[ In all honesty, Erik wasn't there when Charles did it, and the explanation he got was lacking in specifics as to how it happened. ]

It was a rather specific set of circumstances, and involved a lot of things happening on the astral plane, as he likes to call it. But in the future there was another mutant who could send a person's consciousness into their younger self, which she did. We met that younger version, and my friend went into the mind of that person and met his future self who was doing the same.

[ He sighs. ]

I mostly deal in physics and engineering.