Weblog | Archives for April 2005
Past posts.
Processing Beta

Processing is finally in beta, with its first public release.

O'Reilly Radar has a good piece on what Processing is and what's special about it.

Slow Ride

Navigating Celestial Currents
"Math leads spacecraft on joy rides through the solar system"

By studying the mathematics underlying subtle gravitational interactions, researchers are starting to create an atlas of this superhighway. Engineers are designing trajectories to send spacecraft coasting along these routes to make voyages that were previously unimaginable.

Traditionally, spacecraft have used fuel-guzzling engines to punch their way across the solar system, says Edward Belbruno, a mathematician at Princeton University who masterminded the first spacecraft journey along low-fuel highways in 1991. Travel on the interplanetary superhighway works with gravity, not against it, he explains.

Between any two celestial bodies, there are four "Lagrange points" — places where the competing gravities are equal and a ship can remain stationary. Lagrange points are perfect locations for many telescopes and probes, since they don't need to burn fuel to stay in one spot.

Even better, the competing gravities form a number of paths between Lagrange points that an object can simply drift along without using fuel. These paths change chaotically as the bodies move, but they regularly intersect at a number of points, leaving the option to jump between paths.

This is really cool. The only drawback is that the paths are usually very indirect: a trip to the moon took four days for Apollo, but would take two years on the fastest known drift path.


Yesterday was the first anniversary of Beth and I dating. On Friday we went out for a nice dinner at Yemanja and drinks at Venice Cafe. The weather was beautiful, and we got the same table at Venice as on our first date.