You mention the speed of light, which is important in general relativity.
More information can be seen at Tests of general relativity.
Simply the best guide to general relativity for the lay person.
The question of whether general relativity is an effective theory has been raised for a long time.
A second, similar type of time travel is permitted by general relativity.
I also began to understand general relativity and to make progress with my work.
He is the author of a book on general relativity.
"The smart money says that something is going to happen; general relativity won't last another 200 years."
These considerations led to and past the development of general relativity.
Thus the effect can be fully explained by general relativity.