We are all star stuff!

Carl Sagan once said "We are all star stuff".  This statement could not be more true, because we are!  The Sun did not even exist around six billion years ago, so we cannot have existed either.  So where were we?

Stars are the chemical factories of the Universe.  Stars are the only places known that produce any other elements other than Helium & Hydrogen, read Supernova to find out how.  There are around 118 elements known on Earth, and as stars can only produce elements up to Iron (56) that leaves 62 elements, so where did they come from?  Well all the other elements up to Uranium are made in the after math of supernovae, all the others are man made.  Even during the explosion itself new elements are formed.  As the core of the exploding star is thrown outward, the pressure of the outward rushing shells causes a flood of fusion to take place of all the elements already produced i.e. Nickel isotope decays into radioactive Cobalt which decay's into stable iron.  It is this series of events that form the basis of life.

Once a star has become a star and started to fuse it will blow away all the surrounding gas and dust that helped to make it through stellar winds and radiation pressure.  If the original dust cloud starts to accrete in two places, a Binary star system will form.  Depending on the size of the cloud in the first place, 3 or even 4 stars may form.  There may only be enough for one star, or, if there is a bit left over, one or more planets may form as did in our case.

Throughout this remaining enormous cloud, smaller accretion occurs on an huge scale.  Hundreds of billions of comets/asteroids will form, ranging from small rocks to mountain size rocks.  These would be attracted towards the large moon size rocks that have already been slowly accreting for many thousands of years (planetesimals).  Over a long period of time these would travel in orbit around the new star gravitationally sweeping everything in it's path, gradually get larger and larger until most of the accretion matter had been consumed.

How does this relate to star stuff?

Well, what you must remember is that these Planetesimals (planets to be) all started out as atoms, molecules, and dust particles, and over a period of hundreds of millions years grew remarkably in size.  All planets from Mercury to Neptune (sorry Pluto) formed in this way.  Yet for certain reasons life only formed on Earth.

Now if you think about it, all planets are composed of exactly the same stuff but in differing quantities and forms.  All these planets formed from the original STAR STUFF, and as WE formed from the raw elements on one of these planets, we too must have been a part of the original accretion disk.  

Now, this disk of gas & dust did not come from just 1 supernovae, but from the interaction of many gas clouds from many supernovae so they could interact in the first place.  The interaction of at least 2 gas clouds would be needed to form the original accretion disc to start of the solar system.  The fact that these clouds themselves were once part of a star that also underwent the same process, means that the atoms in your body have more than likely been inside up to 3 stars in the past 14 billion years.

As the title of this page suggests "you are star stuff", in fact we are all star stuff.  Every atom on this planet was at some point inside a star.  Where do you think the Iron in your blood and the calcium in your bones comes from?...find out

 You are very well travelled indeed.