The Miracle of Life on Earth
Book review: John Gribbin’s ‘The Reason Why: The Miracle of Life on Earth’, Penguin Books London 2012
Most people, if you ask them, will say that they think there is most probably intelligent life elsewhere in the Universe. They would base that assumption, first, on the apparent tenacity of life wherever it gets a foothold and, second, because of the fact that there are up to one trillion (1,000,000,000,000) stars in our own galaxy and about the same number of galaxies in the observable Universe, and probably many more beyond (which means there are more stars than there are grains of sand on all the beaches of the world, and more). So, based on probability, one might think there must be more intelligent life in the Universe than just ourselves. The traditional scientific view of Earth was that it is an ordinary planet orbiting an ordinary star in an unspectacular galaxy, and we are ordinary animals.
Yet an astrophysicist who trained at Cambridge University has published a bestselling book called ‘The Reason Why’ in which he accumulates a huge amount of scientific evidence which points to us being “the unique products of an extraordinary set of circumstances that have as yet occurred nowhere else in the Galaxy and possibly not in the entire universe”. There are simply far too many “cosmic co-incidences” needed to make the formation of an intelligent-life-friendly planet like Earth at all possible. “The reasons why we are here form a chain so improbable that the chance of any other technological civilization existing in the Milky Way Galaxy at the present time is vanishingly small. We are alone and we had better get used to the idea.”
These cosmic coincidences include, for example, the mysteriously invisible “dark matter”, without whose gravitational pull the galaxies could not have formed. Secondly, the more complex elements needed for life, like oxygen and carbon, resulting from millions of degrees heat in burned out stars, are relatively rare in the Universe (hydrogen and helium make up 98% of matter in the Universe), but our Sun was in the right place (a very old galaxy) at the right time to receive these elements. One of these rare elements is iron. Without Earth’s iron core, still swirling in a molten state as it is today, we would have no magnetic field and life would be destroyed by cosmic rays. Even after billions of years the core is still molten because it happens to be laced with radioactive elements which release heat as they decay. Thirdly, our Sun is a rare type of star that is particularly massive, so that it burns brightly, but it is small enough so that it can burn for billions of years, allowing enough time for life to evolve. Our Sun happened to evolve in a very “quiet” part of the galaxy, less bombarded by meteors and cosmic debris, which would destroy life. Also, the orbits of the planets are almost circular because there were not many other bodies in the vicinity when they were formed. The planets would freeze and water would vaporize if their orbits (as is usually the case) were elliptical. And, of course, our Earth is just at the right distance from the Sun for water to exist in its liquid form.
Talking about water – it is a unique substance, ideal for the chemical reactions for the formation of life. But only about one percent of planets in the galaxy have it. Earth has it – and at just the right amount. If there were too much of it, the oceans could be hundreds of kilometers deep and there would be no land. And one more thing: if water did not have the weirdly unusual quality that its solid form (ice) floats, the Earth would be in a permanent ice age (the ice has an insulating effect for the water beneath).
Even the type of solar system that we have, with planets in stable, orderly orbits is an extreme rarity in our galaxy and requires exactly the right conditions throughout their formation period. Just a tiny change in the position or size of any of the starting conditions of the planets would create a mathematical chaos with a ‘butterfly effect’ causing the planets to collide, throwing them out of their orbits into space or plunging them into the parent star. It seems inconceivable how the different sizes of planets happen to be in the right orbits, stable, and in a relatively peaceful cosmic environment. The ‘big bang’ at the beginning of the Universe seems to have been entirely calculated because the exact velocity at which matter sped through space in the first moments determined the later possibility of gases accumulating to form stars and planets!
The Universe is a very dangerous place. There are not many peaceful areas of the galaxy such as the region where we live. Supernovas (exploding stars) even as far as 300,000,000,000,000 kilometers away would destroy most life on Earth through radiation. Giant meteorites, like the one that wiped out the dinosaurs 65 million years ago, are extremely common in the galaxy, but Earth has luckily received very few of them. The main reason is that there is a gigantic planet just the right distance away from Earth that acts like a protector, deflecting away cosmic debris from Earth’s orbit through its strong gravitational influence and parking it at the edge of the solar system. Jupiter is larger than all the other planets put together and physicists are still trying to understand how such a giant planet can exist so far away from its star.
Next, passing through a cloud of dust and gas is a very usual event for a solar system, but our solar system passes through such clouds very rarely because our Sun happens to have an unusually circular orbit around the hub of the galaxy. The last time the Earth passed through a dust cloud (250 million years ago), 95% of all marine species on earth were wiped out.
Earth happened to be “lucky” and experience just the right number of cosmic collisions at just the right time in its evolution. One such collision was that with a planet about the size of Mars early in the life of the Earth. This collision resulted in the formation of our unusually large moon and also gave us lots of iron for our core. Without our huge moon, Earth would wobble on its axis and no advanced life could exist. This cosmic collision gave earth her light tilt (without which there would be no seasons) and speeded up Earth’s rotation so that our night and day are 243 times shorter than Venus’.
Very important: without this gigantic cosmic collision, the Earth would not have its tectonic plates. The collision was “just right” to give the tectonic plates their ideal thickness and fragmentation, floating on liquid rock, enabling volcanoes to exist, which in turn are part of a delicate feedback process between living beings, water vapour and carbon dioxide. These gases come from below through volcanoes, regulating the Earth’s temperature and preventing it from becoming an ice block. Without tectonic plates there would be no water cycle (because there would be no mountains). As water dissolves rock during the water cycle, it binds carbon dioxide. This production and binding of carbon dioxide enables the Earth to be like a living body. The movement of the tectonic plates is also responsible for the laying down of deposits of metals and bringing them to the surface of the earth. Without this process, there could have been no industrial revolution and no technological age…..
The number of “coincidences” goes on and on. There are simply too many “coincidences” needed to produce a place like Earth, capable of developing and sustaining intelligent life and a technological civilization, even considering the vast numbers of stars in the Universe.
The incredible odyssey that has made the Earth the place it is – bountiful and beautiful beyond all description – was only possible through the harmonizing of an infinite number of cosmic and terrestrial events, chemical and geological. The creation of the Earth was a complex process beyond our imagination.
Yet, the author of the book, John Gribbin tends to think that all this is a product of chance – perhaps because it is a taboo these days to think that God may have created. For me, when we grasp the extent of the “ingredients” that went into the creation of Earth and human beings, it seems irrational to believe that they are all the result of accident. Rather, the Earth and the human race are clearly here through the will and design of a cosmic will and intelligence. And we should not assume that the processes necessary were all the result of the omnipotent God simply waving a magic wand. The effort required is unimaginable. God’s intelligence was moving within matter, within each atom, from the beginning of time, shaping the course of events that led to where (and even who) we are today.
Mark Bramwell