Wonders of the Universe

A VERY PRECIOUS TIME

The fact that the Sun will die, incinerating Earth and obliterating all life on our planet, and that eventually the rest of the stars in the Universe will follow suit to leave a vast, formless cosmos with no possibility of supporting any life or retaining any record of the living things that brought meaning to its past, might sound a bit depressing to you. You might legitimately ask questions about the way our universe is put together. Surely you could build a universe in a different way? Surely you build a universe such that it didn’t have to descend from order into chaos? Well, the answer is ‘no’, you couldn’t, if you wanted life to exist in it.

The arrow of time, the sequence of changes that will slowly but inexorably lead the Universe to its death, is the very thing that created the conditions for life in the first place. It took time for the Universe to cool sufficiently after the Big Bang and for matter to form; it took time for gravity to clump the matter together to form galaxies, stars and planets, and it took time for the matter on our planet to form the complex patterns that we call life. Each of these steps took place in perfect accord with the Second Law of Thermodynamics; each is a step on the long road from order to disorder.

The arrow of time has created a bright window in the Universe’s adolescence during which life is possible, but it’s a window that won’t stay open for long. As a fraction of the lifespan of the Universe, as measured from its beginning to the evaporation of the last black hole, life as we know it is only possible for one-thousandth of a billion billion billionth, billion billion billionth, billion billion billionth of a per cent.

And that’s why, for me, the most astonishing wonder of the Universe isn’t a star or a planet or a galaxy; it isn’t a thing at all – it’s a moment in time. And that time is now.

Around 3.8 billion years ago life first emerged on Earth; two hundred thousand years ago the first humans walked the plains of Africa; two and a half thousand years ago humans believed the Sun was a god and measured its orbit with stone towers built on the top of a hill. Today, our curiosity manifests itself not as sun gods but as science, and we have observatories – almost infinitely more sophisticated than the Thirteen Towers – that can gaze deep into the Universe. We have witnessed its past and now understand a significant amount about its present. Even more remarkably, using the twin disciplines of theoretical physics and mathematics, we can calculate what the Universe will look like in the distant future and make concrete predictions about its end.

This colour image of the Earth, named the ‘Pale Blue Dot’, is a part of the first-ever portrait of the Solar System taken by NASA’s Voyager 1. The spacecraft took 60 frames which could be used to create a mosaic image of the Solar System from a distance of over four billion miles from Earth.

NASA

This seemingly insignificant image of a pale blue dot is in fact one of the most important and beautiful images ever taken, revealing our planet at a distance of over six billion kilometres away.

I believe it is only by looking out to the heavens, by continuing our exploration of the cosmos and the rules that govern it, and by allowing our curiosity free reign to wander the limitless natural world, that we can understand ourselves and our true significance within this Universe of wonders.

In 1977, a space probe called Voyager 1 was launched on a ‘grand tour’ of the Solar System. It visited the great gas giant planets Jupiter and Saturn and made wonderful discoveries before heading off into interstellar space. Thirteen years later, after its mission was almost over, Voyager turned its cameras around and took one last picture of its home. This picture (left) is known as the Pale Blue Dot. The beautiful thing, perhaps the most beautiful thing ever photographed, is the single pixel of light at its centre; because that pixel, that point, is our planet, Earth. At a distance of over six billion kilometres (3.7 billion miles) away, this is the most distant picture of our planet that has ever been taken.

The powerful and moving thing about this tiny, tiny point of light is that every living thing that we know of that has ever existed in the history of the Universe has lived out its life on that pixel, on a pale blue dot hanging against the blackness of space.

As the great astronomer Carl Sagan wrote:

‘It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known.’

Just as we, and all life on Earth, stand on this tiny speck adrift in infinite space, so life in the Universe will only exist for a fleeting, dazzling instant in infinite time, because life, just like the stars, is a temporary structure on the long road from order to disorder.

But that doesn’t make us insignificant, because life is the means by which the Universe can understand itself, if only for an instant. This is what we’ve done in our brief moments on Earth: we have sent space probes to the edge of our solar system and beyond; we have built telescopes that can glimpse the oldest and most distant stars, and we have discovered and understood at least some of the natural laws that govern the cosmos. This, ultimately, is why I believe we are important. Our true significance lies in our continuing desire to understand and explore this beautiful Universe – our magnificent, beautiful, fleeting home

Our time on Earth is precious and fleeting. The most important use of this time that we can make is to ask questions about our wonderful universe, so that perhaps one day one of our descendants will truly understand the natural laws that govern our cosmos.

‘Somewhere, something incredible is waiting to be known’

—Carl Sagan, 1934–1996

© CORBIS