Monday, April 16, 2012

How to make iron (8) BANG!!

Finally, with cool professionalism, Jim Kaler tells us how the life cycle of stars is involved in the making of iron.

And we learn that the making of iron in space is really a magnificent process - one of the most awesome things in the Universe visible to naked eye - not a whisper in moonlight, not afternoon sunshine but a truly glorious Supernova that can be seen even in daylight.

The inner war of forces in a star is battle between gravity and the outward expansion of nuclear reactions that prevents the star from collapsing into itself. And the battle does not end in a whisper but in a big BANG the like of which would easily destroy planet Earth. (Military people, take notice... oh, you already have...)

Finally, the silicon and sulfur fuse to iron, an element that is incapable of energy-generating fusion reactions.

Gravity now wins the war that has been going on for the star's lifetime, and since
the iron refuses to support itself,
the core catastrophically collapses.

The iron breaks down into its component particles, protons, neutrons, and electrons (the constituents of atoms),
and the whole mass gets compressed into a tight ball of neutrons only a few tens of kilometers across.

The collapse produces a shocking blast wave that rips through the surrounding nuclear fusing shells and the remaining outer envelope, and rips the rest of the star apart.

On Earth we see the star explode in a grand " supernova," an event so powerful it is easily visible even in another galaxy a huge distance away.

The part of the star that is exploded outward is so hot that nuclear reactions produce all the chemical elements, including a tenth of a solar mass of iron, which then blend with the gasses of interstellar space, out of which new stars are formed.

So this is how iron is made and distributed in the universe.


Note that I am only studying one single introductory page in STARS website. There is much more where this information came from, STARS and Mineral Information Institute.

Thank you, professor James B. Kaler and people at Mii!

(All possible mistakes in the series How to make iron? are my misunderstandings and will be fixed ASAP when pointed out to me.)

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