Light speed is frequently spoken of as a universal speed limit … but not everything plays by these rules. In reality, space itself can expand quicker than a photon could ever think to travel.
Cosmologists are rational time travellers. Looking back over billions of years, these researchers are able to follow the evolution of our Universe in surprising detail. 13.8 billion years ago, the Big Bang happened. Fractions of a second later, the fledgling Universe stretched exponentially during an extremely brief period of time called inflation. Over the ensuing eons, our universe has grown to such a massive size that we can no longer perceive the other side of it.
But how can this be? If light's speed marks an intergalactic speed limit, how can there probably be regions of spacetime whose photons are incessantly out of our reach? And even if there are, how do we know that they are present at all?
This post was written by Usman Abrar. To contact the writer write to firstname.lastname@example.org. Follow on Facebook