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UsesProzac Gets RUBY! (Femme Talk Post)

James Burke takes a ride on the Vomit Comet

Ornthoron says...

I did this when I was a physics student. It's really like no other feeling in the world. Everyone instinctively start to swim in the air to orient themselves, to no avail. It can be quite scary at times when your head is pointing to the floor and it's only a few seconds until the 2g phase sets in again.

Quantum Field Theory Made Easy! - Feynman Diagrams

Ornthoron says...

@offsetSammy (I'm a physicist.):

Basically what @GlasWolf said. There are in principle an infinite number of things that can happen between the input and the output (you may for instance always add an extra self-energy term as shown in the video at 5:30 onwards), but usually only a few of all these infinite possible processes make up most of the total process.

To understand what I mean by that, it's important to remember that we are talking about quantum physics here. When we say that the different subprocesses have different probabilities, we don't mean that the particles choose (with a certain probaility) one of the possible Feynman diagrams to follow. No, in fact all the possible diagrams are followed at the same time. But the fact that some of the diagrams are more likely than others means that they are weigthed more heavily in the calculations. All the diagrams that contribute a tiny part to the total process can therefore be ignored, making the calculation much easier. And if your calculations turn out incorrect, you can simply add a few extra diagrams and try again.

This is also related to why the Feynman diagrams at first were met with scepticism by the physics community. Particles behave according to quantum mechanics, and don't go along straight lines as in the diagrams. But it turns out that they are very useful for translating the inherently counter-intuitive quantum physics into a language that is easier for the human brain to understand. They were therefore accepted as a very valuable tool, even though they are technically unphysical.

The ennui of Henri 2, Paw de Deux

VW Rollgolf

oritteropo (Member Profile)

Cutting Down Your Own Tree - Not The Best Idea You Ever Had

World Record Paper Airplane Throw

Amazing antique singing bird pistols

WW2 Train De-Railment Experiment.

WW2 Train De-Railment Experiment.

AdrianBlack (Member Profile)

Beyonce's All Out Funky All-Girl Band - "Put a Ring on It"

Online Indian Wedding Cards (Love Talk Post)

What are you reading now? (Books Talk Post)

Ornthoron says...

@oritteropo

Cheers, mate! I'll put an amazon link for you above if you want to order it and support videosift at the same time. (Edit: It seems I can't submit the british amazon link, but I believe this book from amazon.com to be the same one with a slighly changed title.)

A word of warning, though: The dramatis personae of The French Revolution is huge, and if you are not familiar with french names you will quickly confuse all the different individuals with each other. It does not help that the author will sometimes throw in a reference to some character that was last mentioned 50 pages ago. But the index in the back is quite extensive, so if you forgot who someone was you can just look up where they were first mentioned and get back on track.



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