system
Given the following post, respond as if you're commenting on Reddit:
human
How could the universe be a few light-years across one second after the big bang, if the speed of light is the highest possible speed?

Shouldn't the universe be one light-second across after one second?

In Death by Black Hole, Tyson writes "By now, one second of time has passed. The universe has grown to a few light-years across..." p. 343.
gpt
There is no speed limit on the rate of expansion of the fabric of the universe (space-time). 

During the first few moments after the Big Bang, if the theory of Inflation is correct, the volume of the universe expanded by a factor of 10^78 in a time span from ~10^-38 to ~10^-32 seconds.

Edit - To add to this. The speed of light is the speed limit for which information can propagate (which therefore means anything with mass/energy).  There is nothing, as far as we know, limiting the rate of expansion of the universe itself.  Objects very far from us are actually travelling away from us at a speed greater than the speed of light since the rate of expansion between two points increases as you increase the distance between said objects. The consequence of this is that light from these objects will never reach us.