Neil deGrasse Tyson would be the closest in today's age that I'm aware of (I don't track astrophysicists...sadly lol). Tyson however always seems like he has a much bigger ego so he's definitely a bit of a distant 2 behind Sagan.
Forrest Valkai has a very different style, and mostly about evolutionary biology instead of space, but is pretty cool. Nobody else has successfully gotten me excited about mitochondria.