“The Fabric of the Cosmos,” four-part series on “NOVA,” 9 p.m. Wednesdays, OPB

The fact that I’ve watched the first two episodes of Brian Greene’s “Fabric of the Cosmos” on “NOVA” and that my head doesn’t hurt speaks volumes about how the well-known string theorist makes science fascinating even for those who only took earth science because rocks made more sense than periodic tables and eviscerated frogs.

It’s not that I’m dumb, it’s just that I thought “cosmos” were just what the women drank on “Sex and the City,” but that may only be because I’m old enough to remember the late Carl Sagan’s PBS science series “Cosmos: A Personal Voyage.” To some, the label “popularizer” is demeaning, but guys like Sagan and Greene have legitimized the practice by finding ways of explaining complicated material to just plain folks without talking down to them.

“What Is Space?,” the first of the series’ four parts airing today on OPB, may not turn you into an Einstein, but you’ll come away with at least a general concept that space is not vast nothingness.

While many mortals have sat around trying to grasp whether or not space is infinite (put the bongs down!), the real mystery has always been in the nature of space. Sir Isaac Newton, the dude with the apple, determined that space was a fixed framework for things like planets, stars and asteroids. In the last century, a patent clerk in Switzerland named Albert Einstein and later scientists concluded that space is malleable and inextricably linked to space. Greene demonstrates this by launching pool balls across a felt-covered pool table. But if the surface of the table wasn’t hard but, rather, rubbery and if you dropped a large heavy orb into the middle, that would affect the speed of the pool balls and actually put them into orbit around the big ball in the middle of the table.

The second part of the series, “The Illusion of Time,” ties directly to the first show because it builds further on Einstein’s belief that time and space are linked. Things get even more challenging here because Greene and others attempt to explain that the time-space connection means that when things are moving, time slows down, and when they aren’t, time speeds up.

That’s the “for dummies” summary of the theory. It gets more challenging when Greene explains that what we think of as past, present and future are merely arbitrary conveniences and that time itself doesn’t move forward. Greene suggests that all time exists all at once, which theoretically means that you could move from one part of time to another.

Now my head is beginning to hurt, but in a good way. Greene may use everyday objects as teaching tools, but he explains complex information in a straightforward and patient way that provokes us to think about it. In other words, it’s not like the high school physics class I slept through.

The final two parts of the series are “Quantum Leap” and “Universe or Multiverse?” I for one don’t intend being late for class.