Is there anything that is truly odorless?

[Flander]

@Mangetout

I guess that would be a legitimate category of odpurlessness though - things that actively prevent you from smelling them. An atomic explosion, for example.

I hear that cures hangovers, too.

[antechinus]

@jtur88

Horses cannot detect distilled water, but they can smell the vegatation aromas that occurs on the banks of natural waterways. Similarly, ancient mariners in sailing vessels could smell "land ". Which means they could smell the aroma of land-based life.

Every emanation into the atmosphere has an “odor”. in that it is chemically different from others and can potentially be detected, but there may be some that are not detectable to any known evolved organism.

Yes, as Blake also said, horses cannot smell pure H20. The olfactory apparatus consists mainly of water. As a WAG I expect horses are smelling the chemical geosmin.

[TruCelt]

I learned on TV recently that a black bear has a sense of smell 4,000 times more sensitive than that of a bloodhound. Having experienced some pretty intense and far-ranging games of hide and seek on a farm - against a kid with a pet bloodhound, I found this to be utterly amazing. They said a black bear can smell blood from ten miles away. When shopping for pots and pans I proved to my companions that I can smell the difference between aluminum and stainless steel. I am far better at smelling and tasting than most humans; the bear is umpteen thousand times better at smelling than I am.

Does he have a receptor for nitrogen? I don’t know. Sharks are also pretty sensitive, do they have one? Is that within the parameters of the question? Or is the question whether there is any substance which could not be smelled by any creature regardless of sensitivity or receptivity?

I think in order to achieve an answerable question you’d have to define the temperature and atmospheric pressure, then find a material which could achieve zero volatility within those parameters.

Otherwise, it’s 42.

[Mangetout]

@Flander

I hear that cures hangovers, too.

We certainly haven’t had many complaints.

[johnpost]

if a being could smell nitrogen then they would be blinded.

[burpo_the_wonder_mutt]

^ Are they smelling it at night?

[dtilque]

There’s another reason nitrogen won’t be on any being’s smell list: it’s prevalence. It makes up some 78% of the atmosphere, so there’s always going to be lots of it to smell. There’s no point in smelling it, since it’s always there.

But more significantly, its concentration never changes. Smell is actually the detection of a change in the concentration of some chemical. If you stay in an environment with a constant concentration of X, you quickly stop smelling X. I remember once staying in a town that had some hot springs in the area. At first I noticed a sulfur (actually hydrogen sulfide) smell in the area. By the next morning I didn’t notice it anymore unless I went closer to one of the springs. Then the concentration was higher and I would notice it again. But as I said, the concentration of nitrogen never changes, so this wouldn’t apply.

Anyway, there’s no point in any animal evolving the ability to smell nitrogen. Even if it weren’t so difficult to get things to react with it, the ability is useless.