Why haven't you read Einstein's E=mc² proof?

This video is a look through Einstein's original proof of E=mc2 published in 1905 (the english translation).

This video was sponsored by Wren.

[WWTormentor]

My 14 year old daughter and I accidentally stumbled onto your channel. We have been watching other channels about science in general including biology, chemistry, physics, and astronomy. We have to say that we are surprised that you don’t have more followers as rich, entertaining, and informative as your channel is. Thank you for the great job and looking forward to more videos. PS. She says she wants to be the next Stephen Hawkins!

[ryan-cole]

Could you make this a series going through some other original papers? There is surprisingly almost no videos on YouTube that does this.

[qwel]

I dont think anyone here has read the original paper

[henrycadman]

Even though I am a musician and struggled greatly with math in school, I have always found physics and its equations/representations very beautiful for some reason. Your videos are amazing and I really appreciate them. Thank you.

[MrDrociuk]

E=mc^2 appeared in Poincare's paper in 1904, in the form Einstein wrote it.

[aydin]

Great video, but there is a mistake, I think, at 7:33. The kinetic energy of the electron Einstein refers to is not ½mv², but rather the relativistic kinetic energy he had derived in his previous paper, which is mc²(γ-1) and only in the 1st approximation is ½mv². Hence, this formula has to be used for the equation on the left hand side. This mistake seems to have happened quite often, so that some physicists until today believe that Einstein‘s derivation is not correct. This might have been caused by the english translation, because reading the paper in German, it is more obvious.

[divyanshidubey]

I started getting interested in papers and thesis because of your precise and simple analysis of them. I tried reading papers before, but with no guidance and proper skills I felt like I didn't gain anything significant from them.
Thanks you for igniting my spark again! And do make these videos more. I personally enjoy these more than examination analysis (maybe because I have extreme exam anxiety). But I love the sheer raw knowledge you gain from academic papers ( and other sources as well).

[iamtheusualguy]

One of the coolest things being a German speaker is the ability to read all of these papers in the original language :D With all the English language dominance these days, it's not that usual to read anything of significance in science that isn't in English.

It also is a reminder that the German speaking world once housed the best and brightest in the world of science and the inevitable decline of the language as a language of science shortly after Einstein.

[jansagichnicht]

Your calm way of talking is so unique all over YouTube. This is the first video I have seen on this channel and liked this style of talking since the first second. Thanks a lot!

[SiqueScarface]

I actually read Albert Einstein's proof. And I read it it in the Annalen der Physik in German, as I am German ;)
PS: Isaac Newtons famous quote of the dwarfs on the shoulders of giants is itself a quote from Bertrand of Chartres, as quoted by John of Salisbury. Even the quotes are standing on the shoulders of giants.

[earthling]

i always admire your talent for wording as well as your talent for science, unique combination I find- although I know many scientists who are very eloquent as well … still I always notice this

[garymartin]

There was a derivation in my freshman physics textbook which was quite simple and elegant. All it used, as I recall, was a right triangle, formula for inertia of a pendulum and the speed of light, I was astonished how it just dropped out with some expression manipulation.

[GeertDelmulle]

At 1:36 the sentence actually says: delta mass = delta energy over c squared.
It’s a difference statement. Following from that we can discuss the ground state of things and the granularity of those differences.
As it turns out those differences are multiples of a finite quantity related to Planck’s constant.
Heisenberg’s inequality didn’t simplify things, either, imposing some more constraints on the matter (make of the pun what you will).

[III-zyjf]

My community college professor taught in an insanely tiny classroom all the math leading to E=mc^2, and twenty years later I still think about that moment and the shock and excitement. I retook that class at another college, and those equations weren't taught. He was a black professor who read a Chinese newspaper everyday, too.

[PatrickSmeaton]

You should narrate audiobooks....seriously.

[MohamedSalah-gbtc]

You always giving me passion to study more, toby.

[frede]

I took a while to get through the full context of this equation by not only reading through this paper, but also getting through the context of it (by reading through large parts of the electrodynamics of moving bodies paper). This largely meant reading his derivation of the relativistic Doppler shift formula. His derivation of this equation is a lot more satisfying than all other sources I've seen on the topic, which typically find it by using Planck's law to relate the energy of the EM wave to frequency, whose Doppler shift formula is well known. Einstein, however, used classical electromagnetism to derive the formula, solely using the formula for electromagnetic energy density. This not only makes the derivation more satisfying, as Planck's equation came later, but it also helps to justify Planck's equation in the first place, as it shows that frequency and electromagnetic energy have the same Doppler shift (PS. in response to the controversy part, I've found a slightly modified version of Einstein's derivation that invokes momentum conservation in addition to energy conservation. This result is particularly powerful, as you can generalize it to obtain the relativistic equations for momentum/energy (E=mc^2 of course only applying when the mass is at rest)).

[Keaza.]

I listen to your videos whilst I work. It helps me feel less anxious and stressed, plus I learn a lot too!

[PetraKann]

E=mc^2 is not the original and full equation.
It is a special case for the rest mass.
It should be written as E=m0 c^2.
The actual equation is:
E2=p2c2+m2c4
For a body at rest the velocity and therefore the momentum, p is equal to zero, so
E2 = m2c4
Therefore
E = +/- mc2

The +/- is important

[goonrick]

Thank you, Toby! Your approach to science is calming.