Why is Relativity Hard? | Special Relativity Chapter 1

  • Published: 01 February 2018
  • Thanks to brilliant.org/minutephysics for supporting this video!

    Thanks to my friend Mark Rober (stms.pro/video/3blue1brown/video.html) for inspiration.

    Support MinutePhysics on Patreon! patreon.com/minutephysics
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    This is the first in a series of videos about special relativity. This is definitely not an academic course, but it's going to be a more in depth and developed exploration of a single topic than a typical standalone MinutePhysics video. I've been greatly inspired (and heckled) to do this by my friend Grant Sanderson of 3blue1brown who's set the standard for this kind of thing with his excellent series - serieses? - on calculus and linear algebra.

    So, special relativity. Special relativity is one of the most popularly famous ideas in physics – it's that thing that Einstein figured out about the speed of light and space and time and E=mc^2! It changed our understanding of the universe. And its core ideas are accessible in principle to anyone who understands some basic algebra and geometry - you don't even need to know calculus!

    And yet in spite of this, special relativity is one of the subjects in physics that confuses the most people, and in many cases turns them away from physics altogether.

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    Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!

    Created by Henry Reich
  • Science and Technology Science and Technology

Comments • 1 791

  • Giulio Personeni
    Giulio Personeni  1 days back

    If matter and light are the same thing, then no reason to think light has finite speed no? This is gonna be the most important question of the century

    • Yoonho Ro
      Yoonho Ro  1 days back

      You do know that relativity is not a law. Still is hypothesis not is proven to make theory. Just because it was made by Jewish white guy doesn't mean it's a law. One equation e=mc2. kind of need to be worked on. By finding out there a pratical that travel fast then speed of light. So yeah just and idea with math not factual yet.

        JORDAN SHOES  3 weeks back

        hello....listen ..u r starting by the presumption that einsteins Theory is fact....no one has every seen, proved the exsistance of or measured THE ELECTRON. , nor has it been the result of any experiment ever!!! JJ thompson even stated in many papers, that his premise of the electron was odd, and wrong. until they said they would give him the nobel prize if he just claimed it did exist!! Nor is there such thing as a photon...so if i take pictures all day is my camera full of photons...do i have to empty it out?
        your chasing particles that dont exist and have never been seen but were given a quantifiable mass in order to make equations balance.... AND ALL CURRENT PHYSIC'S THEORY IS BASICALLY BASED UPON THESE FALSE PREMISES.
        DOUBLE SLIT EXPERIMENT YOU SAY? its called constructive interference. light is neither a wave or a particle, there are no dualities in mother nature. Light is simply a FIELD perturbation....oh and by the way...ask any physics phd or "quantum" mechanist to define what a field is....
        NOT WHAT IT DOES OR WHATS GOING ON IN A FIELD...BUT WHAT A FIELD IS??????? his mind will implode because he cant answer you..
        wake up guys...think outside the box...use your brains and stop regurgitating what you learned from other people who also presume the theory of relativity has some basis in reality...NOT EVERYTHING IS QUANTIFIABLE....if you can figure out what that last sentence means, then you are on your way....

        • ADKforever
          ADKforever  3 weeks back

          The narrator, Henry, needs to speak much more slowly in order for the concepts to sink in. I found that I had to slow the video down by half.

          • Abu S
            Abu S  1 months back

            Maybe we are in a big black hole

            • Spectre 017
              Spectre 017  1 months back

              Sell spacetime globes. Please.

              • Zombie Salad
                Zombie Salad  1 months back

                If anyone's struggling with special relativity, try watching Stanford's lectures on it by Prof. Susskind.

                • mahdi komaiha
                  mahdi komaiha  1 months back

                  E, m, c, v, t and many weird symbols....

                  • mahdi komaiha
                    mahdi komaiha  1 months back

                    i really hate physics😒

                    • Sachin Cb
                      Sachin Cb  1 months back

                      1:31 breath dude 😢

                      • clarkkent1616
                        clarkkent1616  1 months back

                        minutephysics: series ? series’s ?

                        me, a genius: seriei 😎

                        • нαρρү мεllσ
                          нαρρү мεllσ  2 months back

                          I didn't check physics since a long time,like i was so much curious in past,but youtube never recommend it,so i focused on other things and forgot my passion about it(found this in someone's favorites).thank you💕

                          • matej luptak
                            matej luptak  2 months back

                            Are you actually drawing in the video, or using some software like videoscrbie?

                            I can't tell

                            • RIT123
                              RIT123  2 months back

                              lol no.. he draws it on paper

                          • Shart Bake
                            Shart Bake  2 months back

                            Ooohhh! I want a space time globe!

                            • TIJEY BEG
                              TIJEY BEG  2 months back

                              Excuse me minute physics, but may I have the stack of books you showed in that video? 😀 For me it was great fun to learn relativity with 16 years, even when no one of my teachers could help me. But before my study of Physics and Mathmatics I can need it to refresh my knowledge.

                              • TIJEY BEG
                                TIJEY BEG  2 months back

                                This is a good question. In my opinion, relativity was never difficult for me.

                                • Ben Helmet
                                  Ben Helmet  3 months back

                                  I'm third year physics, in the first year we spent a week on the basic concepts with some easy math.

                                  The second year we pretty much done the same thing but spent 4 weeks on it, was really easy.

                                  The third year we spent 2 weeks and it was the hardest thing I've tried to learn in my life (mostly math/hamiltonian mechanics).

                                  • Paola Ochoa
                                    Paola Ochoa  3 months back

                                    This series accomplish the purpose every class should accomplish, allow me to answer "why" to the things we learn

                                    • Malki sehgal
                                      Malki sehgal  3 months back

                                      What are the mathematical prerequisites( in order )

                                      • Tora Blaze
                                        Tora Blaze  3 months back

                                        Because is hard

                                        • Craigy B
                                          Craigy B  3 months back

                                          Oh no. Cue the reams of comments from the "I'm smarter than or just as smart as Henry" brigade who are just pedantic mickey mouse silly billies.

                                          • Sava Jevtić
                                            Sava Jevtić  3 months back

                                            _turns them away altogether_

                                            Special relativity literally made me *love* physics lol

                                            • AARTI
                                              AARTI  3 months back

                                              Earth is not round🤨

                                              Its spherical 🔴🔵⚪⚫

                                              • Kyle Anderson
                                                Kyle Anderson  3 months back

                                                I come for the blues clues music

                                                • Dj Boom
                                                  Dj Boom  3 months back

                                                  i see what you did there 3:51

                                                  • Breakingworse
                                                    Breakingworse  3 months back

                                                    If space is ever expanding wouldn’t space be faster than light?

                                                  • Md. Anwarul Islam Sarker
                                                    Md. Anwarul Islam Sarker  3 months back

                                                    He speaks faster than anyone I ever knew

                                                    • Md. Anwarul Islam Sarker
                                                      Md. Anwarul Islam Sarker  3 months back

                                                      He speaks faster than anyone I ever knew

                                                      • Cordelia Maynard
                                                        Cordelia Maynard  3 months back


                                                        • Velimir Stanimirovic
                                                          Velimir Stanimirovic  3 months back

                                                          All that staff is illusion! Is light a wave or photon and does it have a mass?

                                                          • Дмитрий Прищепа
                                                            Дмитрий Прищепа  3 months back

                                                            Light is a wave and a stream of photons, depends on a theory you use. Each photon on its own doesn't have mass, but have energy, but a system of two or more photons have some equivalent mass, which is still not quite the same as real mass.

                                                        • ResidentEvil302cuba rican215

                                                          I hate people who think the earth is flat they need 2 die off

                                                          • aniruddha patil
                                                            aniruddha patil  3 months back

                                                            Damn! Take a bow!

                                                            • DynestiGTI
                                                              DynestiGTI  4 months back

                                                              3:33 I recognise that font, Hergé

                                                              • Aidan Abregov
                                                                Aidan Abregov  4 months back

                                                                Like here if you're a flat-earther who dabbles in quantum mechanics. (This comment better not get any likes!)

                                                                • Mesa Prime
                                                                  Mesa Prime  4 months back

                                                                  Grant Sanderson: I will make people smarter *whether they want to be or not*

                                                                  • Chris Behrens
                                                                    Chris Behrens  4 months back

                                                                    Emc is of course some nice system use...but it does not explain why you all think ,why are you here again...and why it feels like a deja vu and why some type stuff you could had wrote...earth itself is a bio living constructed test time machine ... All things are safed data..in relativity what could be if you choose to make a baby or not...nothing or something...what impact could had it if some stop or go further with civilasation grow..are we act like a script given..is free will some stuff of a other person before etc...are dreams a givn information from some to show a programing direction ya go...and why you people had diffrent systems...ya own modern control ..the fear of loose is the humans most tragically expierence...and yes we all are a hord of paranoid bunch of emc victims..lol

                                                                    • david young
                                                                      david young  4 months back

                                                                      space & time are identical; equal; liken to light year;
                                                                      once you grasp this . . theory of relativity is easy to get; or not;

                                                                    • alex xander
                                                                      alex xander  4 months back

                                                                      NOTHING CAN GO FASTER THAN LIGHT?? REALLY???

                                                                    • Samuel Saunders
                                                                      Samuel Saunders  4 months back

                                                                      Your red hand is distracting me

                                                                      • Icey Junior
                                                                        Icey Junior  4 months back

                                                                        Good. Finally something not less than a minute. Do electromagnetism as well, I’m sure many still confuse E D B and H.

                                                                        • Gene DeClark
                                                                          Gene DeClark  4 months back

                                                                          By 1:41, you just summed up exactly what's wrong with (at least) the American educational system. We put so much emphasis on *how* to do something, but very, very little emphasis on the *meaning* behind it. *Why* would one care enough to do this in the first place? Without that information, so many people care so little about the *how* that they stop paying attention, without even realizing they've done so. Also, I'm not a physicist (I have degrees in psychology and computer science) so I have no idea about the approach of physics departments, but every discipline seems to have a "cut class" at about the 200 level that's (seemingly) designed to weed out people who aren't passionate enough about the field. (Statistics in psychology, data structures and algorithms in CS, for example.) It seems as though perhaps SR is used in that way? Even though it's not substantial enough to warrant its own course, you did say that it turns many people away. Could this be intended?

                                                                          • Alexander Karapiperis
                                                                            Alexander Karapiperis  4 months back

                                                                            "nothing can go faster than the speed of light" that's incorrect actually. We just can't find/detect these particles yet, if they have mass that is

                                                                            • skylord_wars
                                                                              skylord_wars  3 months back

                                                                              @Alexander Karapiperis No, your comprehending everything wrong. Even travelling faster than the speed of light doesn't help you escape the black hole. All directions will point towards the singularity. You need to go back to the past to escape the black hole.

                                                                            • Alexander Karapiperis
                                                                              Alexander Karapiperis  3 months back

                                                                              @skylord_wars what you mean with information? the energy carried in electromagnetic energy (light) ? if so then what about the information from gravitational fields of a black hole which have faster speed than light and that's why it's sucked in

                                                                            • skylord_wars
                                                                              skylord_wars  3 months back

                                                                              It's true that information can't go faster through space than the speed of light.

                                                                          • MadFoxMax
                                                                            MadFoxMax  4 months back

                                                                            owo do I hear flat earther jokes coming on?

                                                                            • Jasleen xo
                                                                              Jasleen xo  4 months back

                                                                              Couldn't get my eyes off from the red hands lol

                                                                              • Himanshu Suyal
                                                                                Himanshu Suyal  4 months back

                                                                                Special relativity and quantum mechanics are my favorite topics in physics.
                                                                                Don't know why people are usually very confused and be afraid of these two amazing topics

                                                                                • Saburou Saitoh
                                                                                  Saburou Saitoh  4 months back

                                                                                  Could you apply our new results?

                                                                                  The famous problems were solved as follows:

                                                                                  Dear the leading person:

                                                                                  How will be the below information?

                                                                                  The biggest scandal:

                                                                                  The typical good comment for the first draft is given by some physicist as follows:

                                                                                  Here is how I see the problem with prohibition on division by zero,

                                                                                  which is the biggest scandal in modern mathematics as you rightly pointed

                                                                                  out (2017.10.14.08:55)

                                                                                  A typical wrong idea will be given as follows:

                                                                                  mathematical life is very good without division by zero (2018.2.8.21:43).

                                                                                  It is nice to know that you will present your result at the Tokyo Institute of Technology. Please remember to mention Isabelle/HOL, which is a software in which x/0 = 0. This software is the result of many years of research and a millions of dollars were invested in it. If x/0 = 0 was false, all these money was for nothing.

                                                                                  Right now, there is a team of mathematicians formalizing all the mathematics in Isabelle/HOL, where x/0 = 0 for all x, so this mathematical relation is the future of mathematics.


                                                                                  José Manuel Rodríguez Caballero

                                                                                  Added an answer

                                                                                  In the proof assistant Isabelle/HOL we have x/0 = 0 for each number x. This is advantageous in order to simplify the proofs. You can download this proof assistant here: https://isabelle.in.tum.de/

                                                                                  Nevertheless, you can use that x/0 = 0, following the rules from Isabelle/HOL and you will obtain no contradiction. Indeed, you can check this fact just downloading Isabelle/HOL: Isabelle

                                                                                  and copying the following code

                                                                                  theory DivByZeroSatoih

                                                                                  imports Complex_Main


                                                                                  theorem T: ‹x/0 + 2000 = 2000› for x :: complex

                                                                                  by simp


                                                                                  2019/03/30 18:42 (11 時間前)

                                                                                  Survey draft:



                                                                                  Close the mysterious and long history of division by zero and open the new world since Aristotelēs-Euclid: 1/0=0/0=z/0= \tan (\pi/2)=0.

                                                                                  Sangaku Journal of Mathematics (SJM) c ⃝SJMISSN 2534-9562 Volume 2 (2018), pp. 57-73 Received 20 November 2018. Published on-line 29 November 2018 web: http://www.sangaku-journal.eu/ c ⃝The Author(s) This article is published with open access1.

                                                                                  Wasan Geometry and Division by Zero Calculus

                                                                                  ∗Hiroshi Okumura and ∗∗Saburou Saitoh


                                                                                  • George Romasanta
                                                                                    George Romasanta  4 months back


                                                                                    • Rahul Shinde
                                                                                      Rahul Shinde  4 months back

                                                                                      This series is so gooooood.