In organic chemistry, a heterocycle is any ring molecule containing one or more atoms other than carbon. Adenine (mentioned in a previous post) is quite a good example of a heterocycle.

A lot of these have been searched for in interstellar space, including furan, pyrrole and imidazole. Furan is particularly popular as a target by astrobiologists, due to it’s structural similarity to ribose and deoxyribose (better known as the backbone for DNA molecules). Unfortunately, no concrete evidence has been found for any of them. This is strange, because three chemicals found commonly in interstellar space (acetylene, hydrogen cyanide and carbon monoxide) all contain an isoelectronic triple bond. Theoretically, they should react in very similar ways such that if PAHs are common in the universe, heterocyclic aromatic compounds should also be. Seemingly, unless we’re all missing something, they aren’t.

Although it’s probably a painfully obvious answer (such as a matter of enthalpy or reaction kinetics), I can’t help but wonder why…

About Invader Xan

Molecular astrophysicist, usually found writing frenziedly, staring at the sky, or drinking mojitos.
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4 Responses to Heterocycles

  1. invaderxan says:

    Yeah, you’re probably right about the low orbit being the cause there. It’s cool all the same — nice find! :D

  2. underwr1tten says:

    I have been doing a little research on olfaction on my own, which is why I asked.
    According to ISS Science Officer Don Pettit, space smells like ozone. I’m thinking that’s probably just due to the relatively low orbit of the ISS, but it’s still neat. http://spaceflight.nasa.gov/station/crew/exp6/spacechronicles4.html

  3. invaderxan says:

    Interesting question… To be honest, it depends on your definition of smell.
    Technically, the sense of smell (or olfaction, as it’s more properly known) is the ability of a creature to discern volatile chemicals in the atmosphere they’re breathing. In a funny way, the NASA Mars rovers were “smelling” the air when they detected the chemicals in the atmosphere.
    Some things have smells and some things don’t. Take methane for instance (often found in space), which has no real smell. On the flipside, hydrogen sulfide is also common in interstellar space, and that stuff smells like rotten eggs! By far, the most common element, in any case, is hydrogen — which doesn’t have a very strong scent.
    It’s possible, at the sort of concentrations found in dense nebulae or circumstellar disks, the human nose could detect something… But I’m not too sure (I’m no medic). :)
    On a side note, dust from the surface of the moon apparently smells a lot like gunpowder…

  4. underwr1tten says:

    When you mentioned PAHs in a previous post, I had to look them up, because smelly space particles just seem weird (I hadn’t heard of PAHs before, obviously). But I’m wondering, would a person be able to smell space? I know the colors of nebulas are caused by the different types of gases (before artists get to them, anyway), and most of those gases are quite odiferous. Ignoring the fact that we can’t breathe without apparatus, are the particles too dispersed to create something a person could smell, or would it actually be something we could experience?

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