This clip shows how carbon is made up from sub-atomic particles. Electron shells are mentioned. Two extra neutrons are added to make an unstable isotope which explodes at the end. This clip could be ...

This clip shows how carbon is made up from sub-atomic particles. Electron shells are mentioned. Two extra neutrons are added to make an unstable isotope which explodes at the end. This clip could be ...

One single atom of a certain isotope of hafnium found on Earth would prove that a supernova once exploded near our solar system. The problem is how to find such an atom - among billions of others.