Curiosity is one of the human animal’s essential qualities, and two questions – where did we come from, and how did we get here? – continue to express the insatiable curiosity that animates human consciousness. Today, when we consider our place in the universe, the cosmos remains the supreme frontier of mankind’s propensity to wonder at its origins.

Last month, an event in a remote corner of our universe, another contemporary reminder of this timeless curiosity, hit the international headlines with the dramatic verification of a concept first predicted by Einstein in 1915: gravitational waves.

In the words of the New York Times, “a minuscule jiggle, discovered in an exotic physics experiment” saw two teams of American scientists, in collaboration with British and German partners, overcome almost insurmountable odds “to open a vast new window on the cosmos”. This, in simple language, was the wider significance of the moment – an astronomical “first” – when the Laser Interferometer Gravitational-Wave Observatory (Ligo) announced that a signal from gravitational waves had been discovered emanating from the collision and merger of two massive black holes (collapsed stars) more than a billion light years away.

The mind-dizzying scale of this data only begins to come into focus when you remember that just one light year is approximately 5.88 trillion miles. Welcome to Stephen Hawking and his universe.

He devoted the final chapters to 'wormholes', 'spiral galaxies' and, perhaps most controversial, 'superstring theory'

It was, rather less distantly, in 1988 that Hawking confirmed his place as the most brilliant British scientist of his generation with the publication of A Brief History of Time, a succinct, entertaining and brilliantly lucid account of our relationship with the universe. In addition to his review of all the great theories of the cosmos, from Galileo and Newton to Einstein, Hawking, who was already renowned for his work on black holes, took the opportunity to explore and publicise some of the most speculative contemporary ideas about space and time. He devoted the final chapters of A Brief History to “wormholes”, “spiral galaxies” and, perhaps most controversial of all, “superstring theory”, in a complex narrative that was also a sketch for Hawking’s goal of a “complete, consistent and unified” theory of physics.

It was his ambition, he wrote, to facilitate “the discussion of the question of why it is that we and the universe exist. If we find the answer to that, it would be the ultimate triumph of human reason – for then we would know the mind of God.”

What, you might ask, is the use of such hyperbole? What, indeed, is the justification for a highly theoretical department of science, such as astrophysics, that doesn’t contribute to the improvement of the physical world (safer aeroplanes; faster cars; better washing machines)? Here we have to acknowledge the immense but intangible cultural significance of scientific inquiry, especially its ability to change mankind’s perspective of its place in the universe.

Who knows what the Ligo experiment or A Brief History will achieve? If history is any guide, however, the impact on our consciousness is potentially profound. Already, as my Observer colleague Robin McKie recently reported: “It is now clear that astronomers have created a new type of astronomy: gravitational wave observation.” The Ligo breakthrough joins an extraordinary tradition of scientific endeavour. As one of the scientists behind Ligo put it, “This confirms the existence of a range of intermediate black holes, about which we had theoretical doubts. Now those have gone. We’re already going places.”

Over the centuries, Aristotle, Copernicus, Galileo, Newton, Einstein and many others, often at great personal cost, have changed our understanding of the universe. Hawking’s own boastful calculations of his book sales suggest that A Brief History will have influenced the minds of a generation as few other contemporary titles will have done. Translated into 40 languages, as he writes in the introduction to the latest paperback edition, A Brief History has sold “about one copy for every 750 man, woman and child in the world”. Not bad for a book that, Hawking freely admits, he never expected “to do anything like as well as it did”.

From its opening page, in which he repeats the apocryphal tale of the little old lady who told Bertrand Russell that “the world is really a flat place supported on the back of a giant tortoise”, Hawking’s intention is to instruct and entertain. He recounts, tongue in cheek, that when Russell is said to have replied, with a smirk, “What is the tortoise standing on?”, the old lady answered, “You’re very clever, young man, very clever. But it’s turtles all the way down.” Plainly, Hawking can appreciate the ironies implicit in the speculative side of quantum physics.

We are each free to believe what we want and it is my view that the simplest explanation is there is no God

In fact, what follows is not fanciful but hard-nosed, an authoritative account, addressed to the layman, of Hawking’s understanding of space and time, the expanding universe, particle physics and the origins of the universe. Nearly 30 years from publication, Hawking has refined some of his ideas. In 1988, he seems to have been tempted by quasi-spiritual distractions. In 2011, he spoke out unequivocally in favour of an aetheistical understanding of man’s origins: “We are each free to believe what we want and it is my view that the simplest explanation is there is no God. No one created the universe and no one directs our fate. This leads me to a profound realisation. There is probably no heaven, and no afterlife either. We have this one life to appreciate the grand design of the universe, and for that, I am extremely grateful.”

Hawking’s own life and his heroic struggle with the debilitating effects of motor neurone disease have become braided into the world’s response to A Brief History and many of his subsequent speculations, as if his suffering has somehow sharpened his perception of the cosmos and its mysteries. For the media, the oracular nature of his utterances, and the remarkable courage with which he has defied all predictions of his imminent mortality, have imbued some of his theories with a quasi-mystical status. The most cursory reading of A Brief History of Time will remind his readers that there is nothing fuzzy or untested about the intelligence behind this contemporary classic.

A signature line

“Our goal is nothing less than a complete description of the universe we live in.”

Three to compare

Isaac Newton: Mathematical Principles of Natural Philosophy (1687)

Albert Einstein: “On the Electrodynamics of Moving Bodies” (1905)

Aristotle: On the Heavens (circa 340 BC)