Scientists Say Grandfather Paradox Doesn't Actually Block Time Travel

The grandfather paradox has puzzled scientists for decades. The classic problem asks: what happens if you travel back in time and kill your grandfather before he has children? You couldn't exist to make the trip in the first place.

But new thinking suggests this paradox doesn't ban time travel outright. MIT researchers note that the paradox shows how a time traveler "could both have and lack a given ability on a given occasion." This means the universe might have built-in rules that prevent certain actions.

Instead of making time travel impossible, these limits would work like invisible barriers. A time traveler might find their gun jams, or they get lost, or some other event stops them from creating a paradox.

This approach keeps the laws of physics intact while allowing time travel to exist. The universe would essentially protect itself from contradictions by making harmful actions fail automatically.