Origins of Life on Earth

In the words of Monty Python, and now for something completely different.

Among other things our travels have shown us is that life is unimaginatively adaptive, diverse, pervasive, and robust. One explanation of scientific discovery helps understand Darwin’s contribution: Seeing what everyone else has seen and thinking what no one else has thought.

During days at sea, they work hard at entertaining us. One of their better attempts, at least for me, is a fascinating and provocative lecture series by Chandra Wickramasinghe, professor of Astrobiology from Buckingham University. His thesis, which he has been advancing for the past 40 years, is that life did not originate on Earth. He has some provocative data.

But first he walked us through the history of astronomy. Many ancient societies had a better understanding of the universe, or at least the solar system, than did Western Civilization before Copernicus. Based on the designs of temples and things like Stonehenge and Mayan pyramids, they clearly understood the movement of the sun and planets. In some cases, they produced drawings suggesting that the Earth was not the center of the universe. ‘Educated’ Europeans were burning people at the stake for even suggesting that less than 400 years ago.

Chandra eventually got us to Hubble and other space-based telescopes. Everything we know now suggests the Universe is 15 to 18 billion years old. The sun and our solar system, including the Earth, have been around about 4.5 to 5 billion years. The sun will exhaust its fuel in about another 5 billion, taking the solar system with it. That what stars do.

The Earth is orbiting a very ordinary star in a very ordinary galaxy. Our ordinary star is one of about 140,000,000,000 in the Milky Way, located about two thirds of the way out from the center. I’m not sure what the current guess is about the number of galaxies but it is certainly billions and almost everything we see (and we don’t see anywhere near everything that’s out there) in the night sky and call a star is actually a galaxy, some smaller, some larger, some about the same as ours.

That is all pretty standard stuff; nothing revolutionary.

What would have gotten Prof. Wickramasinghe burned at the stake is the question, Why would we think that one planet in an ordinary solar system with an ordinary star in an ordinary galaxy is unique in any material way? That question is not at all original; philosophers have been asking it for a couple thousand years. Some were burned.

Wickramasinghe gives it a different spin, What is special about our planet that life should arise here and nowhere else? Or is life so easily generated that it has happened repeated on widely separated planets? Isn’t it more reasonable to assume that the incredibly complex arrangement of molecules required for life happened only once and then was spread throughout the universe?

What has Chandra particularly excited at the moment are, first, the on-going and now almost routine discovery of more Earth-like planets (including one at our nearest neighbor) and, second, very recently published evidence of microbial life in rocks that are over 4 billion years old. This was the Hadean geological period when the Earth’s surface was molten from a constant bombardment from comets and meteorites. This environment, he argues, would be completely inhospitable to the formation of the complex proteins needed to form reproducible life, so they necessarily had to come from somewhere else.

He believes that this evidence of microbial life forms in rocks that old means life did not originate on Earth but was carried here on comets or similar objects after originating somewhere in deep space. This process ‘seeded’ the entire universe and life took root whenever and wherever conditions supported it.

If there is life anywhere, there is life everywhere. Or so, Prof Wickramasinghe would have us believe.

Not everyone buys his argument. Is there any other interpretation of the evidence of microbes in the ancient rocks? (they didn’t find any actual microbes, just evidence that they might have been there.) Although we know microbes can survive incredibly harsh conditions for unknown lengths of time, how did anything survive the Hadean Era? While the creation of a life from inanimate chemicals is a very improbable event, based on what we know now, is it any more or less improbable in deep space than on Earth?  And of course, if life didn’t originate here in the primordial soup or deep-sea vents, where and how it did originate?

No matter how improbable the sequence of events to create life, it happened. And a quote from the great 20th century philosopher, Calvin of Calvin and Hobbes, The strongest evidence supporting the idea of intelligent life elsewhere in the Universe is that they haven’t tried to contact us.

 

6 thoughts on “Origins of Life on Earth

  1. Given that the spontaneous generation of life is highly improbable, if you have trillions of environments working on it, some of those would probably get it done. Those places could be all over our galaxy, not just Earth. No good reason to think we are unique.
    On the other hand, given that a viable organic molecule exists on a planet someplace, how does it leap off the planet and catch a ride in a comet?
    Hmmm… things to think about.

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    1. Dr. Wickramasinghe’s thesis is that not only are we made of star dust, we are made of comet dust, which contains all the components for organic molecules. Whether it happened as the aftermath of the Big Bang or a run of the mill super nova, the complex, self-replicating molecules need be generated only once in interstellar space, perhaps before it was interstellar, and spread around the Universe in the form of comets Much of his thinking starts with the very, very small probability of it happening at all and he would be comfortable with the idea of a higher being being involved..

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