Space: Who Knew, #15

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Supernovae

Ever since I started researching astronomy I've been struck by the beauty of the universe. I know how cheesy that sounds, but it really is quite beautiful. A huge part of this beauty, to me, begins when a star expires in a supernova.

http://en.wikipedia.org/wiki/Supernova
http://en.wikipedia.org/wiki/Stars

Here are some interesting facts about them:

• When a star goes supernova, it often releases more energy in one gigantic stellar explosion than the entire energy output of our Sun across its entire life.
  
  
• A supernova's shock wave can travel up to 1 tenth the speed of light, or 29,979,245 meters per second.
  
  
• Supernovae are considered rare, scientists estimate one happens every 50 years in a galaxy the size of the Milky Way. A few future candidates for supernova explosions are IK Pegasi and Betelgeuse.
  
  
• Some distant supernovae appear dimmer than what has been expected, this data suggests that the universe is still expanding.
  
  
• Nucleosynthesis during a supernova is responsible for creating much of the elemental abundance beyond iron in the universe. AKA- we're all made of stardust. Quite literally!

I read a book a while back by Michio Kaku called: Parallel Worlds. Read my review here. In the book he talked a little about what it would be like if our universe had a nuclear force that were different from the one currently at work today. He thoroughly discussed the idea of multi-verses, and hypothesized that different verses could theoretically maintain different force strengths for each of the four forces. Those being-

1. Gravity
   
2. Electromagnetic Force
3. Strong Nuclear Force
4. Weak Nuclear Force
   

A universe for example, might have a weaker nuclear force than we observe in our universe. If that were the case, stars might not have enough nuclear energy to form, stars would thus never go supernovae and thus the universe could never create heavier elements and eventually form life.

On the flip side, if a universe had a stronger nuclear force, stars might burn out more quickly, and life would not have the time necessary to evolve on planets such as our own Earth before being consumed by the nuclear forces at work in the universe.

Thinking the same about gravity, you could envision a universe whose gravity were much stronger than ours, the universe would not expand at the same rate, and might, if strong enough, collapse back into itself before life could evolve.

If gravity were any weaker than what we observe in our universe, the night sky would be extremely dark, because we'd have accelerated away from many of the stars in the sky. Perhaps more importantly though, the sun might not have enough strength to even influence planets the size of Earth.

I thought that was an interesting perspective and had to include it here. A couple more interesting tidbits then I'm done...

• The shock wave of material supernovae emit eventually cools, but not before sweeping through the interstellar medium. The expansion has been known to last for over 200 years, eventually creating what are called Planetary Nebula.
  
  
• Planetary nebula are stellar nurseries. These clouds, rich with elements are the birthplace of new stars and star systems.
  

Last but not least, here are a couple pictures of Planetary Nebula. Note that these are not the actual colors that humans might see. The particles in these images are represented in different colors to better designate what their make up is. This is called False Color:

Who knew???