Wonders of the Universe

EL TATIO GEYSERS, CHILE

High in the Andes Mountains, in the far north of Chile, you will find the spectacular El Tatio Geysers. Erupting at 4,200 metres (13,800 feet) above sea level, this is one of the geological wonders of Earth’s Southern Hemisphere. Not only is it one of the largest geyser fields in the world, it is also one of the highest. For those who journey here to witness the eruption of the jets of water skywards there is only one time to visit – sunrise.

In the early morning, as the Sun begins to peer over the horizon, the combination of super-heated water and freezing cold air produces a rare phenomenon. Like all geysers, the boiling water delivered to the surface by the geological plumbing bursts out and flashes into steam, forming the majestic columns. But here, because of the high altitude and bitter temperatures, the steam rapidly condenses and returns to its frozen state, covering the ground with sheets of ice. It is surely one of the most spectacular naturally occurring locations on the planet in which you can see water in all three of its phases: liquid, vapour and solid ice. It is this rapid transformation of water through its three familiar phases that provides us with a nice analogy to discuss events that happened in the very early life of the Universe.

A water molecule is made up of two chemical elements: oxygen and hydrogen. Oxygen and hydrogen atoms are symmetric when they are alone and uncombined. This particular use of the word symmetric is perhaps unfamiliar; what is meant in this context is that the atoms themselves would look the same no matter what angle you viewed them from. In the language of physics, this is called rotational symmetry. A perfect sphere has perfect rotational symmetry, because whichever way you look at it or spin it around it looks exactly the same. When an oxygen atom combines with two hydrogen atoms to form a water molecule – H₂O – this rotational symmetry disappears because the water molecules have a particular shape – there is an angle of 105 degrees between the hydrogen and oxygen atoms. A physicist would say that the symmetry is now broken, because the water molecule has a distinct orientation. We can break the symmetry of water still further by cooling down all the molecules until they stick together and solidify into ice. Now the crystals of ice are beautiful and almost impossibly intricate; full of structure and a complexity that completely hides the perfect symmetry of the original atoms, and also the simple but different symmetry of the water molecules themselves.

Approximately 70 per cent of Earth’s surface is covered by water. At the El Tatio Geysers you can see water in all its three forms. Walking through pools of water on the ground, I held a sheet of glass in the geysers’ steam and watched ice crystals form on it.

Exactly like the journey of steam to ice, of chaos to order, this was the Universe in transition. A transition where the structure and substance of all the particles of matter emerged for the first time.

The important point here is that all this complexity emerged when the symmetry was broken, but we did nothing to the water itself to break its symmetry other than cool it down. So although it looks for all the world as if a master sculptor sat down and chiselled out beautiful patterns in the ice, this intricacy and beauty emerged completely spontaneously out of building blocks that are themselves utterly symmetric.

Physicists call this process spontaneous symmetry breaking, and it is this idea that lies at the heart of our understanding of the early Universe