The Theory of Everything
By Michio Kaku
Time Magazine chose him as Man of the Century. Albert
Einstein had three great theories. His first theory of Special Relativity
(1905) gave us E = mc², which led to the atomic bomb and unlocked the secret of
the stars. His second great theory was General Relativity (1915), which gave us
space curves, the Big Bang, and black holes. But many don't realize that his
greatest theory was never finished: "a theory of everything".
Einstein's crowning achievement was
to have been the unified field theory, an attempt to "read the mind of
God".
But on the
third try, Einstein failed. He spent the last 30 years of his life chasing
after an equation that would explain all physical phenomena. Everything from
Creation to atoms and molecules, perhaps even DNA, people, and love was to be
explained by this equation. If discovered, it
was to have been the ultimate achievement of 2,000 years of investigation into
the nature of space and matter, ever since the Greeks asked what was the
smallest particle and the smallest unit of space. Although there are many
unresolved questions, today the leading and, in fact, only candidate for the
Theory of Everything is superstring theory, defined in 10 dimensional
hyperspace. Superstring theory, in turn may one day answer some of the deepest
questions of the universe, such as: What happened before the big bang? Is it possible
to build a time machine? Can we punch a hole in space? Not only has the power
of this theory startled the world of
mathematics and shaken the world of physics, it is also the craziest theory
ever proposed.
Four fundamental forces
Today,
we realize that the entire universe is governed by four fundamental forces:
- The gravitational force,
which keeps us from flying into outer space, and prevents our sun (a
gigantic hydrogen bomb) from exploding outward.
- The electromagnetic force,
which light up our cities and energizes our lasers and our computers.
- The strong and weak nuclear
forces, which lights up the stars and
galaxies.
Gravity
can be described by Einstein's general relativity theory. Matter warps the
space surround it, thereby creating the "force" of gravity. Imagine
an ant walking on a crumpled sheet of paper. The ant would say that there was a
mysterious "force" which pulled it left and right. But we know that
there is no "force" pulling the ant; there is only the crumpled sheet
of paper pushing the ant left and right. Gravity does not pull: empty
space pushes.
But after decades physicists have unified these three quantum forces into
what is called the Standard Model. Remarkably, all known physical phenomenon
can, in principle, be described by these two great theories, relativity and the
quantum theory. But why should nature, at the most fundamental level, create
two totally dissimilar theories? Sadly, every attempt to merge these two
theories has failed. Some of the greatest minds of the century have tackled
this problem, only to be unsuccessful.
Superstring theory combines relativity and quantum in
an elegant, intuitive way. First, it describes a great number of quantum particles of nature because each
particle represents a "note" on a vibrating string. Think of a violin
string. No one says that A or B is more fundamental than C. What is fundamental
is the string itself.
Superstring theory says that, if we had a
supermicroscope and could peer at an electron, we would see a string vibrating
in a certain mode. The string is extremely small (10 to the minus 33 centimeters!)
so that the electron looks like a point particle to us. If we shake the string,
so it vibrates in a different mode, then the electron can turn into something
else, such as a quark, the fundamental constitute of protons and neutrons.
Shake it again, and the string could vibrate in the mode which describes
photons (the quanta of light). Shake it again and it turns into a graviton (the
quanta of gravity).
The superstring theory can also explain gravity. When
the superstring moves in space and time, splitting and rejoining into other
strings, it forces the space-time surrounding it to curl up, just as Einstein's
equations predict. In other words, even if Einstein never dreamed up general
relativity, we might have discovered it through superstring theory.
Superstring theory, of course, has its
detractors. Many point out it predicts
the universe is defined in 10 dimensional hyperspace, which sounds more like
science fiction than real physics. It's indisputable that the universe exists
in four dimensions (3 spatial dimensions and one time dimension). Every object
in the universe, from the tip of your nose to the farthest star, can be located
by giving just 3 co-ordinates (length, width, and height). If we also give the
time, then we can describe every event in the universe with just four numbers.
For example in New York, we might say to a friend, "meet me at 42nd street
and 5th avenue, on the 25th floor, at 12:00." Thus, four numbers
(42,5,25,12) completely specifies this event in space-time.
Superstring theory, however, predicts the
universe should exist in 10 dimensions, not four. To explain where the other
six dimensions went, physicists believe that the universe originally existed in
10 dimensions. However, at the instant of the Big Bang, for reasons we don't
understand, six of the 10 dimensions "curled up" and collapsed, while
the other four dimensions expanded rapidly. In some sense, our universe
expanded at the expense of a twin universe which collapsed down to microscopic
size.
1.
Which
of the given words is closest to crowning in the first paragraph?
a.
highest b.
weakest c. ancient d. accessible
2. Which of the given words
is closest to startle in the second paragraph
a. upset b. change c. surprise d. create
3. Which of the sentences
given below is true according to the text?
a. Of all his great achievements Einstein’s superstring
theory was the best to explain the origin of the universe.
b. Greeks tried to answer the questions about the origin of the universe.
c. Einstein tried to find a formula that would explain all
the facts in physics.
d. Einstein was crazy to propose the Theory of Everything.
4. Which of these sentences
is NOT true according to the text?
a. All the theories which
meant to solve the mysteries of the universe were unsuccessful to explain the
combination of relativity and quantum theory.
b. If shaken a string turns
into something different such as quarks and photons.
c. If Einstein had not
introduced the gravity theory, it still would be possible that we would
discover it thanks to string theory.
d. Everything in the universe
can be specified by the co-ordinates and time.
5. What does it refer in the
second paragraph?
a. Reading the mind of God.
b. Investigation into nature
of space and matter
c. An equation that would
explain all physical phenomena
d.
Creation,
atoms, molecules, Dna and love
Answers
1. a 2.c 3. c 4. a 5. c
