The part of Earth’s atmosphere we live in, fly airplanes in, and which contains over 90% of our oxygen is called the troposphere. It is much thinner than you may realize. Earth’s diameter is about 8,000 miles, and the thickness of the troposphere is much less than eight miles, making it one one-thousandth of the diameter of Earth. Our air is like an onion skin around our planet. Earth’s twilight daily reminds of the thin blanket that protects us.
You might wonder if the thin nature of our atmosphere is not a risk to us. The truth is that our troposphere is a uniquely designed structure, and if it were any different, life could not exist on this planet. The troposphere has to be…
…thin enough to allow enough light in for the photosynthetic processes of plants, but thick enough to burn up hunks of rock from space as they are pulled in by Earth’s gravity.
…thick enough to provide oxygen to breathe, but not so thick as to create pressures that would cause oxygen toxemia.
…thick enough to trap enough of the Sun’s heat to keep us warm, but thin enough to not overheat us.
…thick enough to refract and scatter dangerous radiation away from us, but thin enough to allow critical wavelengths to reach Earth’s surface for biological purposes.
…thick enough to allow water to exist as a liquid, but not so thick that other gases liquefy or dissolve in water,
These are just a sampling of the critical elements involved in the design of the troposphere. There are additional layers above the troposphere that do other things to support life on this planet. As science has examined the atmospheres of other planets within our solar system, we see that they are very different. The acid air and greenhouse effect of the atmosphere of Venus has turned it into a hellish environment. We do not have the ultraviolet light that bathes and sterilizes Mars because our ozone layer filters out much of that destructive component of the Sun’s light.
Each day as we watch Earth’s twilight come, we should be reminded of the incredible wisdom built into the structure of our atmosphere. As the sky turns from blue to a brief green, to yellow, to orange, and then red, we are seeing the longer wavelengths which we don’t see in the daylight because they are mixed in our atmosphere. Our air keeps X -rays away from our planet. Its density allows flight and keeps the lakes and oceans from evaporating. Its low density allows it to move and carry warmth and moisture from one area of our planet to another so that life can exist from the equator to the poles. Earth’s twilight is a daily reminder of the care and design built into our planet because of God’s love and wisdom.
— John N. Clayton © 2019