# The God Equation by Michio Kaku - Blinkist

What’s in it for me? A brief foray into the history and future of physics.

Ever since our early ancestors first gazed up at the stars, we’ve been curious to understand the laws that govern life, the universe, and everything.

And while humanity’s sharpest minds have made great strides in understanding the physical world, many mysteries still remain.

Our ongoing quest to understand the nature and structure of reality is a fascinating tale.

These blinks tell the whole story, starting with Isaac Newton’s first formal descriptions of gravity and traveling up through contemporary debates about quantum mechanics and string theory.

Along the way, you’ll learn how scientists have slowly uncovered the mind-bending physics which govern space and time as well as which big, fundamental questions about the world are yet to be answered.

In these blinks, you’ll find out  how Earth is like a bowling ball; what makes ten dimensions a real possibility; and why some cats are both alive and dead.

Early thinkers Newton and Maxwell laid the groundwork for modern physics.

Is there an underlying order to the universe?

It’s a question that’s puzzled humanity since the dawn of time.

After all, while life can feel chaotic, certain patterns remain stable.

The sun rises and sets each day; apples always fall to the ground.

More than 2,000 years ago, Greek philosophers were already attempting to explain the nature of reality.

Aristotle suggested that all matter was made up of four elements: earth, air, fire, and water.

Another philosopher, Democritus, proposed that the world consisted of tiny, indivisible parts called atoms.

These early theories are noteworthy for their novelty and insight, but, as classical civilization rose and fell, progress on these debates slowed.

But as Europe entered the Renaissance and beyond, a new batch of thinkers began to examine the laws of reality.

The key message here is: Early thinkers Newton and Maxwell laid the groundwork for modern physics.

By the seventeenth century, scientists were again seeking to understand the universe.

In Germany, Johannes Kepler used careful observation to accurately describe the motion of planets in the sky.

In Italy, Galileo Galilei used a telescope to first record the details of celestial bodies.

But, the two greatest breakthroughs came from England.

Before Isaac Newton, common wisdom said that the heavens and Earth were governed by separate laws.

But, in 1666, Newton suggested the opposite.

He argued that all motion – from apples falling on Earth to the moon orbiting above – was determined by a single power.

He called this invisible force gravity and proposed that it acted on all physical objects equally.

What’s more, he showed that gravity’s effects could be calculated and predicted using simple mathematical equations.

Some 200 years later, James Maxwell used math to demystify another invisible force.

Building on the earlier experiments of Michael Faraday, he showed that electricity and magnetism were actually one united force, which hence became known as electromagnetism.

In a series of equations, Maxwell showed that electromagnetism was propagated by oscillating waves and that you could transform electricity into magnetism and vice versa.

Newton’s laws of motion and Maxwell’s equations provide an astoundingly accurate view of the physical world.

These twin insights paved the way for all our modern engineering feats, from skyscrapers and space flight to microwave ovens and radio.

Yet, in the early twentieth century, another thinker would complicate these theories.

We’ll explore that in the next blink.

Einstein showed that physics is more complex than even Newton predicted.

Let’s say you’re riding a train, but not just any old train.

This is a special train that can reach the speed of light.

Now, imagine that while you're chugging along at top speed, you encounter a beam of light traveling in the same direction as you.

If you look out of the window, what do you see?

Well, it depends.

According to Newton, since you and the light beam are traveling at the same speed, you’ll both appear motionless to the other.

However, Maxwell’s equations give a different answer.

They say that the beam wouldn’t appear stationary.

Instead, it would move away from you at the speed of light.

Obviously, there’s a contradiction here.

Luckily, a clever young Austrian patent clerk named Albert Einstein was able to sort it out.

The key message is: Einstein showed that physics is more complex than even Newton predicted.

Newton’s theory of gravity and his laws of motion are very accurate and useful in most day-to-day scenarios.

But, they break down when put to the test under certain conditions, such as the thought experiment with the high-speed train.

In considering this experiment, Einstein realized that Newton’s answer was likely incorrect.

This insight led him to his two greatest discoveries: the theory of special relativity and the theory of general relativity.

According to Einstein’s theory of special relativity the speed of light is a universal constant.

That is, light always moves at the same rate, while everything else, including space, time, and energy distort around it.

This means that any measurement is changed by the observer's frame of reference.

So, if you’re on an ultra-fast train, time will seem to move normally, but, to an outside observer moving relative to you, all your actions will appear in slow motion.

If this seems a bit mind-bending, Einstein’s theory of general relativity adds another layer: in this theory, gravity isn’t caused by an invisible force but is instead an effect of space itself curving.

Picture a bowling ball sitting on a mattress.

As the ball’s mass bends the cushion, it creates a depression that would capture any stray marble that happens to roll by.

Gravity works the same way, except on a much larger scale.

Just swap the ball and mattress for a planet and the fabric of space-time.

While counterintuitive, these laws have since been experimentally confirmed.

For instance, atomic clocks placed on high-speed planes do indeed tick more slowly than the same clocks on the ground.

Yet, despite his brilliance, Einstein couldn’t predict the next big revolution in physics: the tangled science of quantum theory.

Quantum mechanics describes the strange world of subatomic particles.

In 1910, the physicist Ernest Rutherford put a chunk of radium in a lead box.

The container had a small opening which faced a thin sheet of gold.

Rutherford expected the radium to fire a beam of radiation through the hole and onto the sheet, creating a pattern.

But, instead of a pattern, there was nothing.

The radiation passed right through the gold.

As Rutherford continued the experiment, he came to a startling conclusion.

Atoms, the building blocks of matter, were not as solid as previously thought.

In actuality, they consisted of a tiny nucleus orbited by even tinier electrons.

They were mostly empty space.

This unusual discovery was just the beginning.

As it turns out, the laws which govern those tiny particles are even stranger.

The key message here is: Quantum mechanics describes the strange world of subatomic particles.

While Newton proved that the same laws of motion apply in both the heavens and on Earth, the same cannot be said for the inside of an atom.

You see, at minuscule scales a new set of physical laws emerge.

These are called quantum mechanics and the world they describe is very different from the one we experience in our everyday lives.

One strange aspect of quantum mechanics is that it isn’t deterministic.

While Newton’s and Einstein's laws give predictions about the world, quantum mechanics only gives probabilities.

To understand this, it helps to look at electrons.

While electrons are particles, they behave like waves.

So, while they occupy specific locations, knowing exactly which locations is difficult.

We can only guess the probability that an electron will be in a specific space at any time.

This is sometimes called the uncertainty principle and was first elaborated by physicist Werner Heisenberg.

This uncertainty is illustrated by the famous Schrödinger’s cat thought experiment.

Imagine a cat in a box with a bit of uranium.

When the uranium decays, it triggers a gun that kills the cat.

Yet, that radioactive decay is a quantum event – we can’t predict when it will occur.

So, until we actually open the box and check on the cat, the poor animal exists as both living and dead.

If this all sounds complicated, don’t be discouraged.

Such odd properties even flummoxed Einstein who famously thought quantum theory was preposterous!

But, despite objections, its accuracy is unparalleled.

Using the laws of quantum mechanics, scientists have made serious advancements – from discovering antimatter and DNA to building transistors, lasers, and the atomic bomb.

The Standard Model brings us one step closer to a theory of everything.

According to physicists, our universe contains four fundamental forces.

First, there’s gravity, the space-time warping effect described by Einstein.

Next, there’s electromagnetism, which accounts for the behavior of light and electrons and is detailed by Maxwell’s equations and quantum theory.

And finally, there is the strong force, which binds the nuclei of atoms together, and the weak force, which drives their decay.

While these various forces are understood in isolation, scientists believe that each is just one piece of a larger puzzle.

To truly grasp the underlying structure of the universe, there must be a theory which unites all these elements into one system, a so-called theory of everything, or God equation.

So far, no one has been able to solve this puzzle – yet, some attempts have come tantalizingly close.

The key message here is: The Standard Model brings us one step closer to a theory of everything.

The quest for a theory of everything has stumped many brilliant minds.

Throughout the years, Einstein, Schrödinger, Heisenberg, and many others tried and failed to produce a workable solution.

Part of the issue is that the more scientists learn about the physical world, the more complicated it becomes.

But, by the 1970s, a general consensus emerged around a theory called the Standard Model.

The Standard Model comes from decades of research by hundreds of different thinkers.

To build the theory, scientists used machines called particle accelerators to break apart protons and neutrons into even smaller particles called quarks and leptons.

By studying the behavior of these truly minuscule specks, researchers wrote equations uniting quantum mechanics with the weak and strong forces.

The Standard Model is celebrated for precisely describing much of the world.

For instance, the model predicted the existence of the Higgs boson, an elementary particle that gives other particles – like quarks – mass.

In 2012, scientists working with the Large Hadron Collider, a giant particle accelerator in Geneva, Switzerland, found evidence of the boson, confirming the theory.

But, problems remain.

The Standard Model is ridiculously complicated.

Its equations contain many mysterious constants that scientists don’t understand.

And the model doesn’t account for gravity at all – in fact, troublingly, any attempts to integrate gravity into the model have failed.

Given these gaps in knowledge, the model doesn’t fit some of the universe’s most curious anomalies, like black holes.

We’ll take a closer look at these phenomena in the next blink.

Deep space provides an excellent environment to test new theories.

Let’s take a trip 53 million light-years from Earth.

Out here, deep within the center of a galaxy called M87, is a monster.

Weighing in at five billion times the mass of the sun, this gargantuan entity has enough gravity to consume anything that comes near.

We are, of course, talking about a black hole.

These strange phenomena occur when objects become so massive and so dense that not even light can escape their gravitational pull.

The forces present in a black hole are so extreme that even Einstein originally dismissed them as impossible.

Yet, we now know the universe is full of them.

Studying the quirks of these bizarre objects, and other cosmic anomalies, helps us refine our current theories.

The key message here is: Deep space provides an excellent environment to test new theories.

Sometimes, the best way to refine scientific theories is to examine extreme cases that push them to the limits.

For this reason, researchers attempting to develop a unified theory of everything often turn their gaze to the vast reaches of space.

Carefully investigating the cosmos has revealed where current theories break down as well as potential opportunities to move forward.

For instance, black holes were once considered to be dead ends.

According to Einstein’s view of gravity, anything inside one is lost forever.

Yet, Stephen Hawking argued that this isn’t necessarily true.

By applying quantum theory’s uncertainty principle, Hawking suggested that black holes should gradually emit stray particles.

And, sure enough, scientists have detected this so-called Hawking radiation, proving that quantum mechanics and gravity interact in previously unknown ways.

Another phenomenon, called cosmic microwave background radiation, or CMBR, suggests quantum mechanics had a key role in the formation of the universe.

CMBR is the energy left over from the big bang.

Quantum theory predicts that this radiation isn’t uniformly distributed.

And indeed, it appears to be full of ripples, showing that quantum forces were operating from the very earliest moments of our universe.

But many questions are still unanswered.

For instance, the universe is expanding at an ever-faster rate.

Currently, scientists explain this acceleration using a concept called dark energy.

Yet no one knows for sure exactly what dark energy is or how it works.

But, of course, there are theories.

We’ll explore those next.

String theory has the potential to unite Einstein’s theory of gravity and the Standard Model.

For the past century, Einstein's theory of gravity and quantum mechanics have stood side by side.

These two fundamental theories are both useful, yet deeply incompatible.

The problem is, combining them requires a particle that carries gravity, called a graviton.

Yet, any calculation including a graviton produces meaningless results.

The math just doesn’t add up.

But, beginning in the late 70s, a handful of scientists took a new approach.

They proposed that subatomic particles weren’t mere points, but instead they emerged from the vibration of immensely small strings.

Each different vibration produced a different particle, including the mysterious graviton.

And, crucially, in this model, the math works.

String theory could describe interactions between gravitons and other quantum particles.

The key message here is: String theory has the potential to unite Einstein’s theory of gravity and the Standard Model.

String theory is built on a foundation of extraordinarily complex mathematics.

Yet its appeal as a theory comes from its stunning simplicity.

You see, the theory demonstrates symmetry.

In physics, this means that the equations describing particle interactions always balance out.

While previous theories often produced infinite, and therefore meaningless, results, string theory describes interactions much more smoothly.

One way string theory does this is by pairing particles with a superpartner, or sparticle.

Electrons are paired with selectrons, quarks with squarks, and leptons with sleptons.

Including these sparticles in equations allows for difficult mathematical components, called quantum corrections, to cancel out.

What’s left behind are equations that accurately reflect the behavior of all four forces.

String theory calls for us to expand our understanding of reality in new ways.

For the math to work out so perfectly, the universe must have more dimensions.

While classical physics relies on four dimensions – three spatial, plus time – string theory requires ten, or in some cases eleven.

According to string theorists, these extra dimensions are “curled up” or folded in ways that make them largely inaccessible to us but meaningful to the strings themselves.

Unsurprisingly, such an abstract theory has its detractors.

One central criticism is that while string theory is beautiful on paper, it hasn’t been experimentally confirmed in any way.

To detect the theory’s graviton would require a particle accelerator a quadrillion times stronger than Geneva’s Large Hadron Collider.

In the future, new approaches may refine and rework the theory, but for now, many physicists feel it is our best model yet.

A theory of everything raises many deep, philosophical questions.

In his later years, Einstein remained a towering intellectual celebrity.

Due to his notoriety, he received a constant stream of mail from admirers.

Most of the letters didn’t concern physics, though – many just asked if he believed in God.

As it happens, Einstein didn’t believe in the biblical God.

That is, he didn’t see God as a benevolent deity concerned with human affairs.

But, he did believe in God as described by the philosopher Spinoza.

This God is more of an idea.

It’s the very concept that the universe has a deep, lasting, and beautiful order.

In some ways, a theory of everything would fulfill this same role.

It would reveal that all of reality is organized in a profound and elegant way.

The key message here is: A theory of everything raises many deep, philosophical questions.

Let’s say that tomorrow scientists discover a theory of everything, one that is testable and true beyond any doubt.

How would your life change?

Honestly, probably not that much.

While an accurate physical model of the universe may unlock technological breakthroughs down the line, there’s no guarantee it would change anything for you on a day-to-day level.

No, the implications of such a theory are more philosophical in nature.

A theory of everything would show that the entire fabric of reality, from the tiniest, fleeting subatomic particles to the grand expanding vastness of space, is governed by a single order.

For many, understanding this order is the closest humanity can get to reading the mind of God.

But, a theory of everything wouldn’t settle every mystery.

It may describe how our universe came to be and why it looks the way it does, but it leaves an open question: Why does it exist at all?

What force put these physical laws in place?

And what preceded our universe?

This enigmatic force is sometimes called the First Mover, and for some, this is God.

There’s also the alluring possibility that our universe is not alone.

Rather, it’s just one realm in a wider, eternal multiverse.

In this conception – which is supported by string theory and quantum mechanics – outside our universe lies a type of hyperspace where new universes are constantly bubbling in and out of existence.

Each could be radically different from our own.

For now, they remain a mystery, but as science progresses, we may unlock their secrets as well.

Final summary

The key message in these blinks: Humanity has long sought to understand the world around us.

Since Newton’s first forays into describing the laws of motion, the modern science of physics has made great strides in unlocking the mysteries of the universe.

Today, three of the four fundamental forces are united under the Standard Model while gravity is still understood through Einstein’s laws.

Yet, string theory, a radical new approach to physics, shows some promise in uniting all these forces using a simple set of equations which are both elegant and symmetrical.

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