Our Elastic Spacetime: Black Holes And Gravitational Waves

L. Smarr and W. H. Press American Scientist, 66, 72-79 (1978).

Most people with a scientific educa tion have at some point encountered the statement “Spacetime is curved in Einstein’s general theory of rela tivity.” This sounds very mysterious. What is curved spacetime? Is space curved, or time, or both? Curved space is something that many people can imagine (because the standard pictures of the 2-dimensional surfaces of spheres and saddles have been so widely reproduced). But what does curved time mean?

LINK TO ARTICLE