How did Iron come to earth (millions of years ago)?
Iron is made inside stars.
Iron is made inside stars, specifically red super-giants. The elements form together inside a star during fusion. When the supernova occurs, the iron fragments are blasted into the space.
This is how Iron came to Earth millions of years ago. You can see the image below of a 20 Solar Mass(
When stars form, immense gravitational force starts to fuse lighter elements to heavier elements.
For example, when stars start to form, Hydrogen particles fuse together to form Helium particles, which again fuse together to form Carbon and so on. Iron is the heaviest and last elements formed in a star at the core.
This is in response to the question from Lucio Margherita about natural elements on earth that contain more protons than iron.
These occur when neutrons break down into protons and electrons.
When the star does explode into a supernova, we are dealing with a nuclear explosion so immense that it is almost beyond explanation. But, there are experiments going on at the University of Oslo that may give us a clue as to the results.
The explosion results because the star has burned off all if its fuel, and its gravity is so powerful that only the iron core is left.
For iron and heaver elements, fusion is no longer an option. The power of the gravity can only be released by fission, or the immediate breakdown of the iron in an explosion.
The explosion is so intense that many new elements are formed, some of which will quickly decay to form those we already know. Others will form the elements we are aware of with elementary numbers greater than that of iron.
Because the temperature and pressure inside these explosions are so high, it is thought that the neutrons in some atoms are being split into protons and electrons to provide us with the heavier elements we are discovering.
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