Scents of other habitable planets?

[PlutonianEmpire]

Recently, I've been writing a new science fiction short story, and one of the ideas that came to me was that different habitable planets would have different scents; not just from plants and animals, but also whatever compounds that might be present in the atmosphere, or simply the way the air is set up. It would probably be that natives wouldn't notice any smell, because they'd have been evolved to be used to it, but when they'd visit a different habitable planet, they'd notice different scents.

The sci-fi I've read and seen hasn't touched on this, but there might be ones that I haven't seen yet that do....

Anyways, does anyone agree or disagree with me about these thoughts? Either way, what do you think? And of course, the obligatory question: If aliens visited Earth and had the ability to smell things, what might they say about Earth, assuming they visited the natural areas, away from the pollution of big cities?

[bdm]

Foundation's Edge by Asimov mentions this theme.

[ajtribick]

So what are the various micro-organisms are going to do? Bearing in mind they may well be operating with biochemistry that may have significant differences to our own? I'm not a biologist/biochemist so I have no idea here. Would it be a case of "smell Earth II and die"?

[PlutonianEmpire]

So what are the various micro-organisms are going to do?

No matter what, they're gonna invade your body. It just depends on how well your body can put up a fight.

Bearing in mind they may well be operating with biochemistry that may have significant differences to our own?

There's only three scenarios: 1. Your body is like a magnet, and you attract them like you wouldn't believe. 2. Something about your body repels them, and they avoid you at all costs. 3. They're indifferent either way and treat your body like they treat all the other bodies on the planet you're visiting.

I'm not a biologist/biochemist so I have no idea here.

Neither am I.

Would it be a case of "smell Earth II and die"?

It depends on multiple factors, the make up of the atmosphere, the native biology of the planet's life forms, etc.

Pandora from Avatar, for example, is pretty much a "smell Earth II and die" scenario, with a long asphyxiating death.