Sci-fi story help, how would be able to look back in time?

Well, you'd need some very intense gravitational effects, or other forces - maybe the machine alters the Strong and/or Weak force to mimic gravity - instead of only influencing the length of a proton, maybe the machine alters these forces to be infinite - and, with the infinite-acting force, maybe you can't see *our* past, but another *universe's* past - one that's nearly identical to ours, but has some slight differences here & there...