New model 'permits time travel'

If you went back in time and met your teenage parents, you could not split them up and prevent your birth - even if you wanted to, a new quantum model has stated.

Researchers speculate that time travel can occur within a kind of feedback loop where backwards movement is possible, but only in a way that is 'complementary' to the present.

In other words, you can pop back in time and have a look around, but you cannot do anything that will alter the present you left behind."

"... The main headache stems from the idea that if you went back in time you could, theoretically, do something to change the present; and that possibility messes up the whole theory of time travel.

Clearly, the present never is changed by mischievous time-travellers: people don't suddenly fade into the ether because a rerun of events has prevented their births - that much is obvious."

Ah! But how would you know? Hmm?
If someone changed the past, your memory of it would change and therefore you would never know how it had happened before the meddling, temporal interference of the time-travellers. People wouldn't fade into the ether because they wouldn't exist in your timelife.

Obviously you couldn't interfere with your own birth / life without impacting on your present situation and possibly preventing your time travel to your current timepoint where/when you interfered.

Cool, huh?