packthebag

  Physics progresses by breaking our intuitions, but we are now at a point where further progress may require us to do away with the most intuitive and seemingly fundamental concepts of all—space and time themselves. Physics   came into its modern form as a description of how objects move through space and time. They are the stage on which physics plays out. But that stage begins to fall apart on the tiniest scales and the largest energies, and physics falls apart with it. Many believe that the only way to make physics whole again is to break what may be our most powerful intuition yet. In our minds, space and time  seem pretty fundamental,  but that primacy may not extend beyond our minds. In many of the new theories that are pushing the edge of physics, spacetime at its elementary level is not what we think it is. We’re going to explore the “realness” of space and time over a few upcoming episodes. We’ll ask: Do our minds hold a faithful representation of some...

  Here’s the story we like to tell about the  beginning of the universe. Space is expanding   evenly everywhere, but if you rewind that  expansion you find that all of space was once   compacted in an infinitesimal point of infinite  density—the singularity at the beginning of time.   The expansion of the universe from this point  is called the Big Bang. We like to tell this   story because it's the correct conclusion from  the description of an expanding universe that   followed Einstein's general theory of relativity  back in the 1910's. But since then we've learned   so much more. Does our modern  understanding of the universe still insist   on a point-like Big Bang? Recent work actually  gives us a way to avoid the beginning of time. The key to understanding whether the universe had  a beginning is to decide whether there exists what   we call a past sing...