On the macro-level, the size of the universe, its rate of growth, and the nature and existence of galaxies, stars, and planets depend largely on the force of gravity. While we sometimes take gravity for granted, the precisely calibrated gravity in the universe is puzzling; Susskind describes it as an “unexplained miracle.”

The appearance of fine-tuning in our universe has been observed by theists and atheists alike. Even physicist Paul Davies (who is agnostic when it comes to the notion of a Divine Designer) readily stipulates, “Everyone agrees that the universe looks as if it was designed for life.” Oxford philosopher John Leslie agrees: “it looks as if our universe is spectacularly ‘fine-tuned for life’. By this I mean only that it looks as if small changes in this universe’s basic features would have made life’s evolution impossible.” The foundational “laws of nature” are amazingly fine-tuned; there is very little room for alteration. The smallest modifications of these laws would completely destroy the possibility of life in the universe. Theoretical physicist, Stephen Hawking says the laws of physics “appear fine-tuned in the sense that if they were altered by only modest amounts, the universe would be qualitatively different, and in many cases unsuitable for the development of life…The emergence of the complex structures capable of supporting intelligent observers seems to be very fragile. The laws of nature form a system that is extremely fine-tuned, and very little in physical law can be altered without destroying the possibility of the development of life as we know it. Were it not for a series of startling coincidences in the precise details of physical law, it seems, humans and similar life-forms would never have come into being.” The universe appears fine-tuned in three specific ways:

Forces Governing the Atom Are Favorable to Life:

The constants and proportions of the strong nuclear force, weak nuclear force, electromagnetic force and the force of gravity must exist within very narrow ranges in order for life to exist in the universe. The ratio of electrons to protons (both in their numbers and mass) must be precariously balanced. Stanford University physicist and cosmologist, Leonard Susskind, says, “The Laws of Physics begin with a list of elementary particles like electrons, quarks, and photons, each with special properties such as mass and electric charge. These are the objects that everything else is built out of. No one knows why the list is what it is or why the properties of these particles are exactly what they are. An infinite number of other lists are equally possible. But a universe filled with life is by no means a generic expectation…” If the value of this ratio deviated more than 1 in 1037, the universe, as we know it, would not exist today. If the ratio between the electromagnetic force and gravity was altered more than 1 in 1040, the universe would have suffered a similar fate. The nature of the universe (at the atomic level) could have been different, but even remarkably small differences would have been catastrophic to our existence.

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