The miracle of life occurs within a context of awesome dimensions. Firstly, in terms of time: the universe itself is some 14 billion years old, the first mammals appeared almost 200 million years ago, and humankind has existed for around 200,000 years. Secondly, in terms of space: we still do not know whether there is life elsewhere in the universe; since 1995, however, we have been aware of the existence of planets that revolve around stars in a similar way to our own solar system, and it is possible that the universe contains many such planets and suns.
The birth of the Sun, approximately 4.5 billion years ago, brought about a chain of events that established all the conditions necessary to life. It was around this phenomenal source of energy that the eight planets of our solar system were formed. Venus is closer than the Earth to the Sun and is a furnace, whereas Mars is located further from the Sun and is icy cold. The Earth, on the other hand, is located at just the right distance to be able to support life.
But this is not all. Its mass, its metallic core, and the effects of gravity equip Planet Earth with a magnetic shield and an atmosphere that block the deadly cosmic rays, retain the Sunís energy in the form of heat, and protect the planet from being bombarded by meteorites. Finally, with the formation of water on Earth, a cradle for life was created. Environmental conditions, and the intensity solar energy, subsequently remained stable for a sufficient period of time for life to continue and pass from a primitive form to that which we know today, a process that took 3.8 billion years.
Thanks to our mastery of the world, we have a tendency to relate everything back to ourselves and to evaluate everything on a human scaleóthat of the few decades of our individual lives, or the few thousand or million square miles of the country we inhabit. But will we ever take in the bigger picture? Will we ever learn to take care of the planet we inhabit, of its limited and precious resources, so that we can hand it on in good condition to our descendants?