This question is common in astronomy classes: "What star is closest to planet Earth?" Common answers are Alpha Centauri, and others. The correct answer is the Sun. Our own Sun, approximately 93 million miles distant from Earth, is at the center of our solar system. And it is the source and sustainer of life on Earth.

And yet, our Sun is a common star - for a star it is, like millions of billions of others in the universe. The Sun belongs to a class commonly called "main sequence". It is not very large nor very small, not terribly hot nor cool. Just a mere moderate-sized main sequence star. But the most important star to us, because our Sun is the sustainer of life on the most important planet to us - is our own planet Earth.

The Sun is exactly the correct distance from Earth. Venus and Mercury are too close. Mars is too far away. The Sun, at 93 million miles away, is just the right size and temperature to sustain life on our planet. The atmosphere on Earth is exactly the right mixture too. Seventy-eight percent nitrogen, 21 percent oxygen, and 1 percent carbon dioxide (plus trace elements) to sustain carbon-based life-forms as we know them. But we've been tempting fate too long, now carbon dioxide is on the increase; commonly know as a "greenhouse gas."
The Sun does a lot for us. Its rays combined with the atmosphere, warm the Earth to exactly the right temperature. It causes photosynthesis, where carbon dioxide, a bi-product of combustion and respiration, is converted to oxygen. Much of this occurs in the oceans. On land, the rest of it occurs in plants. We've upset the cycle, cutting down most of the rain forests, polluting the oceans, spewing too much carbon dioxide and other harmful gasses into the air.

The action of the Sun provided Earth with almost inexhaustible fossil fuels, such as oil, natural gas, and coal. The Sun powers the winds and weather systems. Everything not living degrades because of the action of the Sun. Even seemingly non-degradables, like grass and metals. Ultimately, the power of sunlight degrades everything. And erosion, mostly from water, wind, oxidation, and temperature and humidity extremes, combines with sunlight to provide mankind with everything we need, and to sustain life on Earth.

Let's take better care of it. Mankind is the dominant life-form on our planet, and the only one with the power to save planet Earth - or to destroy it! Form a New Year's resolution for 2008 - take better care of planet Earth!