RE: what is the size of the universe (observed)?
Until now science has not been able to answer these questions. There are limitations that prevent us from knowing the exact size of the universe.
We still do not know the exact size of the universe and we have approximations for the size of the observable universe which have been made for a few decades. The wording makes it seem like its new relative to our lifetimes (not new relative to the timeline of the human race) but for many people here we have been able to approximate the size for longer than we have been alive. This isn't wrong its just some added notes for people whom may read this.
Based on the special theory of relativity published in 1905, the speed of light or c is the maximum speed for energy, matter, and information to move in the universe.
From wikipedia. Anyways I will argue that special relativity was not the thing that proposed a constant speed of light (that was discovered beforehand) and as such it is misleading to say that we know light moves at a constant speed based off of special relativity. SR would have never come to light(pun intended) so to speak because nobody would be searching for it. Before SR we had Galilean Invariance (GI) which stated that all laws of motion are the same within their respective inertial frame of reference (i.e. if you throw a rock at 5m/s towards the front of a train moving 45m/s then the speed of the rock relative to you is 5ms but to someone outside the train it is 50m/s) and if we had not discovered that the speed of light is constant then we would have never searched for a way to update it (now it will be 5m/s relative to you but is 49.99999999999999972222222..... m/s. So when moving at non relativistic speeds, which humans don't do, we won't notice it).
I know this seems nitpicky and stuff but I don't know.
But, not so when compared with the rate of expansion of the universe. The expansion of the universe can exceed the speed of light.
Be careful with how you word this. While its true it could be misleading to some who don't understand why/how and they might think that the edges of the universe expand outward, in every direction, faster than light but that isn't exactly how it works.
thanks for the correction,
yes, it makes a lot of people still confused if there is a chance going forward I will describe more general.