Tuesday, April 14, 2009

Fine tuned?

It has been argued that the entire universe is fine-tuned for life. Any changes to the fundamental physical constants would make it impossible for life to develop anywhere, especially Earth. For example, change the magnitude of the strong nuclear force and stars cannot produce heavier elements necessary for life. Change the gravitational constant slightly, planets and stars cannot form. Clearly, we have the perfect combination of fundamental constants in our world and that is why we are able to be.

I've never liked this argument for a few reasons. First, how does the arguer know that changing these constants wouldn't lead to life in currently barren regions, despite making Earth uninhabitable? How do they know that there are regions that wouldn't benefit (in terms of supporting life) from these changes? Secondly, we know that life is tenacious. When we think we know what the requirements are to produce and support life, we find something on our own planet that surprises us. An excellent example is the discovery of tube worms that live near undersea volcanic vents (these animals need NO sunlight and survive in incredibly hot waters!)

A scientist at the University of Michigan (hail to the victors) decided to test the impact of changing the fundamental physical constants on a developing universe. He ran computer simulations of many universes, each time changing the gravitational constant, the fine structure constant, and a constant that represents the rate of various nuclear processes. He found that one-quarter of all the simulations ran yielded energy-producing stars- the first and most essential building block in a life-supporting universe.

As usual, this is far from a final answer on this topic, but it continues to provide evidence that life is fine-tuned to the universe, not the other way around.


  1. Would you then not agree that the hole in the ground was finely tuned for the water that formed a puddle there?

  2. I don't see a clear analogy to the story, but let me try: In the case of a typical puddle, no- the water fits to the shape of the hole; the hole does not change its shape to better accommodate the water. Similarly, the universe is not the way it is so that life can form. Rather, life forms and adapts to the environment around it. Perhaps a better way to end this post would have been to say that life adapts to the surroundings rather than the environment adapt so that life can come about.

    If you want to get more profound, you could argue that many puddles over many generations erodes the hole to create a shape that allows the water to flow more naturally. You could argue that life works to change its environment to make surroundings a better fit, just as the water, over time, changes the hole. This does not refute my original point, however- the universe is not here just so life, especially human life, could exist.