The general theory includes the earlier special theory of relativity but goes on to explain accelerated frames of reference. Also, it extends the special theory by proposing a general theory of gravitation.
Einstein understands gravity as arising from a curvature of space and time. The general theory presents the universe as a four-dimensional space-time continuum. So the presence of mass ‘curves’ space so as to create the effect of gravity.
Perhaps even more radical, the special theory predicts that as objects move, time slows down. And the general theory predicts that gravity effects the passage of time. Both of these hypotheses have been supported by atomic clocks and GPS measurements.¹
So, quite unlike idle speculation and imaginary fantasies, Eisntein’s seemingly “weird” ideas are supported by empirical evidence. While other theories of gravitation exist, they tend to have much in common with Einstein’s.
- Top 100 Stories of 2011: #83: Gravity Probe B Gives Einstein an A (discovermagazine.com)
- New telescope array will capture the first-ever photograph of a black hole (dailymail.co.uk)
- The Einstein Theory of Relativity: a 1923 Silent Animated Film (singularityweblog.com)