It’s Got to be Believable

My neighbor and good friend, who happens to be a forest climatologist, once told me he had one regret about learning so much about the weather. “I can no longer just look up into the sky and say, ‘what pretty clouds,'” he told me. Learning can be a curse that way. I find that it manifests itself for me when I’m watching movies. Particularly movies involving outer space.

600px-JupiterEver since the Matrix ™ movies, I promised myself that I’d try to watch whatever movies the Wachowskis made. And I’ve pretty much held to that. My latest was “Jupiter Ascending.” A lot of the action of this movie took place on and around the planet Jupiter. One of the bad characters had built a huge complex beneath the atmosphere of Jupiter’s red spot.

Like every Wachowski movie I’ve ever seen, this one was a very good story and well told. In a scene toward the end of the movie, our heroine was trapped on Jupiter (which interestingly had exactly 1G of gravity.) Her brave hero was on a large ship in what appeared to me was geosynchronous orbit just above the red spot. His smaller more nimble ship was inside the big ship, and when it became clear that he needed to swoop down to the planet to rescue our fair maid, he flew his small craft out of the mother ship, and straight down to the planet’s surface.

This bothered me. The international space station is approximately 205 miles above the surface, and orbits the Earth every 90 minutes. GPS satellites in Earth orbit are 12,540 miles up, and stay more or less stationary over a particular spot on the planet. Should something nudge one of these satellites from its carefully calculated orbit, would it fall straight to earth? No! As I understand it, once below geosynchronous orbit altitude, celestial mechanics would dictate the object would start moving faster in orbit the closer to the earth it came. I suppose it would be possible for this “falling” object to fire rockets against the direction they tried to orbit, with the effect that they’d fall to Earth all the faster.

At some point, the piper would have to be paid though. If you didn’t want to hit the spot on the planet you were aiming for pretty hard, you’d have to give up a significant amount of energy somehow. And you need to be mindful that a fragile human body could not handle more than a few Gs of force without destroying itself.

So when the hero flew his ship straight towards his destination, and landed his ship a few minutes later with a puff of air, I groaned. Fortunately for me, however, when I walk outside and look up at the sky, the clouds look pretty.

Leave a Reply