Tag Archives: General Relativity

Old School Viral

Remember when “going viral” didn’t mean hospitalization and possible death? (Obviously if we go back even further to the original meaning, it did.) I had an old post go briefly and mildly viral last week. Big traffic spike with a very rapid tail-off. Most bemusing.

I’ll tell you about that, and about a spike on another post, this one weirdly seasonal — huge spike ever September for three years now. I have no idea what’s going on there. Most puzzling.

There is also a book about the friendship and conflict between Albert Einstein and Erwin Schrödinger that I thoroughly enjoyed despite it not being my typical sort of reading (I’ve never gone in much for either history or biography).

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Gravity Waved!

LIGO-0It took almost exactly 100 years. In 1905, über-geek hero Albert Einstein presented four papers of major significance to the world. One of those was about Special Relativity. It took Einstein ten more years to figure out the General theory of Relativity. He presented that work in November of 1915.

One of the predictions of General Relativity is that gravity warps space, creating gravity waves (which move at the speed of light). And while many other predictions of GR have been tested and confirmed (to very high precision), we’ve never quite managed to detect gravity waves.

Until September 14th of 2015!

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Thinking About Time

dog in the nowWe sometimes say that dogs are living in the now. Sometimes we say that of people who live in the moment and don’t think much about the future (or about the consequences). Whether we mean that as a compliment — as we generally do with dogs — or as an oblique implication of shallowness depends on the point we’re making.

There is the tale of the ant and grasshopper; it divides people into workers who plan for the future and players who live in the now. The former, of course, are the social role models the tale holds heroic. The grasshopper is a shifty lay-about, a ne’er do well, a loafer and a moocher, but that’s not the point.[1]

The point is our sense of «now» and of time.

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SR #1: Motion in General

accel plane

A fun way to feel acceleration!

Last time I introduced some of the foundation concepts required for our exploration of Special Relativity. In particular, that the word “special” in this case refers to a specific kind of motion: constant motion in a straight line.

Which may have caused some of you to wonder: Okay, what about motion that isn’t constant (and what’s that business about “in a straight line” — why keep mentioning that)? As it turns out, when motion involves speeding up, or slowing down, or going along a curve (or even just changing direction), that changes the situation in very significant ways!

That’s what I’m going to discuss today.

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