Dirac equation for electron in layman terms!

What Great Dirac simply did was to take the square root of

He did this simply by assuming this to be equal to square of this

which could only be solved if A, B etc. are matrices because AB= -BA and so on!

more over we can get 4 such matrices only if we go to 4 dimension. There are not enough matrices to go in lesser dimensions.
that's it - it is just a matter of finding these 4 matrices of size 4x4.

But implications are amazing - we get electron spin as well as anti - electron!

Pure beauty of mathematics!

Why we see in visible light?

I was wondering why we see in visible light?

By that I didn't mean why we see in "visible" light instead of "invisible" light! Whatever we see is visible light, by definition.

What I mean is why we see in the range 380 to 750 nm?

for example, our eye could have been sensitive to another portion of Electro magnetic spectrum For example, infra red could have been red, red could have been orange etc. and we don't see violet at all or the other way around.

That is the spectrum could have been 450 to 820 nm.

so what is special about visible part?
it is something special for we earth dwellers.
1. Sun's temperature being close to 6000K its blackbody radiation peaks at this range.
2. Earth's atmosphere has some set of Electromagnetic radiation windows with optical window with this same range being one of them.
This link explains more:
http://www.iop.org/EJ/article/0031-9120/42/1/002/pe7_1_002.pdf?request-id=274078a3-1121-4070-893f-5aabf8d9e489

A cute little fact is rattlesnakes have "eye" to see in infrared - to catch animals like us who radiate in infrared.
So if our sun were to peak in different wavelength range and our earth were to be atmosphere-less [or of different composition] we would be seeing different visible light!
Of course we would be seeing only visible light, by definition!

A beautiful equation

e^i pi + 1 = 0
What a beauty of an equation is this - connects so many fundamental mathematical constants - 0, 1, pi , i and e.
It says all profound concepts in mathematics is fundamentally interconnected.
But I don't like Euler because of his God's existence "proof".

Tragic Logarithmic spiral

Path of an insect flying to a candle is a logarithmic spiral.
It's defining property is angle to the line from centre [candle] and tangent of insect path [instantenous direction of velocity] is constant.
r = ae^bt
t - is an angle.
The reason is they are used to doing this from old times when only sun and moon was there, in which case it led to straight line path.
Unfortunately not anymore, after this species called homo sapiens usurped the planet.
http://en.wikipedia.org/wiki/Logarithmic_spiral

prepare this blank disc in vista

I got this irritating prepare blank disc message with DVDs.
This link solved the problem for me. Goto device manager -> uninstall and 'scan for hardware changes'
http://www.copadata.it/forums/showthread.php?t=239