Four Realms of Physics

Today we introduce four realms of Physical laws that govern the
universe:
(i) Classical Mechanics
(ii) Relativistic Mechanics
(iii) Quantum Mechanics
(iii) Quantum Field Theory

Let us start with our everyday life. Things are going very slow
here. ...Yes. Even on freeways in and around Boston or Los
Angeles! Those crazy drivers who are having the fun of their twisted
mind by cruising at 90 miles per hour are really too slow to catch up
with the speed of light which is about 186,282 miles per second or
about 3 hundred thousand Kilometer per second.

Things that happen in this world - the interaction of forces and
bodies - can be fully described by Newton's three laws which are
introduced in high school Physics courses. Using these equations,
we know, for example, how exactly a projectile traverses its path
in the air, how to determine the slope of a bending freeway so that
at least reasonable drivers do not topple their cars while negotiating
the curve at normal speed, etc and etc ....

In the 16th Century Newton introduced these concepts and
equations and some great Mathematical tools like Calculus to solve
and understand many such problems and mysteries of life.
In general, that is the realm of Classical Mechanics. These equations
were tested and successfully used so many times in so many cases
and situations that at the end of the nineteenth century, some
Physicists came to believe that Physics was coming to an end
... Nothing more to know or understand about Physical laws.

Twentieth century changed all that when scientists tried to look
at microscopic objects and their motion and in 1905 a clerk of
a patent office at Bern, named Albert Einstein, explained what
happens when something approaches the speed of light ...

...And we got into new arenas of Physics - Relativity and Quantum
Mechanics .. and then Quantum Field Theory....

The Shortest Sentence to Describe the Universe

"Four interactions among Leptons and Quarks"

That is the shortest sentence to describe all phenomenon in this
universe [Based on our current knowledge].

There are just 4 types of fundamental forces in nature. We can
present those here in increasing order of their relative strength:

(In the following, say, 10^40 means you need to put 40 zeros
after 1 to get that number)

Gravitational Force [Relative Strength: 1 ]
(That acts among all massive bodies including heavenly ones)
Weak Nuclear Force [Relative Strength: 10^29 ]
(This acts inside the nucleus of radioactive atoms, like Uranium)
Electromagnetic Force [Relative Strength: 10^40 ]
(Electric Motors and generators and lightning
are manifestations of this)
Strong Nuclear Force [Relative Strength: 10^43 ]
(This acts inside the nucleus of all stable atoms and acts among
neutrons and protons)

Note that 'strength' depends on the nature of the source of that
interaction and how far away your reference point is. So, sometimes
in other sources, you may find different numbers from the above.
But the numbers quoted here may give you an idea.

We'll describe these forces one by one more in our next postings.
But wait ... what are leptons and quarks? We'll slowly get into
those too. For the time being ... think that all matter in this
universe are made of two kinds of elementary particles: leptons
(example: electron) and Hadrons (like protons, neutrons). These
Hadrons are basically confined states of more elementary particles
called Quarks.

We know... we know... you need more and clearer explanation of
all these topics. Yes we'll do that. This is just an exposure of a few
essential information. You may not understand everything now
... but be with us.. and for the time being .. just get exposed to
some information ... and slowly you'll see a pattern is coming up in
your mind ... and before you know ... you'll find that your way of
looking at the sky and your surrounding has changed ...

Physics Book Recommendation

[Category: Semi-popular]

"The First Three Minutes: A modern view of the origin of the Universe"
- Steven Weinberg
[1993 Publisher: Basic Books, NY]

Steven Weinberg won Nobel Prize in 1979 with Sheldon Glashow
and Abdus Salam for their path-breaking work on unifying
Electromagnetic and Weak Nuclear interactions in matter
[read our next posting]. He is Josey Professor of Science and
Astronomy at University of Texas at Austin.

This book came out first in 1977 and became an instant hit among
all people interested in Physics and other people who were just
wondering about this Universe and its origin but was not getting
something that could tell them this story spanning a large spectrum
of Physics topics.

Weinberg gives a frame-by-frame almost movie-like account of
what happened in those very crucial first few moments after the
Big Bang as we understand and guess from what we know or
understand from General Physics and Astrophysical observations.

This book is a great synthesis of cosmology, particle physics and
Astrophysics and tells the story in great style.

We put this in "Semi-popular" category because some exposure
to College-level Science is needed in order to fully appreciate the
greatness of the content of this classic book.

Physics: from Electron to Universe

... and what about your cellphone or the large TV in your living room?

In 1897 .. when J. J. Thompson conclusively discovered electrons,
many might have wondered what could be the use of learning about
such small particles ... a few millions of which can be accomodated
on the tip of a needle.
[Electron's 'classical' radius is about 2.8 X 10^(-15) meter
which means you need to divide 2.8 meters by 1 million billion.
Why 'classical?' - Be patient. We'll explain that later]

But within a few decades the world got revolutionized mainly with
the use of electricity (which is nothing but flow of electrons in wires)
and the great discovery of semiconductors in which energy of electron
is controlled in such a way that the device can be assigned to do
various kinds of logical operation and used to make wonderful
things ... like radio, T.V, telephone .... computer .... microwave oven..
Our modern day life is so much dependent on electrons that we
almost forget that these is being put to work day and night like slaves
by our technology experts for helping us to communicate and do
important jobs and provide us comfort!

Electron is a true revolution in mankind's history.
Alas! We never celebrate it!

Words from '2Physics'

Our aim is to give you some good reading and information
and concepts every day.

You'll notice we'll avoid using hyperlinks. Hyperlinks are
very useful things but we feel a reader get easily lost from
his/her goal of enjoyment if he/she gets too many opportunities
of getting into newer and newer links of information.

Our aim again is your entertainment - through Physics.
If you get interested, you yourself will start searching for
more information or will leave your comments and requests.
We'll certainly follow those comments ...

1905: The most productive year of Einstein

In 1905 Einstein gave the world three exciting ideas in 3 separate papers:

(i) The application of the concept that light also behaves like a particle
even though many of its behaviour are more like waves.
Einstein later got Nobel Prize for this paper which explained the
photoelectric effect.
The photoelectric effect is something that converts light into electricity
and works in photocells.
You know what photocells are! Nowadays in most public toilets
it automatically switches on flushes as you leave!

(ii) The brownian motion - the kind of motion of you see among dust
particles if you throw some in a glass of water. The statistics of this
motion is very interesting to Physicists and its knowledge is applied
in understanding so many other things - FROM the transfer of heat
among bodies TO how stars got formed in the first place!

(iii) The Theory of Relativity: Who have not heard of it?
This is the paper which revolutionized mankind's concept of time
and space in which they lived.
Einstein showed us that time was no more an absolute concept.
Your time could be different from my time if we move to or from
each other at constant speed.
These concepts gave us the most well-known scientific equation:
E = mc^2 and taught us that mass can be converted into energy.

We will elaborate on these concepts more. ... one by one ...
We will discuss about what else Einstein did and Others also followed.
How were experiments done to prove Einstein's concepts?

This is just an introduction. So many more stories to tell ....

Wait and check us regularly ....

This is THE YEAR OF PHYSICS

2005 is the year of Physics.
Here you will find exciting facts and information regarding
latest advancements in research, education and use of Physics
in Technology and daily life.
We will also post interesting stories about scientists and
their discoveries.

So, check out from time to time. You may not be an expert
in Physics. But you will like it. After all, how can you avoid
knowing in simple terms how small things like electron and
big things like the universe are working around you.

Keep your comments if you donot understand something.
We'll explain each item again in simpler terms for you.

Our postings will start soon!