (shudder...) astrology. But listening to your attempts to sort out and understand how something as yet still poorly understood as dark matter into a very practical and very real explanation as to how it would interact and behave in a much more understood and observed setting are absolutely fascinating for one. And more importantly for myself, allowed me to more firmly grasp the concept of dark matter as something actually real and observable, at least theoretically and to a limited point. But far more real for me than when I started watching this video. Well done! Thank you!
The answer to a question in a title/headline being no is called
Betteridges law.
It's intuitive when you think about it, neutrinos are also weakly interacting, don't form accretion disks, and likely have the same low probability of passing within the schwarzschild radius.
Look up DIY Sound Deadening panels for a cheap way to improve your audio 😁
TBH, It sounds like lav mic didn't work for some reason and they had to make do with camera mic
TBH, It sounds like lav mic didn't work for some reason and they had to make do with camera mic.
Edit: 12:29 Yep
@@Turalcar eh, lap mic will still get a lot of echo without the reduction. Sound reaction always makes audio better.
Soft furnishings, blankets , throws etc. are a cheaper easier option for sound deadening. This may not be practical though.
phasing 2 sources
Supermassive Black Hole Hysteria is the best hysteria, Muse-puns intended.
Thank you for taking something confusing and making it a little less confusing.
It makes very little difference, but for some reason i find it really pleasant to hear a british voice explaining science for a change. I seem to follow all the american science channels. Subscribed, and totally not biased.
Just found your channel. Great question, great video, great explanation.
Had to pause it to think through what you had just said at some points. {Me}
Isn't the answer to all dark matter questions currently, "we don't know"?😂 great video! Thanks for keeping us all up to date on the status quo :)
There is also some new math that eliminates the need to account for dark matter and dark energy.
@@orlock20 there isn't. But people are working on trying to find it. So far it is widely inconsistent with observations though.
It's more like "We don't know much.."
@@RurikLoderr yeah I am aware of that, but that is why scientists are trying to detect dark matter, formulate alternative gravity theories or try to get rid of the neccesity for it. Anyhow, I am excited to see how this problem will be solved!
Love Dr. Becky's bloopers, nice touch...
I like that you do a great job explaining complex topics in a way that is very easily follow. Also cool how you bring in studies by others. Interesting how your videos teach about the topic but also about the study behind the topics. Of course the outtakes are great as well 😄
Nice work! Subscribed!
Since we infer the existence of Dark matter by its gravitational interaction with normal matter, that would seem to imply that it would still feel the gravitational attraction of a black hole. Further if it can't loose it angular momentum via collisions and thus can't fall into a black hole, then would Dark matter pile up around a black holes due to being attracted gravitationally and but being unable to fall in?
And wouldn't that add greatly to the mass of a black hole?
How would the dark matter wind up in a low orbit like that to begin with though? I could imagine a stellar mass black hole capturing a clump, or cloud, or whatever of dark matter the same way a star would capture an asteroid, but what force could make that orbit shrink further from there?
M_Chupon I am not envisioning it piling up at the accretion disk but more on a larger scale. I was curious if overtime more and more dark matter would migrate toward the vicinity of a black hole due to gravitational attraction. If this was the case I wonder if on a larger scale the attraction due to dark matter and that due to the black hole would begin to function as one.
It might lose energy to gravitational waves?
no. if you're collisionless, being attracted doesn't mean you stay there. you swoop in by whatever happenstance, then your enormous velocity gained makes you swoop off. we're so ingrained to think of attracted things going splot and losing their momentum we don't notice everyday "attraction" is two things, attraction + a lossy interaction that doesn't apply to dark matter
What would happen if anti matter fell into a black hole? Would it add to the mass or remove mass?
Mario Hendriks it would add mass. It still has the same mass as regular matter just an opposite charge.
Add mass. Black holes don't care what they eat, all that matters is mass, spin, and charge. And the only thing that they do is they change the properties of the black hole by adding the properties of whatever went in - a charged object will make the black hole slightly charged, for example.
No, antimatter=opposite charge, same mass. So the "anti" just refers to charge.
When a particle and its antiparticle "collide" they give off 2 times the particle's equivalent mass energy
But can the energy escape the black hole or not?
Only in the VERY rare case that the particle/antiparticle pair are created at the event horizon under such conditions that one is inside the event horizon and one is outside.
Simplified: The energy to make both particles is "borrowed" from the energy of the vacuum of space. Energy can be borrowed from the vacuum due to the uncertainty principle, where uncertainty of energy times uncertainty of time is equal to the modified Planck constant.
Since the event horizon is preventing the particles from ever meeting up again and giving their energy back to the vacuum, the energy loan for both particles is paid for by the black hole (when this happens the "virtual" particles become "real"). Notice the black hole only gets to collect one particle's worth of energy back so it is at a net loss. This is Hawking radiation.
Nothing inside the black hole ever escapes besides this type of energy bookkeeping.
Loved the video! Clear and to the point but without forgetting to quickly explain other stuff like gravitational lensing. And you're good to listen to as well.
This is the first video that I've found on this channel, but I already know this Dr. Becky is a great place to go for physics. The information is simple yet profound, the script is very natural, which makes me think that you know a lot about the subject you're explaining. Also, the ideas for the videos I've seen so far seem to be varied, thought-provoking and original. One thing: invest in a camera. I know you've probably got this often, but if you do invest in a camera, you'll be all set! I know that it will cost a lot, but I find that upgrading your kit will be a big step forward for this channel. I see a stellar future for this channel, good luck!!
Then black holes usually friendzone dark matter with very low chance of collision ;)
Dr. Becky, does the recent picture of the M87 black hole put some light into this question?
I see what you did there...!
I've actually thought of black holes growing from dark matter too, but i figure the professional scientists would have thought of that already. Does dark matter not collide with itself in a hypothetical dark matter accretion disk? For that matter, would there be dark matter "stars?" Just balls of dark matter that doesn't glow, but has an unexplained planetary system or system of gas and dust around it? Hard to detect for sure since its not something you could see in a telescope until it birthed a star of its own.
From what I understand, Dark Matter doesn't clump up the way regular matter does. Since it doesn't seem to interact with itself, it tends to stay in those Halos that Becky mentioned in the video. Also, if the hypothetical Dark Matter Star had enough gas and dust around it to form a planetary disk, the majority of that matter would probably condense down into the dark matter star and become a regular star.
@@NatalieNirian Ah okay so it doesn't self-interact either. Thanks! And yeah that was what my "birth a star" comment was referring to, because eventually the regular gas and matter itself would form a regular star, so when you finally see it it would just look like a regular star system.
Improved audio would have made this video much more enjoyable. I almost clicked off in the first 5 seconds based on poor audio alone. My curiosity of the title kept me here, but I assume most missed this interesting video. All other quality metrics are great! Subject, Editing, Camera. I look forward to the success of this channel and enjoying more content. ;)
Edit: I just watched the last few seconds that you say your mic battery died.
Dr. Becky your hair looks extra fabulous today. 😍
Doesn't dark matter orbiting black hole lose energy via gravitational radiation or is this so slow process that it does not matter?
If so, this does bring up interesting question. Which one happens faster: black hole evaporation via Hawking radiation or dark matter absorption due gravitational radiation?
I had the same thought.
In the paper that suggested up to 10% of the mass could be dark, was this due to the dark matter bleeding off energy via gravitation waves, or how does even 10% end up dark? Or was this 10% just due to the "ideal" initial conditions?
Not just gravitational radiation. There is gravitational attraction between the flow of "frictionful" matter which emits its energy and frictionless dark matter which doesn't. They form a mechanical system which as a whole loses energy. As soon as there is difference in velocity of the two, the kinetic energy of faster flow will be drained by slower flow, and then it will be lost by friction in the slower flow. Admittedly, dark matter loses energy at slower rate though, but with steady influx of ordinary matter into accretion disk, amount of captured dark matter increases too. Vice versa, with great amount of accumulated dark matter orbiting the black hole, we will observe an incredible amount of energy radiated by collisions of ordinary matter, with it apparently losing very little of its kinetic energy, as it's energy is replenished through gravitational interaction from huge pool of dark matter orbiting the event horizon.
@@salec7592 ah thanks, that makes perfect sense. I had figured that gravitation waves would have far too little an affect to significantly effect the dark matter. But normal matter acting as a 'break' explains it.
Just a general comment, Dr. Becky...I really appreciate your videos, you explain things so well and it's exactly in the range of understanding that I look for in these subjects. Your qualitative and visual approach to describing cosmic phenomena is very clear. Keep up the awesome work. I also love the outtakes!
I asked a question along these lines several years ago, and the only one time I got an answer was by someone that totally misunderstood what I was asking. I have emailed physicists and commented on youtube videos, and no one ever came up with an answer, and as I don't know the physics really, I don't even know if I am just failing to understand. I titled my question "Stable Pulsar's disprove WIMP model of dark matter"
Points:
1. WIMP's would travel far below the speed of light to be able to stay roughly connected through gravitational attraction to galaxies, anything traveling at the speed of light would not stay bound to anything other then inside a black hole, so there could be no dark matter halo.
2. We don't see neutron stars and or pulsar's that appear to gain mass and eventually collapse into a black hole on their own.
3. There are many paths for any given object in the presence of a strong enough gravitational field, and not traveling at the speed of light, a set of paths that will leed to capture of that object into orbit of the the strong gravitational field.
4. A portion of dark matter WIMP's that cross paths with a neutron star, even if they manage to not interact with the basically solid matter ball that it is, could end up in orbits, likely below the surface, of the neutron star.
5. No matter how non-interacting they are, they should over time build up in mass inside the star, eventually pushing it past the mass limit for a black hole.
6. And or conversely, they do interact enough, that the stars should gain heat and only ever get hotter and brighter the longer the exist, due to the interactions with the WIMP's
www.forbes.com/sites/startswithabang/2016/10/28/why-doesnt-dark-matter-form-black-holes/#60f1cef83de1
I barely understand a tenth of what you are saying, but I love the enthusiasm. What is your take on quantized inertia? (no dark matter at all, just a Hubble scale casimir effect)
It fails completely at explaining things like the bullet cluster and gravitational affects where there is no visible matter.
@@lordgarion514 I would still like to hear what she has to say. There was an alternative explanation posited by Mordehai Milgrom. We have been looking for dark matter for ages and still haven't found direct evidence. en.wikipedia.org/wiki/Bullet_Cluster
@@hibiscus779
So what you're saying is so we need multiple theories instead of just one?
And just so you know, it took about two and a half decades to find the neutrino from the time it was first theorized.
Not to mention, the very beginnings of quantum mechanics go back to the mid-1800s, and we still aren't even close to having that all figured out.
It's a little stupid to start talkin three or four theories instead of just one.
Also, if you'd actually read that Wikipedia article you would have realized it said it doesn't get rid of the need for all dark matter. But then they go next level stupid and say they "expect" that to be ordinary matter we just haven't found yet.
You should probably try thinking about this a little bit more.......
@@hibiscus779
Forgot to mention, in the bullet cluster the effects that we call dark matter only exist in the galaxies themselves. There is no effect of dark matter inside the gas cloud in between the galaxies even though there is more matter(and US gravity) inside the gas cloud then and either Galaxy on its own.
Which means any explanation has to be able to turn the effect that we call Dark Matter on and off, even at the scale of entire galaxies.
No one who talks about either MOND, or QI has ever explained how it turns off in a bigger Galaxy worth of matter, but on in a smaller Galaxy worth of matter.
@@lordgarion514 no. I mean, I would like to hear Becky talk about it :) I heard Anton Petrov's take on it and found it fascinating, but I believe he lacks Becky's credentials. ruclips.net/video/VYdebV9YlnI/видео.html
As Stars orbit galaxies, why don't they accumulate dark matter along their orbital path, when the speed is about the same as the dark matter?
I think that it is because orbital mechanic- when you encounter dark matter it is accelerated to star, but it means that it will have huge speed near star and just fly away. In two bodies orbital mechanic you cannot change type of orbit (elliptic or hyperbolic) with just gravity. Orbits are symmetrical- if matter goes into sphere of influence with speed X it will leave SOI with speed X. Same way we do not have thousands of moons around Earth, because asteroids come and go. Or with Oumuamua.
Perhaps because of conservation of momentum? If they don't collide then there would be no momentum transfer thus the dark matter would probably just pass right through. Of course any dark matter particles that wander into something moving at velocities greater than the masses escape velocity could presumably be trapped in bound orbits of course dependent on what dark matter is.
Syriusz B As the black hole (or star for that matter) orbits the galaxy I think it's conceivable to capture dark matter into some sort of orbit with one of those backwards gravity assists? If that *is* possible the orbit would probably be very elliptical.
@@m_chupon5131 Yes, it is possible, but very unlikely so we do not have much of this. Not enough to see it at least (as gravitational disturbance, lensing would not work here I think). To capture something with gravity assist everything have to be just right. And black holes would be much likely to capture black matter and since it is very rare according to simulations, it is even rarer with regular solar systems.
Syriusz B Yeah the amount of dark matter that could hypothetically get captured like that would surely be too small to detect with lensing.
You are my favorite channel right now.
Subscribed today. Weird RUclips hasn't recommended these videos to me before.
Black holes contain donuts. Prove me wrong.
Ockam's Razor bro
It's kinda the other way around, everything is donuts. A black hole is just the side of a donut that is facing this Universe. At the singularity of a black hole spacetime turns inside out so the other side of the donut that we don't see, ie "inside" the black holes event horizon, those are the big bangs of other Universes. Consider that we can look 13 billion lightyears in any direction, but instead of a sphere 26 billion light years across, the edge of the visible universe is a single point 13 billion years ago, so this Universe is inside out too!
Wikipedia states that donuts have their origin in the beginning of the 19th century.
The nearest black hole is 1120 light years from earth.
Since donuts don't travel faster than light, black holes don't contain donuts.
...barring of course an infinite improbable scenario that a complete donut has spontaneously quantum tunneled into one.
Muse, Super massive black holes
Besides the answer "we don't really know" it seems the current papers are saying that we don't expect significant amounts of dark matter to be captured by black holes. The reason I hear in this video is that dark matter doesn't strongly interact with itself or with normal baryonic matter through the electromagnetic force. This weakly interactive behavior stops it from clumping like normal baryonic matter so it doesn't lose energy and fall into black holes, or stars, or planets.
This is quite non-intuitive but if there is no electromagnetic interaction (friction) to slow things down, a piece of dark matter would travel right through a star or planet as if it weren't there. Gravity would speed up as it approached the center of mass and slow it down as it passed by until it was back to the initial speed it had before the interaction.
Unless it were on a collision course with the event horizon (where it would be stuck in the black hole), it would follow a parabolic path around a black hole and continue on its merry way. This is why so little dark matter is captured in the black hole.
Thank you so much for explaining this.
First time tuning in. Great job in explaining the proposition of dark matter vis-a-vis black holes. Enjoyed it.
Yup, "Dark Matter" sure is versatile.
But that's how it is, when you make stuff up. Then it fits however you want.
Guess you,re correct,because Dark Matter is mostly Hypothetical,since there,s no direct evidence for it.
@@derlinclaire1778 yep... Scientists of today should take a cue from the great Richard Feynman here...
Try and have a look at "Quantized Inertia" or "QI". Its a "so called" fringe theory. But it is a much better model than Dark matter.
QI can even explain binaries that are very far apart. Dark matter cannot explain this.
I dont think she got the memo...
@@AnimalChinz oh well, I reach who I can reach ;)
Damn your lovely eyes, i come here for the science, and have to watch twice because I haven't listened properly. Thanks for the vids, Becky
Really enjoy the presentations of this channel. Dr. Becky makes it understandable for us all.
Thanks for adding the bloopers at the end, makes me feel better about taxing my brain to follow someone far cleverer than I. 👍
It's like asking do unicorns fart rainbows? ALL of it is mathematical nonsense and entirely fictional.
What an odd way to admit you don't understand the math. for the record, the math is DESCRIPTIVE, not PRESCRIPTIVE. As such, it's not fiction, and isn't nonsense (unless you have something actually useful to enlighten us on).
Buy a couple books mate.
Imagine, maybe there is no such thing as "dark matter".
It is, on its face, the dumbest model in current physics. It is the aether of our generation of science. Hopefully we can one day get rid of the model and replace it with something better, and translate things like this video to the new model.
That theory is being twisted too much now.
Regardless of what you call it, there is a physical interaction in the universe that functions the same way as gravity. The "matter" part is speculative but since mass is what makes gravity it's a fairly natural title for the unknown agent responsible. Dark is simply an accurate descriptor that we don't directly perceive it visually.
While we can speculate about its exact nature quite a lot, imagining it not existing would require contradicting more physical evidence than I'm personally comfortable with. YMMV.
We don't know if dark matter is a "thing", but we definitely know there is an extra source of mass in our galaxy which isn't accounted by the total mass of regular matter, given our understanding of gravity. That unknown source is called "dark matter". Because we cannot see or interact with it, but we know it's there, since we have observed that it exerts gravity on regular matter.
@@esdev92 Not just on matter but also light. You can view it indirectly when a region of apparently empty space causes gravitational lensing. When that happens we see Einstein Rings, almost like rainbows, from the defracted light.
This might just be a "humans are visual creatures" thing but personally I find being able to see it, at least indirectly, to be the most persuasive evidence.
Very easy to understand explanation. Dark matter has to lose energy in order to be drawn in past the event horizon. I wonder though if there are quantum effects, such as virtual "particles" to where one virtual dark matter "particle" would be drawn into the hole while its entangled twin did not. Yes particle physicists hurry up why don't ya! I am now a new subscriber Dr. Becky. Thank you!!
I arrived here almost directly from Straya's Bin Chicken video.. Good show, Dr Bec.
Dark matter is made up of the souls of undead bunnies
Dark matter only exists between the ears of theoretical physicists.
@@thishandleistacken , lol, triggered fanboy is triggered.
Neil De Grasse Tyson and wikipedia?
seriously?
The problem with stupid people is that they are too stupid to know how stupid they are.
@Axe Man Did you watch the video? It shows the bullet cluster and explains how it proves that dark matter exists.
@@danielauto3767 ,simply bullshit, it's just wrong assumption built on top of wrong assumption no more real that the flat earth.
Maybe dark matter and energy is/are other dimensions.
We can't interact , but all that stuff is still there even though, it's not...
What needs to happen, is a visit from Uncle Martin.
To explain how to simply manipulate space time.
it may just be a branch of physics that is yet to sprout.
We can't seem to de linear ourselves or separate perception from thought.
There are ways
But it's a family show....
We have never measured any spatial or temporal dimension other than our 3+1. This is why the R^2 law is so common is physics, for electromagnetism and gravitation.
@@stefanozurich true, but without faith...... *joke
Speaking of dark matter, a good friend of mine is a physicist and he told me about the theory of quantized inertia, which, among other things, says we don't need dark matter to explain our observations. It's a pretty interesting idea, and I know it's just a fringe theory, but I'd like to hear your take on it if you think you could make a good video on the topic.
I think that one was recently disproven and put to rest.
Love the quirky bits at the end and of course the video..always extremely informative
Great content, bad audio
Dr Becky marry me, I love you brain :) lol
Are you zombie?
Damn, you got me thinking now. Colisionless matter... that only interacts through gravity. A whole new research venue, just like discovering where exactly the mass property lies.
Astonishing, keep up the good work!
Hey, just wanted to tell you you're great, have a great way of explaining things followed by awesome animations unlike most space related channels out there who mostly borrow already overused animations from old documentaries :) Good luck!
Just found your channel. I'm a huge fan of "what the math" with Antone and your channel is a great compliment to his content. Love your style
You're doing great videos and keeping me scientifically curious. Thanks, fun to watch!
this channel is awesome and should be larger.
Hi. Wow. What does it feel like to think so deeply? I mean "normal" people don't really think about this stuff, right? But I find this stuff fascinating. Thank you for sharing your finds. 👏👏👏🇿🇦🇿🇦
I love your content, please never stop.
It was spectacular watching CHANDRA go up on Columbia. Such an underappreciated observatory.
OK, we need a Dr. Becky blooper reel-dedicated video, stat!
Thank you so much for uploading this video. It is helping me to get through the pandemic!
As soon as I read the title I was wondering, but I did not quite come up with the angular momentum barrier fast enough. Keep up the great content, don't let some fraction of the comment section get you, although quite a tough read at times...
Hi Dr. Becky. If you are up for some questions: (1) Does dark matter pull on other dark matter? (Or it only attracts matter? This might affect every simulation...) (2) What is the temperature at the center of a black hole? (Infinite? Or... zero... because nothing can move???) (3) Do we know the crushed diameter of everything subatomic particle - including photons? (Why can't we assume zero space in between and calculate the core diameter of a black hole from its known mass, based on the diameter of the calculated number of all of the subatomic particles it contains - making some assumptions course?) (4) Why does everyone believe a black hole can exit via a white hole through other dimensions? (If the mass of a black hole is known then it's all trapped in there - right? Being squished to somewhere else would reduce the measurable mass - right? (5) Can a "black hole made up entirely of photons really exist? (If not then why can't you "evaporate" a black hole made up of matter by throwing an equal amount of antimatter into it? (Yes - initially the photons would be trapped. But after enough matter - antimatter masses are all converted to photons, then the black hole no longer has sufficient mass to sustain a sufficiently strong gravitational field to hold itself together.) -- Thanks, and great work!!
Dr. Becky's channel is by far my current favorite! But the tiny plant looks so lonely :( Can I donate a bigger plant to keep it company? Maybe they will collide to form one BIG plant? A dark supermassive plant!! I think she needs a bigger stage set that is fitting of her brilliance!
And your hilarious in your bloopers lol
Smart funny and beautiful is a rare and unique combo.
I subscribed 😸
Thank you for this wonderful explanation! I once had a very cool discussion about a very similar topic with a group of folks much more educated on Physics than me at a Science Getaway (with Dr. Phil Plait). While several folks there were physics PhDs, none were as tuned into this as you, so we were all just kinda speculating about the dark matter halo and whether it would ever get captured by black holes or other dense gravitational areas (stars, etc). We *guessed* that the lack of friction would mean the DM wouldn't slow down enough to get sucked in, so you might wind up with a slowly growing mass of orbiting DM. It was a wonderful midnight discussion with finger-drawings of potential DM orbits in all three dimensions on the table... I am super glad to know that we were at least in the realm of plausibility with you folks who actually know this stuff. I can't wait to hear more as we learn more.
Alot of physicists rather attribute 'Dark Matter' as Dark Gravity as far as I know. Since the only current way for us to oberve this phenomenon, is due to its gravity properties and the way Galaxies cluster.
That being said, since Black holes have infinite density is it not possible that 'Dark Matter' increasing a size of the black Hole and only measurable by its gravitational pull, not so much matter being sucked in, but the gravitational properties of the 'Dark Gravity' being added to the black hole?
Since the way we describe how 'heavy' a black hole is due to its equivalent gravity properties to mass, even though the Black holes gravity attraction is proportional to its radius, we cant say how heavy it actually is?
Im an engineer, not a physicist, so I might be completely missing the ball here though.
I think the last few sentences sum up most of my astrophysics experience: "maybe/we don't know" lol
I did my bachelor's thesis on the question if baryonic feedback can be sufficient to form cored dark matter density profiles in faint galaxies and you can guess the results
Dr Becky please have a part of your podcast when you answer questions. Unlike dark matter orbits of reflective matter experience drag and that would cause their orbits to decay and end up in black holes. However dark matter does get pushed away by matter either. Once any massive object comes into contact with dark matter it will hold on it and if the object falls into a black hold so will the dark matter.
Even Dr. Becky's flubs at the end sound smarter than me on a good day. Can't wait till you good scientists figure out what this weird dark matter is!
Dunno how I missed this one .. but good job, thank you and it's too bad your mics were all ran down .. Keep it up, love watching ..
We always come because of the outtakes =)
Have been learning about superconductivity this week, and how you describe dark matter as collisionless reminds me of quantum fluid. There appears to be a new theory that the surface of black holes are actually surrounded by a superconducting plasma, and if the mechanism of accretion is collision then that would mean that the frictionless quantum fluid is never accreted.
Feels like the pieces of the puzzle are only waiting to fall in place.
There's many pieces, since there's quite a number of possibilities as we don't have *any* idea what dark matter is made of - and perhaps not 'matter' at all! I were going to add the most outlandish tinfoil idea to give an example of that, but only came up with one that's outlandish but actually have been suggested - sorry about that. ;)
And that idea is that we live in a brane, while there's another brane nearby in a higher dimension.
The 'dark matter' we see the effect of, is actual normal matter in that other brane universe, the matter in that dimension accumulate close to our galaxies etc since gravity is the only force that can be transferred between the two brane dimensions. While we see that as 'dark matter' here - without any other effect and completely impossible to detect.
Fascinating subject that I've wondered about myself. Thanks, Dr. Becky.
Feedback for Dr in the house. I have watched plenty of your videos and I really enjoyed this one. It was definitely worth making. Great job.
Thank you for taking the time to tell us this.
And Becky is a star !! Love your videos.
Great video, I love the out-takes at the end too...also your hair and your eyes and...
Dr. Becky. I have two questions: One reasonable and one wild, and I'd be flattered if you'd humor me by answering both. 1. Why isn't dark matter just referred to as "unexplained space-time curvature"?, and 2. Has anyone considered dark matter as being curvature caused by a large mass from *outside* our universe--i.e. a nearby parallel universe, and we assume gravitational waves can permeate beyond our four known dimensions and towards other parallel universes?
Good to see the ventriloquism lessons are paying off at the end there....
I feel your pain re: motorbikes. Used to have a Harley-Davidson owner just down the street who always seemed to know just when I was recording!
That "collisional/collisionless" outtake made me smile.
Last Friday at the Delaware Valley Astro Club, we heard a timely talk by Dr. Joseph Neilsen, Villanova University on Black Holes. Dr. Joe has degrees from Harvard & MIT, so he is top knotch. Our club meets close to the University who has added outstanding talent to its physics department. I shared your YT video with him. He's very young like you and demonstrates lots of enthusiasm also like Dr. Becky! 🤗
So glad you covered this topic. I had been thinking about this question a bit over the last few months, especially relating to supermassive black hole formation in the early universe. Whatever dark matter actually is, when it was first formed with the rest of the universe, and was incredibly dense, would it be possible that the densest areas of dark matter could have created supermassive black holes under their own gravity, while normal matter was being prevented by collapsing due to the intense heat it was subjected to?
What I think is much more interesting is that if a black hole can be at least partially made up of dark matter, then in theory it should be converted to energy via Hawking radiation. So in theory you could map out where the bigger clumps of dark matter are, carry along a portable black hole (assume that's possible for the moment), and convert it to energy via Hawking radiation. So in theory we have more energy than previously thought. This should also mean that once a black hole explodes it should convert not just regular matter but also all of the dark matter into energy (unless I'm mistaken which is distinctly possible.)
All of this was much above my head even though I find it fascinating but my hat's off to your taste in music. Keep expanding our understanding of reality and putting it out there in chunks us mere mortals can possibly understand :D
very clear :) on black holes
Has any progress been made about what dark matter isn't? It's an odd question, but since we don't what dark matter is, have any promising theories been ruled out?
There have been a lot of groups which have ruled out many things (like neutrinos and primordial black holes and newly hypothesized, prevalent black hole swarms), but others who have ruled them back in. When I go to conferences, however, people seem pretty prejudiced about what has been ruled out.
Nicely explained cheers. I guess there's still the possibility that dark matter behaves strangely in accretion disks but of course that's pure speculation.