Light

[Guest guest]

Further to posting from

Anurag Goel <anurag

12 May 2000 08:02

Re: [ramakrishna] light

 

> Jay yesterday a friend raised some doubts and after that i sat down to

> understand the constancy of speed of light.

>

> This constancy of light

> sounds mysterious, I was trying to understand it and then as I was reading

> through the article which said that light propagates as alterations in

> magnetic and electric field. .

>

> Then I thought that this way if speed of light is going to be constant

> then we will always be at rest with respect to speed of light.

> Meaning universe is at rest with respect to speed of light.

>

> It's confusing and my explanation seems wrong because if such is the case

> then light will never be able to reach us.

>

> What do u say Jay ?

>

> love,

> anurag

 

 

Hi Anurag

 

Light is one of the most interesting aspects of Physics. It gives us a hint

that it is something more than mere physical phenomenon.

According to me this is the link between Physics and Indian Metaphysics.

( I am working on this theme right now).

 

The only thing Physics can do is to look at this phenomenon and try and come

to terms with what it does and does not do!

 

Let me draw on some of the interesting aspects of light

 

(1) It travels at constant speed in vacuum. (about 300,000km/sec) -If you

decide to run with a light beam at say nearly the same speed to try and

catch up and then look at it - you find that it is still racing away from

you at the same 300,000 km/sec.

In fact it was this mental picture that Einstein used to develop his theory

of Special Relativity. He said - that he imagined himself to be racing with

a beam of light at the speed of light - then what would he see? Would the

beam of light appear stationary to him?

It is a fascinating way to do Physics -- 'just thought experiments'.

 

He came to the conclusion that light cannot be stationary - hence something

else has to give way. The result was the abandonment of ideas that space

and time are separate and absolute - they were replaced with Relativistic 4

dimensional Space / Time.

 

It says my perception of space and time and your perception of space and

time are relative but both of us will agree on the same speed of light.

Conclusion: Light in a sense is more absolute than space or time.

Further development of this 'unusual feature of light' translates into the

famous equation E=mxspeed of light squared.

Again equivalence of mass to energy comes via this speed of light.

 

(2) This is just one aspect of Light - In the other field of Physics -

Quantum Mechanics it plays an even more central role.

We can perhaps develop this further some other time.

 

regards

jay