Friday, March 9, 2012

Fun Facts Friday - What Am I?

I live in space and can be seen on a clear night. My Northern cousin is the brightest and the easiest to spot. A group of us can make up what appears to be objects in the night sky (the Big Dipper). Plus, I can live to be over a million years old.

What am I?

A Star!
Like people stars are all different. And like people stars go through many stages in their lives. Stars are born, mature, grow old, and eventually blink out. The bigger the star is the faster it will live its life. Yes, it’s actually good to be small if you’re a star it means you get to live a trillion years instead of a few measly million.

The Nebula Nursery

Space is full of clouds made up of gas and dust particles. These special clouds are called nebulae. A baby star is formed when the gases and particles of these clouds are pulled together by gravity. This infant star is called a protostar. But it doesn’t look or shine like a star yet. At this stage of its life, it’s just cold dust and gases.

Star Shine

Stars stay babies for millions of years. During this time gravity is shrinking and squeezing the star’s hydrogen particles together -so if a protostar starts off a trillion kilometres wide, it will shrink to a mere million kilometres wide. However, as the baby star gets smaller a lot of pressure and heat is created. When the stars temperature reaches about 10 million degrees Celsius the star stops contracting. How does the star get its shine? By changing its own hydrogen gas into helium.

The Growing Star

Imagine you had to eat yourself to stay alive. That’s what stars do. The energy produced from changing hydrogen to helium, not only makes the star shine brightly, but also feeds it. In fact, they spend 90 percent of their lives doing this. Big, bright, blue giant stars eat up more hydrogen which makes helium very quickly. And just like a helium balloon will float away the stars mass also disappears. Smaller, dimmer stars called ‘red dwarfs’ eat very slowly since they have less hydrogen to consume. In fact, these guys can live for billions of years.

The Beginning of the End

Even though stars live for millions and trillions of years, eventually they all get old and blink out. When this happens, the star is mostly just helium with an outer shell of burning hydrogen. This makes the star shine bigger and brighter, but only until it reaches 100 million degrees. When this happens the helium gives off flashes and for the next few million years the star will blink.

The Old Timer

Old stars fall under different names. A white dwarf is very dim and has lost most of its mass. It’s mostly carbon and only has a thin layer of burning helium. Eventually white dwarfs burn themselves up. When this happens they no longer have a shine and are just floating balls of carbon called black dwarfs. Gigantic stars more massive than the sun go out with a bang – An explosive bang. This is what we call a supernova. Stars going supernova are very hot – 600 million degrees hot. This turns the stars core into a steel-like ball.

To learn more about stars and space check out your local library or just look up on a clear, dark night.


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