Turning Outward – Proverbs 25:2 (NIV) It is the glory of God to conceal a matter; to search out a matter is the glory of kings. – Finding God in the world around us.
So now we move from looking at the stars, turning outward and looking at the earth around us.
PHOTO: The Earth’s colorful horizon with a silhouette of the space shuttle Endeavour. The orange layer is the Troposphere, where all of the weather and clouds which we typically watch and experience are generated and contained. This orange layer gives way to the whitish Stratosphere and then into the Mesosphere.
What factors make the Earth uniquely designed to support life as we know it? Why isn’t every rocky planet, like Venus, Mars or any number of the 3000+ planets that we have found circling the stars above, suitable for life? Referring to the same Reasons to Believe list of independent, fine tuned, environmental factors that we referenced in the last few blogs, we find some possible answers.
There are numerous factors that relate to the composition of the soil (quantities of specific elements), the oceans, the crust and mantle and the core of the planet but for the discussion today we will limit ourselves to factors related to the characteristics and composition of our atmosphere. To date, no known exoplanets have been found to have an atmosphere with a composition like that of the Earth’s atmosphere.
Our atmospheric pressure at the surface is roughly 14.7 pounds/sq inch. If that pressure was somewhat smaller, liquid water would evaporate to quickly and then not condense in sufficient quantities. Nor would our lungs function as they do. These factors would decrease or eliminate the chances of advanced life. If the pressure was too high, liquid water would not evaporate easily, leaving the land too moisture rich for land life. The cloud cover would be too thick reducing the sunlight reaching land. The weather would be too consistent to allow for seasons and we would again have difficulty breathing. (probability of 0.01)
Life also requires a clear atmosphere too allow for sunlight and the solar radiation to promote photosynthesis and warm the planet. If the air did not allow for solar radiation in a wide range of wavelengths, the planet would be cold and barren of plant life. If too wide a range of radiation were to pass through, adverse effects from that radiation would harm or prohibit life. (probability of 0.01)
Surface Gravity & Escape Velocity
Surface gravity is required to hold on to the atmosphere. Too low and the atmosphere would be stripped away by solar winds. Even if the gravity was enough to retain an atmosphere, too much water could be lost if the escape velocity was still low. If the gravity was too high, toxic compounds heavier than water, such as methane and ammonia, would be retained inhibiting or preventing life. (probability of 0.001)
Oxygen & Nitrogen Balance
To promote life, the atmosphere needs a proper balance and quantity of nitrogen and oxygen. If too much oxygen, advanced life functions tied to respiration would proceed to quickly. The risk and extent of combustion or fire would be higher as well, with organic matter burning too quickly and easily. If the nitrogen was too high, respiration would be insufficient for adequate oxygen intake. Plants would fix nitrogen at too high a level, inhibiting diversity of plant life forms. (probability of 0.1)
Carbon Dioxide & Water Vapor
The levels of carbon dioxide and water vapor are also critical for advanced life. Too much of either of these molecules and we would have runaway global warming. Too little carbon dioxide and photosynthesis would be hindered and too little water vapor and there would be insufficient rainfall for advanced land life forms. (probability of 0.01)
Rainfall & Erosion
Rainfall needs to be sufficient and widespread (cover the earth). Too little rain and there would be inadequate water to support life on land and inadequate erosion to support the cycling of nutrients from the soil to the sea. If too much rainfall, there would be too much erosion with the subsequent flood of excess nutrients into the sea and a resultant extinction of species that help maintain all life. (probability of 0.01). Erosion is also impacted by the slope or relief of the land masses. Too much slope and erosion is too high. Too little slope and erosion is inadequate. (probability of 0.1)
The final factor we will consider is atmospheric ozone (O3), discussed previously in The Wizard of Ozone. It is a complex factor in that not only does the overall ozone level impact life but the level in the upper, middle and lower atmosphere have different effects on life.
Overall ozone levels that are too high reduce the surface temperature of the planet, impacting life. Not enough ozone and surface temperatures and UV radiation levels would be too high to sustain life.
Ozone in the Troposphere (0-7 miles above the surface of the earth) inhibits reduction of biochemical smog if levels are too low and causes respiratory failure in animals if too high. Stratospheric ozone (7-31 miles up) blocks too much UV radiation reducing plant growth if levels are too high and allows in too much UV radiation, causing skin cancers and reduced plant growth if levels are too low. When Mesospheric ozone (31-50 miles up) is too high or too low, it disrupts levels of life essential gases in the lower atmospheric levels, affecting an overall decrease in life on the planet. (probability of 0.01)
In the last blog, “Looking Upward Part Three – The Heavens, we identified 17 possible finely tuned parameters that reduced the estimated 25 trillion trillion planets in the universe to just 360 possible habitable ones. Adding in just these eight additional factors (a total of 25 out of over 300 possible) means we would need to search approximately 30 trillion UNIVERSES to have a chance of finding just one planet that met all 25 factors we have examined so far.
Romans 1:20 (NLT) – For ever since the world was created, people have seen the earth and sky. Through everything God made, they can clearly see his invisible qualities—his eternal power and divine nature. So they have no excuse for not knowing God.