Cosmology Lecture 1

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  • Опубліковано 27 січ 2013
  • Help us caption and translate this video on Amara.org: www.amara.org/en/v/BWxP/
    (January 14, 2013) Leonard Susskind introduces the study of Cosmology and derives the classical physics formulas that describe our expanding universe.
    Originally presented in the Stanford Continuing Studies Program.
    Stanford University:
    www.stanford.edu/
    Stanford Continuing Studies Program:
    csp.stanford.edu/
    Stanford University Channel on UA-cam:
    / stanford

КОМЕНТАРІ • 930

  • @Incognito-vc9wj
    @Incognito-vc9wj 4 роки тому +1614

    It's nice to be able to learn without the distraction of grades.

  • @mahakalkrishnaji1289
    @mahakalkrishnaji1289 Рік тому +76

    I am. 82 years old.. I watch this to expand my knowledge. Thank you sir.

  • @andrewstang-green3107
    @andrewstang-green3107 8 років тому +881

    I love that we get to experience a higher education, even without the money we are so fortunate to have this information public.
    The world is truly waking up! Thank you!

    • @Frosty-oj6hw
      @Frosty-oj6hw 7 років тому +30

      And I would say ideally support this by buying his books, they support the series really well and put money in his pocket for this fantastic work.

    • @PaperPlateClorox
      @PaperPlateClorox 5 років тому +7

      agreed

    • @michaeljorfi3552
      @michaeljorfi3552 5 років тому +5

      @John no

    • @skeeterburke
      @skeeterburke 5 років тому +3

      now all we need is to convince Elon Musk to take some flat earthers up to the ISS so they can see Earth's curvature for themselves #hisnameisYehoVAH #RONWYATTWASNOTAFRAUD

    • @darcyh1241
      @darcyh1241 4 роки тому +5

      I love listening to lectures as well. Dr. Susskind is an excellent lecturer.

  • @janeg8536
    @janeg8536 9 років тому +416

    Loved watching this! I am a senior in high school planning on majoring in astronomy and I can't wait to learn more about our universe!
    Update: I don’t remember making this comment lmao, it’s been a long time. But for those asking I did get my undergraduate degree in astrophysics and I am now a physics PhD student studying gravitational waves!
    Update again: As of March 2024, I have officially passed my thesis defense and now have my doctorate in physics! I spent my time studying how noise can impact the gravitational wave detectors.

    • @joniaui6809
      @joniaui6809 6 років тому +1

      Jane Glanzer The universe is dark

    • @frontl1ner
      @frontl1ner 6 років тому +17

      Jane Glanzer been 3 years since your comment how did it go?

    • @alexrodriguez9520
      @alexrodriguez9520 6 років тому +5

      Jane Glanzer how beautiful is your conscious expanding

    • @awkweird_panda
      @awkweird_panda 5 років тому +4

      Are you through with your major yet? Do Let us know.

    • @empty2110
      @empty2110 5 років тому +2

      Jane Glanzer legend has it she will never tell us

  • @PurnamadaPurnamidam
    @PurnamadaPurnamidam 2 роки тому +213

    Sitting in a small island in the Indian Ocean and learning from such a distant place without any fear is what UA-cam should be. Thankyou Susskind sir you are one of a kind.

    • @emilianotristan3900
      @emilianotristan3900 2 роки тому +3

      I'm also in a island

    • @PurnamadaPurnamidam
      @PurnamadaPurnamidam 2 роки тому

      @@emilianotristan3900 Nice Emiliano but which country u r from?

    • @TheOmnipotence
      @TheOmnipotence 2 роки тому +1

      Are you from Maldives or Sri Lanka

    • @PurnamadaPurnamidam
      @PurnamadaPurnamidam 2 роки тому +4

      @@TheOmnipotence Mauritius

    • @TheOmnipotence
      @TheOmnipotence 2 роки тому +2

      @@PurnamadaPurnamidam Oh wow. The only African country that's very highly developed. (Maybe Seychelles will be too this year)

  • @RodneyAllanPoe
    @RodneyAllanPoe 5 років тому +91

    "The Hubble...thingy." Thank you for uploading these. Gold.

    • @nidhi4079
      @nidhi4079 4 роки тому +5

      Exactlyyy, i absolutely ADORE him!!!

  • @ottofrank3445
    @ottofrank3445 2 роки тому +25

    No fancy stuff just a marker and a whiteboard and you learn the universe! That's the power of sir Susskind!

  • @Brian.001
    @Brian.001 9 місяців тому +5

    Leonard is 83 now, and one of the absolute best presenters of science on UA-cam.

  • @3lit3gn0m3
    @3lit3gn0m3 9 років тому +101

    Even though I'm not an equations kinda guy, I'm glad to have the privilege of watching this, especially free and from home.

    • @RomanDmosski
      @RomanDmosski 9 років тому

      3lit3gn0m3 what kinda guy are you then?

    • @3lit3gn0m3
      @3lit3gn0m3 9 років тому +9

      Christian Rosenkreutz Someone interested in anything to do with space. o_O
      I'm not being graded, so I enjoy picking out the few things I do understand. :D

    • @ABlackGuy10
      @ABlackGuy10 9 років тому

      3lit3gn0m3 iry whistle "oooooweeeee ooooooooo"

    • @3lit3gn0m3
      @3lit3gn0m3 9 років тому

      nostradomis Eerie?

    • @andrewmartin9469
      @andrewmartin9469 9 років тому

      3lit3gn0m3 Forget that, what the hell is talking about? +nostradomis

  • @ibazulic
    @ibazulic Рік тому +5

    Professor Susskind is an amazing professor, his lectures on whatever subject I watched were amazingly detailed and very methodical. And this one is no exception. Thank you, Stanford, for these lectures! And thank you, prof. Susskind, for allowing recording of your great lectures.

  • @bakersmileyface
    @bakersmileyface 6 місяців тому +1

    This dude is a legend. I've read so many of his books. I didn't realise he did lectures online for free and now I'm gonna watch all of them.
    Thank you for posting this. I am not very clever and am not confident in going to university to study this because it's a lot of money and time even here in the UK. But I'm really interested in it so I'm grateful that I can take my time to learn for free like this.

  • @johnb4314
    @johnb4314 9 років тому +78

    A pleasure to view. Prof Susskind is an excellent lecturer in addition to the significant contributions he has made in his field. Thanks for putting all his lectures up.

  • @MrFancyGamer
    @MrFancyGamer 2 роки тому +7

    bruh it’s been 6 years since i’ve done high school math and I understood most of this, this professor is incredibly clear and makes it super interesting as well

  • @BoooDave
    @BoooDave 2 роки тому +4

    I tell anyone who will listen... Stanford has several very interesting lectures online for all to watch. I wish everyone did the same

  • @kspangsege
    @kspangsege 11 років тому +136

    "If only Newton had been a little smarter" - LOL!!!

  • @brianruppert1071
    @brianruppert1071 2 роки тому +16

    My late brother would have loved all this. He passed in 2005, so he missed out on the transformational introduction of college physics courses free on the internet. Remarkable development.

  • @VidelicetMoi
    @VidelicetMoi 2 роки тому +5

    To be honest, this class (because I despise "equations"-- class 1, 2, and 3) is way over my head; however, the manner in which it is presented is above par. I will watch again and again and again to grasp the instruction.

  • @sleepful1917
    @sleepful1917 3 роки тому +3

    my favorite branch of physics, i was so happy when I saw that lenny has lectured on it

  • @ritemolawbks8012
    @ritemolawbks8012 Рік тому +2

    I enjoy his lectures and can listen to him for hours. If only there wasn't a language barrier, I would have loved to have experienced the classroom lectures from Albert Einstein, Isaac Newton, and Galileo Galilei. The Q&A sessions would have been legendary.

  • @anilsrivastava3635
    @anilsrivastava3635 9 років тому +28

    Dear Susskind, you are one of the greatest teacher of all.

  • @Aiden057
    @Aiden057 11 років тому +9

    Thank you Dr. Suskind and Stanford for this and all the videos you make available to us who watch here on youtube.

  • @kuckaf01
    @kuckaf01 11 років тому +16

    Thank you from those of us who can not afford to attend college.

  • @FreakinKatGaming
    @FreakinKatGaming 4 роки тому +2

    What's sad is No the fact that knowledge is easily obtained and can be found with curiosity and searching. The sad and frustrating part is, so few of us actually search and seek to learn more and more than the normal.

  • @liamroche1473
    @liamroche1473 4 роки тому +4

    Minor historical correction 2: Newton was born 5 years after the Tulip bubble of 1637. He did however get burnt badly by an investment in the South Sea company, whose share price rose meteorically and then collapsed in 1720.

  • @ibn3670
    @ibn3670 11 років тому +9

    Thanks "Stanford" do helping the world to get into "the knowledge culture"

  • @derpyorandom
    @derpyorandom 2 роки тому +2

    I'm in 5th grade and listened this in my sleep

  • @kylemcgrath84
    @kylemcgrath84 11 років тому

    I love Suskin, anyone who routinely says " It's called ****, but I'm going to intermittently refer to it as something else" is awesome! I love being kept on my toes.

  • @jceeross6763
    @jceeross6763 2 роки тому +4

    I just love these lectures so much thank you

  • @audreymciver3087
    @audreymciver3087 4 роки тому

    you are a blessing! Thank you for your videos they are very informative- may I add you are a very intelligent man. Thank you for your kindness.

  • @vukasinspasic6099
    @vukasinspasic6099 2 роки тому +1

    Can't regret enough of pursuing a petroleum engineering career. This and few other related fields are my true love and interest.

  • @CelticXAngel88
    @CelticXAngel88 11 років тому +3

    These are ideal for those who either cannot afford college, who are lifelong scholars or who just cannot decide on just one major.

  • @MegaLESM
    @MegaLESM 11 років тому +22

    26:21 "I don't know what happened to my Universe, I had my Universe here, but..."

    • @toomanydrugsinmysys5414
      @toomanydrugsinmysys5414 4 роки тому +1

      Could have sworn it was right here, eh maybe I was just delusional. I’ll grt another one

    • @anneneville6255
      @anneneville6255 3 роки тому +1

      It was swallowed by a black hole 🕳 :p

    • @sunitalymon1925
      @sunitalymon1925 3 роки тому +1

      Then he simply drew it back. Dot dot dot 😂😂😂😂

  • @pvgaming1740
    @pvgaming1740 Рік тому

    How much indian Future cosmogist are watching the whole series.
    Thank you so much sir for making this video.
    Take my respectful blessings in yours charan

  • @sciencefirst7880
    @sciencefirst7880 10 місяців тому

    It's interesting to see the progress that's been made in ten years.

  • @bhavyajoshi3362
    @bhavyajoshi3362 10 років тому +11

    The way he is he is explaining the things is really good and awesome to understand the point.
    looking forward to see the whole series. :D

    • @rraajj_j
      @rraajj_j 6 років тому

      bhavya joshi You indian
      I indian
      Doing different dfrnt

  • @RedSquirrelEater
    @RedSquirrelEater 6 років тому +9

    This was my favorite course that he's done so far. I also liked the GR course, but this one was more enlightening.

  • @user-gj7vp6wk3e
    @user-gj7vp6wk3e 4 місяці тому +1

    I AGREE. IT IS VERY NICE TO LEARN WITHOUT THE DISTRACTION OF GRADES.👍

  • @user-cx5ni7me6l
    @user-cx5ni7me6l 2 роки тому +1

    Thank you and thanks to everyone who made this video possible.

  • @KaliFissure
    @KaliFissure 2 роки тому

    Isomorphic in general, but with an extreme variation in energy and mass densities. Sin(cos(u/2)cos(v/2),cos(u/2)sin(v/2),sin(u)/2) 0

  • @EdSmiley
    @EdSmiley 5 років тому +11

    "I don't know what happened to my universe." Suskind has a dry sense of humor.

  • @sissichen8715
    @sissichen8715 5 років тому +14

    Really learned a lot!!! Thank you so much professor Susskind!

    • @Mike-uo2gg
      @Mike-uo2gg Рік тому

      It's all backwards and wrong. The universe is not stagnant its moving its not moving in the same direction every where nore is it moving in the same direction outward or inwards its not contracting we are still expanding and accelerating. Look at the Eons channel check out the Great Attractor.

  • @TravelTheGalaxy
    @TravelTheGalaxy 2 роки тому +1

    I am so very grateful for the information and knowledge Stanford and this professor are willing to provide. I would still love to learn about the deep history of where this all comes from. I know there is an eventual disconnect between belief and science but that is where my heart and mind pull me toward and I wish I could find somewhere that would bridge the two together.

    • @nmarbletoe8210
      @nmarbletoe8210 Рік тому

      belief is said to be subjective and science objective.
      but, how to define objective? maybe it's basicaly the sum of all subjective views

  • @brainstormingsharing1309
    @brainstormingsharing1309 3 роки тому +1

    Absolutely well done and definitely keep it up!!! 👍👍👍👍👍👍

  • @Badroucl
    @Badroucl 11 років тому +5

    Adding a subtitle when a student asks something would be useful for the completeness of the lecture It was an erudite lecture, thank you.

  • @alphaenemy
    @alphaenemy 11 років тому +9

    What a great find. A free Cosmology course? Thank you Stanford!

  • @xinzeng-iq7zv
    @xinzeng-iq7zv 25 днів тому

    i am watching these lectures for the sheer thirst of knowledge

  • @aizaali2988
    @aizaali2988 4 роки тому

    This lecture is about 1 hour 35 minute but it seems like 20 minutes thank you stanford for uploding this

  • @nickhyland4527
    @nickhyland4527 11 років тому +16

    These lectures are fantastic. Thank you so much!

  • @omersalman571
    @omersalman571 2 роки тому +5

    I am an MSc Student from out of the USA and have watched 2 times this lecture video in 2021 and I need to watch it again but I am not sure why I will watch it again, to understand more or to listen to these articulate expressions :) thank you soo much for these wonderful lecture videos

  • @kathiravanvelsamynadar2534
    @kathiravanvelsamynadar2534 4 роки тому +1

    Thank you very much sir..!!! Million respect and gratitude..!!! Kathiravan from India..!!!

  • @ridhipalia4789
    @ridhipalia4789 4 роки тому +12

    What a lecture! Kudos sir! Such a knowledgeable one!

    • @doggee09
      @doggee09 2 роки тому

      Which class ur?

  • @mietschj
    @mietschj 11 років тому +10

    This made me realise I should be studying for my physics final next week...

  • @bobbwest
    @bobbwest Рік тому +1

    What a great lecturer!

  • @jeanetjensen6474
    @jeanetjensen6474 2 роки тому

    Thank you thank you so much for these wunderful lectures from Standford 🙏⚘🇩🇰😃

  • @lsbrother
    @lsbrother 10 років тому +6

    I think - without being absolutely sure - that most of his lectures over last few years have been not to students but are more of an evening class for anyone interested.

  • @jimkeller3868
    @jimkeller3868 7 років тому +8

    Have great respect for Prof. Susskind. I do not resonate with this particular form of teaching however. I usually like if some sort of overview is given first: what are the problems we are trying to solve? What is the direction that we are heading? It seems to me that rather than provide context, he keeps building small components without explaining why. It would be like explaining a combustion engine by starting with "this is a spark plug" "this is a piston ring" ..... He even says it at 39:19

    • @Edruezzi
      @Edruezzi 2 роки тому

      The topic is cosmology. He said that at the beginning. The UA-cam title says it.

  • @marcusvaughn7019
    @marcusvaughn7019 2 роки тому +5

    I am amazed with all of you guys who comprehend, what is in my opinion, difficult math. I tested with a 132 IQ, but I could barely remember my times table. I excelled in many of my classes, but could never master math. It wasn't until I was in my late 20's when I learned that I am very dyslexic and finally understood what was going on. If math comes easy to you, count your blessings and push yourself to the maximum in school. I envy you folks.

  • @adamwatson7669
    @adamwatson7669 11 років тому +1

    No, I am merely pointing to the observation that all galaxies are uniformly receding from us at a rate proportional to their distance. The velocities of peculiar galaxies has been accounted for, and there is no discrepancy. The CMB can only be explained as the event when the universe became transparent, and the anisotropies observed from COBE and WMAP (1 in 100,000) match very well with the large scale structure of the universe.

  • @ethiopianspacescience6504
    @ethiopianspacescience6504 Рік тому

    One of my favorite teacher ❤️ ♥️ 💙

  • @Ukdroneshots
    @Ukdroneshots 11 років тому +4

    I left school with no grades. I feel unchallanged in life. No college would accept me and lessions like this are what keep me going!

  • @literaway7714
    @literaway7714 3 роки тому +3

    If you can find a center of the universe it automatically means that universe is limited

  • @barakaobama9081
    @barakaobama9081 7 років тому

    Great video, and great teacher!

  • @scotttrent4721
    @scotttrent4721 2 роки тому +2

    Mike Ehrmantraut is a man of many talents

  • @qwadratix
    @qwadratix 10 років тому +12

    26:22 Quote:(Only a physicist)
    I don't know what happened to my Universe, I had my Universe over here but err.....

  • @AGMRockstar
    @AGMRockstar 11 років тому +10

    I hope to go to stanford when i go to collage I am 14.

  • @abcde_fz
    @abcde_fz 5 років тому +2

    OMG I got one right... After the joke about "What's the first thing we do when we set up a problem in physics, (or solve a problem), and it's not 'sharpening your pencil'?" He said "Set up your coordinates". I had guessed "Know your boundaries", so, I'm going to give myself one point for that one. Kinda' half right, anyway. I'm so happy I finally got one HALF right... :-)

  • @garysuarez9614
    @garysuarez9614 2 роки тому

    I really enjoy this lecture.

  • @CERTIFIEDBABEWRANGLER
    @CERTIFIEDBABEWRANGLER 2 роки тому +3

    Look ma, I'm in Stanford

  • @Blackburrd
    @Blackburrd 11 років тому +5

    Teaching students in Kenya using these lectures

  • @jasonspades5628
    @jasonspades5628 2 роки тому

    This is awesome. I've always wanted to learn about putting on my make up

  • @MortimerYoung
    @MortimerYoung 9 місяців тому

    This lecture series is above my head but it's great to sleep to

  • @trunkten5452
    @trunkten5452 4 роки тому +6

    Now I can proudly say that I am studying in Stanford University

    • @mickeyj440
      @mickeyj440 3 роки тому

      LOL

    • @Edruezzi
      @Edruezzi 2 роки тому

      Nope. You haven't registered.

    • @Edruezzi
      @Edruezzi 2 роки тому

      Nope. You haven't registered.

  • @Purrebark
    @Purrebark 9 років тому +51

    You've gotta stop moving around so much. The students are gonna get a soar neck 56:46

    • @XxxclarityxxX
      @XxxclarityxxX 8 років тому

      +Super Bork xD

    • @stephenphilbin3919
      @stephenphilbin3919 8 років тому +10

      +Super Bork For most people, the motion is not a problem because they have vertebrae in their neck to allow for this sort of thing.

    • @selimhassairi
      @selimhassairi 8 років тому +1

      I do this a lot too, I understand him x) Really, you should give it a try, it helps you to keep focused, it also gives you a pace

    • @jimkeller3868
      @jimkeller3868 6 років тому

      His motion has nothing to do with it. It's the fact that the camera is following him with each motion.

    • @81atanas
      @81atanas 6 років тому +2

      you are unbelievable...

  • @pankajnegi9795
    @pankajnegi9795 4 роки тому

    Awesome work Stanford

  • @jaz.923
    @jaz.923 5 років тому +2

    I doubt that anyone is still looking at comments here, but I feel the need to express my profound admiration and respect for Dr. Susskind. He is the wisest, kindest, the most patient, and certainly the most interesting professor I have ever listened to. Stanford students are extremely fortunate. I wish you well. Dr. Susskind, and thank you so much.

  • @A_Dopamine_Molecule
    @A_Dopamine_Molecule 11 років тому +5

    Might wanna start out by learning how to spell college....
    Seriously though, good luck :)

  • @harrailiaskou725
    @harrailiaskou725 10 років тому +23

    the more we know the more we know we don't know,actually...

    • @thekkl
      @thekkl 8 років тому +4

      harra iliaskou You know it's been a good day if you have more questions today than you had yesterday.

    • @harrailiaskou725
      @harrailiaskou725 8 років тому

      ***** i totally agree with you! :)

    • @fiddlesticksbessette398
      @fiddlesticksbessette398 5 років тому

      YOU WONT LEARN NOTHING IF THE ONE'S THAT'S TEACHING YOU DONT KNOW THEMSELF'S.'' SOME WERE BRAIN WASHED ABOUT 12 YEAR'S AGO.AND BE CAREFUL WHAT YOU HEAR,AND READ THESE DAY'S,AND I DONT CARE WHAT SCHOOL'S,OR COLLEDGE YOU WENT TO...EVEN YOUR PARENT'S WERE NOT TOLD THE TRUTH ABOUT SOME THING'S...LIES,JUST GO ON AND ON,AND ON.BE CAREFUL WHAT YOU TELL PPL,OR BELEIVE''BECAUSE IF ALL YOU KNOW IS WHAT PEOPLE TELL YOU,AND THEY JUST HAPPEN TO BE A DEAN,OR PROFESSOR,YOU JUST MIGHT BELIEVE IT MORE THEN IF YOU HEARD SOME ONE ON THE STREET TELL US.BUT TRUTH IS TRUTH,AND LIE'S,ARE LIES,NO MATTER WHO THEY CLAIM TO BE...FIND OUT WHO IS IN THE KNOW.DONT BELIEVE A LIE FOR 50 YEAR'S.CHECK THING'S OUT YOURSELF..

  • @mayankmishra7288
    @mayankmishra7288 6 місяців тому

    A big fan of you Sir

  • @jasonbutler9362
    @jasonbutler9362 6 років тому

    @20:00 if D is the actual distance in meters the delta x would have to be in units of seconds^2 as acceleration is in m/s2. What is the physical significance of a coordinate system in units of seconds^2 ?

  • @duckythegamer9059
    @duckythegamer9059 5 місяців тому

    Good job! I know this video is 10 years old, but I really enjoyed your work.

  • @tonyguerrero9264
    @tonyguerrero9264 3 роки тому +2

    This is an amazing Vid I Hope to get a degree in cosmology, one day ! I’m about to be a junior in high! One day! 🙏🏼

  • @DAFANNIN
    @DAFANNIN 11 років тому

    Science is about the focus of your mind on the beauty of what you find in the very large, the very small and the very fast. There is a universe of fine detail in all of the scales. We live in an unprecedented age of knowledge. Never in the history of man has our perception spanned such an explosion of reality. It is entirely possible to be left behind in our old ideas and facts. It is vital that we be on the cutting edge of understanding. We are not immortal.

  • @cacogenicist
    @cacogenicist 2 роки тому

    How can we have these very large-scale structure -- i.e. galactic superclusters, and the larger-scale galactic threads? Is there an increasing amount of space between the galactic clusters within the galactic threads? An increasing amount of space between the galaxies/locally bound galactic groups withing the clusters?
    Are galactic threads a product of objects within the threads being gravitationally bound, or are they just remnants of gravitationally bound structures in the very early universe?

  • @jto541
    @jto541 2 роки тому +2

    Anyone else always fall asleep watching Vsauce videos and wake up to this?

  • @PaperPlateClorox
    @PaperPlateClorox 5 років тому

    Thank you, Stanford. Thank you.

  • @silviawalker9759
    @silviawalker9759 3 роки тому +1

    One is free to make inquires. I am learning however. That if I listen and pay attention. Eventually questions in my head will show up in the Lecture. Took a while for me to get it. dr. Serwaa, FMU.

  • @shafiqulislam-zr4ng
    @shafiqulislam-zr4ng 4 місяці тому

    Very very thanks!May Allah bless you are all.

  • @TheGat2012
    @TheGat2012 11 місяців тому

    The hubble constant as derived by about 25:00 requires that "a" is only a function of time and not a function of position or mass density or anything else. Has any work been done to explore the possibility of expansion being a function of mass? maybe expansion is not the same at the center of a galaxy as it is in the space between galaxies?

  • @liamroche1473
    @liamroche1473 4 роки тому +1

    Minor historical correction: Alexander Friedman is reported to have died in 1925 from typhoid, not in WW1. Susskind may have been thinking of Karl Schwarzschild, who died during WW1, but of an autoimmune disease while serving the Russian front.

  • @lordcringe1339
    @lordcringe1339 2 роки тому +1

    6:30 - We cannot see in all directions while standing on any one spot on earth. The fact of the matter is that we cannot observe what is below us.

    • @lordcringe1339
      @lordcringe1339 2 роки тому

      @@wrinklesmile8973 Not at all, you never can see below us while standing on this planet. Its just how it is....

    • @lordcringe1339
      @lordcringe1339 2 роки тому

      @@wrinklesmile8973 Yes

  • @AndrewNicoll
    @AndrewNicoll 10 років тому +2

    Very well presented

  • @lucyoriginales
    @lucyoriginales 4 роки тому +1

    Do particles manage a volume?
    Shouldn’t it all be particle shaped?

  • @indranilsen9279
    @indranilsen9279 4 роки тому

    Hi, I have some question, that if rho=0, ie hypothetically if the density is 0, then from a''/a=-4/3 pi G rho, we have a''(t)=0 gives a(t)=At+B, what about that parameter, I mean what is the interpretation of that value of a(t)?

  • @RobeonMew
    @RobeonMew 25 днів тому +1

    This was the moment Mike Ermantrout became a Professor

  • @visaoholistica205
    @visaoholistica205 3 роки тому

    I was intrigued. How to explain the action at a distance from gravity in this derivation? This would be the question I would ask.

  • @4kstreamer44
    @4kstreamer44 4 роки тому

    What is the potential energy equation here? I have mMGx instead of dividing x

  • @T8ersalad
    @T8ersalad 2 роки тому +1

    I playback at 1.5x speed and turn on Subtitles, only then am I able to capture the essence of what he is explaining in his lecture videos.

  • @thorsteinssonh
    @thorsteinssonh 6 років тому +1

    if it was isotropic but not homogeneous, yes it could be shell-like, but I like more the possible situation that it was more dense near the observer and less dense far away, or vice versa. This would maybe highlight to the observer that he is very special, all the stars and galaxies wanting to be near the observer, or... all the galaxies hating to be near the observer.

  • @peterfawzy8261
    @peterfawzy8261 2 роки тому

    excellent explanation!

  • @spacekiwikit
    @spacekiwikit 11 років тому

    with a to the third in the denominator, the term will approach 0 but never reach it. However, in the escape velocity case, we do reach escape velocity without hitting a ceiling when we do. So where am I wrong?