Do you think the government is spying on you, looking through your window with satellites and reading your mail? Can it control what you think? You might think that and more, if you watch too many movies. Tune in today and watch as I debunk some common movie myths.

Stop me if you've heard this before, but movies aren't exactly bastions of accurate science. Sometimes they come close, but more often the science -- and the technology -- is more fantasy than reality.

And now, another summer, another crop of bad science in movies.

Blockbuster movies tend to lean toward science fiction. It was 1998 that saw not one but two error-prone, death-from-the-skies movies: "Armageddon" and "Deep Impact."

But in the movie biz those are ancient history. What's new in Tinseltown?

Star Wars: Attack of the Clones
Perhaps you heard that a new "Star Wars" movie has come out. I heard it did fairly well at the box office. Too bad that its success didn't extend to its scientific accuracy.

A big scene in the movie shows Obi-Wan chasing the mercenary Jengo Fett through an asteroid field. True to "Empire Strikes Back," the rocks are thick, and the ships must dodge and weave their way through the tumbling boulders.

In real life, things would be considerably more boring. Our own solar system has an asteroid belt, but it's a bit more thinly populated; the average distance between fair-sized asteroids can be as high as 2 million kilometers! Probes sent to the outer planets are in no danger of getting hit. In fact, to see an asteroid in any detail, the mission must be planned carefully to ensure it gets near enough to the asteroid.

Perhaps asteroid belts as thick as those in "Star Wars" do exist. But the rocks would be small! Asteroids packed that tightly would undergo violent collisions, breaking the big ones into teeny ones pretty quickly. But then, a spaceship chase through a dust field wouldn't be as exciting.

Men in Black II

Ah, back in black. The first movie was so great, and this one -- well, wasn't so great. There really wasn't a whole lot of science in it, less even than the first one. But both movies have scenes where Our Heroes sit on a bench in New York City at night and look up to see a sky full of stars.

If only it were so. In reality, a sky in a big city is almost completely devoid of stars. The culprit is what astronomers call "light pollution," the needless waste of light from streetlights, buildings, and the like. That light gets thrown in to the sky instead of illuminating the ground, and that extra light washes out the stars. It's a real problem for observatories, where it's getting harder to find truly dark skies.

The solution is actually pretty easy: Use better lighting. There exist lower-wattage lights in more efficient housing that actually illuminate the ground better without wasting light. These lights use less power that way, making things better both for astronomers and for the taxpaying public, which funds the government's electricity bill. And everyone gets to see the stars again.

Reign of Fire

Remember "Dragonslayer"? Or "Dragonheart"? Those were pretty good dragon movies. I wish someone would make another one. "Reign of Fire" sure ain't it.

Can dragons exist? Well, there are problems. For one, it's hard to get something as big as a dragon to fly. To lift its weight off the ground, it needs a certain amount of lift, provided by wings. The heavier the weight, the harder it gets to lift. The dragons in "Reign" would need vast wings, much larger than depicted.

Of course, pterodactyls were pretty big in their day. But they were gliders, according to current thinking. They probably launched themselves off cliffs, and used thermals to get height. Flapping a wing is a lot harder and requires strong muscles. Muscles are heavy, which means the wing must be bigger, so the muscles must get bigger -- and you see this gets to be a problem quickly. You need a dragon infinitely big to fly at all. That makes filming it difficult.

In the movie, too, the only surviving dragon from the last time they ruled the Earth was a male. Being a male, I happen to know that laying eggs is rather hard for my particular gender. They never explain this in the movie. Some species of fish and frogs can switch gender, but it's a stretch to imagine a dragon going from male to female to male again as easily as a light switch being thrown. But maybe that's easier to believe than Matthew McConaughey as an embittered military macho crossbow-slinging tank-riding bald-headed scraggly-bearded dragon slayer.

Phil Plait, Ph.D., is the education/public outreach research manager for the Gamma Ray Large Area Space Telescope (GLAST) at Sonoma State University. Visit his website, Bad Astronomy.

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