Despite the impression you may have from watching too much TV, movies are not about reproducing reality. They're about telling stories.

While about one-third of Americans believe in ghosts, you won’t find many exhibits on these spooky beings down at the local science museum. Why? Well, one explanation that you might consider, ghosts are just figments of our highly fertile imaginations!

We’re hard-wired by 200,000 years of evolution to be sensitive to the idea that someone might be watching us. They might be predators, after all. An uneasy feeling is perfectly natural if you suspect that someone has you in their ocular sights, whether it’s a ghost or just some guy at the bus stop.

The number of habitable worlds in our galaxy is certainly in the tens of billions, minimum, and we haven’t even talked about the moons. And the number of galaxies we can see, other than our own, is about 100 billion.

Five centuries from now – barring unimaginable catastrophe – the moon will be developed real estate. There’s economic incentive to exploit the moon – the helium-3 will be useful in powering fusion reactors, and the rare earth elements could supplant the limited terrestrial supply of these materials.

Our brains are wired to interpret shapes as faces and bodies. That’s why people see the Virgin Mary in the clouds or even in cheese sandwiches. It’s your cytoplasm, not some strange ectoplasm.

Star Trek's genial premise is that the cosmos is flush with intelligent species, and our descendants will interact with them face-to-face, thanks to warp drive and some winsome space cadets.

Diminutive worlds are more likely to be rocky, and lapped by oceans and atmospheres. In the vernacular of 'Star Trek,' these would be M-class planets: life-friendly oases where biology could begin and bumpy-faced Klingons might exist.

The Moon stabilizes Earth's obliquity. Well, almost. The tilt actually varies between 22 and 24.5 degrees - and the variation is enough to induce such environmental inconveniences as the occasional ice age. Without the Moon, it might be much worse.

The fact that we can't easily foresee clues that would betray an intelligence a million millennia farther down the road suggests that we're like ants trying to discover humans. Ask yourself: Would ants ever recognize houses, cars, or fire hydrants as the work of advanced biology?