Life Cycle of the Sun

A coronal mass ejection, or major solar flare, erupted in the sun’s corona on January 22, 2012, sending a mass of highly charged protons streaming toward earth at 5 million mph (8 million kph). The jolt hit earth on Jan. 24, causing spectacular aurora borealis displays over Norway, Alaska, and other Arctic and Antarctic areas. It was originally thought the ejection was strong enough to disrupt satellite communications, but there were no reports of problems.

This solar activity serves as a reminder that those of us living on planet earth today are a lucky bunch. We are about midway between our sun’s origin 4.7 billion years ago, and its likely demise 5 billion years hence. It is a time when the temperature range and availability of water make it possible for earth to support a flourishing animal and plant life.

It was not always so. Scientists believe our earth was formed about 4.5 billion years ago from the same space dust and gasses that formed the sun. But the sun was too cool to support life until a billion years ago, when it became strong enough to allow life to begin developing. In another 5 billion years the sun will begin its transformation into a red giant, the phase of a star’s life when it runs out of hydrogen fuel and expands before its core finally collapses and the star contracts into a cool, white dwarf. However, long before the transition to red giant begins, earth will gradually become too hot to support life. Water, including the oceans, will evaporate and earth will become an uninhabitable desert. Some scientists estimate that phase could come as early as 1.4 billion years from now.

A few facts about the sun. It is a relatively small star located in the Orion arm of the Milky Way galaxy. It is 109 times the size of the earth, but weighs proportionately much more. Its mass is estimated at 330,000 times that of the earth. The sun is 93 million miles from our planet (150 million kilometers). Its composition is 98% hydrogen and helium, and 2% other chemical elements, including carbon, nitrogen, and oxygen. Its surface temperature is 5,770° Kelvin, or 9,930°F. Its core temperature is 15,600,000°K, or 28,000,000°F. The sun’s surface temperature is slowly rising, and its brightness increases 10% every one billion years.

Will the human race be able to escape its fate by relocating to another planet? NASA’s Kepler satellite telescope has been searching outer space for evidence of planets orbiting other stars. Kepler has already identified thousands of such planetary bodies, but so far only one planet seems to be located in the so-called Goldilocks zone — the right distance from its star to have the temperature range that could support life. The composition of the planet is not known, and whether or not it has water is not known. Even if the perfect planet were discovered, could mankind ever develop the technology to safely transport human beings millions of light years through space?

Here on this earth, It’s true that we have to cope with earthquakes, volcanoes, tsunamis, floods, fires, drought, and dozens of other natural and manmade disasters. Plus disease and life’s many challenges. But we are nevertheless fortunate to live on a planet under a warming sun, with the air, water, and soil that makes it possible for life to flourish. Wouldn’t it be great if the nations, races, religions, tribes, and clans on earth, large and small, could settle their differences and concentrate on making our special planet a better place for all.