For most of us, or perhaps all of us, it's impossible to imagine a world consisting of more than three spatial dimensions. Are we correct when we intuit that such a world couldn't exist?

But beyond these dimensions, collectively known as 'spacetime', there may be more that we cannot perceive – including the fabled fifth dimension. In an episode of 'The Twilight Zone', the ...

Since this fourth dimension cannot be introduced into space, as commonly understood, we require a new kind of space for its existence, which we may call time-space. There is then no difficulty in ...