Alone?
War of the Worlds, X files, Star Wars, Missions to Mars, SETI, and a gold disc on Voyager.
There can be little doubt that we are excited about the prospects of extra terrestrial intelligence. The “first contact” is much anticipated, and feared. Would aliens be hostile? Well, I have a much more terrifying, and perhaps plausible, possibility.
We are alone.
There is no other intelligent life. There is no other life. There is only this cool blue spec of dust that had the incredible fortune of spontaneously creating life.
So, why is it important to know if there is any intelligent life elsewhere in the universe? Let’s suppose you are planning a picnic for tomorrow. Do you bring sunglasses or an umbrella? The answer, of course, depends on if you think it will rain.
Likewise, if you want to decide how important it is for us as a species to invest in space exploration, you need to decide how likely space exploration is to be important to our children’s future. Knowing that there is, or is not, extra-terrestrial life is an important concern in that regard.
There are three possibilities:
- There is other intelligent life in the galaxy and at some point humans will encounter it
- There is other intelligent life in the galaxy, but we will never encounter it
- There is no other intelligent life in the galaxy.
Let’s suppose there is life, and we will encounter it. Human history has shown that the “discoverer” has made out a lot better than the “discovered”. Would you rather be an American Indian, or a European Settler? Which would you want your grandchild to be? If we sit on this planet, and there is intelligent life elsewhere in the galaxy, then we are waiting to be discovered. I feel the consequences of this possibility are well covered by the human imagination, so I don’t feel there is much to be gained spending time rehashing it.
Aside: Please note that I recognize that the term “discoverer” is a relative term used to describe the historical conqueror. I am also morally disgusted by the behavior of the “discoverers”.
Much energy seems to be focused on exploring space based on the assumption “they’re out there”, and that’s why space exploration is important. I want to make a counter point based on the assumption that there is no other intelligent life in the galaxy, and consider the ramifications of that with regard to human energy directed at exploring space.
The next two scenarios are really the same. The existance of other life is irrelevant if we never encounter it. In fact, I would argue that if there is intelligent life and we never encounter it, it’s because one of the two species was destroyed before they had the opportunity to encounter the other.
Regardless, for practical discussion, possibility 2 and 3 are the same.
In order to understand how likely it is that there is other intelligent life in the galaxy we first need to look at the incredible circumstances probably required to create life on earth.
First, a planet coalesced from stardust with a good amount of water (or other good solvent) and carbon (possibly sulfur) compounds. It orbits at an appropriate distance from the sun to cool to a temperature supporting complex chemical compounds. It’s not so hot as to boil everything, nor so cool that everything is frozen. This event actually seems pretty plausible, since there are several planets and moons in our own solar system that seem to have had (or may still have) these conditions.
What’s less likely though is that in its infancy, the planet/planetoid would collide with another planetary body. This collision provides enough energy to create a molten core of swirling metals hot enough to take many billions of years to cool and solidify. At the same time, the collision is not energetic enough to shatter the planet into debris. The swirling metals (iron) are extremely important since they create a magnetic field which diverts much of the sun’s radioactive energy. This shields the planet’s gaseous atmosphere, which provides enough temperature stability to allow the complexity of compounds to increase over time, giving rise to life.
To understand the importance of our ferrous molten core, take a look at Mars. Because Mars never collided with another planet-sized body, its core - which is similar in content to the earth’s - cooled and solidified. Because Mars’ core is solid and not moving molten metal, Mars does not have a magnetic field (north & south poles) like the Earth. There is evidence that Mars once had liquid on it’s surface, and it still has remnants of a very thin atmosphere. But without a magnetic “shield” solar currents buffet Mars and, over the course of hundreds of millions of years, have stripped the atmosphere from the planet. Without an atmosphere, the liquids (water) that evaporate into Mars’ atmosphere are also stripped from the planet - removing the solvent so vital to creating the chemically complex “soup” needed to support assembling the pieces of complex biological processes.
Aside: The fact that the earth collided/merged with another body early in its formation is a theory. It is based on evidence gathered by examining our moon. It’s thought the moon was formed by material “knocked off” the Earth in a planetary collision. The moon consists of material found in the Earth’s crust, does not contain a core of it’s own, and does it contain consequential quantities of metals found in the Earth’s core. In short, the moon is made of the same stuff as the earth’s crust.
Mars does not possess magnetic poles, which suggests it’s iron core is solid - though conclusive measurements to this fact do not exist. That Mars ever had an atmosphere is conjecture based on surface features suggesting water and wind activities. The loss of it’s atmosphere is generally thought to be due to it’s weaker gravity, but recently the protective effects of the magnetic poles has come into consideration as well.
In other words, the science I suggest here is not universally accepted. I am not aware of evidence contradictory to these theories, however.
So, the miracle of life on earth probably isn’t due to what we started with (water, carbon), but rather it was a colossal collision that happened billions of years ago. This collision holds the secret to life on Earth. It imparted an vast amounts of energy, which has resulted in the Earth sustaining a magnetic field, which helped us keep our atmosphere, and therefore maintain an environment (solvents, rich chemical diversity, relative stability in temperature) that allowed the opportunity for complex chemical life to develop. Without this collision Earth’s core would have solidified billions of years ago, our atmosphere may have been stripped away, the water would have disappeared from the surface of the Earth, and life (if it would have gotten started at all) would have died. Earth would have ended up looking like Mars.
There is a famous equation, called the “Drake Equation” that tries to determine the likelihood of intelligent life somewhere else in the universe. Because we have very little experience with regards to what the rest of the universe is like, the numbers we attach to this equation always make it seem likely that there should be life elsewhere in the universe. This is mostly due to the fact that there are an immense number of solar systems in the galaxy, so even something unlikely seems possible given the huge number of opportunities for it to occur. For example, it’s highly unlikely that you would ever flip a coin and it would land on it’s edge. But if you were to flip it 300 billion times (the number of stars in the Milky Way), then it does seem plausible that a few times it actually would land on its edge.
I would propose, however, that the odds are much worse than we typically assign, especially with regard to the “Ne” factor, which is the number of suitable planets per solar system. I don’t think Ne is typically assigned a value that is small enough because I don’t think most people consider the unlikelihood of a planetary magnetic field lasting long enough to provide an adequate nursery for intelligent life. The conditions required to support the chemical complexity for the amount of time required to give rise to life seem, based on Earth’s history, incredibly unlikely.
So, whether you agree with my science or not, let’s suppose that this is the only place in the galaxy with life. Let’s suppose there are no aliens, no other-worldly intelligence. How would that change your feelings about the importance of exploring space? Does it change your feeling about the Earth? Does it give you a stronger sense that what we have here is precious?
For me, being alone in the universe increases the importance of getting off this planet, simply because I don’t like the idea of putting all our eggs in one basket. We must diversify. If the precious gift of life is only going to be found on this planet, then it is just a nuclear war, a meteor strike, an ozone layer, a magnetic field, or a freak solar event away from destruction. The sooner we learn to move through space, the better we’ll do insuring survival for our sons and daughters.
So, regardless of the scenario, extra terrestrial mobility is critical for the well being of our children. Let’s stop waiting and get serious about investing in space travel and exploration.