If the universe is everything, and scientists say that the universe is expanding, what is it expanding into?
It's expanding true, but it's not expanding into anything. I can't remember the exact name but it's called the something shift. The universe is exapnding and that has been proved. Eventualy it will "Emplode"
it has to be expandidg into something. its like bread. you can let it rise but when it runs out of room to rise, it just squishes. it still expands, but it is being compacted as it does so.