ŷ������

Hai guys , finally the time has come for us to start the Group Reading , hope you are all ready for it and it Starts Today , any discussions related to the book can be in this folder .......Happy Reading

Hi ..readers ....Anyone is the Group read?

I am here reading with the group , who else

Me too , i don't think many are in here Alok , you told you need minimum of 10 and i agree it too , but i can hardly see 3 or 4

Ok Thank you both of you and i appreciate you both taking part in the Group read , But this is turning out to be a failure ..........Again!!!....i thought we will have more active readers...But ..i don't get it

Maybe we should just continue our normal discussions for now in the group ....I don't think we should have a group read any time soon......it will be a failure as it turns out !!!! ....

One more here...

Wow!.....Glad we have another one....So what's our next move?

I have just started the book. I am going through my first chapter. It will be interesting to read this, especially because I have just finished Cosmos by Sagan. How far are you guys?

I actually read about 90 pages last month , but for the sake of Group reading , i have restarted .......right now i am near newton Theory of Gravity part

Hai people i am into it and this book is very interesting and i finished off the first chapter but i wont spoil you with my review Doing Good so far

It's just like a miracle , everyone is popping up slowly..and i am happy about it , Good going guys ......

Dont worry moderator , this group is awesome

hahaha ....i am not used to being called moderator friend , you can call me Alok .......I am just one of you 57 people hoping for some knowledge and thanks for the compliment

Alok you are good man

Thanks.... So we need we will all discuss about the first chapter by tomorrow?

yup

Yes

I read this about 30 years ago.

Well .......i am just thinking of how many books you could have read in these thirty years following The Brief history of time , i am sure it's a lot of books ,you re a perfect guide for us young readers Mr.Bill , we are very glad to have you in the group , you could guide us in the right direction regarding books......

Great thing about this book is, that it is being updated. Firt was in 1996 and the second update was more recently in 2016! So even if you read it 30 years ago, it might still be interesting read it again!

Ya but i needs a major update now , because it says Gravitational waves have not been discovered , but it was discovered in the end of 2016

My book has an update in the apendix about the detection of dravitational waves by LIGO.

mine hasnt got that update

Hi guys , how is the reading going on ?

Hello there! I am currently at chapter 3. The first chapter was nice and easy. Mainly a history lesson. I was lauthing at the part with the turtles. It is amazing how far did we go, what we learned.

i was going to say the same thing it is a good little humor which also tells us,how far ahead we actually are i am in the second chapter and it is bit of a history lesson too i m enjoying it though

In the second chapter , Mr Hawking Speaks a little about Poincare , If you know about the Great Millennium Problems , Poincare Conjecture is one among the 7 Millennium Problems .............Millennium problems are 7 Great and meaningful Mathematical problems Solving even one of those you would me awarded the Fields medals .....only one of those 7 problems are solved and that is Poincare Conjecture....other six are unsolved . This Conjecture was solved by Grigori Perelmen ....quite recently

We indeed have come a long way in exploring our cosmic habitat & laws of nature with respect to the dawn of our civilization which is not a very long span of time considering the age of Earth , let alone the age of our Cosmos. As cited in this fantastic book in the first chapter that, even Newton thought that there may be infinite stars as he mentioned in his letter to Bentley in the late 17th Century. Followed by that about a century and a half since then came the Olber's paradox resolving which our understanding was reformed...

same is true with the speed of light which acvording to Newton, could be relative & attain any values ... Rømer's work helped to agree on the finiteness in the speed of light, Fizeau worked on finding accurate value of speed of light, Michelson & Morley showed that the speed remains unchanged regardless of how you arrange your interferometer and finally Einstein made the foundation rock solid with his Special Relativity theory in 1905...
since then everybody became cautious of paradigm shifts which can happen anytime based on wild ideas but rooted to the systematic approach of science.

This book is among the very early attempts of scientists to make science accessible to every one... Happy reading !

that is a very good insight from Arko this book is very famous great and sold the copies it has sold majorly because it has almost all concepts of cosmology explained in a surprisingly simple way it is more reachable to a common man and it was a first of its kind . i am enjoying it very much reading it though

hi guys how far you all are? i am done with chapter 3 . what actually gets me surprised me is we humans a beings on a Pale Blue Dot ( like Carl Sagan Says) have figured out a way to precisely tell the composition of a star light years away it seems NoBigDeal but when i think about it i cant help but be astonished and Mr.Hawking mentiions that every element has its own spectral lines but i coundnt get it through my skull ,Why does every element has its own Spectrum ?

it has something to do with the energy bands of electrons

the basic idea is , Electrons give out light when it jumps from high energy level to low energy levels , Energy levels are , you can say different orbits , if electron jumps from higher orbit to lower orbit , it gives out a photon which is you can say a light particle of a certain wavelength , the electron which jumps from higher energy emits a light of shorter wavelength , keeping this idea in mind , now every element has its own number of energy levels and electron , and we now exactly know which elements gives out what spectra , when we create a spectrograph of a star we can compare it with out earthly analysis , we will know the composition of the star ........

Exactly Alok. Each atom in a element has its unique arrangement of electrones. Electrons have their energy level, and when one jumps from higher energy to lower - photon is being emitted. The bigger the energy of photon - the shorter the wavelenght. Different wavelenghts = different cololor

Hi folks i am in 4th chapter. And i think this is a quite complicated compared to the other chapters

Just finished chapter 5. Whoa! The quantum physics makes my head spin!
So, do I understad it correctly:
Protons and neutrons are made from quarks.
There are six flavours of quarks : top, bottom, up,downd, charm and strange.
The quarks are held together by strong forces:
Strong nuclear force, where messenger is Gluon
Electromagnetic force, where messenger is Photon.
Wesk nuclear force, that has three different messengers Vector Bosons W+,W-,Z^o.
Then there is Gravity with its graviton. That doesnt really work with the quantum world.

Each subparticle has a spin. Mass particles have 1/2 spin, force particles are either 0,1,2

Is this about right? Or do I need to read it again?

And a question! What do Weak nuclear forces do? Thanks

One more questio: the spin gives the “color�� to the sub atomic particle. And they then bundle into groups creating “white�� , right? Is that the “function�� of the spin?

Hi Veronika,
Weak force is that force which is responsible for radioactivity. Like the strong and electromagnetic forces, it is also found to be mediated by two types of bosons namely W (+/-) & Z. It can also be understood in this way that for a fermion to get converted into its other energetic but respective types ( like a quark to another quark or a lepton to another lepton) it requires this weak force to be active. Most importantly it should be noted that weak force and electromagnetic force are two sides of the same coin being called Electroweak force. Weinberg, Salam and Glashow showed in the 1960s how these two forces are unified and received the Noble prize of 1979 after experimental verification from Gargamelle chamber of CERN.
To answer your question on color, you should have in mind that color here is not the same color which we understand caused by the visible electromagnetic spectrum. Color charge is a property of quarks and gluons which interact via strong force. In 1964 Oscar Greenberg introduced the notion of color charge to explain how quarks could coexist inside some hadrons in otherwise identitical quantum states without violating the Pauli's Exclusion Principle. Pauli Exclusion Principle states that no two objects with all same quantum numbers can occupy the same quantum state, it is impossible for one particle to contain two of the same kind of quark. Yet the proton is found to be made up of two up quarks. Because of this contradiction, it was proposed that quarks must have another property with six manifestations: red green blue+ anti red antiblue anti green. This new property was labeled color and hence the subject of this study is called Quantum Chromo Dynamics. Whether it is a function of spin, that I personally dont know. I have scanty knowledge in QCD so far. I request input from others in this.

Thanks.

Damm ! Today i am gonna sleep peacefully this night because i learnt something new and i am perfectly sure that i woudnt have gone any where near understanding this chapter if you guys hadnt explained it Now i am pretty ok with it i am gonna read it once again anyway Thanks Arko and Veronika

Thank You, Anko, do you recomend a book for particle physics? This is very interesting to me, and I would like to read up on it some more. Thank You!

Yes surely:

The Infinity Puzzle by Frank Close

Massive: Higgs Boson & the greatest hunt in science by Ian Sample

Particle Zoo by Gavin Hesketh

Smashing Physics By John Butterworth

Supersymmetry by Gordon Kane.

These are the books which I have read so far on particle physics...

You may also want to browse : A map of the invisible by John Butterworth.

Happy reading !

Arko wrote: "Yes surely:

The Infinity Puzzle by Frank Close

Massive: Higgs Boson & the greatest hunt in science by Ian Sample

Particle Zoo by Gavin Hesketh

Smashing Physics By John Butterworth

Supersymmetr..."

Thank You so much!

The Particle Hunters

This is a great book for particle physics too ......

And Arko , I just saw your post 2 hours back and i immediately posed the question to a professor i knew .....If spin and color are were dependent on each other ....and he said NO , But he couldnt justify it ......... But he was very sure about it

Hey Alok,
that is very kind of you to consult with a Professor.
thanks for recommending the book Particle hunters by Ne'eman.
I would try to read more on QCD.
on a different note I have also come across a book in Amazon by Wilczek named Lightness of being.... but I haven't purchased it yet... hoping it has something on QCD ...

Thank you Arko .....

this book was written purely to tide over the financial crunch in which hawing found himself. For every equation, he was told, the sales would be cut by half. The amazing part is how difficult it all is and yet it was sold out on the very first day, leaving the amazed publishers with an embarassing binding mistake (some pages upside down), which they hoped to correct and called for unsold copies from the bookstores to find none left A poll to purchasers revealed that they could not really what their motive was, but the vast majority just left it partially read on their bookshelves.
Mrs hawkins answer to why she thought the book stayed for years on the top position of the best sellers' list, Well because it was written by my son"{ conceals perhaps, the unconscious reason. As for me, i got it for rs 2 from the footpath decades ago .

Even Mozart wrote some of his Compositions Just because he badly needed financial support , And centuries later , his music still remains the Greatest

Vivek wrote: "this book was written purely to tide over the financial crunch in which hawing found himself. For every equation, he was told, the sales would be cut by half. The amazing part is how difficult it a..."

That's great ...i had never heard of that
But my friend Vivek , i think you may be one of those "vast majority just left it partially read on their bookshelves" because i dont see it in your READ shelves ...i assume you haven't read it yet