How Large is the Universe?

Recently I was reading the November 2017 issue of Scientific American when I came across this image and caption.

Caption to an image in the November 2017 issue of Scientific American.

I had to do a double take when I first read this caption, and for awhile I was convinced the caption was wrong.  It states the observable Universe is 93 billion light years in size.  A light year is the distance light travels in a single year.  The speed of light is VERY FAST, so 93 billion light years is VERY large.

So why did I think, at first, this statement was incorrect?  Astronomers have determined the age of the Universe to be 13.8 billion years old.  This is through a multitude of high quality data.  Using telescopes we can directly observe all the way back to 380,000 after the Big Bang.  The first 380,000 years are known through a series of models and known physics through experiments here on Earth, but that's a discussion for another time.  When I first read this caption I had it in my head it was describing the early light in the Universe that did travel 13.8 billion light years.  Light from the early part of the Universe has taken 13.8 billion years, covering a distance of 13.8 billion light years.  But during that time the Universe has continued to expand and data tells us the Universe is expanding at an accelerating rate.  Thus the actual size of the Universe today is not 13.8 billion light years, but something large.  That larger something has been estimated by astronomers to be around 93 billion light years.  

What did I learn through this?  It's always okay (and important to question) things that do not make sense.  At first reading, the 93 million light years did not make sense to me.  So I questioned it and sat in my chair for a few minutes thinking this through.  Then I realized I was the one who was wrong, not the magazine caption.  The take away from this is that it's good to question, but when you do question, be open to the fact that many times you are the one who is wrong.  Not always, but sometimes.  That's part of critical thinking.  Recognizing when you are wrong.  It may be hard to admit you are wrong, but it's what makes a critical thinker a good critical thinker.