Like stretch marks left on skin that expanded too quickly or cracks embedded in freezing ice, cosmic strings are artifacts of what the universe looked like in the moments before it rapidly changed ...

One of the weirdest theories in cosmology is the holographic principle, the idea that our universe is a three-dimensional image projected off a two-dimensional surface — the idea that, yes, we are ...

Maine The post How can the visible universe be 46 billion light-years in radius when the universe is only 13.8 billion years old? appeared first on Astronomy Magazine.