Imagine that you’re a stingy cartographer and that you want to make a colored map of the united states. Because you’re stingy, you want to avoid spending money on ink. You have to color the map so that no two adjacent states are the same color—otherwise you wouldn’t be able to tell them apart! If you want to buy the fewest colored pens possible, how many colors must you use to make your map? Very early on, mathematicians guessed that the answer was four colors. However, no one could prove it. An example map is in the tittle figure,
April 2013
Geometry / Mathematics / Physics / etc.
Stuff From Shape — Kaluza-Klein Theory
There is geometry in the humming of the strings. There is music in the spacing of the spheres. ~Pythagoras When Albert Einstein and David Hilbert published the theory of general relativity, they weren’t just proposing a new theory of gravity. They were proposing a new way of thinking. In general relativity, gravity isn’t a force. Instead, it’s a natural consequence of the shape of the universe. Force comes from stuff. Matter pushes and pulls on other matter. A proton may need to use its electric field to attract an electron, but the field is a property of the proton.
Physics / Relativity / Science And Math
More on General and Special Relativity
Last time, I answered some questions from readers Ms. C and Mr. A on special and general relativity. Mr. A asked some very deep follow-up questions, so I thought I’d share them. Mr. A asks: I believe you already answered what I had intended to be my follow-up question: spacetime curvature accounts for the acceleration of an object already in motion; but why does a body at rest being to move (e.g. why doesn’t a stationary object hover in the air until someone touches it)? If I understand you’re post correctly, Einstein would say that there is no such thing as being at absolute rest —
Uncategorized
Beware Water And Laptops
So I missed my promised deadline for my late post this week. I’m sorry about that, everyone. I spilled water on my computer last night and was thus unable to type anything. The computer came out fine, fortunately. I immediately turned it off, unplugged it, and took out the battery. Then I wiped everywhere I could reach dry and turned it over and let a fan blow warm air on the keyboard overnight. Runs fine now. If I’d waited to turn the computer off, though, something might have shorted. Unfortunately, I’m now really busy with the week’s classwork. I
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Perimeter Institute
So I just got back from visiting the Perimeter Institute as a prospective graduate student in Waterloo, Canada. It was really fantastic! For those of you who don’t know, the Perimeter Institute is a theoretical physics think tank in Waterloo, Ontario. They do a lot of science outreach, too; they’re responsible for the amazing Minute Physics youtube videos (check the links). Anyway, the reason I bring it up is that I just got back after a day of airtravel and thus my post will be delayed until tomorrow evening. Sorry about that, everyone!
Physics / Relativity / Science And Math
Rock Me, Einstein — Some Questions on Special and General Relativity
In 1905 Albert discovered Relativity, in 1906 he invented Rock and Roll ~Yahoo Serious In the last week or two, I’ve gotten several excellent questions on special and general relativity. I’d like to devote this week’s post to presenting and answering those questions. For the sake of anonymity, I will call the people who asked the questions Ms. C and Mr. A. I hope you enjoy! A Question on Special Relativity The first question is by Ms. C, who asked: I’ve read your article “The Speed of Light is Constant.” I’ve… got a question on the speed of light
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slight delay
Sorry for yet another delay, everyone. I’ll get the post up either tomorrow afternoon or late tonight.