Monday, March 1, 2010

A Brief Planetarium Show - Act 3

Act 3 - The Sun

Now that we've seen a few of the classical constellations of antiquity in our skies, we gracefully set the stars in motion as they wheel past and the night wears on. The later the hour becomes, the more we begin to see the evening constellations in the seasons to come - by dawn, we are seeing a preview of evening constellations almost 6 months from right now. Lets stop now just before dawn's light begins interfering with our starlight. Before we see our own star at close up range after its nightly absence, an experience we more commonly know as 'morning', lets stop to consider for a moment, what exactly is a star? Many people don't realize the sun is a star, and the stars are suns. There are many variables in why the two seem different - the most obvious being distance. Our sun is 93 million miles away - most stars we see are dozens or hundreds of light years away. Light can travel around the Earth 7 times in one second, so imagine how far it travels in a year! Though the stars may be far larger and brighter than our own sun, and most are, they are so far away they appear as tiny bright pinpoints sparkling in our sky.

Most people also don't realize that many many 'stars' we see in our sky are actually the combined light of double or multiple stars. These cosmic partner revolve around each other in an endless dance, having formed together in the distant past. Mizor and Alcor are just such a pair in the Big Dipper. Watch now as a red dwarf star dances around its yellow giant partner - its a sight seen only in telescopes and in slow motion - imagine how majestic such a sight would be from a nearby planet, as depicted here.

What is a star? We go back to the creation of the universe. The elemental building block of nature is the simplest of atoms - the hydrogen atom. The most elemental force of the universe is gravity, the attraction of two bodies together. Albert Einstein proved early in the 20th century that a body, or mass, creates a distortion in the very fabric of space which causes objects to be attracted, much like a ball rollilng down into a drain - this is how gravity works. Gravity attracts hydrogen atoms together - if there are enough of them, they compress and heat up. If enough heat builds up, nuclear fusion of hydrogen into helium begins, which releases tremendous amounts of heat and light, then a star turns on and burns millions or billions of years. Each star you see in the sky is a giant nuclear furnance, turning hydrogen into helium and releasing heat and light. Einstein's famous formula tells us how much energy, E=MC squared. The E, or energy released will be equal to the enormous product of the Mass itself, in a stars case the hydrogen atoms, times the huge number C squared, the speed of light times itself! The bottom line is this - nuclear fusion releases enormous amounts of energy, and a chain reaction like this in a star can last billions of years. And so the stars burn on, revolving in their galaxies, as their spinning galaxies fly ever further apart from the Big Bang.

Now, without further facts or science or cosmology, perhaps the next time you witness the most predictable event in our very lives, the sun coming up, you will appreciate that which made our planet and our lives possible - the sun! And hopefully you'll remember where it came from, what family it belongs to, and where it is headed. The next time you see our sun come up, appreciate it! It is the founder of our feast here on Earth. We are its children. Hopefully it gives a whole new perspective to the well known phrase . good morning!

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