Why do stars die?

Why do stars die?

When we look up at the stars, they seem like they have been there forever. Every night, we can count on seeing the constellations, and know that they will be there tomorrow night.  Many of the stars that we see are actually suns, very similar to our own sun. To understand why stars die, we have to learn how stars are born.



StarsLike everything else in our universe, a star has a ‘lifetime’.  Stars are born in a cluster of gas and dust called a ‘nebula’.  Once pressure builds up in the nebula it will bring the gas and dust together and produce what is called a ‘protostar’. The heat inside this protostar is pretty intense and when it gets hot enough, it can explode into a star.  The core or ‘center’ of the star is a swirl of pressure treated gases that are constantly battling to keep a balance.  It is thought that this entire process takes about 50 million years.



Stars come in all different sizes. Our own sun is considered to be a medium sized star. The creation of a star will almost always end up with lots of extra gas and dust. These broil, crash together and can eventually become asteroids and then planets.  A star always has a gravitation pull, and the strength depends upon the size of the star.  The bigger the star, the more gravitational pull it has on the objects around it.



When we see a star, including our sun, we are watching it as it burns the hydrogen contents of its core (the center). This process takes billions of years and it creates heat that is spun off into the universe.  We experience this when we go outside and feel the heat of the sun on our skin. 



You would think that the bigger the star, the longer it would exist, but it’s really the exact opposite. Larger stars burn up their hydrogen core much more quickly that small and medium sized stars. When that happens, there is an intense new process that begins, called fusion. When the star doesn’t have any more hydrogen, it is like being starved.  It slowly begins to collapse in on itself and, in the process, tries to use up all of its resources to create different kinds of materials. 



If you look at a dying star, you would see that the light actually pulsates and can get larger. This is because it is no longer stable and is using everything it has to try to keep from dying.  You might be surprised to find that some of the materials that it is creating at this point includes helium, silicon, and oxygen.  It will continue to create materials until it gets to one point. When it creates iron, it’s all over.  Once the core turns to iron, it doesn’t have the ability to ‘burn’ anymore.



When a star can’t burn anymore, due to an iron core, it begins to collapse in on itself. Due to intense gravitational pull, in just a small amount of time it can shrink from the size of the earth to about 6 miles wide. The core continues to heat up to billions of degrees until it finally explodes. This is called a star going ‘nova’. This blasts out all of the material into space. It may take billions more years for all of that stuff to gather again to form a new nebula and then make new stars and eventually planets. 



Stars die – so that new suns and planets can be created. It is all part of the life process of the star. If you think about it, as part of our planet we are made and grow from everything around us, and therefore we are all made of ‘star stuff’.


Useful Websites

NASA - Stars

howstuffworks.com - How Stars Work

Youtube - Nice Video