# Does smell work the same in zero gravity? **URL:** \ **Category:** Factual Questions\ **Created:** [August 2, 2006, 11:22pm UTC](https://boards.straightdope.com/t/does-smell-work-the-same-in-zero-gravity/367097 "2006-08-02T23:22:18Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Hedda\_Rosa](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hedda_rosa/32/1204_2.png) [@Hedda\_Rosa](https://boards.straightdope.com/u/Hedda_Rosa)\ **Post date:** [August 2, 2006, 11:22pm UTC](https://boards.straightdope.com/t/does-smell-work-the-same-in-zero-gravity/367097/1 "2006-08-02T23:22:18Z")
Saw a movie last night about the International Space Station and watched all the usual zero gravity antics; spheres of water floating through the air, handfuls of popcorn drifting along, an orange floating past the camera. All this food play made me wonder. Does smell work the same in zero gravity? My understanding is that smell molicules drift through the air from the smelly object. My nose collects the molecules, and those molecules bump into the cillia in my nose and something is triggered in my brain that is my sense of smell. So do smell molecules behave differently in zero gravity? Do they make it into a nose in the same way? Slower? Faster? Maybe in less concentration or more? Are things smelly in space? ---
**Author:** ![Tripler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripler/32/21807_2.png) [@Tripler](https://boards.straightdope.com/u/Tripler)\ **Post date:** [August 2, 2006, 11:50pm UTC](https://boards.straightdope.com/t/does-smell-work-the-same-in-zero-gravity/367097/2 "2006-08-02T23:50:20Z")
A fart in space still stinks just the same. It all depends on the motion of air through the station, in order to spread the aroma/odor molecules around. I would figure they’re regularly circulating the air up there, so yeah, I’d make an educated assumption the molecules would reach your nose and thus induce the proper olfactory senses to your brain. Astronaut in sleeping bay: _ **BRRRRRRRRRRRAPP!** _ Astronaut in Command Module: "Aw sh\*t man! Yevgyeni just dropped a “borcht bomb” again! Tripler And remember, zero gravity adds to the “floatability” of the fart, increasing it’s ‘linger time’. :eek: ---
**Author:** ![Anne\_Neville](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@Anne\_Neville](https://boards.straightdope.com/u/Anne_Neville)\ **Post date:** [August 3, 2006, 12:35am UTC](https://boards.straightdope.com/t/does-smell-work-the-same-in-zero-gravity/367097/3 "2006-08-03T00:35:20Z")
I read in a book by a former astronaut that you tend not to smell things as well in zero gravity. The reason is that, without gravity to pull them toward your feet, your head tends to get stuffed up with fluids. He said it was kind of like having a cold, and that astronauts tend to order food that will be prepared for a mission to be more heavily seasoned than they would normally like, to compensate for that effect. That said, **Tripler’s** “borscht bomb” scenario is really funny 😃 At least if you have the sense of humor of a 10-year-old, like I do, it is. ---
**Author:** ![flight](https://avatars.discourse-cdn.com/v4/letter/f/bbce88/32.png) [@flight](https://boards.straightdope.com/u/flight)\ **Post date:** [August 3, 2006, 1:58am UTC](https://boards.straightdope.com/t/does-smell-work-the-same-in-zero-gravity/367097/4 "2006-08-03T01:58:45Z")
They do circulate the air in space stations and on the shuttle, which means smells transmit just fine, though as **Anne Neville** said, you may be a little too stuffed to notice. They have to keep a steady breeze blowing so the astronauts do not suffocate. It turns out that in zero g without some artificial breeze the CO2 you exhale tends to form a cloud around you and suffocate you, or so I have hear from astronauts. ---
**Author:** ![Anne\_Neville](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@Anne\_Neville](https://boards.straightdope.com/u/Anne_Neville)\ **Post date:** [August 3, 2006, 2:18am UTC](https://boards.straightdope.com/t/does-smell-work-the-same-in-zero-gravity/367097/5 "2006-08-03T02:18:59Z")
> [@flight](#): > > They have to keep a steady breeze blowing so the astronauts do not suffocate. It turns out that in zero g without some artificial breeze the CO2 you exhale tends to form a cloud around you and suffocate you, or so I have hear from astronauts. Even if you didn’t suffocate, having no air circulation might not be too pleasant. I’ve found that the moving air from the fan in a car can make me significantly less likely to be motion sick. It would probably also be unpleasant if you were doing some work that made you sweat- the sweat wouldn’t evaporate if the air weren’t circulating. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [August 3, 2006, 5:01am UTC](https://boards.straightdope.com/t/does-smell-work-the-same-in-zero-gravity/367097/6 "2006-08-03T05:01:02Z")
> [@Tripler](#): > > Astronaut in sleeping bay: _ **BRRRRRRRRRRRAPP!** _ Do they use sleeping bags in the Space Station? I though I saw diagrams with part of it labeled as ‘crew quarters’ or something like that. Wouldn’t they have more permanant sleeping arrangements, like built in bunks or at least hammocks? ---
**Author:** ![Bear\_Nenno](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bear_nenno/32/3358_2.png) [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)\ **Post date:** [August 3, 2006, 11:16am UTC](https://boards.straightdope.com/t/does-smell-work-the-same-in-zero-gravity/367097/7 "2006-08-03T11:16:55Z")
Zero-G hammock? Isn’t that just a net? ---
**Author:** ![flex727](https://avatars.discourse-cdn.com/v4/letter/f/258eb7/32.png) [@flex727](https://boards.straightdope.com/u/flex727)\ **Post date:** [August 3, 2006, 1:38pm UTC](https://boards.straightdope.com/t/does-smell-work-the-same-in-zero-gravity/367097/8 "2006-08-03T13:38:54Z")
> [@flight](#): > > They do circulate the air in space stations and on the shuttle, which means smells transmit just fine, though as **Anne Neville** said, you may be a little too stuffed to notice. They have to keep a steady breeze blowing so the astronauts do not suffocate. It turns out that in zero g without some artificial breeze the CO2 you exhale tends to form a cloud around you and suffocate you, or so I have hear from astronauts. Not sure I buy this. I don’t think sitting in zero-g would be any different than sitting in a stagnent room on Earth. I agree the the concentration of CO2 would increase in the vicinity, but [diffusion](http://en.wikipedia.org/wiki/Diffusion) (not to mention the breeze from breathing itself) would carry it away rapidly enough to avoid suffocation. Diffusion is also the answer to the OP. Smell will traverse a room just fine without either breeze or gravity. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [August 3, 2006, 1:48pm UTC](https://boards.straightdope.com/t/does-smell-work-the-same-in-zero-gravity/367097/9 "2006-08-03T13:48:30Z")
I believe that **flex** has it right. Arthur C. Clarke took on the idea that you needed gravity to help get rid of CO[sub]2[/sub] in one of his stories about space stations (I think it was **The Other Side of the Sky** , where an older crewman tries to spook a rookie with the concept of suffocating if the ventilators shut down, illustrating it with a match supposedly killing its own flame with its waste carbon dioxide. But it’s revealed to be a hoax – they just wanted to freak him out. Diffusion will help spread odors just fine in the absence of gravity. If you canm’t smell it because your nose is clogged, it’s not becasuse the odor molecules aren’t there. In the book **A House in the Sky** , about life aboard SkyLab, they talk about the constant air circulation, and how anything lost will probably turn up on the air filters (including big things, like wrenches). I don’t recall them talking about clogged noses in zero-g, though. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [August 3, 2006, 3:31pm UTC](https://boards.straightdope.com/t/does-smell-work-the-same-in-zero-gravity/367097/10 "2006-08-03T15:31:48Z")
For some reason this thread reminds me of a rather unsavoury episode on the [Apollo 8](http://history.nasa.gov/ap08fj/05day1_black.htm) mission: > [@](#): > > …Frank [Borman] feels awake enough to participate in the flight. However, he has woken up from his poor sleep feeling unwell. He vomits twice, has a bout of diarrhea and the episode is making the interior of the spacecraft particularly smelly and uncomfortable. Two excellent books that deal with Frank’s illness, Genesis: The Story of Apollo 8 by Robert Zimmerman and A Man On The Moon by Andy Chaikin, discuss this episode further, describing how Jim and Bill chase after floating vomit and feces and how Bill became fascinated by the physics displayed by the blobs of vomit in front of him. :eek: