Life on Earth

We don't know much about anything.

Photography credit from Astronomy picture of the day. Galaxies look very much like cells when seen in reduced scales. They process energies in very complex ways. They make new substances and spread them. They consume matter from outside themselves.

How do we know they aren’t living creatures in their own right? We don’t.

Today we’re going to take a look at why it’s highly likely that life did not originally evolve on earth.

In the 1980’s prominent Astronomer Fred Hoyle argued that life began too early for the extremely complex and incredibly sophisticated DNA molecule to have originated and involved in place here on earth. That should be obvious enough to begin with; evolution is a very complicated process and DNA, at the first moment signs of life appear in earth’s rocks—Life was present on earth 3.7 billion years ago—was already the amazingly, even impossibly, sophisticated molecule we are all familiar with. Now, Earth is about 4.5 billion years old— and when it first formed the general agreement is that it was way too hot to support life. Let’s assume it cooled in 500 million years., which is a very aggressive but interesting assumption. (Most scientists would say it took a lot longer.) That would give us about 300 million years for life to arise. A very, very short time indeed—any biologist would probably tell you the odds of life spontaneously forming and evolving from its necessarily tentative original form into an organized system of the trillions of different molecules required for a single cell to the complex form of DNA are just about nil. In order for it to happen, every inevitable accident of evolution would have had to be a happy one, and everything would have had to go perfectly from one step to another. We can all estimate just how likely that is.