Monthly Archives: July 2000

The Loss of a Great Library

About 2200 years ago there existed a Great City called Alexandria and in this great City there existed a great library “The library of Alexandria ” . It was near Cairo in Egypt .

 

      It was build by Ptolemy the successor of Alexander and the king of Egypt . Ptolemy had a GREAT interest in books . Ptolemy had a great Ambition : ” to possess all the books that the world had ever produced .

And thet too in the orignal . Remember in those days books were not published . They were hand written . Ptolemy wanted the Author’s hand written copy . He wanted to collect these books and store them in his library .

 

      His methods to acquire these books was unique . He wrote a letter to all kings of the world requesting them for the orignal books . He said that he will copy them and reurn the orignal . But what he did was to keep the orignals in the library and return the copies 🙂 . All ships that stopped in Alexandria were searched for books and if found they were taken to the library .

 

      The library became a great centre of learning . It had over 120,000 books . The library also became a place where scholars and scientists could live and do their research . Here Eratosthenes calculated the size of the earth , and made its map . Hipparchus made a theory of the formation of the stars and catalogued their positions . Euclid produced his books on Geometry . Arichmedes invented the screw . The first woman Physicist and Mathematician Hyphatha also lived , lectured and was killed here. Galen wrote the basic works of Anatomy and Healing which dominated medicine till Renaissance .

 

      This library was a tribute to man’s quest for knowledge !

 

      But it was destroyed by the baseness in Man which so often overpowers his intellect . When Julius Caesar invaded Egypt the library was destroyed . The Romans did not share the  love of learning that the Greeks had and found no use of the books there . They burnt the library and not a single scroll remained !!! The Romans were crazy . They were stupid . They were barbarians . They were *#$%##%* !

This was in approx 55 BC .

 

      How can anyone burn a book ?????? Anyway the library were destroyed and so much orignal work that mathematicians and Scientists had done was destroyed with it .  For example of the 123 plays of Sophocles only 7 survived the destruction .

 

      See Carl Sagan’s Cosmos for a beautiful account of the library and  its destruction . 

Bode’s Law

Before we begin today’s VERITAS a little quote that both inspires and amuses :

 
        If this world were good for nothing else ,
        it is atleast a fine subject for speculation

Today we are going to see an example of scientific guessing and how scientists sometimes guess at an answer,see if it works and then try to find a theory that explains it .

Scientists since Kepler wondered about a formula that could predict the spacing between planets in the Solar System . Then in  1778 J.E Bode guessed at a theory . To find the ratio  of distance between planets do this :

Take the sequence of numbers :

0 3 6 12 24 ….

Add 4 to each number and divide by 10 to get :

.4  .7  1  1.6  2.8  5.2  10.0  19.6  38.8

Now these are the approx distance of planets from the sun in terms of Astronomical Units . ie if you take the distance of earth from the
sun as 1 AU( Astronomical Unit ) then Mercury’s distance is .4 AU . Venus .7 AU . Earth : 1AU . Mars 1.6 AU etc.

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This comes REALLY close to the actual distances . And not only that , this theory predicted something too  . Jupiter is at 5.2 AU .
Mars is at 1.6 AU . So what is between them ? at 2.8 AU . The Astronomers searched and found the Asteroid belt at 2.8 AU !!!!!!!!!
WOW !!! Also this theory predicted a planet at 19.6 AU . And much later Uranus was discovered !!! cool aint it

But this theory does not work for Neptune and Pluto ! Which led some Astronomers to reject the Bode law . Other Astronomers suggest that
Neptune and Pluto were one planet earlier and that planet followed the Bode law 🙂

Nobody knows if this theory has any scientific explanation . Or is it just a mathematical coincidence.

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A similar case of “scientific numerology” happened when in 1885 a Swiss Mathematician proposed a numerical theory that worked for the spectral series of Hydrogen . Later Neils Bohr used the quantum theory to predict exactly the same spectrum series . This series is name after the same Swiss Mathematician J.Balmer and is called the Balmer Series . What was a guess earlier is now a law .

It is funny how nature plays games with us and then gives  subtle hints to help us understand why she did what she did 🙂

 

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Veritas by Kanwarpreet Grewal is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License.

Raman Effect

Hi . All of us know that CV Raman won the Nobel prize in Physics for his Raman Effect . But what exactly is the Raman Effect ?

      When incident light is focused on a material the molecules of the material get excited . These molecules then radiate themselves to come back to their nonexcited states . Most of the radiation that comes out is of the same frequency as the incident light . But some of this radiation is of a different frequency . This light of different wavelength is said to be Raman scattered . This light is weaker than the incident / same freq light . This kind of light is radiated because the incident light causes some changes in the molecular motions of the material . The Raman effect is very weak . For example , for a liquid substance the intensity of Raman radiation may be 1/100,000 of the incident beam . The spectra of the radiation that comes out tells us about the molecular bonds in that material .

      So if u strike a liquid with a intense light and then record what comes out of it and take only the Raman Radiation then that radiation will tell you about the properties/strengths of the chemical bonds in that liquid . Because the ability of the incident light to be able to change the motions of the liquid depend on how strong the bonding between its(liquid) molecules is .

      This is the priciple of Raman Spectroscopy . This method is used to very accurately study the properties of materials without changing them in any way . It is a very powerful and popular technique .

      Sir CV Raman did the series of experiments to prove the existence of this radiation in 1928 . He got the Nobel Prize in Physics in 1930 .