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Red giant

Visible to anyone in the world
Edited by Richard Walker, Wednesday, 17 Mar 2010, 18:35
Last night it was very cold and clear here, near Cambridge UK. I looked up and saw the star Betelgeux, in Orion, and every time I see this star I remember seeing a TV programme long ago - maybe 'The Sky at Night' - where we were told Betelgeux is red giant and if you at even with the naked eye you can see it is red. We all ran outside to look and yes! It is visibly red. So next time you see the stars during winter months look for Orion - a bit like a giant letter H and see Betelgeux, the one at top left, is red.
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Star dust

Visible to anyone in the world
Edited by Richard Walker, Saturday, 13 Feb 2010, 05:27

Hello stardust

For that's what you are, reader.  Here's the story, please read it, it concerns you and I.  Sorry it is a bit long but it took billions of years to happen, so it is hard to squeeze into one blog post.

Long long ago when the universe first began there was only hydrogen.  Later some helium formed.  Then some lithium and probably a little beryllium. Even a little carbon.  But nothing very heavy.

After quite a while some large stars formed.  In the heart of these stars helium was forged from hydrogen and the change threw off lots of energy. The helium could even form other elements by combining and this too produced energy. This energy flow kept the stars inflated, although gravity was trying to make them contract.

Over time these stars began to run out of hydrogen and helium, and eventually they collapsed.  This is what causes a supernova!  The star implodes violently in a short time -- days only -- but then as it smashes in on itself all sort of new elements are formed by the pressure -- including many necessary to life.  Before the implosion there might have been a little carbon perhaps but no iron for blood, or oxygen for breathing.

Now this explosion blew the heavy elements formed out at great velocities and over billions of year the atoms ended up with some other dust, and some hydrogen and helium, and gravity made it swirl together.  This formed a new star and some planets.

But some of the little planets were too small for their gravity to hold on to all the hydrogen and helium they began with. Part of their hydrogen combined with oxygen to make water, which has remained.  But mostly what was left was heavier elements -- think rocks. Still all the same the wet bits on the surface acted a home for the evolution of life.

Of course this life used many heavy atoms from supernovas billions of light-years away and billions of year before.  You and I would not exist without the dust from those ancient stars.

Literally stardust.





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