Pretty much all of the above. Becuase it has multi-dimensional arrays in the language it makes programming much easier and debugging easier as array bounds can be easily checked. It also makes it much easier for the compiler to optimise code and also variable aliasing does not occur. Memory mangement also avoids many problems while being very efficient. The biggest win is that almost everything can be done without pointers and pointer arithmetic which avoids many errors and again greatly improves the compilers ability to optimize

The two must fundamental things in physics are nothing propogates faster than the speed of light and conservation of energy, i.e. KE+PE. It is totally fundamental.

It's a fundemental violation of the laws of physics. Mass-energy can neither be created or destroyed. Nothing can "disappear" it can change state and move at the speed of light at best. Even the interactions of quantum mechanics and general relativity, e.g. Hawking radiation, conserve mass-energy and involve propogation of nothing faster than the speed of light. Quantum teleportation is no different.

Of course he didn't speculate on impossible events. It is well known in philosophy that if you assume a counterfactual, i.e. something impossible like the earth ceasing to exist, you can prove anything including things which are false. If the earth ceased to exist as matter, e.g. some unknown physcical processes converted it to photons", then they would still result in the same gravitational potential field since teh source of gravity is mass-energy not just mass in general relativity. There is a deeper question of energy conservation in general relativity due to the self-energy of the gravitational field itself, a completely different matter than gravitational potential energy which is the energy of objects in the field, which is poorly understood and does not appear to be conserved though this is controversial

You should know that modern Fortran is till by far the best language for many types of scientific computing.