Noun
(uncountable, physics) The four-dimensional continuum of the three spatial dimensions plus time.
An event is a point in spacetime, specified by the coordinates x, y, z, and t.
(physics) An n-dimensional continuum consisting of dimensions of both space and time. Normally spacetime is considered as having 4 dimensions (x, y, z, t), but higher-dimensional spacetimes are often encountered in theoretical physics, e.g. the 5-dimensional spacetime of Kaluza-Klein theory or the 11 dimensions of spacetime in M-theory.
a Minkowski spacetime
a 5-dimensional spacetime
(relativity) A specific region of the universe with mathematically different properties than the surrounding spacetime. Synonymous with "metric" within the context of general relativity.
a Schwarzschild spacetime
a Reissner-Nordström spacetime
There was a long history of speculation that in quantum gravity, unlike Einstein's classical theory, it might be possible for the topology of spacetime to change. Edward Witten
Spacetime tells matter how to move; matter tells spacetime how to curve. John Archibald Wheeler
(By moving) I'm making sounds on the drums of spacetime"... "Space itself wobbles and rumbles like a drum... Black holes can bang on spacetime like mallets on a drum. Janna Levin
General relativity has changed our understanding of space and time. ...The spacetime of general relativity ...is likely to be just a classical approximation that loses its meaning in the quantum theory, for the same reason the trajectory of a particle does. Carlo Rovelli
On the other hand, we don't understand the theory too completely, and because of this fuzziness of spacetime, the very concept of spacetime and spacetime dimensions isn't precisely defined. Edward Witten
4D spacetime If we extend this to three spatial dimensions, the null geodesics are the 4-dimensional cone: : so : This null dual-cone represents the "line of sight" of a point in space. Source: Internet