Originally formulated in the 1970s, string theory hypothesizes that particles such as electrons and quarks are not actually point-like objects. Rather, if viewed through a very powerful microscope, those particles would look like little, tiny, closed loops of string. According to the theory, these strings can vibrate and rotate, and as they do so, they take on different configurations. Professor Strominger compares the process to the way that sounds are made by a guitar string. If you pluck a guitar string, it will vibrate and emit a certain sound. If you put your finger over a fret and pluck the same string again, the frequency will be different. The string is the same, but the sound is not. Similarly, in physics, if you change the vibration of one of these theoretical strings, it will still be a string, but it will look different.
Using detailed and complex math, string theorists have probed this concept of the vibrating string for 30 years now. And though the theory hasn't been proved, yet, the work has led to some exciting implications: namely, the different configurations of these little strings look "tantalizingly" close to all the different particles and forces in nature, perhaps helping to describe the basis of the universe. "If string theory works," says Strominger, "it means that all particles and forces in nature are different manifestations of the same object."