# How could the universe be a few light years across just 1 second after the big bang?

I was skimming through Neil deGrasse Tyson's book Astrophysics for People in a Hurry when I noticed he says something curious on page 26:

"By now, one second of time has passed [since the big bang]. The universe has grown a few light years across."

How could the universe have expanded to a few light years in diameter in just one second if nothing can travel than light? By definition of a light year, wouldn't take a 1+ years for the universe to get this big?

• The space time fabric can expand faster then the speed of light, this is the basis for the Alcubierre drive Commented Dec 25, 2017 at 4:16
• At the time - in the inflation period - it grew exponentially. Commented Dec 25, 2017 at 9:18
• youtube.com/watch?v=XBr4GkRnY04 watch this veritasium video Commented Dec 25, 2017 at 10:57

Your question hinges on the misconception that nothing can travel faster than light. No physical object can move faster than light, but plenty of non-physical things can. For example, take the straight line $y = mx + c$. If one varies $c$, the x-intercept of the line also changes. It's possible that this x-intercept moves faster than light for a suitably small $m$. The caveat is that this intercept is a mathematical point, and it cannot be used to transfer information. Relativity isn't violated.