Wednesday, August 08, 2012

Sail on! sail on! and on!

Almost as incredible as the safe landing of Curiosity on Mars was the image of the craft parachuting to the surface by the Mars-orbiting HiRISE satellite.

Let's put this in perspective.

In recent years we have got used to a new kind of warfare, drone warfare –- a controller sitting at a console in Utah (or wherever) guiding a rocket-armed robotic plane that takes out a truck, say, on a rural road in Afghanistan. Pretty amazing, when you think about it, but nothing like sending Curiosity to Mars and having it land on a dime. Or taking a picture of its descent.

Let me drag out my old analogy.

Imagine the Sun as a basketball on the 50-yard line of an American football field. The Earth would be a pinhead on, say, the home team's 20-yard line. But of course it's not just sitting there; it's revolving on its axis and moving in a big circle that will take it in half a year to the opposing team's 20-yard line.

Mars is an even smaller pin head -- a grain of salt say -- on the 5-yard line, also spinning on its axis and circling the basketball Sun in a big orbit that pretty much encloses the field.

A pinhead and a salt grain orbiting a basketball, filling a stadium with their orbits, spinning on their axes, one taking a year to circle the Sun, the other almost two years!.

Humans on the pinhead Earth contrive a machine that they send on a nine month journey across the vast emptiness of the stadium, its target an oval (about the size of New York City) on the floor of a particular crater on the spinning salt grain.

The physics and mathematics to do this have been around for a long time. But the calculations for so precise a feat of navigation would not be possible without powerful artificial brains, brains that for this sort of thinking are faster and more powerful than our own.

But let's not give the credit to computers. It was a young human genius sitting under an apple tree who gave Curiosity its genesis. And the collective smarts all of those men and women at NASA's Jet Propulsion Laboratory who built the machine and programmed the computers that guided it to its destination. Human curiosity hurled across the universe, sitting down in a dusty desert, on site, on time.

If we hadn't watched it happen –- that billowing parachute –- we would hardly believe it was true.