There is an important and unresolved tension in cosmology regarding the rate at which the universe is expanding, and ...

We know that planets rotate, but what about the universe as a whole? No, the universe doesn't appear to rotate; if it did, time travel into the past might be possible. Although people throughout ...

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Time dilation: It’s a staple of science fiction, and whether you’re familiar with the term or not, you’ve probably encountered it in print or film. Fly fast enough to the speed of light, and your ...

Time is a fickle thing. Depending on your frame of reference, it can appear to pass slower or quicker, thanks to a wonky phenomenon known as time dilation that was described in Albert Einstein’s ...