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 (jakart.info/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 • 1 766

  • Sava Jevtić
    Sava Jevtić  16 hours back

    _turns them away altogether_

    Special relativity literally made me *love* physics lol

    • AARTI
      AARTI  1 days back

      Earth is not round🤨

      Its spherical 🔴🔵⚪⚫

      • Kyle Anderson
        Kyle Anderson  2 days back

        I come for the blues clues music

        • Dj Boom
          Dj Boom  1 weeks back

          i see what you did there 3:51

          • Matheus Leite
            Matheus Leite  1 weeks back

            0:15 top 10 anime crossovers

            • Breakingworse
              Breakingworse  1 weeks back

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

            • Md. Anwarul Islam Sarker

              He speaks faster than anyone I ever knew

              • Md. Anwarul Islam Sarker

                He speaks faster than anyone I ever knew

                • Cordelia Maynard
                  Cordelia Maynard  2 weeks back


                  • Velimir Stanimirovic
                    Velimir Stanimirovic  2 weeks back

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

                    • Дмитрий Прищепа
                      Дмитрий Прищепа  7 days 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  2 weeks back

                      Damn! Take a bow!

                      • DynestiGTI
                        DynestiGTI  2 weeks back

                        3:33 I recognise that font, Hergé

                        • Aidan Abregov
                          Aidan Abregov  2 weeks back

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

                          • Lord Ornstein
                            Lord Ornstein  3 weeks back

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

                            • Chris Behrens
                              Chris Behrens  3 weeks 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  3 weeks 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  3 weeks back

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

                              • Samuel Saunders
                                Samuel Saunders  3 weeks back

                                Your red hand is distracting me

                                • Icey Junior
                                  Icey Junior  3 weeks 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  3 weeks 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 weeks 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

                                      • CaptainQLK
                                        CaptainQLK  4 weeks back

                                        owo do I hear flat earther jokes coming on?

                                        • Jasleen xo
                                          Jasleen xo  4 weeks back

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

                                          • Himanshu Suyal
                                            Himanshu Suyal  1 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  1 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  1 months back


                                                • Rahul Shinde
                                                  Rahul Shinde  1 months back

                                                  This series is so gooooood.

                                                  • Abdul Ghani
                                                    Abdul Ghani  1 months back

                                                    the problem is we couldn't perceive time

                                                    • Abdul Ghani
                                                      Abdul Ghani  1 months back

                                                      we need a proper way to perceive time. hence spacetime

                                                  • Doron Barzilay
                                                    Doron Barzilay  1 months back

                                                    This is all fine and good.
                                                    But, you guys the young you-tubers will never be able to teach anyone anything or even create an interest as long as this "fast talking" and "no gap editing" continue.
                                                    i understand you think this is modern and therefor necessary. But the gaps between sentences are there for a reason. its there so the person listening to you (if he is listening) have a second to process the information you gave him. If you cant understand that, pleas dont bother explaining relativity.

                                                    • K A
                                                      K A  1 months back

                                                      I'm only here because I got bored dating the same men. Getting into physics is 1 million timesmore exciting lol

                                                      • Random Guy
                                                        Random Guy  2 months back

                                                        So this is the intro to the Intro to Special Relativity Course?

                                                        • Rohan Aich
                                                          Rohan Aich  2 months back

                                                          "army of the square roots"....i witnessed this

                                                          • Tyler Christensen
                                                            Tyler Christensen  2 months back

                                                            I sure hope that we'll find a loophole or something some day to be able to travel faster than light.

                                                            • Éric Jacques
                                                              Éric Jacques  2 months back

                                                              Exactly, Einstein was a quack! Rewrote Maxwell's formula, made mistakes and 'TA-DA' ....E=mc2.

                                                              • Arthur Speirs
                                                                Arthur Speirs  2 months back

                                                                Moens sent me.

                                                                • Dun Mealder
                                                                  Dun Mealder  2 months back

                                                                  last 3 days been rewatching the essence of calculus and i know so little about relativity so...cant wait

                                                                  • Stafford Campbell
                                                                    Stafford Campbell  2 months back

                                                                    I like the video but I make two comments, meant constructively. (1) You talk too fast. (2) The hand holding the pen is too big; it obscures rather than reveals.

                                                                    • Mira Jain
                                                                      Mira Jain  2 months back

                                                                      i love going through my old liked videos it's like "turtle playing never gonna give you up on an otamatone" and then "Hi, I'm gonna talk about special relativity" this is why i don't know what to say when people ask me what i like

                                                                      • mrbigheart
                                                                        mrbigheart  2 months back

                                                                        wow! this is AWESOME!!!!! :D great job! ..and, thank you!!

                                                                        • Conan the Destroyer
                                                                          Conan the Destroyer  2 months back

                                                                          Question please: if you travel 80% the speed of light away from a companion who is also traveling 80% the speed of light away from you, and the 3rd person stands on the planet in between and watches both travel away from them, will the two traveling age the same and the 3rd age faster?

                                                                        • Anonymous
                                                                          Anonymous  3 months back

                                                                          It's insane to think that without youtube, I'd be living my life thinking that "the Earth is flat".

                                                                          • Timothy Monge
                                                                            Timothy Monge  3 months back

                                                                            I've realized when watching the videos, and reading comments, that the issue isn't so much they through equations at people, is that they throw these equations without every explaining anything of why or how they work, or having the courses way before the necessary math background. My high school physics did this with motion (velocity and acceleration) and it was brutal to understand where or how the equations work. Then comes basic calculus and boom - all those motion things would have made so much more sense.

                                                                            I feel like the same thing is happening when schools go to relativity. They throw a bunch of equations out, and do not explain where any of the math comes from and expect you to almost more memorize the equations and where they work, rather then getting students to intrinsically understand how the math relates to what is going on. For example, (going off 3erd video) someone could say light is the eigenvector of the Lorentz transformation, and while most of us common people, and likely so many of the people that they try to teach SR/GR to, have no idea what that would mean. Those that know however can understand where and how the equations work, how they function visibly and no longer rely on rote memorization.

                                                                            • Chanuth Gunawardene
                                                                              Chanuth Gunawardene  3 months back

                                                                              My brain R.I.P!

                                                                              • fe dwe
                                                                                fe dwe  3 months back

                                                                                my college of physics opens modern physics course in this semester but I can't attend due to other schedule. So I'm very happy to find this video. I expect that it can be very helpful.

                                                                                • EsoJ H
                                                                                  EsoJ H  3 months back

                                                                                  1:49 this is the reason why the educational system is flawed, they follow what the discoverer's path, rather than the easy and simpler path provided by our more sophisticated technology

                                                                                  • Sommath
                                                                                    Sommath  3 months back

                                                                                    If you, Henry, could make a series about general relativity, it would be cool, and if you could make it with 3Blue1Brown and Veritasium it would be much cooler.

                                                                                  • meteor09
                                                                                    meteor09  3 months back

                                                                                    This is awesome! I am always looking for better ways to teach this subject, especially for my class of non-science track students.