The results suggest that not only might time travel be logically consistent, but the universe could even reset certain aspects of reality—like memory and aging—inside a time loop.

For decades, astronomers have been trying to nail down the value of the Hubble constant—a measure of how fast the universe is expanding. But some cosmologists say there’s evidence that the universe is ...

However, the observable universe extends farther than 13.8 billion light-years in every direction because, for all the time space has existed, it’s also been expanding.