The meaning of E=mc²
The most famous equation may not be what you think it is. For example, it’s not about converting mass into energy. And, it’s only a part of the whole thing.
general relativity
Einstein’s special relativity in under 6.999 minutes for people on the move
Especially for people on the move, we discuss as briefly as possible the intricacies of Einstein’s special relativity.
What is a spacetime interval?
Einstein and collaborators taught us that space and time are not fixed quantities. They can stretch and contract. They vary. There is one thing, though, that does not vary. It is the invariance of the spacetime interval.