The Anthropic Principle

Anthropic Principle:

The anthropic principle (Greek: anthropos, “human being”) says that the universe was suited in the very first moment of its own existence for the appearance of life in general and human life in particular. As agnostic astronomer, Robert Jastrow, noted, the universe is surprisingly preadapted to the ultimate appearance of mankind. For if there were even the smallest variation in the moment of the big bang, making conditions dissimilar, even to a degree that is small, no life of any kind would exist. In order for life to be present today an incredibly restrictive group of requirements must happen to be have been present in the early universe –and they were.

Evidence that Supports:

1. Oxygen comprises 21 percent of the atmosphere. If it were 25 percent, fires would erupt, if 15 percent, human beings would suffocate.
2. If the gravitational force were altered by 1 part in 1040 (that’s 10 followed by forty zeroes), the sun would not exist, and the moon would crash into the earth or sheer off into space (Heeren, 196). Even a slight increase in the force of gravity would result in all the stars being much more massive than our sun, with the effect that the sun would burn too rapidly and erratically to sustain life.
3. If the centrifugal force of planetary movements did not precisely balance the gravitational forces, nothing could be held in orbit around the sun.
4. If the universe was expanding at a rate one millionth more slowly than it is, the temperature on earth would be 10,000 degrees C. (ibid., 185).
5. The average distance between stars in our galaxy of 100 billion stars is 30 trillion miles. If that distance was altered slightly, orbits would become erratic, and there would be extreme temperature variations on earth. (Traveling at space shuttle speed, seventeen thousand miles an hour or five miles a second, it would take 201,450 years to travel 30 trillion miles.)
6. Any of the laws of physics can be described as a function of the velocity of light (now defined to be 299,792,458 miles a second). Even a slight variation in the speed of light would alter the other constants and preclude the possibility of life on earth (Ross, 126).
7. If Jupiter was not in its current orbit, we would be bombarded with space material. Jupiter’s gravitational field acts as a cosmic vacuum cleaner, attracting asteroids and comets that would otherwise strike earth (ibid., 196).
8. If the thickness of the earth’s crust was greater, too much oxygen would be transferred to the crust to support life. If it were thinner, volcanic and tectonic activity would make life untenable (ibid., 130).
9. If the rotation of the earth took longer than 24 hours, temperature differences would be too great between night and day. If the rotation period was shorter, atmospheric wind velocities would be too great.
10. Surface temperature differences would be too great if the axial tilt of the earth were altered slightly.
11. If the atmospheric discharge (lightning) rate were greater, there would be too much fire destruction; if it were less, there would be too little nitrogen fixing in the soil.
12. If there were more seismic activity, much life would be lost. If there was less, nutrients on the ocean floors and in river runoff would not be cycled back to the continents through tectonic uplift. Even earthquakes are necessary to sustain life as we know it.^[1]

^[1] Geisler, N. L. (1999). In Baker encyclopedia of Christian apologetics (pp. 26–27). Grand Rapids, MI: Baker Books.