Cosmology | Lecture 1

Lecture 1 of Leonard Susskind's Modern Physics concentrating on Cosmology. Recorded January 13, 2009 at Stanford University.
This Stanford Continuing Studies course is the fifth of a six-quarter sequence of classes exploring the essential theoretical foundations of modern physics. The topics covered in this course focus on classical mechanics. Leonard Susskind is the Felix Bloch Professor of Physics at Stanford University.
Stanford University:
www.stanford.edu
Stanford Continuing Studies:
continuingstudies.stanford.edu/
About Leonard Susskind:
www.stanford.edu/dept/physics/...
Stanford University Channel on KZbin:
/ stanford

[@tomaascespedes]

Who came here from MIGALA? Just found this on his Philosophy playlist

[@pensionistakawaii220]

Same

[@EduardoHuerta4]

Me too

[@alonso2254]

Same

[@mewe1717]

No mames---

[@rubendario474]

Yo estoy aquí por pasado de verga nomas

[@masseffected20]

I have learned physics I and II, linear algebra, quantum mechanics all in about two years through free lessons and lectures. I now have a job at a small particle physics lab in Colorado. You do need a degree to get certain careers, however you can do it on your own without paying to go to Stanford or MIT. It does help to buy some textbooks although.

[@user-ls8ks7kv8c]

Massive respect

[@INHeadKay]

It's always been one of my dreams to get cosmology lectures from Leonard Susskind one of the greatest minds of our time, so thank you Stanford for this great opportunity, and for supporting the spread of knowledge, its really awesome!

[@Martin.Farras]

Llegué acá porque estaba en una lista de reproducción de Migala

[@El_Berto]

yo igual

[@max_gabriel_1238]

Igual yo, sabes como lo puedo escuchar en español o subtitulado al español?

[@nighatshafi3109]

@@max_gabriel_1238 qq

[@7ssidane]

yo

[@nighatshafi3109]

@@El_Berto 01p"""ł

[@joabrosenberg2961]

Scale factor in 1-dimensional case 9:00; Hubble constant 17:30; Homogeneity and isotropy of the universe 34:00; Geometry of space 49:00; Closed Universe 1:14:30; Life on a circle 1:22:30;

[@sznaimer]

Susskind is an incredibly brilliant communicator, distilling the story of cosmology down to its essence. He keeps all the math the provides insight , but never gets bogged down by tedious derivations. We are very lucky he contributed his time and teaching skill to this series.

[@laurencrom]

I love how this professor starts simple and builds up perfectly as the students' understanding increases! This is truly an invaluable resource.

[@Matt77125]

Lecture 1 : 250k views Lecture 2 : 8k views Great attention span there :L

[@frogz]

7 years later and its more a 4/1 ratio, 480k views vs 128k views

[@Gismho]

These are EXCELLENT lectures. Prof. Susskind obviously knows how to explain this subject. Thank you.

[@MonkeyPoida]

Just what I was looking for. A lecturer with high knowledge of cosmology and who writes neatly! Great series.

[@Moath1277]

"No matter how much you believe it to be true, or how elegant and well versed its mathematical and geometrical model may be, a theory proposed in areas where no human experience is possible or attainable, will never be anything more than naturalist mythology! No better than the myths of creation adhered to by the tribesmen dancing around the fire praying to a totem in the forests of Africa." -Dr. AbulFeda Bin Massoud kzbin.info/www/bejne/mqi8fJqqn6yErw

[@youraverageidiot6474]

Moath Ibn Jabal wut

[@Moath1277]

Cool Guy cosmology is a pseudoscience basically

[@lipton3120]

@@Moath1277 ok

[@mannys9130]

@@Moath1277 Spoken as an ignoramus, the likes of whom can't grasp nor explain what is discussed in this video. 😸😸😸 Go play with your fidget spinner and listen to your QAnon.

[@nicodanny2112]

These lectures are fantastic. Not only does it give a great description of the world around us but it's also caused me to adopt "everywhere's " and "somewhere's " cuz it just sounds cool.

[@foruharfarah742]

Until now I learnt soooooo much from this great man....I just want to say one sentence: I love Susskind for spreading his Knowledge....And of course thank you Stanford!

[@anmartine]

I'am very greatfull for all this lectures... And yes older people want to be informed and learn again and again! In these lectures my past, what I learned about fysics, etc... reawakens and adjust! Wonderfull!!! Thank you L. Susskind! Jou're a great theacher! And thanks to the Stanford University to make it possible! I know that the coming winter I will turn to all this lectures again... and again! It is better and worthfull than ordinary TV!!! Thanks so much!! Learning keeps people yong!

[@allanoates2418]

I was trying to get some answers about the purpose of this course in modern cosmology. Professor Susskind is a wonderful lecturer and I enjoy every course he presents. I know he's not God to know everything , so I asked/exchanged some ideas with other people and I got some Godlike answers, excathedra fully blasting my boat off the waters. I returned with humility back to the course since it seems very interesting to me and with more questions. One of them is if this course is talking about

[@jordanbarker676]

he is the perfect physics teacher, the way he is able to convey ideas is so brilliant and easy to understand. he also sounds really wise (haha that important with a physics teacher, if they sound boring the lessons will be boring). a very clever bloke who has a great talent for teaching, very well done!

[@Computerdisplay]

wow...I watched this video months ago and thought this man was just an ordinary teacher (a very good one though) from a great university....but I just found out he is one of the leading intellectuals in physics!!

[@johnreymillete5862]

When quarantine is too much that I unintentionally having interest with this topic

[@tehsma]

Sharing these lectures with us was very generous. Thank you Standford!

[@RodneyAllanPoe]

Susskind and Wolfram have a hypnotic way of talking. Thanks for posting these lectures.

[@serbanmike]

Einstein postulating the speed of light as 300,000 Km/s was one of the Einstein’s shortcomings. In actuality the speed of light was calculated before him and the results varied.What Einstein missed was the fact that the speed of light depends of the fluid of space in which it is observed. If the energy-density in the space through which the light travels is different, the speed of light is different and can be above or below the postulated limit. His big error was that he eliminated the "ether"

[@bienneswitzerland]

“Just for fun let’s suppose that we have t squared dt squared. Just for fun” Leo Susskind

[@jamil5454]

Thanks Stanford for helping to educate the masses about our physical reality!

[@gulshankhanna1687]

great work. Thanks Stanford.

[@bienneswitzerland]

“Alright I’m not going to tell you the entire history of cosmology” Leo Susskind (Lecture 1)

[@BarriosGroupie]

Susskind is one fantastic lecturer. He's brilliant because he knows what he's talking about and is like a conductor conducting an orchestra - his mind

[@perrodisgustadoconlosfideo5672]

Qué chingados hace en la lista de Migala?

[@NeedsEvidence]

Einstein introduced the cosmological constant to explain the seemingly static universe he thought he lived in, based on limited data available to him. He withdrew this not because it is an actual mistake but because it appeared superfluous given better data becoming available, showing the universe expands. It is now re-introduced in the face of even better data, showing that the universe's expansion is accelerating. These is all data-driven, intellectually honest conclusions.

[@franklunetta752]

Extremely helpful, totally simple explanations

[@jonathanbyrdmusic]

Thank you so much for making this available. This is incredible.

[@SeaAquaBlue]

Comprehensive & very well taught!! Great series - thank you very much!...

[@blackwaterlegacy]

I find fascinating the way Susskind understands physics. He makes thing way too easy. It will be a pleasure talk to him about physics.

[@joaop3268]

WELCOME TO 20st century, where HIGH QUALITY EDUCATION is for free, and for everyone, you just need an internet connection. Blesses from Brazil

[@cellofingers]

I like his layout of lectures. I'd be scared as hell to take a test under this guy he's brilliant!

[@NeedsEvidence]

Two pieces of matter that are close to each other have less positive energy than the same two pieces a long way apart, because you have to expend energy to separate them against the gravitational force that is pulling them together. Since it takes positive energy to separate the two pieces, gravity must be using negative energy to pull them together. Thus, the gravitational field has negative energy. In a flat universe, negative energy exactly cancels the positive energy of matter.

[@Nirvanaaist]

never give up man ! I am now in the university studying this stuff but I did not have chance to watch these videos when I was 13 ! Learn science and math very well till you start university !

[@Imafungi123]

Time doesnt exist apart from energy/matter. The dynamical description or measurment of changes in energy/matter existing in space is time. That is how they are intwined, energy exists and acts in space, this activity can be measured with time. Just as energy/matter acting across space can be measured with distance. so a curve in time, would be an object taking longer to get to us because the curve in space.

[@Moopy241]

In most cases I think so George. It's not quite so "cold and faceless" and a class filled with students is not always so interactive. But I understand your point.

[@TheRaccoonable]

@xCosmicProductionsx i am completely with you. i love anything and everything that has to do with space and the cosmos, it is just so facinating learning about how endless the universe is.

[@lsbrother]

"" I can learn everything I want without having to spend thousands of dollars going to college? Nice."" -- and even better - there's no exam at the end!!

[@NeedsEvidence]

Not the Big Bang is an artifact (we don't know what it was) but singularities (infinities) appearing in current physical theories extrapolated to the conditions of the Big Bang. The Big Bang might be something finite, non-singular. An improved theory extrapolated to the Big Bang might not have singularities at all.

[@Sparklngcrystalz]

This teacher is great. The video is a solid argument for attending an ivy league college.

[@coastwalker]

I'm looking forward to the lecture on curved space time already :-) This is brilliantly explained.

[@NeedsEvidence]

Conservation of the total energy is a direct consequence of a basic symmetry called time invariance of the equation of motion. But if the space expands, this symmetry is broken, hence what we usually call energy is not conserved. Example: An isolated photon loses energy simply traveling through expanding space (it is red-shifted). Where did the energy go? Energy is not well-defined in the theory of general relativity. One can address this by including gravitational interaction energy density.

[@askshbni]

amazin...........i learnt soooo much....he has such an interactive way of teaching......!! thnx professor

[@hasanshirazi9535]

Great explanation of Hubble parameter as well as metric of space-time.

[@hjembrentkent6181]

son u be trippin susskind is the realest OG of physics

[@Dexteritye]

This is like a home school :D Thanks for everything on all your videos :D!

[@Piitsi]

Good camera operator! Susskind is brilliant as usual.

[@paolaarnez5840]

Ni siquiera hablo bien el idioma, tampoco tengo una base más que un poco de educación mediocre en el tema y aún así me pareció una clase realmente interesante, resolvió muchas dudas que otros simplemente no me explicaban, creo que tener la capacidad de explicar algo tan complejo de forma tan simple es un rasgo de un buen profesor.

[@NATHANTHEPIMP]

This is awesome. I think I'm picking up on some of it.

[@chicalleje]

This has been measure watching star in neighbour galaxies, but the number of detection does not acccount for all the mass that is necesary to hold the star in a galaxie toghether. So now we pretty much know that dark matters are particles that weakly interact (like neutrinos, but not moving so fast) and not MACHOS in any significant amount. Sorry if my english is not perfect, I have a hard time even writing in spanish. Hope that helps

[@mellobassman]

You're welcome Professor Susskind. Over several centuries, people have been compelled to believe in ideas that actually and factually symbolize the Universe and the celestial bodies.

[@serbanmike]

Thanks. I was reading your response and now I see what the problem is with this Universe which started out of a minuscule ball of energy and expanded to what we have today. Actually reading Max Plank, I found one of his thoughts regarding our Universe ”Science cannot solve the ultimate mystery of nature because, in the last analysis, we ourselves are a part of the mystery we are trying to solve” so we actually are part of the set we are trying to solve. We have to be outside it to solve it.

[@enoughzenough]

Thanks, I'll have a look at this lecture you're talking about.

[@enoughzenough]

Thanks, this makes very much sense. Yet what I've read about the Cosmic Crystallography theory is very interesting indeed, but this approach has very much scepticism in it. Thanks for the information.

[@terrafirmaterrafirma]

@MrSpacetimeTraveller I am glad you think so.

[@petesmith3516]

Well explained.

[@raunaksarada]

seems like he looks same from thousand year😁 such a nice man is susskind

[@allanoates2418]

I am pressed by time and I want to take advantage of what is the newest in the field. I would not spend time on something that would be of no use to me in the near future. To round myself off, I would take courses in the history or development of the science to have a better idea of the status quo , current and future trends. I bet there is a lot going on in this field, as much as in physics that would not be "orthodox " by the current standards and "swallowed" easily by the establishment.

[@allanoates2418]

Thanks for the input. I just wonder if you can give me/us some references. I want to go beyond the videos on the Utube, I want to check sources myself and to corroborate them. Do we miss something in schools? Is this info readily available?

[@deedubya286]

You have to look on a scale large enough that the filaments and voids become a repetitive pattern. Looked at on a small scale a piece of cloth has obvious threads and gaps analogous to galactic filaments. Looked at on a scale of a square foot or so, it becomes a homogeneous tapestry.

[@xacupofteax]

Excellent watch!

[@chicalleje]

Most of dark matter is particles that gravitates but don't interact in any other way. Friction doesn't affect dark matter like affect our own matter, so dark matter does not condense in a small region like thecenter of a galaxie. So the gravity is not much per volume to bend the light or other electromagnetic radiation. That is "most" of dark matter, there are some jupiter-like and little black holes out there that "CAN" bend the light creating a lensing effect.

[@omandscience]

Sir,which book is referring for cosmology?

[@metafa84]

Thanks very much for posting !!

[@nurlatifahmohdnor8939]

Page 42 1. rubber = ge-tah 1| Pounds per square inch = E = 0.001 × 10 to the power of 6 (i.e. 1,000) 2| MN/m to the power of 2 = E = 7 pounds > tons Stiffness = Young's Modulus = E 2 Unreinforced plastics 0.2 , 0.0014 mi 3 Organic molecular crystal, phtalocyanine, a blue pigment 0.2, 0.0014 mi 4 Wood (about) 2.0, 0.014 mi 5 Concrete 2.5, 0.017 mi 6 Bone 3.0, 0.021 mi 7 Magnesium metal 6.0, 0.042 mi 8 Ordinary glasses 10.0, 0.07 mi 9 Aluminium 10.5, 0.073 mi 10 Steel 30.0, 0.21 mi 11 Aluminium oxide (sapphire) 60.0, 0.42 mi 12 Diamond 170.0, 1.2 mi

[@giovannasculli5073]

I love professor Suskind! 🥰

[@deedubya286]

I'd never heard of the Sloan Wall so I had to Google it. According to Wikipedia it is the largest known galactic filament but is still only 1/60 the size of the observable universe. You're right about his comment of "a few hundred galaxies" being misleading. I found he is often very imprecise about cosmic measurements. In one of his previous lectures he was clearer about the homogeneous scale lying between filaments and the distance at which the universe becomes too young for structure.

[@NeuroScientician]

Yes pretty much. Usually is more interactive and you also get some handouts.

[@starhawks1]

@a3th3r two more I forgot.. those in the lecture would have had to have taken pre-requisites that would allow them to actually understand the material, and they can ask questions

[@will2see]

What would it mean if the 1 (the gtt) in the spacetime metric is also some function of time t? Would the model still be homogeneous and isotropic?

[@JamesTKirkCobain]

Ooh cosmology! I am like so totally interested in this. I always wanted to work with make-up and stuff.

[@cityfoxx4051]

Alot of you have been asking questions i feel are simply explaind bye dr. David butler in his "how far away is it" a must see on youtube for any1 with interest in cosmology

[@2020bane]

Love these videos

[@MiSsDallo0o3a]

"this is worse that flatland; this is lineland." HAHA I LOVE THIS GUY :D

[@LeonhardEuler1]

@TheYoungCosmologist You should start studying the mathematics!! They are equally interesting in and of themselves!!! I particularly like the study of Riemann surfaces, as well as symplectic topology.

[@xrayquantic]

“What if truth itself is non-all, affected by the real-impossible of an erreducible antagonism? However, does Deleuze also not follow this path?”.. ŽIZEK, Slavoj - Organs Without Bodies on Deleuze and Consequences - THe blind spot: There is a Non - LInear Geometry Topology and Events are in and out of Caos in the Horizons of it, so the consequences, are the limits (of truth) our Mind, but not in Ramanujan's Topology, so to speak.

[@enoughzenough]

Thanks for the information.

[@sc0rpi0n0]

How did energy turn into building materials or matters? It's explained in Einstein's general theory of relativity. In fact, matter like atom is actually still in energy form. It is something to do with our consciousness that we see and feel energy as matter. Matter is just our perception of this special form of energy. Mass is given to certain particles such as neutron, proton and electron by the elusive Higgs Boson, and Higgs Boson itself is also a form of energy.

[@MumblingMickey]

This is about as simple as it gets from a guy who is recognised as one of the best lecturers worldwide... They have cats doing tricks on youtube too! Maybe you're in the wrong place?

[@ratioveritas9983]

00:50 "But of caaawse" Sounds kind of NY, then at times LA. Good professor and nice man he seems. Great lecture

[@scooterbaldwin]

my question would be if space and time are always intertwined, and space is curved, how can we calculate a curve in time?

[@ignatei]

These are the standard notations in many calculus textbooks, Δx denotes the difference between x's, not exactly the same meaning as dx. And in many differential equations textbooks the dot notation is used, x^. meaning dx/dt or y^. = dy/dt esp when dealing with a system of DEs.

[@clevelandtyler2]

What kind of prerequisite classes would I need to take a class such as this?

[@allanoates2418]

What is the principle of conservation of energy good for? Is that for close systems only? The way you explain it there is Energy Created as we speak. We are living in an expanding Universe, are we?

[@MumblingMickey]

17 dislikes? who watches almost two hours of a lecture on cosmology by Len Susskind to then clicks dislike? wtf? lol

[@philipkatzan9973]

Good program!

[@tabaks]

As I'm listening to this lecture, I keep thinking about one issue in my mind. The "farther" we look, the farther into past we're looking, not knowing at all what current layout of observed region is. I also firmly believe that we philosophy

[@TaraBryn]

That maybe so, if the universe is big enough to get to that scale (I believe the sloane wall is the largest structure so far known to man), but certainly, that scale would be much much larger than what seemed to be implied by what Mr. Susskind said ("a scale bigger than a few hundred galaxies" could be a supercluster, and a single filament is composed of many superclusters)

[@metanosis]

@TheNickFlurry short answer...math,math,math.....there are two hard things about physics, [1] being able to visualize and understand complicated physical processes, i.e. physical intuition [2] MATH. Now, if you are good at math, the math can help with physical intuition. I would do at least a masters in math or the equivalent for starters, i.e. analysis, algebra, and topology especially for cosmology, other than that, just the regular physics coursework leading to specializing in cosmology.

[@viktorsabo]

love the analogy to flatland book. :)

[@FinisReflectatOpus]

@starhawks1 Yes, I see what you are saying: all the rigor is missing when it comes down to it. Whoever has survived university training knows this as an experiential fact (we know that no ordinary power could possibly have driven us to learn so much so fast). Of course, this gives those of us who have survived "special forces training" (and excelled within that system) a special right of opinion. Exercising that right, one also has the creds to dissent. Well, unless you want a grant that is!

[@alexloosen]

This guy is brilliant

[@oanadb]

@antimatterXXXIII Could you post a link of a video where a professor doesn't, in your opinion, suck at lecturing in either Physics or Math? I'm sincerely interested.

[@manvanthar1993]

I love an old man teaching my fav topic

[@freshramses]

Thank you!

[@allanoates2418]

In the begining was NOTHING, then it was a fluctuation of that NOTHING that turned into SOMETHING. That SOMETHING blewup and formed a bunch of energy, which formed into gas, which formed into matter. which then formed stars, which formed galaxies, and in galaxies planets were formed.

[@arthurlewis9193]

There was never "nothing."

[@ianmathwiz7]

Variable *frequency*, not speed. The speed of light in a vacuum is constant, no matter how dark it is.

[@terrafirmaterrafirma]

At around 38:58 minutes the comment: I don't know if Pythagoras new the 3 dimensional Pythagorean Theorem? Answer: No! The Pythagorean Theorem introduced here is a result of the introduction of the Cartesian Coordinate Sytem. The idea of this system was developed in 1637 in two writings by Descartes and independently by Pierre de Fermat, although Fermat used 3 dimensions and did not publish the discovery.

[@allanoates2418]

I don't get it. In lecture 4 Prof. Susskind states right at the beginning in a Q&A session that galaxies move at speeds over c, Even in Newton law of Gravity F= G.m1.m2/d^2 The gravitational interaction must happen at superluminal speeds. If that would not happen the orbits of the planets would decay in time since the distance from Sun to Earth is taking light 8.3 minutes , so the orbits would decay and planets fall into our Sun.