Anthropic Constant 1: Oxygen Level—On earth, oxygen comprises 21 percent of the atmosphere. That precise figure is an anthropic constant that makes life on earth possible. If oxygen were 25 percent, fires would erupt spontaneously; if it were 15 percent, human beings would suffocate.
Anthropic Constant 2: Atmospheric Transparency—The small window the astronauts must hit reflects the exacting standards by which the universe has been designed. While the atmosphere presents a reentry problem for the astronauts, its present qualities are absolutely essential for life here on earth. The degree of transparency of the atmosphere is an anthropic constant. If the atmosphere were less transparent, not enough solar radiation would reach the earth’s surface. If it were more transparent, we would be bombarded with far too much solar radiation down here. (In addition to atmospheric transparency, the atmospheric composition of precise levels of nitrogen, oxygen, carbon dioxide, and ozone are in themselves anthropic constants.)
Anthropic Constant 3: Moon-Earth Gravitational Interaction—As the astronauts begin to sling around the moon, they encounter another anthropic constant. This one regards the gravitational interaction that the earth has with a moon. If the interaction were greater than it currently is, tidal effects on the oceans, atmosphere, and rotational period would be too severe. If it were less, orbital changes would cause climatic instabilities. In either event, life on earth would be impossible.
Anthropic Constant 4: Carbon Dioxide Level—Of course such a rig is not necessary here on earth because just the right level of carbon dioxide is maintained naturally in the earth’s atmosphere. This is another anthropic constant. If the CO2 level were higher than it is now, a runaway greenhouse effect would develop (we’d all burn up). If the level were lower than it is now, plants would not be able to maintain efficient photosynthesis (we’d all suffocate).
Anthropic Constant 5: Gravity—The gravity that is pulling the astronauts back home is still another anthropic constant. Its strength may be terrifying, but it couldn’t be any different for life to exist here on earth. If the gravitational force were altered by 0.00000000000000000000000000000000000001 percent, our sun would not exist, and, therefore, neither would we. Talk about precision!
- If the centrifugal force of planetary movements did not precisely balance the gravitational forces, nothing could be held in orbit around the sun.
- If the universe had expanded at a rate one millionth more slowly than it did, expansion would have stopped, and the universe would have collapsed on itself before any stars had formed. If it had expanded faster, then no galaxies would have formed.
- Any of the laws of physics can be described as a function of the velocity of light (now defined to be 299,792,458 meters per second). Even a slight variation in the speed of light would alter the other constants and preclude the possibility of life on earth.
- If water vapor levels in the atmosphere were greater than they are now, a runaway greenhouse effect would cause temperatures to rise too high for human life; if they were less, an insufficient greenhouse effect would make the earth too cold to support human life.
- If Jupiter were not in its current orbit, the earth would be bombarded with space material. Jupiter’s gravitational field acts as a cosmic vacuum cleaner, attracting asteroids and comets that might otherwise strike earth.
- If the thickness of the earth’s crust were greater, too much oxygen would be transferred to the crust to support life. If it were thinner, volcanic and tectonic activity would make life impossible.
- If the rotation of the earth took longer than twenty-four hours, temperature differences would be too great between night and day. If the rotation period were shorter, atmospheric wind velocities would be too great.
- The 23-degree axil tilt of the earth is just right. If the tilt were altered slightly, surface temperatures would be too extreme on earth.
- 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.
- If there were more seismic activity, much more 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. (Yes, even earthquakes are necessary to sustain life as we know it!)
Astrophysicist Hugh Ross has calculated the probability that these and other constants—122 in all—would exist today for any planet in the universe by chance (i.e., without divine design). Assuming there are 10^22 planets in the universe (a very large number: 1 with 22 zeros following it), his answer is shocking: one chance in 10^138—that’s one chance in one with 138 zeros after it! There are only 10^70 atoms in the entire universe. In effect, there is zero chance that any planet in the universe would have the life-supporting conditions we have, unless there is an intelligent Designer behind it all.
Geisler, Norman L.. I Don’t Have Enough Faith to Be an Atheist (Foreword by David Limbaugh) (p. 98-106). Crossway. Kindle Edition.