Wednesday, February 2, 2011

Our Place in the Universe (Or How to Feel Really Small)

Everybody wants to feel important. But wouldn't we rather have the truth, even if it made us feel a little bit unimportant? If you agree, then let's go on a whirlwind tour of some of the most amazing science from biology and astronomy. It can be a bit disorienting at first, but that's the point of this essay.

We might as well begin with evolution. Always a good place to start. So, in short, evolution is a fact. Never mind that most Americans don’t believe in it. For any doubters out there, check out herehere, and here.  And despite our nation's collective ignorance of what has been known for 150 years, every living organism, including humans, have evolved from a common ancestor, and continue to evolve today. The reason people usually disbelieve in evolution is that they haven't been exposed to it, and the major reason for their lack of exposure to evolution is religious opposition. Given evolutions apparent religious implications for the grey-bearded God of the Bible, the reasons for religious obfuscation is obvious.

Just consider this fact: there have been 25 different hominid species. That is, there have been 25 different prototype human species that lived before Homo sapiens, the only living hominid species still living on the planet. We like to think of ourselves as the be-all and end-all of evolution, the pinnacle of creation. Religion has reinforced this view with creation myths and Savior myths and afterlife myths. Religion traditionally has taught that it was all created for us humans: that we are God’s most amazing creation. I will admit that we, and the universe we inhabit, are truly amazing and awe inspiring. But I don’t think God has anything to do with it. The facts tell seem to tell another story. Here is the real (and much better) Genesis story.

The universe was created from an explosion of unimaginable violence about 14 billion years ago. The Big Bang didn’t need any God to get it started, as Stephen Hawking describes in his new book The Grand Design. It happened spontaneously, and then gravity, created in the first nanoseconds of the Big Bang, takes over and does the rest. We live in a relatively ancient galaxy (some of the stars in our Milky Way galaxy are 13 billion years old). If that makes you feel special, consider that there are 200-400 billion other stars just in our galaxy. Our Sun is only one of these. Astronomers think there are as many as 100 billion other galaxies in the universe. That means there may be nearly 300 sextillion stars in the known universe. (For anybody wondering if 300 sextillion is a real number - it is. It's a 3 followed by 23 zeros: 300,000,000,000,000,000,000,000.)

Of these 300 sextillion stars, our medium sized Sun is just one star that is only 4.5 billion years old. Our own Sun is a second generation star; formed from the blown up remains of a first generation star that underwent a supernova explosion (when it died). Yes, stars are born, and stars die (just as ours will someday). The planets in our solar system were formed from the left over star dust that the Sun didn’t use up during it's birth. The planets were made from the minuscule left-overs, sorta like what is left-over in the brownie bowl after pouring all the batter into the pan.  And just remember, that for 2/3 of the universe’s existence, our Sun didn’t even exist! So our Sun, a relatively latecomer as stars go, is nothing special in the universe.

Neither, it turns out, are earth like planets. In September 2010, NASA announced the discovery of a rocky earth like planet orbiting the Goldilocks zone (not too cold, not too hot) around a star much like our Sun.  We will find many, many, many more of these types of planets as our telescopic powers grow greater and greater. And even if only one in a billion such planets supported life (a conservative guess) then the number of planets supporting life in the universe would be in the trillions. Therefore the number of planets on which life can evolve is pretty high: there is a lot of real-estate out there for it to exist on.

Once the conditions for life are met on these rocky planets, orbiting in the “Goldilocks zone,” then life probably begins fairly quickly. We know that on our own planet, life began about 4.5 billion years ago (the Sun formed 4.57 billion years ago, and the Earth about 4.54 billion years ago). So life began only a few hundred million years after the Earth was formed. Scientists have been able to recreate the basic building blocks of life, amino acids, from simple elements that were present when Earth first began. And once life began, it took off and thrived, formed different species who were more and more expert as gene-replicator machines, adapting in order to survive and reproduce in their different environments, thereby creating the incredible diversity of life we witness today.

Simple single celled life (procaryotes and eucaryotes) formed in the ocean, progressed to simple multicellular organisms, which changed into different aquatic animals, which evolved to various amphibious and terrestrial reptiles, which evolved into birds, mammals, and primates. Our hominid species, Homo sapiens, is just a small twig on the vast tree of life. If you trace each of the twigs and branches back over the billions of years of life’s history on Earth, we all share the same origin 4.5 billion year ago.

So life evolved on our planet. However, almost as soon as life began, it went through 5 major cycles of extinction.  The Permian-Triassic cycle alone killed about 83% of all life on Earth. It was only after the most recent cycle of extinction, the Cretaceous-Tertiary, that mammals - and then human like hominids - began to exist. To put this in perspective, 99.96% of the universe’s history had already occurred before the first hominids showed up on the scene! Another analogy that puts our existence in perspective is to imagine that the history of our planet is represented by the height of the Empire State Building. If Earth-time was represented in this way, the amount of time that modern humans have been on the planet would be represented by a postage stamp at the top. If we are the purpose of God’s creation, He sure took a long time to get around to making us (and He sure destroyed to extinction a lot of other species in the process: about 99% of them).

So after the 5 cycles of extinction, mammals and humanoid species show up on the scene. Somehow, Homo sapiens survived - but just barely.  Looking at the facts, it never seems that our place at the top of the species pyramid was a given. At one point between 195,000 and 123,000 years ago, the number of Homo sapiens plummeted because of a global ice age (known as Marine Isotope Stage 6) from about 10,000 individuals to just hundreds. Hundreds! That’s all that were left! These lucky hundreds of humans probably managed to stay alive by clinging to life in caves near the coast of South Africa (Curtis W. Marean in “When the Sea Saved Humanity,” Scientific American, August 2010). 

Now, despite the information I have just reviewed, some may still think that humans were the soul reason for the Universe existing; an act of special creation by God. In other words, despite the fact that there are 30-70 sextillion other stars out there; 100 billion other universes; 200-400 billion stars in our Milky Way galaxy; trillions of other Earth-like planets; 4.5 billion years of evolution that occurred before humans even arrived on the scene; millions and millions of other species (most of which are bacteria and small insects like beetles) of which humans are just a single species who are more closely related to chimpanzees than chimpanzees are to gorillas; with 25 other extinct hominid prototype species that came before us . . . . .  despite all this, many people still believe God created it all for us.

Now, as I’ve already admitted, I can’t prove that God didn’t create us in a crowning act of special creation.  However, given the facts, doesn’t this sound just a little bit arrogant?  The ethnocentric religious idea that we are specially created by God, at the peak of His creative prowess, runs into problems when it confronts the facts we know about the universe. (Oh, and I almost forgot to mention that astrophysicists think that our universe may just be one in a innumerable number of other universes: a multiverse. So even our universe isn't at the center of anything.) This is why scientific facts, when they bump into religious explanations, can seem threatening.

However, they don't necessarily have to. Religion eventually got over the Copernican revolution, and it is slowly coming to terms with Darwinian evolution (emphasis on slowly).  Religion can change as science expands our knowledge about our place in the truly amazing universe we live in. Just remember who is leading, and who is following.

I'll end, appropriately, with a thought from Carl Sagan:

How is it that hardly any major religion has looked and science and concluded, "This is better than we thought! The Universe is much bigger than our prophets said, grander, more subtle, more elegant?" Instead they say, "No, no, no! My god is a little god, and I want him to stay that way." A religion, old or new, that stressed the magnificence of the Universe as revealed by modern science might be able to draw forth reserves of reverence and awe hardly tapped by the conventional faiths. 

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