Thursday, May 14, 2009

Multiverses and Life Elsewhere

The May 2009 issue of "Discover" has an article title "Cosmic Abodes of Life". It can be found on pp. 46-51.

There were some parts of the discussion that I wanted to share on this blog.

It turns out that life may not be so unusual after all. The discussion in the magazine covers many things that support that claim.

A portion of that article discusses "multiverses". That is the idea that there may be many universes with different physical laws. Apparently string theory allows for such things and it calculates the possibility that there are 10**500 (a '1' with 500 zeroes after it) possible universes.

A scientist did a calculation and found out that fully 25% of those universes, even with different physical laws, would allow for heavy stars (i.e. heavy elements). Though life needs more than heavy elements, it is surely a requirement. Of course life as we know it may not be the only possible life. It is possible, for example, that under different physical laws other elements might be able to form the complex molecules that only carbon seems able to produce in our own universe.

Possibly the most interesting suggestion is the one that each and every black hole results in the creation of a new and different universe. In that case, the physical laws would necessarily be effectively the same in each new universe. That fact suggests a certain type of Darwinian selection. Any set of physical laws that allowed black holes would be strongly selected among all of the other possible sets of physical laws.

These same scientists are suggesting that this hypothesis is testable. That test is that our universe should be optimal for producing black holes. So if it is true that changing any of the physical constants (such as the speed of light, the force of gravity, etc.) diminishes the conditions needed for black holes then we have that optimal set of conditions and - voila - we have an explanation for why the universe is as it is.

No God needed.

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