I recently stumbled across a SpaceRef article from last year on Deep Impact smacking into Comet Tempel:
so far the scientists report seeing only weak emission from water vapor and a host of other gases that were expected to erupt from the impact site. The most conspicuous feature of the blast was brightening due to sunlight scattered by the ejected dust.
Dust? Things got drier?
It turns out that when Shoemaker-Levy broke up prior to smacking into Jupiter, telescopes were trained to catch the increased emission of water due to the freshly exposed ice surfaces... and there was none.
Again, when Comet Linear startled everyone by blowing up and disintegrating, there was “gas and dust” in the observations — no water vapour — except (in the case above) in the explanatory sidebar.
Dry comets. What will they think of next?
Scrolling back through the blog, I’m wondering if there’s an award somewhere for “least homogenous set of interest threads” in blog posts?