![the end of the sun the end of the sun](http://www.thetreefarm.com/media/catalog/product/cache/1/thumbnail/9df78eab33525d08d6e5fb8d27136e95/f/i/file_147_8.jpg)
The hydrogen fusion would never happen.īut free neutrons can approach even the heaviest nuclei, and once they make contact, it is essentially a given that they will "fuse" with it. This is even greater than the force that opposes carbon-carbon fusion. Uranium has 92 protons, so if you tried to initiate uranium fission with a proton, the repulsive force would be 92 times that of hydrogen fusion. It is no accident that Figure 2 on the solar birth page shows a neutron "bullet" headed towards the uranium atom.
![the end of the sun the end of the sun](https://cdn.images.express.co.uk/img/dynamic/151/750x445/1127102.jpg)
They can approach a nucleus as leisurely as you wish, and still make contact with it. Neutrons, however, have no electric charge at all. It is notoriously difficult to fuse even hydrogen with hydrogen, and hydrogen has only a single positive charge. The single most overwhelming obstacle to nuclear fusion is the electrostatic repulsion between nuclei. These elements easily constitute the bulk of the Earth's mass (over 96%), but the other elements must still come from somewhere. But as noted in Table I in the page on massive stars, direct fusion can never produce any element beyond iron, even though there are over 60 elements beyond iron! In fact, direct fusion only produces about a dozen of the elements: carbon, nitrogen, oxygen, neon, magnesium, silicon, sulfur, argon, calcium, titanium, chromium, and iron. We have now seen what part of that someplace is: stars can forge elements beyond helium through nuclear fusion, then spread them throughout space via the emission of a planetary nebula, or in a supernova explosion.
![the end of the sun the end of the sun](https://thumbs.dreamstime.com/z/sun-end-day-taken-end-daysun-set-time-sun-look-like-orange-just-like-orange-hanging-up-158325370.jpg)
In the second paragraph of the description of the Sun's birth, I noted that all the "dirt" in the Universe comes from someplace other than the Big Bang.