One of the basic things about a string is that it can vibrate in many different shapes or forms, which gives music its beauty.

There was a long history of speculation that in quantum gravity, unlike Einstein's classical theory, it might be possible for the topology of spacetime to change.

As for the forces, electromagnetism and gravity we experience in everyday life. But the weak and strong forces are beyond our ordinary experience. So in physics, lots of the basic building blocks take 20th- or perhaps 21st-century equipment to explore.

1/r^2 has a nasty singularity at r=0, but it did not bother Newton-the Moon is far enough.

M stands for Magic, Mystery, or Matrixaccording to taste

We know a lot of things, but what we don't know is a lot more.

String theory is an attempt at a deeper description of nature by thinking of an elementary particle not as a little point but as a little loop of vibrating string.