Re: 'All Our Yesterdays' theory
I thought I'd mention that that's the exact premise of one of Isaac Asimov's books.
A while back I read that book after someone mentioned it. I was also prompted by the write-up in Wikipedia. The technical premise struck me as one of the biggest pieces of handwavium
I'd ever seen.
"No, I better not look. I just might be in there."
—Foghorn Leghorn, Little Boy Boo