[DoctorBeaver]

Elements lighter than iron can release energy by fusion, while those that are heavier than iron can release energy by fission; hence iron is the element with the least nuclear energy.

That's interesting. Does that mean that the lighter elements can't release energy by fission or heavier ones by fusion or just that it's not viable in terms of energy input/output?

[another_someone]

It means that fusion of heavier elements, or fission of lighter elements, is, as far as I am aware, generally endothermic (i.e. you need to put more energy into the reaction than you will get back out).

[DoctorBeaver]

This thing about iron is intriguing me. Is iron exactly halfway between the lightest & heaviest elements? (I'm only talking about naturally-occurring elements)

Can iron be used in both fission & fusion, or in neither?

Isn't iron the most suitable material for making magnets? Is that relevant to the fission/fusion thing?

[Ben6789]

Is there an "edge of the universe?"

[another_someone]

This thing about iron is intriguing me. Is iron exactly halfway between the lightest & heaviest elements? (I'm only talking about naturally-occurring elements)

What do you consider a 'naturally occurring element'.  The elements we have on the surface of the Earth include some long halflife radioactive elements, as well as being missing some short halflife elements that most probably did exist in the early years of the existence of the planet.

But that aside, the heaviest non radioactive element is, as far as I can ascertain, Bismush (atomic number 83, atomic weight 209), whereas Iron is atomic number 26, atomic weight 56, so is well below half even of the lowest non-radioactive elements, let alone the presently still naturally available radioactive elements.

Can iron be used in both fission & fusion, or in neither?

It might possible be utilised to moderate some nuclear reaction, but you could not use Iron to generate energy from from either fission or fusion.

Isn't iron the most suitable material for making magnets? Is that relevant to the fission/fusion thing?

Not that I am aware, but I might be wrong.  Clearly, both are to do with the way the nucleus of Iron is structured, so it may be somebody can come and say what is special about the structure of the nucleus that causes both of these properties, and may know better whether the same facts cause both factors.

[realmswalker]

If you apply string theory (which i have a rudimentary grasp of) to this, there can eventually be a point at which nothing exits.
As the universe expands infinitely the energy becomes more dispersed. On the strings level, if i understand correctly, once the energy gets so dispersed they don't have the energy to vibrate, matter ceases to exist.

[another_someone]

If you apply string theory (which i have a rudimentary grasp of) to this, there can eventually be a point at which nothing exits.
As the universe expands infinitely the energy becomes more dispersed. On the strings level, if i understand correctly, once the energy gets so dispersed they don't have the energy to vibrate, matter ceases to exist.

What you seem to be implying is not spacial dispersion, but dispersion amongst lots of matter.

But how could energy be dispersed so thinly amongst lots of matter?

If you have two pieces of matter, they may share their energy; but if both pieces of matter already have more than the minimum amount of energy before they share, then they will still have the minimum energy after sharing their energy; and if one particle does not start by having the minimum energy, then it cannot exist, so it cannot receive energy from the other particle.

Unless string theory somehow allows a non-existent particle to receive energy, I am not sure how it can allow a dispersion of energy below its minimum threshold?