relativity

Category archives for relativity

“It is conceptually interesting, if not astrophysically very important, to calculate the precise apparent shape of the black hole… Unfortunately, there seems to be no hope of observing this effect.” -Jim Bardeen Black holes were one of the first consequences of general relativity that were predicted to exist, and the more we’ve studied the Universe,…

“It appears, from all that precedes, reasonably certain that if there be any relative motion between the earth and the luminiferous ether, it must be small; quite small enough entirely to refute Fresnel’s explanation of aberration.” -Albert A. Michelson In the 1880s, it was clear that something was wrong with Newton’s formulation of the Universe.…

“If you haven’t found something strange during the day, it hasn’t been much of a day.” -John Archibald Wheeler Today, we take the existence of gravitational waves for granted. They were predicted by Einstein almost immediately following the first publication of general relativity, they were indirectly detected decades ago and they’ve been directly detected multiple…

“I really didn’t have to work, shall we say, with Star Trek. It was a natural. When I opened my mouth, there was Scotty. It’s like I tell people what you see in Scotty is 99% James Doohan and 1% accent.” -James Doohan So, your friend on the USS Enterprise beamed you aboard, took you…

“I want to stand as close to the edge as I can without going over. Out on the edge you see all the kinds of things you can’t see from the center.” -Kurt Vonnegut We all know how explosions work: a tremendous release of energy causes a rapid outward expansion, and the most energetic particles…

Ask Ethan: What Is Spacetime? (Synopsis)

“‘Space-time’ – that hideous hybrid whose very hyphen looks phoney.” -Vladimir Nabokov Sure, you know what space and time are. If you heard of Einstein and relativity, you might know that they’re not absolute quantities, but that how you experience distances and the ticking of clocks is dependent on your motion through the Universe. But…

“The only man who never makes a mistake is the man who never does anything.” -Theodore Roosevelt Scientists make mistakes. We fail. We have our intuition lead us astray; we synthesize information in ways that lead to catastrophically wrong predictions. Whether we make sloppy, calculational errors, have oversights in what we consider, or whether we…

“The very closest stars would require many years to visit, even traveling at the speed of light, which is impossible according to Einstein’s theory of relativity. Today’s fastest spaceships would require 200,000 years to travel to Alpha Centauri, our closest bright star. The energy required to send a hundred colonists to another star, as Frank…

“Each ray of light moves in the coordinate system ‘at rest’ with the definite, constant velocity V independent of whether this ray of light is emitted by a body at rest or a body in motion.” -Albert Einstein, 1905 The more kinetic energy you impart to something, the faster you go. But there’s a limit:…

“It is old age, rather than death, that is to be contrasted with life. Old age is life’s parody, whereas death transforms life into a destiny: in a way it preserves it by giving it the absolute dimension. Death does away with time.” -Simone de Beauvoir If you want to describe your location here on…