“Astronomers find two classes of gas giant planets”

I was undoubtedly quite clueless as a high school student who was idly considering a career in mathematical physics  and as a (non-science but science-interested) undergraduate, but I’m dazzled by how much we know now about exoplanets as contrasted with what I, at least, knew then.  Here’s an example:

http://www.astronomy.com/news/2017/07/two-classes-of-gas-giants