One of the biggest criticisms of string theory is that its predictions canâ€™t be tested experimentallyâ€“a requirement for any solid scientific idea.
Thatâ€™s not true anymore.
At a AAAS session on Sunday, physicists said string theory is making important contributions to the study of two extreme forms of matter â€“one heated to trillions of degrees, the other chilled to near-absolute zero. In both cases the matter became a â€œperfect liquidâ€ that ripples and flows freely, like water. String theorists analyzed the results by applying what they had learned from pondering how a black hole might behave in five dimensions. Then they went on to calculate just how free-flowing these liquids might be, predictions that the experimenters are using to guide the next stage of their work.