One of the most fascinating scientific endeavors going on in our world is the search for extraterrestrial life. That is, life that exists somewhere else other than Earth. Up until just recently, the search for life was confined to our own solar system. However, advances in technology is now allowing the search to go on to other stars and galaxies. The recent discovery of Kepler-22b highlights the possibilities now. This is an exoplanet found orbiting a distant star that was the first one discovered to be placed in what scientists refer to as the habitable zone. However, science has always conducted the search by looking for signs of life as we know it.
When analyzing another planet or satellite, scientists look for certain things when trying to prioritize which celestial objects have the highest probability of harboring life, either currently or in the past. They do this by looking for the fundamental properties that are necessary for life to exist on Earth. Liquid water is the number one priority. When the Viking explorers landed on Mars, they took samples from the Martian surface and looked for waste products. The idea was that anything that is alive must have a by-product, so they looked for emissions in the soil to indicate that life had been present. They did find some evidence of this, much to the excitement of scientists back on Earth, but they eventually determined that the sample may have been contaminated by the probes who, of course, were designed on Earth. This made their findings wholly inconclusive and brought into question just how the search for life should continue.
The problem here is that scientists are assuming that extraterrestrial life would function by the same principles as life on Earth does. Basically, they are looking for Earth-like lifeforms on other planets. Only, there is no guarantee that life outside of Earth’s life-friendly atmosphere would look anything like what we are accustomed to. After all, we have no idea what extraterrestrial life might look like. The age-old Hollywood depiction of “little green men” has put it in our psyche that life outside of Earth will at least resemble us. They must breathe air, right? Excrete methane? Reproduce through some sexual-type process? However, scientists are still learning about life on Earth. A recent discovery of microbes on Earth that were able to live in extreme conditions with only methane for fuel only illustrates the problem. That’s right, there are microbes on our very own planet that can exist with only methane for fuel. The same methane that is poisonous to life in general, and was up until now considered to be a danger and not an enabler for life. With science just now discovering these sobering possibilities on our own planet, it just shows that life on other planets could run on chemicals that would blow our collective minds.
It is reasonable to think that within our own solar system there is a chance that life would be somewhat similar. After all, many scientists have hypothesized that life was brought to Earth through a meteor crashing on the surface carrying microbes. How they could survive on the meteor as it travels through space without an atmosphere is a topic they choose to gloss over. As a matter of fact, the more things they discover, it seems they just find only more questions. On a distant planet like Kepler-22b, it is assumed that there is a fair possibility that liquid water could exist, a “requirement” for life. But what if on this alien world, water was the enemy. Or a waste
product? What if the presence of water actually disqualifies this planet from harboring life?
If you think all of this is silly, think about this. There are numerous plants on the Earth that don’t even appear to be alive at all. They blend so perfectly into their environment that at first glance, you would have no idea they were even a living thing. We are looking for life as we know it, but what about life as we don’t know it. What if the very Martian soil were alive, and we were just not aware of it? In the realm of astronomy, Mars is only a hop, skip, and jump down the road in our neighborhood. Imagine the possibilities of what it might be like on Kepler-22b, or the myriad of other exoplanets that are sure to be found as technology increases and more time is put into it.
Another way that we search for life is by scanning the sky for radio transmissions. SETI, the Search for Extraterrestrial Intelligence, uses powerful antenna systems to search the sky for any type of emission that is not explained by natural phenomenon. Yet again, though, we are looking for life as we know it. We assume that aliens would have discovered radio transmissions and be able to receive and transmit them in the same formats that we do. We assume that they would even try. Or that they don’t have a different mode of communication that we have not discovered or would never understand. Think about radio transmissions. These are invisible waves that are passing through you, and everything around you, all the time. We found a way on Earth to harness that and use it for communication. Electricity was always present on Earth, but until we learned that it was there and how to use it, we were ignorant to its existence. Who is to say there isn’t another medium, another mode of travel for communications that we can’t even fathom?
This article is not intended to post the search for life in a negative light. Actually, it bolsters the fact that the possibilities are really endless. We are searching now for life like us, which is a natural thing to do in the situation we are in, stranded on one planet. However, there is always that possibility that extraterrestrial life is nothing like us, and that only makes the whole thing infinitely more exciting.