I'm a geochemist. In the past ten years I've fixed mass spectrometers, blasted sapphires with a laser beam, explored for uranium in a nature reserve, and measured growth patterns in fish ears, and helped design the next generation of the world's most advanced ion probe. My main interest is in-situ mass spectrometry, but I have a soft spot in my heart for thermodynamics, drillers, and cosmochemistry.
From Cosmic Variance, via Dr. Free-Ride. I think the point is that if we pumped all commercial aircraft down to high vacuum, and cooled the cabin to absolute zero, we wouldn't have to worry about liquids. Or terrorists.