Stephen Hawking - Quest for a Theory of Everything

Review

This book provides a concise "autobiography" of Stephen Hawking and his quest for a Theory of Everything. It follows the mathematician's life and modern developments in physics towards building new theories that propel physics into a new era. These theories allow us to mathematically describe, understand, and predict behaviors of singularities in the universe (black holes, the birth of the universe).

The book also provides a great overview on how abstract mathematics, faith, philosophy and God play a role in the human desire to understand and describe the physical universe. It reminds us that despite everything that modern science has given us, the answer to the fundamental question "why" is still unscientific, and spiritual, in nature.

After reading the book, I pondered how much more could be untapped from Hawking if he was living in our current times with access to modern medicine and technology (e.g. brain/computer interfaces). It also made me realize the importance of improving the lives of the sick, allowing everyone to have equal opportunities to quality of life that empower them to contribute to humanity.

Stephen Hawking

Hawking is born into a non-remarkable family and lived a largely non-remarkable and unmotivated life until he developed Lou Gehrig disease. As he struggled through his disease, he found purpose and was able to fully channel his genius over the decades. It is fascinating to note that any series of events could have easily derailed his eventual contributions to physics:

• Hawking continuing his jaded attitude in university and missing the opportunity to attend the relevant programs and meeting the relevant advisors who would eventually recognize and untap his talents.
• Hawking giving up and losing the will to continue.
• His disease could have developed at a normal rate, leading him to die in the expected 2-4 year window.
• Meeting Lucy, who seflessly cared for him with extreme conviction that could only have been powered by a strong faith in God.

Despite his misfortune, Hawking describes himself as being fortunate when compared with other people. His outlook and spirit to overcome his challenges is an inspirational story to many.

Theories

A good theory must describe a large class of observations accurately with few arbitrary elements. It must make definite predictions for future observations. Arbitrary elements are elements introduced in a theory that are not predicted by the theory (e.g. speed of light), and is therefore a natural weakness in the theory.

Quantum mechanics and general relativity are two successful theories that effectively explain our universe at the small and large scale respectively. However, they completely do not make sense when attempting to describe problems that require both theories. The goal of a Theory for Everything is to explain both spectrums of the theories with a single theory.

The current unified model in physics is that the universe is comprised of fermions (matter particles) and bosons (force particles). Bosons carry the forces between fermions. The four forces (and respective force particles) are:

• gravity (gravitons)
• electromagnetic (photons)
• strong force
• weak force

Without the four forces, every fermion (matter particle) would exist in isolation without any means of influencing the other. Whatever doesn't happen by means of the four forces, simply doesn't happen.

Black Holes

Formal definition An area of the universe, or set of events, from which nothing can escape to a distance.

A black hole is usually formed when a star collapses on itself. As the star collapses, it shrinks and still emits light because light can escape. At a certain point, the gravity of the collapsing star forms the event horizon (an area where the escape velocity is equal to the speed of light). Everything within or entering past the event horizon cannot escape and continues to shrink into a singularity where the density and curvature of spacetime is infinite. Matter and energy outside the event horizon bend to the spacetime curvature as normal.

Matter carrying entropy enters into the black hole. This causes the entropy of the black hole to increase, in the form of a growing event horizon. As entropy increases, energy particles should be emitted. Counter-intuitive to the fact that nothing can escape a blackhole, these energy particles are not re-captured back by the black hole because of the effects of quantum mechanics and the uncertainty principle. At the event horizon (an area of extreme spacetime curvature), the uncertainty principle kicks in and nothing is definite (no zeroes/infinites). Particle/anti-particle pair productions is greatest as there is a continuous fluctuation of energy fields above/below zero to average the fields to zero but never at zero (i.e. conservation of energy). At the event horizon, negative energy is captured by the black hole while positive energy escapes. This accounts for the Hawking radiation in black holes and supports testable predictions that black holes can "cooldown" and shrink in size.

Science, Philosophy and God

Humanity's desire to understand the universe is as old as consciousness. Humans have a gift at noticing patterns, and we have explained patterns in nature with myths, religion, and later mathematics and science.

Without observers, would the universe be exist? Why does the universe bother to exist in the first place? These are questions that are beyond the realm of science, and lie with God.

Perhaps it is man's desire to eventually understand the mind of God. Understanding the universe would then be equivalent to understanding God.

Hawking Quotes

We are such insignificant creatures on a minor planet of a very average star in the outer surburbs of one of a hundred thousand million galaxies. So it is difficult to believe in a God that would care about us or even notice our existence.

If the universe has no boundaries but self-contained... then God would not have had any freedom to choose how the universe began.

The ultimate triumph of human reason is to know the mind of God.