It has been remarked that life on earth is very resilient, and it is.  But when viewed in light of conditions on other worlds in the solar system, life is extremely fragile.  Not only so, but the earth has always afforded an extremely stable environment for life.  Conditions here vary within very close limits.  And these conditions are dynamically maintained by a complex set of controls.

If the temperature of the oceans should vary more than a relatively few degrees they would either boil or freeze solid. Either way, life would disappear.  Scientists tell us that the oceans contain just the right amount of water to maintain proper humidity, and to prevent the earth from being a water planet.

But consider conditions on other worlds in the solar system.  Mars is a barren planet with a thin atmosphere and planet-wide sand storms that reach 300 miles per hour.  The sand has been pulverized to the consistency of talcum powder.  Beautiful Venus has an atmosphere of corrosive acid, and a run-away greenhouse effect by which temperatures become hot enough to melt lead.  Tornadic storms rage constantly over the surface of Jupiter, largest planet in the solar system.  There is a big “red eye” there, observed for centuries, which turns out to be a huge

whirling storm, big enough to swallow two earths.  Mercury, the innermost planet, blasted by a giant pitiless sun has no atmosphere.  Giant Neptune is a gaseous planet, with winds reaching more than 1000 miles per hour.  Pluto is a frozen rock, where the sun possibly appears only as a giant star, affording little heat.

Scientists once thought life might exist on one of these planets, but with the evidence of our space probes that possibility is no longer considered feasible.  A “green” zone around the sun, called the CHZ or Continuously Habitable Zone, includes only one planet, the earth.  Everything about the earth, shows evidence that it was designed as a home for life.  It is no small matter that water exists here in three forms, vapor, liquid, and solid.  Temperature is maintained within limits of about plus or minus 50 degrees centigrade, and the average temperature varies little more than a degree or two throughout the year. 

About 75% of the land lies in the northern hemisphere.  Since land absorbs heat better than water, it is convenient that the orbit of the earth brings it slightly closer to the sun in the winter than in the summer.  Also since the earth rotates at an angle of 23.5 degrees to the plane of its orbit around the sun, the seasons are possible.  Since the continents are mostly triangular in shape, with a point toward the south, the change from land to water, allows the annual change of seasons to be as gradual as possible.  Were the angle of 23.5 degrees much different, either there would be no seasons, or the seasons would be much more violent.  The ice caps at both poles would probably melt and refreeze annually.  French scientists recently created a computer model of the earth/moon system and found that the moon acts as a gyroscope to keep the earth at the precise angle of 23.5 degrees.  If the moon weren’t there, the earth would wobble as much as 85% over a period of time.

The moon causes the tides as it circles the earth.  But it is at just the right distance so that the tides do not flood all the land.  What is less known is that it causes a “land tide”, lifting the land itself a few inches as it passes overhead.

This gentle massage relieves some of the stress of faults which could build up and cause earthquakes more horrible than any we now experience.  Also, the moon does not circle the earth at the equator, but more nearly in the plane of the earth’s orbit around the sun.  Thus it deals evenly with all parts of the earth. The dust of the moon reflects white light, and contains glass beads which function to make the reflected light  even more brilliant.

Earth’s atmosphere is composed of about 20% oxygen and 80% nitrogen with a few other gasses in smaller amounts.  The composition of the atmosphere is just right to avoid spontaneous fires from too much oxygen.  It has a layer of ozone at its top, which conveniently protects us from the ultra-violet rays from the sun.  The atmosphere is thick enough to burn up most meteorites which otherwise could cause great damage.  The carbon dioxide in the atmosphere acts very much as a thermostat to maintain temperature dynamically.  Plants absorb carbon dioxide and produce oxygen.  This has two beneficial effects:  It maintains the balance of oxygen necessary for human beings and animal life.  And it maintains a constant temperature on earth.  When carbon dioxide increases it causes the earth to retain the sun’s heat.  This causes plants to grow more.  As they grow, they produce oxygen, and remove the carbon dioxide.  Thus the temperature drops.

The sun sends out a extremely high speed solar wind, which could be harmful to life.  Unless the wind is stopped, genetic damage on a wide scale would be the rule.  Astronauts going to the moon experienced flashes of light when they closed their eyes.  This was thought to be from the solar wind passing through their ship. But the magnetic field around the earth causes the wind to pass harmlessly around the earth.  We see the result of this in the aurora, the northern and southern lights which appear as the solar wind strikes our upper atmosphere.

These are just some of the amazingly fine-tuned environmental conditions in which we live.  Scientists can only speculate as to why these things are true.  And for some they have no idea at all.  Is it not reasonable to believe that a Supreme Intelligence made it this way?

Bill Carrell