Andrew Strominger

So it hasn't been ruled out as an actual unified theory of nature.

But there also isn't a, in my view, some people would disagree with me, but there isn't a reasonable...

possibility that we would be able to do an experiment in the foreseeable future, which would be sort of a yes or no to string theory.

Well, the basic idea which emerged in the early 70s was that if you take the notion of a particle and you literally replace it by a little loop of string, the strings are sort of softer than particles.

Well, you know, if you hit a particle, if there were a particle on this table, a big one, and you hit it, you might bruise yourself.

Sure.

But if there was a string on the table, you would probably just push it around.

And the source of the infinities in quantum field theory is that when particles hit each other, it's a little bit of a...

a jarring effect.

And I've never described it this way before, but it's actually scientifically accurate.

But if you throw strings at each other, it's a little more friendly.

One thing I can't explain is how wonderfully precise all the mathematics is that goes into describing string theory.

We don't just wave our hands and throw strings around.

There's some very...

compelling mathematical equations that describe it.

Now, what was realized in the early 70s is that if you replace particles by strings, these infinities go away, and you get a consistent theory of gravity without the infinities.

And

That may sound a little trivial, but at that point, it had already been 15 years that people had been searching around for any kind of theory that could do this.

And it was actually found kind of by accident.

And there are a lot of accidental discoveries in this subject.