[ She makes a face, because explaining science is hard enough, but taking science she barely understands and then translating into Asgardian space magic is a little out of her area of expertise. ]

So there was this scientist on earth who experimented with shrinking someone down to a subatomic level and.... look, he got made really really small and wherever he ended up, he found out that time moved differently there. So when he popped back into the real world, he'd only had five hours pass when it had been five years for the rest of us. Taking that, he ran with the idea that if we could find a way to navigate that realm, we could choose the time and place of our exit.

Meaning... [ She lifts a hand to wave it around and gesture at, well. Everything, because this still sounded utterly ridiculous to her. ] We figured out where and when we'd encountered each of the Stones in our past... and then went back to retrieve them to fix our present.