How We Know Dark Matter Exists | The Evidence for Modern Physics
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Just 5% of the universe is made of all known matter in existence-the other 95% is dark matter and dark energy. So how do we detect, measure, and account for it? Prepare for blastoff, cadet; outer space is about to get weird.
This video is lecture 19 from the series The Evidence for Modern Physics: How We Know What We Know
Stream the full series now on Wondrium! www.Wondrium.com/KZread
00:00 What is Dark Matter?
05:45 Fritz Zwicky Coins the Term "Dark Matter"
07:39 Vera Rubin's Observations on Dark Matter
12:56 Gravitational Lensing and Distortion
16:44 Possible Explanations for Dark Matter
21:31 Modified Newtonian Equations
25:10 Testing Theories on Dark Matter
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#DarkMatter #Physics #DarkEnergy
Пікірлер: 440
Or maybe Einstein was wrong and we don’t really understand gravity like we think we do??
@metaparcel
Ай бұрын
I mean you're making a blanket statement. Einstein was right at some level or nothing of what the has formulated and subsequently proven would have provided any foundation at all to not only our current understanding of the Universe but also how time is relative like with GPS satellites and how to adjust them for example or how to identify planet movements to a precise degree. It's also not about Einstein also since even those who are not Einstein don't seem to understand gravity. In fact no one yet understands gravity fully yet this does not mean one cannot make measurements and test them on the local level. I hate to say it but you sound like the typical Reddit university grad that tries to say something clever without really offering anything in return. The fact that you leave two question marks is like the "mark the grass" sign most Reddit trolls give when they think they're making some sort of point. You're the type that doesn't understand what is and isn't understand about gravity and instead just make blanket statements for likes or to sound smart. The irony is you're the one that definitely not only doesn't understand gravity but also don't understand Einstein even at a most basic level. The man wasn't infallible and he was wrong many times but he did open the door for us to try to understand what is space, time and gravity. In fact Newton was the one who started this whole gravity mess yet you don't seem to see that either.
Ok noted… now back to working my mindless 9 to 5 dead end job
@tenormdness
Жыл бұрын
Yo, where do you work? I’m stuck on 8-5 and would kill for 9-5. I might lose an hour to watch stuff like this on lunch though.
@Cardioid2035
Жыл бұрын
@@tenormdness I sometimes pray for the physical manifestation of God to return to save us from ourselves honestly
@steinvonsteinberg3589
11 ай бұрын
Same here
@DirtyLifeLove
10 ай бұрын
@@Cardioid2035or generous Aliens to quickly give us nanobot tech to build free houses, transportation, and food. Guess we have to hope smarter people make it here in our lifetimes
Don Lincoln’s teaching approach is great. He starts with concepts. In the 60s I was in a lecture hall of 300 plus freshmen and they started with a chalk board filled with formulas which we scribbled into our notebooks and made no sense when we got back to our rooms.
@rebellion-starwars
Жыл бұрын
I just discovered this channel and I'm enjoying it for few hours now. I'm following his work at the fermilab channel but that is way shorter than this one, but there he's more precise here he's more general and more simpler for the people who are learning this stuff for the first time, I'm into the subject for long time now and I'm enjoying every second even though I already knew 95%
@SloppyGoat
Жыл бұрын
I used to think so, until I tried to have a one-on-one conversation with him. He really is a PhD snob, who doesn't believe anyone else can know anything about what he knows, without having a PhD. That kind of pisses me off. If you try to have a one-on-one discussion with him, he's going to claim not to be a PhD snob, and then turn around and tell you that you couldn't possibly know what you're talking about, without his level of education. Kind of a closed-minded man, really. 🙄
@scritoph3368
Жыл бұрын
@SloppyGoat he DID say teaching style, not conversation style lol. Really though I don’t imagine there are a whole lot of high level academics without some manner of inflated ego.
@SloppyGoat
Жыл бұрын
@@scritoph3368 Unfortunately, his entire personality is an act. He can't possibly be a very good physicist, if he won't even listen to other people. I call that a lost cause. He will not allow critical thinking.
@rebellion-starwars
Жыл бұрын
@@SloppyGoat yeah but he has a point. I don't like his fake smile, you can see it miles away but for a lot of people the stuff he's talking about is new and he's teaching style is great. I'm following a lot of different physicists and some of them interact with anyone but they aren't professors and they aren't teachers. We didn't say how he's privately, he recorded this to reach broad masses and he did it successfully. I understand why you don't like him personally and that's okay, we are just saying from our own perspective. We aren't going to the university but we enjoy physics.
When you make the math work by creating the matter it becomes circular reasoning. Just saying.
@n3uro42
2 ай бұрын
Yeah, one thing I was always taught in Math that I took to heart, was if your proof includes the assumption of your idea, it is not a proof.
We DO NOT know that "dark matter exists." Dark matter and energy could simply be a misunderstanding in our knowledge of known forces.
@jakke1975
Жыл бұрын
You gotta respect though that he admitted that we (i.e. scientists) are not 100% sure about dark matter and dark energy. But I agree with you 100% that we simply do not know..... and I find it very disappointing that even some very respected scientists just talk about it as if it's all real, "we know it's there, we just can't prove it yet". Well... there's a lot that scientists knew before that has been debunked over time.
@NondescriptMammal
Жыл бұрын
@@jakke1975 Yes, but why title the video "How We KNOW Dark Matter Exists"? It's misleading, for no good reason. Scientists should use precise language, it's just as easy to say Why We Believe Dark Matter Exists or some such.
@alastorgdl
11 ай бұрын
@@NondescriptMammal said "It's misleading, for no good reason" Deceiving cannon fodder to keep their faith in science and their support in these hard times of JWST debunking half of their religion is good enough reason, believe me
@TheM41a
5 ай бұрын
At this point science has just become a religion
@user-hx5lz4qr1c
21 күн бұрын
I KNOW they exist....so zipp it......dimwit human !!!
Alchemists achieved remarkably accurate calculations of heat exchange with models incorporating "luminous aether" - a substance that didn't exist but that explained the gaps in their model well enough to persist as an idea until a better model was accepted. Dark matter is just modern luminous aether, an explanation to explain the failure in our models. Eventually we will develop better models and move on, as we have before and we will again.
Conclusion is we don't want to question our equations but rather want to give a mystical answer. Dark matter means we don't know the answer.
@batu2345
Жыл бұрын
congrats you discovered theoretical physics and this how science progress
@anthonygiambattista6922
11 ай бұрын
@@batu2345 BOOOOOOO!!!!!! Rubbish.
Dark matter, and dark energy was made up to make the big bang theory, and our observations of the universe calculations work.
@justincase4812
Жыл бұрын
It does seem a glorified fudge factor. And it is layered on the uncertainty of how gravity, and perhaps other interactions are not well enough understood. The dark matter energy advocates may as well be saying, "because... Aliens" . And then fill in the blanks with fudge factor data. Can't say there is an inordinate amount of matter missing therefore it must be something we dont detect, see, sense, or comprehend. That is exactly like saying welp, must be Aliens, cuz I don't have anything better to explain it with.
@MrKapeji
Жыл бұрын
Exactly, it's no less a fantasy than any other fiction.
General relativity is very good at explaining the behavior of mass on the scale of a solar system. Why should we expect it to be equally valid on the larger scale of a galaxy? It is like saying since Illinois looks flat, the whole world must also be flat. Dark matter may not exist. It's just that we need a new version of GR for larger scales.
@ijustwanttolikecomments4677
Жыл бұрын
that's a very good point...i never thought of it exactly in those terms, but that was an excellent metaphor(simile?).. definitely adds an extra thought rolling around as i watch things.
This reminds me of the concept of the "ether". That was a dead end.
@jamescollier3
Жыл бұрын
lol. ether = dark matter lol
Thank you! Some of the podcasts I listen to are very science heavy and I love them but I have no higher math and little physics training. So Thank you so much 💓
@charlesrobbins1247
Жыл бұрын
Yu don't need math or physics. Draw the electrostatic field line from a charged particle, accelerate the particle and draw new lines superimposed along with an observer at rest. The observer does not see the new lines because the speed of light has not reached him yet. All the lines are vectors and a vector connecting on old line with a new line is the radiation and you will see it is pointing in the direction of the movement!!
@charlesrobbins1247
Жыл бұрын
Physicists didn't discover thing's using calculus (math), things had been discovered math came later. Einstein didn't use math to discover stuff. He thought about things and used a friend to write the math.
Kopernicus' theory on the movement of the planets correctly predicted where the planets would be in the sky but was still incorrect.
I just had this conversation with a friend and thank you for this.. im later to the ahow but i am here. Just got a new subscriber..
So... If you're looking at a distant galaxy, wouldn't we have compensate for the speed of light. I figure a galaxy is lightyears wide so the light closest to us would be here long before the far side giving us a distorted view of a galaxy?
Thank you for the video.
Due to this presentation, i'm not in the dark about dark matter any longer. Thanks
@haitiyouyou76
Жыл бұрын
Jajajaja 👍
@adibz959
Жыл бұрын
Dark matter still a mystery. So it does leave you in the dark.
@charlesrobbins1247
Жыл бұрын
You have been impressed by non-scientific speech. Our Freedom of speech allows this and it is entertaining but thermodynamics and entropy are still the truths!
@charlesrobbins1247
Жыл бұрын
Another truth. We are in an expanding universe. The distance we can see is 13.9+- billion light years. 5 billion light years from now and we can still only see to 13.9 billion light years!
Great Lecture, Thank you DrDon.
Great lecture. Great lecturer. Thank you.
Not a fan of the dark energy or dark matter thingy..... I would've thought the estimates for galactic mass to be wildly wrong. Heck, i think the modern dark matter thingy is like the aether of yesteryear.. Also, if increased observed speed of stars at the periphery must be caused by an increased galactic mass, shouldn't the same mass also affect the speed of stars near the ctr of galaxy?
It's such a common notion that "we" are so insignificant and "small potatoes to the universe" as you say, that it's always surprising when it's stated in such a way that appears to be intended to surprise us. I'll just point out that quantity and size don't necessarily comprise the qualities that would make something "significant". I feel like this is stating the obvious, but one might even consider things that are present in the greatest quantities -- like dark matter, hydrogen atoms, or statements of the insignificance of humanity -- as being precisely *less* significant than stuff found in less common configuration. Being made of stardust doesn't make a thing "mere" stardust. That is the most basic of platonic understandings
@wildweasel3001
Жыл бұрын
Speak for yourself, I'm very significant and made out of exotic matter
Beautiful videos. Great Imagery
the zuppa galaxy is 200 million light years away from earth...and 3 billion years old....and george bupkis sits at his telescope watching it for 6 hours and concludes that it all should have blown apart 2.8 billion years ago
we might be a dust particle but we are alive, that alone makes us very rare in the universe and big at the same time
if its 95% of the universe then put some in a bottle. till then its just a mathematical construct to fix your broken model.
If there's matter "which doesn't experience electromagnetism nor strong or weak nuclear forces" [ 2:00 ], then wouldn't regions (Voids) with more of it than baryonic matter be more subject to expansion than the regions (Filaments) between them?
I suppose it all depends on if they can agree on how much mass is actually in our Sun. There is a argument on that right now. Since it is the measure, by which we use to rectify masses in/of other stars, there could be huge discrepancies in many things. I suppose you could run both formulae on either mass to maybe help settle the argument it would be a nice data point to have.
@lunam7249
6 ай бұрын
that was solved by newton......a LONNNNNNGGGGGGG time ago
Thank you. Coming back to the arguments about why light bends, why isn't the immediate explanation resorts to the existence of black holes at the center of galaxies?
I loved how you knew what questions I would ask without having to ask them. This was the first time I heard about galaxies behaving properly without dark matter as evidence it exists and that was fascinating to learn. Does the fact gravity has little to no effect at the subatomic level contribute to our expected size of dark matter?
@Ghryst
Жыл бұрын
"you knew what questions I would ask without having to ask them" thats a RED FLAG to any sensible, intelligent person. just like hitler had all the answers, this guy also knows how to create effective propaganda.
@wakankinyan
Жыл бұрын
@@Ghryst it demonstrates organized teaching and thorough understanding. Are you in the right comment section?
@Ghryst
Жыл бұрын
@@vandalayindustries3057 feel free to flog it, it aint dead if its walking
@NondescriptMammal
Жыл бұрын
We don't know whether dark matter even exists, despite the title of this video. He says right in the video that the evidence is "a bit circumstantial" and "we are not absolutely 100 percent sure that dark matter is a real thing". I appreciate his honesty in disclosing that little fact, but it sure is weird they would give the video a title that asks how we know it, when we don't in fact know it.
@Ghryst
Жыл бұрын
@@NondescriptMammal agree'd. as i said in my main comment, the phrasing sounds very familiar... "how do we know god exists"
Excellent lecture.
This gives us significance not the other way
@user-lc8yc4cq5n
Жыл бұрын
You have it backwards.
@hans-joachimbierwirth4727
Жыл бұрын
@@user-lc8yc4cq5n An insignificant commenter like you is not in the position to define what is forwards and what is backwards. It needs significance to do that!
Man i wish there was a betting line on this. Dark matter exists in the same way the sun revolves the earth. As in, it doesnt, but yall havent figured out why not yet. Just wait til yall understand gravity a bit better.
@pointeddown
Жыл бұрын
Potentially no one would collect for a while. String theory has been a thing since the late 60's. Who knows how long it will take to prove or disprove dark matter.
The missing mass is dilated mass. For some reason people don't know that Einstein said that singularities are not possible. In the 1939 journal "Annals of Mathematics" he wrote "the essential result of this investigation is a clear understanding as to why the Schwarzchild singularities (Schwarzchild was the first to raise the issue of General relativity predicting singularities) do not exist in physical reality. Although the theory given here treats only clusters whose particles move along circular paths it does seem to be subject to reasonable doubt that more general cases will have analogous results. The Schwarzchild singularities do not appear for the reason that matter cannot be concentrated arbitrarily. And this is due to the fact that otherwise the constituting particles would reach the velocity of light." We have all heard the phrase "mass becomes infinite at the speed of light" this phenomenon is illustrated in a common relativity graph with velocity (from stationary to the speed of light) on the horizontal line and dilation (sometimes called gamma or y) on the vertical line. Mass that is dilated is smeared through spacetime relative to an outside observer. Even mass that exists at 75% light speed is partially dilated. General relativity does not predict singularities when you factor in dilation. Einstein is known to have repeatedly spoken about this. Nobody believed in singularities when he was alive for this reason. Wherever you have an astronomical quantity of mass, dilation will occur because high mass means high momentum. There is no place in the universe where mass is more concentrated than at the center of a galaxy. According to Einstein's math the mass at the center of our own galaxy must be dilated. In other words that mass is all around us because as the graph shows we are still connected to it. It was recently discovered that low mass galaxies (like NGC 1052-DF2) have normal star rotation rates. This is what relativity would predict because there is an insufficient quantity of mass at the center to achieve relativistic velocities. A simple way to confirm this would be to calculate the star rotation rates of a large number of galaxies. This would show that all the high mass galaxies would have star rotation rates that defy the known laws of physics and all the low mass galaxies (some galaxies can appear to be low mass but can have high mass at the center) would have predictable star rotation rates.
@shawns0762
Жыл бұрын
A fundamental question is "why can't we see light from the galactic center?" The modern answer is because gravitational forces there are so strong that not even light can escape (even though the mass of the photon is 0) Einstein's answer would be because the mass there is partially or completely dilated relative to an Earth bound observer. Einstein's answer explains the greatest mystery in science (the rotation rates of stars in spiral galaxies).
@murraymadness4674
Жыл бұрын
Never heard of 'dilated mass', but this might be something like I have recently considered. Black holes that are actual holes with no mass in the center, but instead the collapsed mass has turned into rotational energy, which effects the surrounding mass that spins around it. Maybe someone can do the calcs to see if that solves the dark matter problem.
@shawns0762
Жыл бұрын
@@murraymadness4674 Dilation is the phenomenon you see on the right side of a 2 axis relativity graph. It is a squared phenomenon, the closer you get to the speed of light it increases exponentially. Black holes were popularized mostly by television in the 1960's and belief in them gradually came to be despite the fact that Einstein said they cannot exist and there was no evidence. 99.8% of the mass in our solar system is in the sun. 99.9% of the mass in an atom is in the nucleus. If these norms are true for galaxies than we can infer that there is 100's of trillions of solar masses at the center of common spiral galaxies. There is no way to know this through observation there is far too much interference, dilation and gravitational lensing. High mass means high momentum. If we attribute a radius to these numbers than we can calculate that relativistic velocities exist in these regions, the same way we could calculate the surface velocity of the sun if we doubled it's mass.
Where are the links to the calculations relating to the inner mass of galaxy? (announced around Minute 9)
last week we were all made of strings....and the week before there were 23 dimensions
Loving the new setup but if you doing side shot and dont look at the camera is really awkward
Photon entropy (decay) explains the background redshift without expansion.
Is it possible that they are overlooking the overall velocity of the area local.
What if Dark Matter is the “liquid” on the River of which all things in space “float” on as they are pulled by gravitational currents immeasurably strong.
@charlesrobbins1247
Жыл бұрын
Poetry! Poetry! Yet you are probably more correct than any of this!
@AGBolish
Жыл бұрын
What if dark matter is space itself 🤯
@charlesrobbins1247
Жыл бұрын
@@AGBolish it is. space itself. Matter and wave duality results in everything is a probability.Sometimes an electron in an atom travels right thru the nucleus. In other words, it has a probability of being inside the nucleus. Any experiment you do to find it always affects the result of the experiment. For example, if you try to find it as a particle (mass) it might act as a wave where the intensity of the wave at any time is the probability that the electron is there. An electron in an atom might sometimes be light years away from the atom, in other words way out in space. That is not highly probable but, never the less, probable. With large spaces (universe) and lots of matter (galazys) , the probability of having matter where there is none is greater than zero. Energy and matter are interchangeable Einstein was right about that. . Dark energy exists by the same mechanism that dark matter exists. The two are different forms of the same thing. Thermodynamics and its laws are very basic and can be used to calculate the amount of matter, dark matter, energy, dark energy in the universe.. Get ready for this, our universe is actually a black hole. We are inside a black hole. We cannot get out. The amount of mass and energy in the universe is exactly the amount for a black hole with a horizon of 13.9 billion light years. Also, there never was a BIG BAng. Observations from James Webb Telescope proves this Far distant galaxys that are billions of years old are just like new galaxys. NO BIG BANG. There is a lot more to dispel from our minds to set us really free but enough for now.
@AGBolish
Жыл бұрын
@@charlesrobbins1247 But how can space be matter? How can we quantify the mass of space?
@TheM41a
5 ай бұрын
@@charlesrobbins1247I’ve been contemplating this probability for some years but I don’t think the scientific establishment is ready to embrace the idea that our observable universe is inside the event horizon of a black hole and the Big Bang was the creation of said black hole.
A much simpler explanation is that time appears slower as you look through more space without gravity. I’m too lazy to do that math, but with that understanding, there’s no need for dark matter, or an expanding universe. Things just look like they’re moving faster as they’re further away.
@charlesrobbins1247
Жыл бұрын
You are right on! Dan Schultz. Equations of motion are not basic/ They are our human derivations. Thermodynamics are basic and a derivation of the universe by simple thermodynamics shows two thirds matter, one third energy which is close to reality. Empty space contains both matter and energy as a probability and accounts for any unknowns.
@charlesrobbins1247
Жыл бұрын
It is very complex to calculate the forces on stars within a galaxy. The distances and velocities are such that relativity must constantly be accounted for and at the time and place it was when I was at the time now. It is nearly impossible. You cannot say simply as is said here, only the stars inside my circle matter!NO NO NO Obviously there were stars on the other side of the center that are attractins
@charlesrobbins1247
Жыл бұрын
This is circular motion in a rotating cordinate system which is not a freshman college math problem. It is beyond college to teach such a problem!
@charlesrobbins1247
Жыл бұрын
I remember a take home quiz in thermodynamics. A box is a cube with side, S, it is filled with gas to a pressure, P. what is the temperature in the box?? Solve for it showing your calculations.
It also could be that thinking it’s a particle keeps particle physicists busy for the foreseeable future? Don?
Just a couple musings.. Could dark matter be the remnants of the matter-antimatter collisions? Could that explain why Webb is finding such large galaxies around z12-z13, since less collisions would've taken place so long ago? Or could dark matter and dark energy be shades of gravity in the sense that the strong and weak force are with electromagnetiam? Could physics be born of two parental forces; OmegaMagnatism and OmegaGravity (bad placeholder name's)? Light world and dark world? Maybe time could be seen as the spirit world. Or Shadow, Ego, Id? Sub/cis/supra conscious?
@cougar2013
Жыл бұрын
Matter/antimatter collisions result in photons, among other things. So we would see that, if that were the case.
what about some variation on machs principle where space is created by particles
Dark Matter was a decent series on the syfy channel!
Still doesn't explain the wind up problem on the spiral arms. How do you know galaxys are bound? What are your assumptions? If you are patching your theory with a theory. And your only evidence for your second theory is that it is a requirement of your first theory? KZread might just be wrong.
Standing on the shoulders of giants. Great delivery and so easy to understand 👌
@dgalloway107
Жыл бұрын
Started talking to you but you arent my target so i removed my comment.
@jestermoon
Жыл бұрын
@Darren Galloway no problem my friend.
could anybody please tell me is antimatter monopole or diapole ?
Beautifully described and illustrated. Much obliged for that. 🙂 🐲✨🐲✨🐲✨
I think Gravity pushes not attract, that is why center of mass is zero G therefore, no dark energy required. Like current in the ocean, in close distance, it is the water that compress and the current created black holes.
Idk how you make dark matter seem so simple, but great presentation. For some reason I just don't believe in dark matter. I think it's unobserved normal matter. This video is compelling evidence against my belief, and I'll keep my mind and ears open for new information
@justaride7444
Жыл бұрын
There is an equal amount of evidence on dark matter as there is the effects observed are actually caused by smurfs smurfing too hard. IE. none
I don't understand this lensing thing. If you're seeing two galaxies at different distances, but the same direction, and the further away you look, the firther into the past you see: Are you actually seeing the same galaxy at differnt times in the past? If not, then galaxies are moving around a lot more and the directional correlations of ripples in the cosmic background radiation is not reliable?
Indirectly detected meaning they are able to measure the motion of stars and galaxies but their velocity is much more than what current theories of gravity and laws of motion are able to explain. That doesn't mean dark matter and dark energy exist. That means scientists are ignorant to explain the actual motion using current equations. I believe I figured out what's causing the unexplained motion occurring to ONLY stars, satellite galaxies and galaxies. The solution also explains why satellite galaxies and stars orbiting their host galaxy at over 1 million mi/h are unable to reach an escape velocity. The solution explains why some stars don't seem to be affected by dark matter while others are. It explains why dark matter doesn't affect the motion of planets, moons and other small bodies having mass yet affects the path of light that doesn't have mass. Something the dark matter postulate is unable to explain. I also came up with equations, that when added to the laws of motion and general relativity dark matter and dark energy disappear. It also explains why the satellite galaxies are orbiting their host galaxy on a completely different plane than the stars in the galaxy disk, which a dark matter halo cannot explain. It also explains the rapid velocity dispersion rate of galaxies without having to evoke the presence of white holes. Trust me, dark matter and dark energy are mistakes in their equations that simply need to be adjusted/fixed. Then those pseudoscience forces disappear.
@mickhealy572
Жыл бұрын
They are a mistake..ever heard of this? PLASMA COSMOLOGY VS BIG BANG MYTHOLOGY EXPLAINED , might be worth a look for you if you are unaware of it ..
@ronaldkemp3952
Жыл бұрын
@@mickhealy572 Yes. We live in an electric universe made of energy for sure. Energy is what causes mass to move. Energy is what causes space to expand and energy is what causes elementary particles to emerge into existence upon coming to a rest relative to the speed of light (m=E/c²). Everything exists and moves because of energy.
The thing I respect about you is that you immediately start by saying that we're not 100% sure about dark matter / energy. Personally, I hate it when every other scientist (or "content creator") talks about it if they're cold hard facts and most of them aren't even open to discussion. To me, that's not science but indoctrination. I agree that we see evidence of these phenomena and they are both very intriguing. But besides some sort of energy or matter, there are other explanations and we're all pretty much still guessing what they actually are, if they even exist or whether we even have the right understanding of gravity.
@NondescriptMammal
Жыл бұрын
Agreed, but they should change the title to not be misleading.
maybe mass at extreme enough quantities has a magnification (warping) property, with some galaxies having denser regions of heavier materials causing discrepancies... and galaxies with insufficient mass don't reach the threshold for mass-warping. If space and time can be stretched (and even punctured) on huge scales, why can't mass.
The first line: “I’m gonna tell you something you might not like.” The interesting thing is that you are right! I might not like it. I might be skeptical about dark matter, dark energy, the red shift, all sorts of things… And I am the person that you are talking to. In MY field, literature, I recognize that both the message and the messenger are significant for the listener. This means that YOU present a message to ME, a person who is literally interested, and I become, by the commutative property, the person who talks to other people who, literally, know absolutely nothing about what you are saying! This is why I enjoy your lessons so much. You are in inadvertently validating my role in the education of the general populace. Thank you. This is Kinda fun.
@TheGreatCourses
Жыл бұрын
Thank you so much for your kind feedback! We truly pride ourselves on our professors and the depth of our content and are very glad you're enjoying our offerings. Thanks for being a fan!
@Thomas_Name
Жыл бұрын
Someone who works in the entertainment industry who doesn't like things like dark matter, dark energy, and black holes??? Nooooo. Really? 😅
@justaride7444
Жыл бұрын
My favoutite part was when he said "this is why we BELIEVE dark matter exists. On a video titled This is how we KNOW dark matter exists. Gotta love dogma in science, such a nice fit :)
"How We Know Dark Matter Exists"... and then in the video: "...the evidence we have so far is strong but a bit circumstantial... which means we are not absolutely 100 percent sure that dark matter is a real thing." We "know dark matter exists" but we aren't sure? How does that work exactly?
At 10:37 this is exactly the opposite from what Oort said according to Wikipedia en.wikipedia.org/wiki/Jan_Oort. Stars closer to the center revolve faster than those at the edge...just like our solar system (differential rotation). This is what happens when you get your science from KZread.
@JohnShalamskas
Жыл бұрын
Stars close to the aupermassive black hole certainly do move quickly, but once you get clear of it, the gravity of the stars and other matter outside the radius of your orbit cancels out, only the matter inside your orbit will pull you towards the center of the galaxy. So galactic orbital velocity is slower at the center and faster as you move towards the edge of the galaxy. If you could burrow to the center of the Earth, you would find zero gravity there for the same reason. There's equal mass in all directions, so the gravity cancels to zero.
@quandaryisme
Жыл бұрын
That is certainly true in our solar system where then sun makes up 99.x% of the total mass. However in a galaxy, the mass is more spread out.
The fact is that we DON'T KNOW if dark matter exists or not. All we know is that for most galaxies (but not all), the gravitational forces holding galaxies together seem to be far greater than can be calculated from the observable mass of the galaxies. The laws of physics governing gravity don't fit the data. So either there is something distorting the data, or the laws of physics are wrong.
“I am happy to be a small potato in the eyes of the cosmos. For most are smaller than a speck of dust in its vastness.” Mr. Potato
Those James Webb picture Professor DrDon! Super Galactic invisible weight that is so prolific it looks like foam ? **YourHumbleStudent** ;-)
Gel? 😳 We live in jello as the pieces of fruit? 😳 We're fruity jello pieces? 😳 Or 😖 slime? 🤢 Oh dear for us. 😬 Oh dear! 😫
Isn't it pretty easy to assume that the strange observations on a cosmic scale would be similar to our quantum observations? I believe dark matter isn't real and it's simply our misunderstanding of physics.
@dzenacs2011
Жыл бұрын
Just cause we are to stupid to understand gravity on galactic scale. So we creating mathematical placeholders to connect the dots
So we need dark matter to pull things together...and dark energy to make things fly away from each other. Or it could be an entire branch of science based on a set of theories that are simply wrong fundamentally. Unfortunately so many scientists are spending time tweaking mathematical formulas to try to make these theories work we may delay finding the real answers for decades or centuries.
We postulated the strong force and the weak force based on the lack, of knowledge that quarks with charge distributions internal to neutrons and protons existed. These charge distributions that we now know exist can account for all forces needed to bind protons and neutrons within the nucleus. Every force is therefore electrostatic/magnetic and all we need is Maxwell's equations . Mass would be the result of accelerating electric fields as scientists long ago concluded. Gluons, and other postulations are just mind images to help us imagine!
At the beginning something created time which became charged space which coalesced into matter explaining quantum and the double hole experiment .
i knew that !!
I have seen thermodynamic derivations of the universe that show empty space has mass and energy of the proper amounts. Since thermodynamics is more relevant (more real should one say?), it appears there is no discrepancy. We are using too simple of a vision.
Alternative Explanation of Dark Matter and Dark Energy - Newly proposed model of Universe can explain both of Dark Matter and Dark Energy Einstein’s theory of General Relativity states that spacetime is curved by the presence of mass. This curvature influences the motion other objects with mass and gives rise to gravitation. Thus, gravity is a result of geometric features in spacetime. However, we also observe gravitational effects - curvature of spacetime - in areas without any detectable mass. This has given rise to the concept of dark matter, which is matter that does not interact in any detectable way with normal matter, except through gravity. So, there is some large quantity of dark matter scattered throughout the universe, which curves spacetime and causes gravitational effects just like normal matter, but we cannot see or detect it with any known method. An alternative theory to the identity of dark matter is proposed - it is not matter at all, but rather an intrinsic curvature of spacetime. In other words, spacetime is not naturally flat. Even in the absence of matter, we observe some inherent curvature of spacetime. So, the question is now - why is spacetime naturally curved? Why is it not flat in the absence of mass? The universe is 4-dimensional, with 3 spatial dimensions and one dimension in time. Rather than consider time as a linear dimension, we can consider it as a radial one. Therefore, rather than describing the universe with a Cartesian coordinate system, we describe it with a 4-dimensional spherical coordinate system - 3 angular coordinates, φ1, φ2, φ3, and one radial coordinate in time, t. We live on the 3-dimensional surface of a 4-dimensional bubble which is expanding radially in time. Thus, the Big Bang represents t=0, the beginning of time. The crucial point is that the expansion of the universe is not homogeneous in all directions. The expansion rate at one point on the bubble’s surface may differ slightly from another point near it. The universe is only roughly spherical in 4 dimensions, the same way that the Earth is only roughly spherical in 3 dimensions. The same way we observe local mountains and valleys on the surface of Earth, we observe local “mountains” and “valleys” on the surface of the universe bubble. The inhomogeneity of the expansion of the universe has given rise to natural curvature of spacetime. This natural curvature causes the phenomenon of “dark matter”. “Valleys” in spacetime pull matter in, similarly to the warping of spacetime of massive objects. So “dark matter” is really “valleys” in spacetime that are expanding slower than the regions surrounding it. These valleys tend to pull matter in and create planets, stars, and galaxies - regions of space with higher-than-average densities of mass. Conversely, “mountains” in spacetime will repel matter away, an “anti-gravitational” effect, which gives rise to cosmic voids in space where we observe no matter. Each point on the surface of the universe bubble traces out a time arrow in 4-dimensional space, perpendicular to the surface. These time arrows are not parallel to each other since the universe is not flat. This causes points to have nonzero relative velocity away from each other. It is generally accepted that the universe is expanding faster than observable energy can explain, and this is expansion is believe to be still accelerating. The “missing” energy required to explain these observations has given rise to the theory of dark energy. The time dilation caused by non-parallel time arrows can be proposed as an explanation for dark energy. Alternatively, dark energy is real energy coming from potential energy gradients caused by non-parallel time arrows. As a sanity check, we can calculate the expansion rate of the universe based on the universe bubble model. Since the radius of the universe bubble is expanding at the speed of light in the time direction, it increases at 1 light second per second. Therefore, the “circumference” of the 3-dimensional surface increases by 2π light seconds per second, or about 1.88*10^6 km/s. This expansion is distributed equally across the 3-dimensional surface, so the actual observed expansion rate is proportional to the distance from the observer. At present, the age of the universe is estimated to be 13.8 billion years, so the radius of the universe bubble is 13.8 billion light years, or about 4233 megaparsecs (3.26 million light years to 1 Mpc). Thus, we can calculate the expansion rate of the universe, per megaparsec from the observer, as: Expansion rate = ((d(circumference))/dt)/radiusofuniverse=(1.88*〖10〗^6 km⁄s)/(2π*4233Mpc)=(1.88*〖10〗^6 km⁄s)/26598Mpc=70.82(km⁄s)/Mpc The popularly accepted empirical expansion rate is 73.5 + 2.5 km/s/Mpc, so our calculated value is close. There may be some additional source of expansion (or observed red shift) to make up for the discrepancy. For example, if two adjacent points have some gravitational gradient due to non-parallel time arrows, then light passing through these points will be red-shifted. - Cited from www.academia.edu/82481487/Title_Alternative_Explanation_of_Dark_Matter_and_Dark_Energy
How we know dark matter exits! Its simple the same way we know unicorns exist.
How we know something is missing in our model that bends spacetime more than expected. Dark matter is a misnomer and leads to nothing. It's information by the way. Hope this helps.
@NondescriptMammal
Жыл бұрын
"Spacetime" is a mathematical abstraction, not an actual substance. So is its "curvature".
We know that if you bump up against dark matter that it’s there , it matter’s to stay away from it
The answer tree (@ 19:00 ) is going to lead you astray. The correct answer will not only join all of the branches of that tree, but explain and modify our understanding most if not all of known physics.
I really enjoy how you lay these out in terms most can understand. The PBS YT channel is good, but it gets too heavy into physics for most. I'm going to stubbornly say I don't believe that dark matter exists. It either means an utterly new type of matter in huge amounts that we can't even identify, or perhaps our understanding of gravity on massive scales isn't complete. I'm going with the latter, because we do know definitively we don't fully understand gravity.
@Metastate12
Жыл бұрын
That's because unlike this channel, PBS is accurate.
Title change: "Why We Think..."
Great content, but I don't understand why so many videos insist on shooting their subject from the side. I find it very off-putting.
If you were to so brazenly measure, to our collective make up and mass within the entirety of the known universe? We are truly an atom scaled entity entirely at the whims of the larger forces encompassing us. So very very miniscule. What is amazes me is that you can keep going and get even smaller and smaller and smaller. From the miniscule to the mega large the universe is quite the joy to think about during the course of a day.
Einstein's theory of relativity is not the do all and end all, as it breaks down as mass approaches infinity (i.e. gravity in a black hole). There is much we do not know and much to still learn if we will be willing to throw out what we THINK we know and start from scratch.
Dark matter is locked up in spacetime itself. If you want to find it you will need to create gravitational waves with enough energy that dark matter radiates the way photons radiate from electromagnetism.
@mickhealy572
Жыл бұрын
or you could check this out ..PLASMA COSMOLOGY VS BIG BANG MYTHOLOGY EXPLAINED
You're starting to get it. Almost there. We are merely bubbles in a gigantic ocean of dark energy.
Has no one ever thought that the galaxies are 72mps per mega parsec closer and much bigger than perceived due to gravity?
Black matter and energy has been added to field eq. To sustain observation, accordig that in field equation there is no spin, no torque, no coriolis effect. E. Rauscher has added spin, torque and coriolis effect in field eq then no more need of black mater neither black energy.
Aren't the stars stationary but the dark matter is what's rotating?
Best explanation so far for people like me who has zero knowledge about this topic.
@TheGreatCourses
Жыл бұрын
We greatly appreciate your feedback.
Someone give Don a dark chair.
Miss your t-shirts
A better placeholder name would be something like "missing gravity". We don't know that dark _matter_ exists. It might get overturned just like the "ether" did more than a century ago.
@BH-ip6ds
Жыл бұрын
Yes and overturning the "ether" hypothesis let to the theories of relativity and other revolutionary ideas in physics. It is amazing how little we understand about the universe.
@mrloop1530
Жыл бұрын
@@BH-ip6ds Exactly. The "dark matter" hypothesis might just be a quick-fix for something more fundamental about the universe that we haven't understood yet. Yeah well, it is also pretty amazing how much we understand about the universe. And (fortunately(?)) there will - presumably - always be a horizon of unsolved puzzles ahead of us.
"Dark Matter" is just a place-holder for explaining why gravity works weird in observation. Saying Dark Matter exists, is silly. But we do know that there's 'something' causing gravity to work differently than predicted. What that 'something' is, is down to a guess. There is something which causes our observations of matter & gravity to mathematically fall apart at a very large scale. Is it matter which is dark (not visible to us)? is it extra-dimensional effects? does relativity need another layer to the equation? is it intergalactic circus clowns? The effect is all we actually know anything about.
Can the existence of a super massive Black Hole at the center of each Galaxy explain the way the Stars orbit the Galaxies too fast??
How do you know these distortions are not caused by the way our brain organizes that light, bends that light through our eye lens etc… Optical illusions are real so maybe these lights have physical properties as well as metaphysical properties and we have trouble deciphering between the two, correctly measuring each because of not taking into consideration variables that effect both.
I may be tiny when compared to a star, but can a star build a 9 second Miata? No. No it cannot.
It’s simple, there is no dark matter. All our observations have not been corrected for gravitational time dilation. The stars appear to be moving too slow in the middle of the galaxy because there is a tremendous amount of gravity causing time dilation effects. Time dilation effects also cause the other perceived dark matter occurrences we observe.
@classica1fungus
7 ай бұрын
Lol
Why is there so many camera angles on one man talking?
I think Dark matter is nothing but frozen time. Dark matter melts into time and expands the space of Universe, it bends light at denser points, yet only detectable by its effect on observer and is always untouchable and unfathomable like time. When velocity of an object increases, dark matter acts thicker to it like ice, rather than liquid, and melts slowly. Hence time dilation in relativity Just like when a spacecraft re-enters earths atmosphere, it feels air thicker than it normally does at lower speeds A wormhole is the absence of dark matter due to excessive melting and it consumes lots of energy to maintain it. Dark matter touches almost everything observable, hence information is passed on between entangled particles Dark matter limits the speed of light. Speeds higher than C is also possible in the absence of Dark matter (Eg. inside Wormhole) Gravity thickens Dark Matter. It melts slowly near the source of gravity and melts faster into time when away from the source of gravity Dark matter exists even before Big Bang and acts as a controlling canvas for Big Bang. And the Big Bang is currently spreading on it
Novel Dark Matter Hypothesis Dark Matter is simply unaccounted for gravity. GR states that gravity is the consequence of the curvature of spacetime. Is it possible that the structure of spacetime itself could be warped without the presence of mass? Spacetime has been shown to react like a fabric by warping, twisting, and propagating independently of mass, and all have been proven with observations from gravitational lensing, frame dragging, and now gravitational waves! Fabrics can be stretched, pressured, and/or heated to the point of causing a deformation and losing its elastic nature. All of these conditions were extreme during inflation, so it is plausible that the “fabric” of spacetime analog could extend having its elastic property have hit a yield point? Therefore, if gravity is strictly the consequence of the warped of spacetime, and fabrics can be permanently overstretched, then those empty warped geodesics would create gravitational wells independent of mass. My hypothesis of DM is subatomic black hole imprints of the quantum fluctuations that popped in at the moment of inflation. The CMB shows where the hot dense regions were they created the galaxies. They would have been the initial cause and location of the warping. These imprints would be clouds of quantum sized floating fixed geodesics, so they couldn’t expand or evaporate. Perhaps nothing has been detected because there is nothing to detect. GR wouldn’t require modification because DM would just be an extension of how spacetime behaves at extreme conditions. No MOND, no WIMPs, and no parallel universes, just empty spacetime deformations that produce gravitational wells to help jump start galaxy accretion processes. Zwicky may have named is Missing Mass correctly since he detected some gravity without mass present to cause it…
He's dapper dan on wondrium but I'm not sure that the awkward side views are necessary.
THANK YOU... PROFESSOR LINCOLN...!!! 1. Dark matter joke : Massive Body , after giving away everything it had RIP ( Rests In Peace )...for a while... until slowly RE- INCARNATE and start roamoing around the PRAPANCHAM... to find the Right SPACE & Right TIME to Settle...!!! Professor, 2.This student, like the small potatoes... because it is packed with energy and flavour and it is unselfish in occupying the Space...!!! 3.Like the smiling galaxy too...!!! THANKS AGAIN DR. LINCOLN...!!! Hope you get my jokes...!!!
@user-lc8yc4cq5n
Жыл бұрын
You forgot garam masala
Dark matter could it be the reason why we can't see it is because it out of our specterem of site the same with light and sound I hope that he sees this
Aha, The bullet cluster on the way to forming dark matter free galaxies. I thibk the dark matter is undetected rocks tp black hole. How about testing n-body gravity? Divide a galaxy up by sectors and compute attaction of each sector to every other sector.
If we don't know about dark energy, and we aren't absolutely sure, how do we know that, "that unknown" is 96% and that finite known matter is 4% - it's like stating "I am 96% ignorant" - how did we measure that - our methods of measurement are flawed
But does dark matter attract dark matter, and if so, does it clump together, eventually creating black holes where no visible mass was detected??
@roundtownKen
Жыл бұрын
Not black holes, "Dark holes"(?)
@user-lc8yc4cq5n
Жыл бұрын
It's the "clump" part I have a problem with.
@charlesrobbins1247
Жыл бұрын
Yup
A good imagination is a way to make believe.