The origins of life have always been fascinating to me. I have not read much on the subject but that question has always been present in my mind. I remember reading somewhere that scientist think the first cellular life coalesced from a mixture of biological soup in the shallows of the warm ocean billions of years ago. How does something like that just happen, how does a single celled organism suddenly come into being?
There are many many theories about how life began on this planet, I found one in particular interesting for a variety of reasons. Panspermia is the theory that life was brought to this planet either on purpose or by accident from a comet filled with genetic material or single cell organisms. From there evolution took over and we are the result after billions of years. Until recently I think this theory was more in the realm of science fiction rather than science fact.
Let’s suppose for a second that this idea is plausible. DNA is the building blocks of all life on this planet, without it life would not exist. To break that down even further, DNA would not exist without Ribonucleic Acid also known as RNA. Scientist have found meteors that have RNA molecules in them, so that idea of Panspermia does not sound so farfetched after all. Since that finding scientist have found that RNA can indeed survive the vacuum of space, so if that is the case then it is plausible that an asteroid or comet could have come to earth billions of years ago and “seeded” the planet not necessarily with life itself but carrying the right ingredients that life could take off.
So if all this is possible then just by doing some simple math there should be millions of planets that have life on them. We should be hosting visits by our cosmic neighbors on a regular basis, but we all know that is not the case. It could be that the government is responsible for one of the greatest cover-ups in human history, I do not think so, or that there is truly no one out there.
In 1961 Frank Drake can up with an equation that could statistically estimate within reason how many intelligent civilizations were out there. It is called the Drake Equation and has almost always been paired with the Fermi Paradox, yep another paradox, but this one is a little more straight forward. There are some problems with the equation as a lot of the values are either unknowns or out best guess, but even being as conservative as possible some estimates say that there are as many as 1,000 civilizations could be present in the Milky Way. Even if that is on the conservative side, and most of the Drake Equation is believed to be fairly accurate, then where the hell is everyone?
That is where the Fermi Paradox comes in, it states that Earth should have already been visited by other civilizations just based on the age of the universe and other stars that could potentially harbor life. But the fact remains that as far as we know that has not happened. So what is the deal, are we alone or what? I wish I had the answer to that one. This is a statement about the Fermi Paradox on Wikipedia:
The apparent size and age of the universe suggest that many technologically advanced extraterrestrial civilizations ought to exist.
However, this hypothesis seems inconsistent with the lack of observational evidence to support it.
I think there is other life out there but as Stephen Hawking claimed in A Brief History of Time, the odds of the peak of our civilization coinciding with the peak of another civilization is very small, if not nearly impossible. We are dealing with infinitely large time frames, so the odds that if, and or when humans are able to achieve interstellar travel that we will cross paths with another interstellar civilization is nearly 0. There are also about a million theories about life and whether or not it is rare in the universe.
The fact of the matter is that as far as we know we are it and we could very well be the most advanced beings in the universe. That is a scary scary thought…