100 Years of Special Relativity

phrotoma writes "Wikipedia notes in their Selected Anniversaries section that today marks the 100th anniversary of Albert Eintein's publication of the third of his four Annus Mirabilis Papers entitled On the Electrodynamics of Moving Bodies; the seminal work that introduced the concepts which would come to be known as Special Relativity. This event is also being commemorated in a UN endorsed celebration of physics: World Physics Year 2005 with talks and events at public schools, museums, and universities the world over."

Comments

Remember though. . .

[smooth wombat]

it's only a theory, not a fact. As such I demand that schools teach that it is tiny demons which are causing the effects we are seeing.

My theory is just as credible as yours since it's only a theory and not a fact.

Ok, now that that diatribe is over, what's truly interesting is not that what Einstein proposed 100 years ago is still being studied and restudied, it's that one portion of it was recently confirmed. Frame dragging was only confirmed last year.

Certainly other parts have been verified (relative time for example) but this portion, frame dragging, puts things in a whole new light. We're not just bodies in space. Instead, are bodies are changing the space around us!

Re:In case of Slashdotting...

[aznrocket]

Good coverage. For those in the Toronto, Ontario, Canada area, there are events being held @ the UofT. http://www.fields.utoronto.ca/programs/scientific/ 04-05/string-theory/strings2005/ for more info =)

The two postulates ..

[RedLaggedTeut]

Since it seemed to me 5 minutes ago that people where reluctant to answer to this topic, I went to read the intro of Einsteins paper. I found one line that is memorable and that might help you to answer the quiz-question "What are the two postulates of The theory of special relativity?" The answer is in this quote:

.. the same laws of electrodynamics and optics will be valid for all frames of reference for which the equations of mechanics hold good. We will raise this conjecture (the purport of which will hereafter be called the "Principle of Relativity") to the status of a, postulate, and also introduce another postulate, which is only apparently irreconcilable with the former, namely, that light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body. These two postulates suffice ..

The thing that needs explaining to me would be "frames of reference". A difference between two frames can be that they are in motion with respect to each other. For example, take a spaceship accelerating to half the speed of light, starting from our resting position. The 2nd postulate explains that the speed of light can be a constant velocity c, both with respect to the frame of the resting observer and the frame(view) of the spaceship. This leads to the question: if you shoot a light ray(velocity c=the speed of light) from the spaceship moving with half= 0.5 c, how come the light ray moves with 1.0 c from the view of both observers, not with 1.5 c from the resting observer?

As Einstein states, he then proceeds to reconcile the two seemingly paradox postulates by formulating laws of electrodynamics that will work.

Re:Depends on How You Look at It

[wass]

Relativity is brilliant, and changed science and culture forever. But it's really an ingenious refinement of Maxwell's field equations, even more than extra precision added to Newton's formulas.

First of all you're only referring to special relativity here, which ignores acceleration and gravity. Secondly, there were still some leaps of faith to be made, such as assuming c is constant in all frames of reference, which Lorentz showed non-Newtonian transformations that would allow this for Maxwell's equations. And expanding the new energy definition and concluding the zeroth-order term (mc^2) is the rest energy of mass also took another leap of faith (although that paper wasn't published until a few months after this first relativistic one).

But even so, discovering the connection between relativity and E&M is still amazing, in my opinion. For examle, the permittivity (epsilon_0) and permeability (mu_0) of free space are two constants that can be measured in the laboratory rather easily. Yet Maxwell's equations in vacuum describe waves travelling at speeds 1/sqrt(epsilon_0*mu_0), which is exactly the speed of light in vacuum (although in Gaussian units this connection is far more obvious). It's pretty amazing to think how these are related. But you still need to make some assumptions to get the Lorentz transforms between reference frames.

Additionally, even simple special relativity was extremely controversial, it rejected many assumed notions of space/time. There were also many paradoxes that took awhile to get ironed out. Many scientists didn't believe in relativity until it was shown in experiment. And in fact the theories of relativity were so controversial that the Nobel committee didn't want to award Einstein the prize based on these, so went for the safer 'Photoelectric Effect' instead.

And thirdly, general relativity, although again not included in this 100 year anniversary, is total genius, and it took Einstein 10 years to come up with the theory. So don't wave off relativity as just a 'refinement of Maxwell's field equations' because it really is much more than that.

BBC radio stories to mark the centenary

[Forget4it]

Theories of Relativity
Five specially commissioned short stories to mark the centenary of Einstein's discovery. Listen to them for next few days only here .
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