No Lightning on Titan

It's a fact of life in science that not all of your hypotheses will turn out to be correct (or even verifiable at all). But there's a bias toward the publication of positive results -- the discovery of this, or the proof of that. So I always find it refreshing to read a publication about hypotheses that didn't work out. A recent paper in Geophysical Research Letters by Georg Fischer and Don Gurnett describes "The search for Titan lightning radio emissions," a search that wound up fruitless.

It wasn't for lack of searching. Fischer and Gurnett used the Radio and Plasma Wave Science (RPWS) instrument, which can detect high-frequency radio emissions, from a total of 72 Titan flybys. RPWS has three perpendicular, 10-meter antennas and doesn't need to be pointed, so it doesn't interfere with the acquisition of data from other instruments (except in terms of how much of Cassini's precious onboard memory is needed to store the data). So RPWS could theoretically operate continuously for as much as 24 hours around Cassini's closest approach to Titan on each of those flybys. It wasn't used quite that much, but Cassini has listened for lightning on Titan for more than 600 hours. That is a lot of observation time. …

See Planetary Society Weblog for links to further info.