Archive for the ‘Relativity’ category

Time to study Relativity (updated x2)

April 29, 2012

Well, after our EPI, it’s time.

Time to get back relativity – but that does bring up the sticky issue of time itself. Time should be the most reliable thing in the universe; after all it is absolute, right? I mean aside from the jokes (like the one on the left), time is defined by how long it takes to complete a task, and that can’t be changed by how fast you are going – can it?

Well, like many questions about this level of physics, the answer is Yes, but No. It doesn’t matter how fast you are travelling, everything takes the same amount of time it normally would… from your point of view.

Ah, it’s those never-to-be-sufficiently-cursed frames of reference again.

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Relativity – it’s all about knowing your place

April 11, 2012

Relativity, along with Quantum Physics are used as proxies for impossible to understand science; they can be used to justify almost anything (1, 2). By the end of this unit, you will have an introductory understanding of the concept of special relativity, and how it relates to our prior studies.

The basic concept of relativity is simple enough; the speed of light is constant and nothing may go faster than it. Not difficult, right? Well the usual example to explain why such a simple concept is problematic is a thought experiment: Imagine a car that could travel near the speed of light (I want one!), then you turn on the headlights. Won’t the light travelling out from the headlights go faster than the speed of light?

Yes? well then the speed of light isn’t a limit.

No? well then velocity vector addition doesn’t work.

Take your pick, but it seems like there are no good answers – either way things don’t seem to work way they should.

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