Without space-timecurvature, there is no meaning to general relativity, ie. , classical gravity… without classical gravity, what is the meaning of quantizing it?
或许在一个时空弯曲不再是必须条件的情况下，能够成功的将引力量子化。
2
With Roger Penrose I showed that if Einstein's general theory of relativity is correct, there would be a singularity, a point of infinite density and space-timecurvature, where time has a beginning.
Roger Penrose 和我曾表明，如果爱因斯坦的一般相对论是正确的，那就会有一个特例，在无限密集和空间时间弯曲这一点上，时间就会有一个开端。
3
Gravitational waves are fluctuations in the curvature of space and time which propagate through the universe as gravitational waves — outward from its source.