In this excerpt from his Floating University/Great Big Ideas lecture, Dr. Michio Kaku explains that string theory begins where Einstein’s framework breaks down.

**String Theory: Finishing what Einstein Started**

Einstein spent the last part of his life trying to find a ‘theory of everything’- one that could tie together his theory of general relativity and quantum mechanics. These two theories are not fully compatible in our current understanding of physics.

As physicists have picked up where Einstein stopped, one solution they have come up with is string theory. String theory combines the two theories by assuming there are multiple universes and dimensions beyond the ones we know.

After getting his PhD from the University of California, Berkley, Michio joined in on this challenge. He co-founded string field theory, a subset of string theory. String field theory uses the mathematics of fields to explain string theory.

More evidence and a better understanding of string theory may one day allow us to travel between universes and into new dimensions, potentially even making time travel possible.