How come the ski editor of the Times is writing a book about cosmology?

I was a scientist before becoming a journalist. After studying astronomy and physics at University College London, I started a PhD in nuclear physics at the CERN high-energy physics laboratory in Geneva, Switzerland. Let’s just say that the skiing got in the way of the research and I ended up whizzing down slopes more often than smashing electrons and positrons together in a particle accelerator. Despite writing about skiing a lot of the time, I’m still very interested in my scientific past.

How would you describe your book?

At some point in their lives, most people ask themselves the question ‘Where did I come from?’. The book tries to answer that at the most fundamental level. Although many science books are stuffy and difficult to understand, this is far from it. I have aimed it at those millions of people who bought Stephen Hawking’s A Brief History of Time and who never got beyond the first few pages.

So, how did the universe begin?

The vast majority of cosmologists and astronomers believe the universe began with an event called the Big Bang some 13.7 billion years ago. At that point, everything we now see in the Universe existed in an infinitely small point with infinite density and high temperature at a known as a singularity. Variations in energy at a sub-microscopic level were suddenly magnified by an enormous factor as the universe began to expand and cool down.

Einstein’s famous equation, E=mc2, tells us that energy (E) and mass (m) are essentially interchangeable – i.e. energy can convert into ’stuff’ and vice versa - and this is what happened in that early era. The high temperature radiation converted into subatomic particles with odd names like quarks and gluons, which eventually started clumping together into larger particles. Eventually these clumps started getting together under the action of gravity, starting to form the galaxies, stars, planets, dust and gas we see today.

Why should be believe in the Big Bang theory?

There are two very good reasons for believing in the Big Bang. In the 1920s, a US astronomer called Edwin Hubble was looking at certain stars in distant galaxies which vary in brightness over regular cycles. By comparing the brightness of these stars with similar stars near to the Milky Way, he worked out how far those distant galaxies are away from us. He then measured something called the red-shift of these galaxies, the amount the light from them has been reddened as a result of their velocity away from us. This is rather like judging how fast a police car is moving away from you by listening to the apparent change in the sound of its siren as it passes you (the so-called Doppler effect). Hubble realised that there was a simple relationship between the distance to these galaxies and their velocity, now known as Hubble’s Law. Extending this relationship back in time, he could see that at some distant point in the past, all the galaxies appear to have been all in one place at the same time.

In 1965, a chance discovery by two engineers called Arno Penzias and Robert Wilson cemented this idea in the minds of modern cosmologists. While trying to invent a form of communication that used microwaves – yes the same as those in your oven – they found that their antenna kept picking up low-level microwave noise. The level of this noise appeared not to change no matter what time of day or night they made their measurements, the season of the year, or the direction they pointed their equipment in, led them to realise that the source of the noise was outside our solar system. Because this so-called cosmic microwave background is so uniformly distributed, cosmologists now believe it is the afterglow of the cosmic fireball that was the Big Bang.

Are we at the centre of the universe then?

If distant galaxies are all rushing away from us, then it would seem that we were at the centre of everything. Much as this so-called anthropic principle sounds appealing, beings in other galaxies would see exactly the same thing. How? Well, what Hubble realised was that this rushing apart was not the same as you expect with the debris from an explosion but the expansion of space itself. If that’s hard to imagine, think of it like this. If you make some dough to make a loaf of bread and you throw in some sunflower seeds to make it taste better, as the dough expands the average distance between the sunflower seeds grows. If you were a minuscule being living on one of those seeds, all of the other seeds would appear to be moving away from you even though you weren’t at the centre of the loaf.

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