5 Reasons Why We'll Probably See Alien Life Someday

Artist Depiction of Kepler 186f
Photo Credit: NASA Ames/SETI Institute/JPL-Caltech

The origins of life on Earth is one of the scientific questions I've been following. Why, one might ask, is a science fiction writer like myself concerned with this? The answer is that I'd like to believe that the worlds depicted (predicted?) by myself and many of my fellow authors—TV shows, and movies included—might actually be possible someday. It's also a natural result of my blended interests in biology and all things space.

Following a recent Star Talk Radio podcast, real-world life on other planets is on my brain. Is it a reasonable assumption that such a thing is not only possible but probable? For me, I break it down this way:

1. The Universe is almost incomprehensibly big:

Looking at the scale of things, Earth doesn't even rate a speck of dust if you compare it to the size of the galaxy, let alone the universe. So to assume this is the only place where life evolved in such a large space, is a very big assumption. It's basically like assuming that all people speak English just because you've never met anyone who doesn't.

2. We find Earth-like planets all the time:

As Kepler has shown us, Earth-sized worlds going around Sun-like stars is not unique to our solar system. Planet formation is now believed to be a natural part of star-formation. Geoffrey Marcy of the University of California Berkeley estimates that 22% of the stars in our galaxy have Earth-like planets with "luke-warm temperatures" (like our world) around them. That translates to about 40 Billion Earth-like worlds in our galaxy.

Also, don't forget we found an Earth-type planet in a solar system much like ours (Kepler 186-f) recently, and we haven't been looking that long!

3. Asteroids are loaded with Amino Acids, the building blocks of DNA (and RNA):

I was surprised to learn that new theories indicate life on Earth may have begun because the building blocks of life were handed to this planet from the stars. A whole group of meteorites, called carbonaceous chondrites are both high in water and amino acids. Why this is the case, is the subject of a recent experiment at NASA in which the building blocks of DNA and RNA were found to form when exposed to the radiation found in space (simulated) on an ice-rich sample of pyrimidine (a substance found in asteroids).

It is known that meteorites bombarded the Earth for about 300 million years during the "Late Heavy Bombardment Period." As this hypothesis goes, it was during this period that the building blocks of life were delivered to Earth (possibly along with its oceans). The fact that we find the building blocks of life in asteroids, which are thought to be very common in the galaxy, could indicate that life as we know it is relatively common when conditions are right.

4. Life arose relatively quickly after the Late Heavy Bombardment Period:

The earliest undisputed evidence of life on Earth dates from 3.5 Billion years ago, about 300 million years after the Late Heavy Bombardment Period. According to Neil DeGrasse Tyson (see the podcast) this indicates life forms relatively easily when conditions are right. 300 million years may seem like a long time, but remember, in terms of the age of the Earth (4.54 Billion Years), 300 million years really isn't that long. Also, something interesting to consider is that it took much longer for complex life to form (about 1.5 billion years after the first single-cell organisms) than for life to start at all, which indicates that it was far easier for life to form on Earth (maybe elsewhere) than for life to evolve into complex organisms—which is why we have a higher expectation of finding simple or single-cell life in places like Mars and Europa than to find something like a fish, etc.

5. The Laws of Physics may dictate that Life has to form:

This is a relatively new but fascinating theory by MIT Assistant Professor Jeremy England indicates that when a group of atoms is driven by an external source of energy (i.e. the Sun) and surrounded in a heat-bath (like an ocean), it will automatically organize itself to dissipate that energy. How does this connect to life? Well, the one characteristic that all life we know shares is its amazingly efficient ability to collect and dissipate energy (what you do when you eat and move around, what plants do when they turn sunlight into food, etc.) In the words of Mr. England: 

“You start with a random clump of atoms, and if you shine light on it for long enough, it should not be so surprising that you get a plant...” (Scientific American, January 28, 2014)

Taken together, all of this suggests that the galaxy, and the universe, is probably teeming with life (at least the single-cellular kind). Until we actually find alien life, we won't know for sure if we're right about all this or not, but for me this means that I can feel 100% justified in writing about aliens and still calling it realistic. It feels good to think that the worlds I write about might actually be out there in some form (though undoubtedly different), and perhaps science fiction isn't so fantastical after all.