Brief Answers to the Big Questions – Stephen Hawking Book Summary

Brief Answers to the Big Questions – Stephen Hawking | Free Book Summary

Brief Answers to the Big Questions – Stephen Hawking

When we see the Earth from space, we see ourselves as a whole. We see the unity, and not the divisions. It is such a simple image with a compelling message; one planet, one human race

Even Light Cannot Escape A Black Hole


Hawking discovered that black holes release particles at a steady rate (Hawking radiation).

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His theory argues that space is filled with particles and antiparticles. They’re in a constant process of bonding, separating, and then annihilating one another.

The complex interaction of these pairs with black holes—particularly when partners are separated by the event horizon—causes black holes to lose mass, shrink, and eventually disappear.

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When you look at the vast size of the universe, and how insignificant and accidental human life is in it, that seems most implausible

What Is A Negative Energy ?


Space and energy can materialise out of nothing. The laws of physics demand the existence of something called “negative energy.”

Imagine a man wants to build a hill , To make this hill he digs a hole in the ground and uses that soil to dig his hill.

But of course he’s not just making a hill—he’s also making a hole, a negative version of the hill.

Here, The Hole is negative energy and the hill is positive energy.

So Where Is All This Negative Energy Today ?

Space itself is a vast store of negative energy. Enough to ensure that everything adds up to zero.

The universe is like an enormous battery storing negative energy.

It means that if the universe adds up to nothing, then we don’t need a God to create it.

The universe is the ultimate free lunch.

Positive energy is the matter which has mass.

What Are The Three Ingredients We Need To Cook Up A Universe?


  • The first is matter—stuff that has mass.
  • The second thing we need is energy.
  • The third thing we need to build a universe is space.

Mass And Energy Relationship


Einstein realised that two of the main ingredients needed to make a universe—mass and energy—are basically the same thing.🤯

His famous equation E = mc^2 simply means that mass can be thought of as a kind of energy, and vice versa.

So instead of three ingredients, we can now say that the universe has just two: energy and space.

It Might Be Possible To Predict The Future –But It’s Unlikely


Laplace argued that if we knew the positions and speeds of all the universe’s particles, we could calculate their future behavior.

But Heisenberg discovered that due to the way , light waves are packaged into discrete units called quanta, “you cannot measure both the speed and position of a particle simultaneously; the more accurately you measure one, the less accurately you can measure the other”. This rule became known as the uncertainty principle.

Quantum Mechanics

In quantum mechanics, particles do not possess well-defined positions and speeds. Rather, these values are represented by something called a wave function. 

A wave function is a set of numbers, each one representing a different point of space. The size of the wave function predicts the probability that the particle will be found in each point of space.

So, We can’t predict the future but we can make it.

To Survive On Earth, We Need To Take Immediate Action


Global warming might be Earth’s most immediate threat, but we also face a greater one: nuclear annihilation.

Our planet could end up like the surface of Venus – a planet not known for its hospitable conditions (250 degree Celcius and evening showers of sulphuric acid).

In the planet’s present state, it’s almost inevitable that either nuclear war or environmental disaster will devastate Earth in the next 1,000 years.

By that point, though, humanity will hopefully have the technology to escape the planet and survive disaster.

Alien Life?

It is estimated that Earth-like planets orbit 20% of all stars in the Goldilocks Zone. (a region capable of supporting life because it is not too far from its star to become an icy wasteland, but also not too close to fry its inhabitants)

Our Milky Way galaxy contains approximately 200 billion stars. This could result in forty billion Earth-like planets in our cosmic neighborhood.

Other lifeforms may not have been so fortunate!

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