The Earth Itself

Earth is the only planet circling our sun on which life as we know it could (and does) exist.

Like no other planet, ours is covered with green vegetation, enormous blue-green oceans containing over a million islands, hundreds of thousands of streams and rivers, huge land masses called continents, mountains, ice caps, and deserts that produce a spectacular variety of color and texture. Some form of life is found in virtually every ecological niche on the earth's surface. Even in the extremely cold Antarctica, hardy microscopic beings thrive in ponds, tiny wingless insects live in patches of moss and lichen, and plants grow and flower yearly. From the apex of the atmosphere to the bottom of the oceans, from the coldest part of the poles to the warmest part of the equator, life thrives here. To this day, no evidence of life has been found on any other planet.

The earth is immense in size, about 8,000 miles in diameter, with a mass calculated at roughly 6.6 x 1,021 tons. The earth is on average 93 million miles from the sun. If the earth traveled much faster in its 584-million-mile-long journey around the sun, its orbit would become larger and it would move farther away from the sun. If it moved too far from the narrow habitable zone, all life would cease to exist on earth. If it traveled slightly slower in its orbit, the earth would move closer to the sun, and if it moved too close, all life would likewise perish. The earth's 365-days, 6-hours, 49-minutes and 9.54-seconds trip around the sun (the sidereal year) is consistent to over a thousandth of a second!

If the yearly average temperature on earth's surface changed by only a few degrees or so, much of the life on it would eventually roast or freeze. This change would upset the water-to-ice ratio and other critical balances, with disastrous results. If the earth rotated slower on its axis, all life would die in time, either by freezing at night because of lack of heat from the sun or by burning during the day from too much heat.

Our "normal" earth processes are assuredly unique among our solar system and, according to what we know, in the entire universe.