I was joined by Carlo Rovelli, and we were able to make a full-fledged quantum theory of gravity... This became loop quantum gravity. - Lee Smolin

Jacob Bekenstein found... in 1971 that every black hole must have an entropy proportional to the area of its horizon... Stephen Hawking then refined this by showing that the constant of proportionality must be... exactly one quarter. ...entropy is supposed to correspond to a measure of information ...Loop quantum gravity... [gives] a detailed description of the microscopic structure of a black hole. ...a horizon can have, for each quantized unit of area, a finite number of states. Counting them, we get exactly Bekenstein's result...

Since the 1950s, the key equation of quantum gravity has been called the Wheeler-DeWitt equation. Bryce DeWitt and John Wheeler wrote it down, but in all the time since then, no one had been able to solve it. We found we could solve it exactly, and in fact we found an infinite number of exact solutions.

There is nothing beyond the world except what we see, no background to it except its particular history.