Why Magnetic Monopoles SHOULD Exist

From the Space Time Corrections Department (aka our always impressive fans) At 3:30, our representation of Maxwell's equations were incorrect. The correct equations can be viewed here: tinyurl.com/2td4v6hm And at 11:09, we mistakenly reused a photo of Gell-Mann instead of Alexander Polyakov. Polyakov's department photo can be seen here: phy.princeton.edu/people/alexander-polyakov

"Everything not forbidden is compulsory" sounds like the physics formulation of rule 34

“Don’t underestimate the power of an obsessed physicist. The great Paul Dirac had a habit of discovering particles just by staring at the math.” That killed me

As a side note, it was the search for magnetic monopoles that led physicist Luis Alvarez to contribute to a theory of what led to the extinction of the dinosaurs: a huge meteorite strike. Luis was using detectors lifted into the atmosphere by balloons to capture cosmic ray particles, among which he hoped to find monopoles. He (or was it someone else doing similar experiments?) thought he might have found one too, but it turned out that Luis identified it to be a platinum (or was it iridium?) nucleus. No monopole after all, but that clued him in on the possible origins of the platinum/iridium in the C-T boundary that coincides with the fossil record of mass extinction. It seems that most platinum on earth has an extraterrestrial origin. Asteroid belt or something.

Great video! You should definitely put links on the description to those past videos you mentioned

Hands down the clearest explanation of USB cables ever.

It is also possible that rather than possessing spin, USB plugs exist in a state of quantum superposition. Thus, turning the plug one way or the other will do no good; you must visually inspect the plug to collapse the waveform, and then you'll know which way to orient it for insertion.

In the mid seventies there was some uncorroborated evidence of the existence of a magnetic monopole. I was in graduate school in Physics at Florida State University. Paul Dirac was a professor at FSU. He graciously gave a seminar describing his work on predicting the existence of the Magnetic Monopole (I was also fortunate enough to have had him as a guest lecturer in my Quantum Mechanics class, where he explained how he predicted the existence of the positron, but that is another story for another time). As you so elegantly explain, he demonstrated on the chalkboard how the quantization of electric charge led to his prediction. One uniquely interesting moment was when he reached into his pocket to pull out a scrap of paper that had Maxwell's equations written on it (no memorization of formulas required). His explanation was simple, clear and precise as though anyone could have come up with it. It was a true sign of genius. With that aside, my understanding of magnetism is that it is a relativistic side effect of a moving electric field. This strikes me as a simpler explanation that the invention of yet another required fundamental force. How does this coincide with the existence of a magnetic monopole?

Actually, this magnet slicing thing reminds me about how there can be no isolated quarks: if you split (say) a pair of quarks, you need to put in enough energy to create two new quarks, so you end up with two pairs of quarks. Maybe those monopoles are similar?

"Actually, quantum mechanics forbids this." "Or does it?" *cue Vsauce music

I misread the title as "magnetic monopolies" and was wondering why this guy would want a few magnet companies to control the market of magnets

so, basically: make the poles really far apart so that for our current human scale they can be approximated as monopoles.

The USB part at the end was awesome not sure how you kept a straight face

In RF engineering, there are some situations where it's way easier to shift the problem to an "anti-world" where magnetic monopoles exist and electric monopoles don't (If I remember correctly it's very useful when dealing with slot antennas, where you can replace the cut in the conductor with magnetic currents) Anyway, it's been some time since I had to do it but I had a blast every time I had to consider using a parallel universe to calculate something!

There's a mistake in Maxwell's equations at 3:34. The second equation should read (on the right hand side) the negative time derivative of B, and the right hand side of the third equation should be zero.

I love how much scientific rigor is put into both the presention & the humor (USB cables). That's the cherry on top for these already very enjoyable and mentally stimulating videos :)

The version of "Maxwell's Equations" you show is in 'Vector Calculus' notation, as developed by Gibbs and Heaviside long after Maxwell was dead. (Maxwell used quaternions.) Interestingly, Heaviside always calculated including the magnetic charge terms. He only set them to zero at the end.

I imagine physicists trying to discuss funding with policymakers after this "So, why do you need millions of dollars and the electricity of a small country again?" "To make magnets without one of the poles" "Right...."

When's the "why magnetic monopoles should NOT exist" dropping?

"If there are magnetic monopoles, then electric charge is quantized" is logically equivalent to, "If electric charge is not quantized, then there are no magnetic monopoles," not, "If electric charge is quantized, there are magnetic monopoles." A statement is equivalent to its contrapositive, not its converse.