Agree with that - thought that series was very interesting, although a lot of it was already common knowledge (to those interested), it was nice to have another take it on it. It was the strength of the first series that got me watching this one really.
It doesn't need to be - unless you want to take it to theoretical levels of explanation - a little bit of analogy or basic; "as distance tends to infinity then the gravitational forces become 0", is neat and self explanatory.
There's a little too much general chat rather than hard scientific explanation - however, in spite of that, it does get the mind wondering and that's the strength of this program, it opens your mind/eyes a little.
Agreed with this.