spacetime

Time Crystal, not like in “crystal ball”

Consider a structure that moves not in space but time, crystals that change shape and move perpetually without energy, and always return to their original state. Such a structure would break the second law of…


Where does spacetime come from?

In early 2009, determined to make the most of his first sabbatical from teaching, Mark Van Raamsdonk decided to tackle one of the deepest mysteries in physics: the relationship between quantum mechanics and gravity. After…


In a happy, happy rainbow universe…..

What if the universe had no beginning, and time stretched back infinitely without a big bang to start things off? That’s one possible consequence of an idea called “rainbow gravity,” so-named because it posits that…