I only studied science up to GCSE level, so most of what I know was basically just what I've read online somewhere. I should have taken it further - it was the only class I always got straight A's in whether I studied or not, but I was kind of pushed into IT and English as I was pretty good at those too and I had no idea what I wanted to do (the problem with being INTP is that we can be all rounders - makes it very hard to pick a career). And generally, yeah, any time my brain is being challenged is a good pass time.
Thanks. I should download a copy to read.
Though I didn't study the field past High School, I do find astrophysics fascinating. I love the sheer scale and weirdness of it all. I like kind of rolling the concepts around my head and I think it's something only we intuitives can grasp as it doesn't correspond to anything our senses can process.