On the Origin of Time summary

On a dazzling summer's day in 1998, a fresh-faced Thomas Hertog crept into the office of the world's greatest living scientist. As a brilliant graduate student in cosmology – the study of the origin of the universe – Hertog was being sized up by Stephen Hawking as a potential protégé.

Almost completely paralyzed by a rare motor neuron disease, Hawking tapped a clicker with his hand. Gradually, through a computer program and speaker system attached to his wheelchair, synthesized speech emerged. By then, its distinct tone and rhythm had already become permanently associated with Hawking.

What Hawking said next laid the foundation for two decades of collaboration between the men, and the book upon which this current Blink is based.

Hawking told Hertog that the universe seems beautifully, impeccably designed to harbor life. Which led to this question: Why did our cosmos turn out to be so sympathetic to us?

The further you burrow into the science, the more you realize Hawking had a point: The laws of physics that our universe must obey seem made-to-order for life to grow.

Take gravity. If this fundamental force were just a tiny bit stronger, stars would shine brighter, because the nuclear reactions in their cores rely on compressing hydrogen atoms together to make helium, which gives off light and heat. Greater gravity would intensify this process.

You might think that sunnier days on Earth wouldn't be anything to sniff at, until you realize that all stars would exhaust their fuel much more quickly, and life on any planet wouldn't have a chance to develop before its sun withered and died. 

Also, when the universe was still in its infancy, areas of the cosmos varied slightly in temperature. These variations were only fractions of degrees, but if these had been even marginally bigger, all galaxies would have grown into giant black holes and plunged everything that ever was and would be into eternal darkness. And if these temperature variations had been smaller, no galaxies would have formed at all!

Let's take another example. In the hard code of the universe that we were given, protons and neutrons – the things that make up the nucleus of an atom – weigh different amounts. 

Again, this difference seems trivial: neutrons weigh just 0.1 percent more than protons. But if the universe's code had decided it wanted these weights to be the other way around, with protons weighing more than neutrons, all neutrons would have decayed just moments after the Big Bang. That means no atoms, and therefore no planets, no stars, and no people.

The Stephen Hawking who wrote A Brief History of Time believed that the laws that underpin our universe are unchanging and timeless. No point asking why – they just are.

But as we'll see, he wasn't satisfied with that explanation – or any other current explanation, for that matter.