Rob's Mind: October 2008

Our sun has been shining on our world for 4 and a half billion years.

It has elicited wonder, fear, awe and legend.

It arose from a swirling cauldron of gas spinning in a lonely part of the Orion Arm of the Milky Way. Billions of years ago that's all that occupied this section of space. As the gases spun around they started to condense and coalesce. As the gases came together and the mass got greater, it began to form the sphere we see today. Gravity, the most pervasive force in the universe, gave it this form as it has for almost every star and planet we see. The force of gravity pulled the edges of the sun inward from all directions making the sun the ball shape we are familiar with.

Not all of the gas went into the sun. Some of the left overs went into making the surrounding planets that would make up our solar system, and the Earth. The early sun was composed of primarily one element --- hydrogen.

Hydrogen is the most abundant element found in the universe. It is the simplest element found on the periodic table of elements. And when the immense force of gravity inside the new sun started to compress these atoms of hydrogen a spark was lit. The fire of thermonuclear fusion began. The sun began to give off the light and heat that would make life on Earth possible and provide the enormous amounts of energy it does today. But the immense pressures did more than just provide light and heat. A bi-product of crushing hydrogen atoms gave rise to all the elements we see today. As they hydrogen atoms were compressed together, they began to form new, more complex, elements: helium, carbon, nitrogen and oxygen. With these elements the planets, asteroids and everything in existence was created. Essentially, everything we see today was created by stardust. Today, the sun (Sol, the latin word for sun) is categorized as a G-Type main sequence star. It stands as the lone master of the solar system. But this is not the norm with stars. Scientists have found that most stars in the universe actually are paired. The majority of

star systems are 2 (binary) or more stars. These stars exert a gravitational force on each other, sometimes with drastic consequences. Our solitary star will continue to burn for another 4-5 billion years. Life will continue to change until the last of the hydrogen is burned away and the sun continues to burn off the heavier elements beginning with helium. This will continue until the star can burn no more of itself and fusion will cease. At that time one of two things will happen. Either the sun will inflate and engulf the inner planets of Mercury, Venus, Earth and Mars before shrinking to a dwarf; or it will explode in a massive supernova. Until that time, we will continue to reap the rewards of this miracle of the universe and enjoy the warm, energetic life-giving rays of the sun.