Marshall Brain - The Second Intelligent Species: How Humans Will Become as Irrelevant as Cockroaches

The following statement is something we all understand, but it bears repeating because it is perhaps the coolest, most interesting scientific fact that we know about our universe and human existence:

Hydrogen, given sufficient time, turns into people.

It is an amazing statement if you think about it. A collection of simple atoms swirling around in the early universe, combined with the ordinary laws of nature like gravity, created human beings living here on planet earth over the course of billions of years.

How does this happen? What path can hydrogen the universe's simplest element follow to turn itself into something as amazingly complicated and fascinating as a human being? The process has been explained by many people in many different ways and is supported by vast amounts of scientific evidence. Here is a summary version....

In the beginning, approximately 13.75 billion years ago, our universe sprang into existence. After a period of rapid inflation and cooling, it came to a starting point where it consisted primarily of normal, empty space and normal matter in the form of hydrogen atoms. That was it empty space and an immense number of very simple atoms swirling around.

So there was hydrogen - lots and lots of hydrogen filling the space of a new universe.

Objects that have mass attract one another, and hydrogen atoms have mass. So the universe's hydrogen atoms had a tendency to clump together.

If a large enough group of hydrogen atoms clump together, there is sufficient gravitational attraction amongst the atoms to create a fusion reactor - a star. It radiates massive quantities of heat and light into space. It also starts creating fusion products in its core. Hydrogen atoms fuse together to form helium atoms. Helium atoms fuse to form carbon and so on, forming all the elements up through iron.

Large stars then explode as supernovae. These explosions are gigantic and the blast pressure from the explosion creates all of the heavier natural elements up through Uranium. A cloud of dust and debris from the explosion, along with a great deal of as yet unused hydrogen, spreads out across space.

The dust from these supernova explosions collects into new solar systems, like ours. New stars form, with orbiting planets made from the fusion products of former stars. The process repeats.

Let's take a quick tangent here to look at the size of our universe. Stars live in groups that we call galaxies. How many galaxies are there? Current estimates run anywhere from 100 billion to 500 billion. How many is that? Let's assume that a single grain of salt represents one galaxy. Take a one pound (0.45 kg) package of salt and pour it out onto your kitchen table. There are approximately 10 million grains of salt in a pound. That little pile of salt on your table contains about 10 million galaxies. So to get 200 billion grains of salt, we need about 20,000 pounds of salt. That's a dump truck load of salt. There are a lot of galaxies in our universe.

But galaxies are not as big as a grain of salt. They are monstrous. The milky way galaxy - our galaxy - is 100,000 light years across. There are 200 to 400 billion stars in our one galaxy. Many of those stars have their own planets just like our sun does.

The point is that our universe is utterly enormous. Planet earth is a tiny speck that is part of a galaxy which, at the scale of the universe, is a tiny speck itself.

Nonetheless, this tiny speck of a planet is us. On this planet we have life. Millions of species form an intricate web of life on planet Earth today. Where did this life come from? Through the processes of abiogenesis and evolution, life arose, life evolved, and today here we are. People. Billions of people, and the number is rising inexorably.

Millions of interlocking pieces of scientific evidence from many scientific disciplines, revealed through several centuries of discovery, paint this amazing picture of our universe.

This is how Hydrogen turns into People. This is our creation story.

Randomness

One problem is that this process is completely random, and the side effects of this randomness are all around us. The fact is that the natural world spawned through this natural process is simultaneously beautiful and appalling, majestic and horrifying.

Therefore, while planet earth can be beautiful, it can also be ugly. For every pretty sunset and rainbow we also have earthquakes, tsunamis, tornadoes, hurricanes, cyclones, floods, droughts, volcanoes, etc.

The same kind of ugliness is true on the biological side. Evolution is all about random mutations that fill ecological niches. You can understand this ugliness by looking at the world from the perspective of a cute bunny rabbit living its life in a forest's meadow. The rabbit itself fills a niche - a rabbit eats grass to sustain itself. Male rabbits look for female rabbits with which to mate. A typical doe can produce 10 to 40 baby bunnies a year, which she will raise happily in her little nest that she's built under a bush or underground. Rabbits would be perfectly happy to live out their days eating grass, mating and raising their young.

Unfortunately, many other species look upon rabbits as a source of food in their niches: wolves, coyotes, foxes, dogs, cats, bobcats, cougars, lynx, hawks, eagles, falcons, owls, snakes, humans, etc. all eat rabbits. So rabbits live in constant terror caused by hundreds of nearby predators. Not to mention the bacteria, viruses and parasites looking to infect rabbits to spread their DNA. Life as a rabbit is no picnic. If you are a rabbit, then at any given moment a predictor can kill and eat you, and if that does not happen you can look forward to the potential of sickness and disease. And if you happen to survive the predators and diseases, your body will degenerate on its own and you die of old age after about six years no matter what.

Nature really is appalling if you take the time to give it much thought. Just about every animal species lives this dual nature: it has to eat, and it is also food for something else. Then there are hundreds of different diseases brought on by bacteria, viruses, parasites, mineral deficiencies, etc. And even if you avoid starvation, dehydration, predation, disease, accident and natural disaster, your own body fails you and you die anyway. How much more appalling can it get?

From this same random process has evolved the first conscious, intelligent species: human beings. We sit at the very top of the food chain and have carved out a luxurious niche for ourselves, relatively speaking. We are largely immune to any natural predator, and we see every other species on earth as potential prey. If there is any economic advantage to be gained by killing and/or harvesting another species, humans will as a general rule kill it or harvest it without any remorse, all the way to extinction if given the chance. As a species we will often do this even if it is not in our own best interest as a group, a fact succinctly captured in the essay The Tragedy of the Commons [1] by Garrett Hardin in 1968, and first explored by William Forster Lloyd in 1833.