These days it's no surprise to come across a gallery of amazing astronomy images. The Hubble Space Telescope, the other NASA great observatories and space probes, the European Space Agency and European Southern Observatory, and many, many dedicated amateurs (among other sources) provide a steady flow of visual riches. Mind-boggling beauty shows up every day; I can barely keep up with it in my Twitter feed.
Sure, Comet G-C looks cool, but what does it smell like? Read on. (Credit: ESA/Rosetta/NAVCAM) But what of the other human senses? Our appreciation of the natural world is bolstered not just in sights but in sounds, smells, and tactile sensations. A walk in the woods would not be the same without birdsong, the loamy odor of decaying leaves, the brush of branches. It's a shame we don't have access to the same kinds of experiences to connect us with the universe beyond our planet. Wait a second! Actually we do, or at least we are starting to. There is no sound in space, of course, but there certainly are ways to hear what the universe is doing. The most straightforward is to convert radio signals to sound, just as an FM tuner does. It's more than a gimmick; the resulting volume and pitch tell you a lot about the kind of radio emission you are listening to. For years, various labs and researchers have posted such sound files on an ad hoc basis, but NASA has just gathered a whole library of them and posted them on a great new NASA Soundcloud page. In addition to the eerie radio music of lightning on Jupiter and plasma waves from deep space, you can also "hear" the shadow of a distant planet passing in front of its star. Or you can choose something more conventional but still plenty invigorating, like listening to the test firing of NASA next big rocket, the Space Launch System, now under development. OK then, what about touch? Not as farfetched as you might think. Astronomers Carol Christian and Antonella Nota of the Space Telescope Science Institute have converted Hubble images into three-dimensional instructions that can be molded in a 3D printer. Shapes can represent a variety things: The contours could literally convey the physical structure of a nebula, for instance, while textures could indicate composition. The connections could be even less literal--based around brightness contours, for instance. Christian and Nota want to make files freely available for download so that any school with a 3D printer can create tactile sky images for students. Although the researchers were initially setting out to make Hubble images accessible to visually impaired students, touchable astronomy is a powerful tool even for people with normal vision. I attended a demonstration at a meeting of the American Astronomical Society and came away with a deep appreciation for the added involvement of being able to feel the universe.
Hubble's universe, the 3D tactile version. (Credit: AAS/STScI) Alas, there is (so far) no equivalent of a 3D printer for smell, but that doesn't mean that you cannot appreciate the odors of the universe. Just yesterday, the scientists working on the incredible Rosetta comet mission posted an intriguing essay about the composition of Comet Churyumov-Gerasimenko, which Rosetta is studying at very close range. The chemicals wafting off from the comet are associated with some intense and memorable odors, which Kathrin Altwegg (principal investigator for Rosetta) describes in wonderfully colorful terms: The perfume of 67P/C-G is quite strong, with the odour of rotten eggs (hydrogen sulphide), horse stable (ammonia), and the pungent, suffocating odour of formaldehyde. This is mixed with the faint, bitter, almond-like aroma of hydrogen cyanide. Add some whiff of alcohol (methanol) to this mixture, paired with the vinegar-like aroma of sulphur dioxide and a hint of the sweet aromatic scent of carbon disulphide, and you arrive at the ‘perfume’ of our comet. After reading that I couldn't help thinking: Those are pretty common compounds. Surely it wouldn't be that hard to create an odor room where people could inhale the smell of comet directly. No need to restrict it to comets, by the way. It would not be terribly hard to simulate moon dust (said to smell like gunpowder), Mars (rusty and dry, I expect), and so on. I'm imagining a "smelletarium" next to the planetarium in your local science museum. Why not? Finally, there is the matter of taste. Probably the same approach could be used to create a comic licking room. As I contemplate putting a sprinkle of asteroid dust on my tongue, though, I suspect that's a step too far. I want to experience space, but I'm not sure I want to be that experienced.