I was thinking about the timeline that brought us here, today, from the origin of the Universe up through the present day. I realized that the most uncertain thing that we know of, the step that we have the least information about, is the origin of life on Earth. All hypotheses about how life on Earth originated fall into three categories:
- Abiogenesis, or the idea that life came from non-life, somehow, on Earth.
- Life originated elsewhere in the Universe, and was brought to Earth, where it now thrives (e.g., panspermia, or exogenesis).
- Life was created or designed by an outside force/being.
Is that it? Does this really encompass everything? Well, I can’t think of another that doesn’t fall into one of these three categories. It should be noted that none of these three have been proven, and that work on a mechanism for abiogenesis, including Oparin’s hypothesis, the Miller-Urey experiments, and subsequent work has not yet yielded life generated from non-life.
However, the panspermia hypothesis has always bothered me, seeming like a cop-out. After all, can you really say the “origin of life” just happened somewhere else, and so we don’t care to investigate any further? Then I came across another one of cdk007‘s youtube videos (from 2006) that articulates what those three options above are quite cleanly:
In a nutshell, alien life had to originate somewhere. If you’re asking about the origin of life in the Universe, the origin of the first living thing that we descended from, there are only two options:
- Either life originated from non-life naturally, or
- Life originated supernaturally.
If we can show that it’s possible for life to originate from non-life, that will remove the last remaining major gap in the scientific creation of our modern world, beginning from the big bang all the way through the present day. Of course, we don’t know how the whole thing started, or where it’s headed, but we’re always learning…