Supposing one is vulnerable to spacesickness (say a .5 on the Garn scale), what happens to the spew? I’m assuming it comes out in a stream of small chunky bubbles.
The behaviour of a fluid in microgravity is determined by the surface tension. Vomit is pretty variable in terms of consistency, and is a odd mixture of solids (particle and chunk), aqueous acid, saliva, mucus and bile. I’d expect that it will take some time to break up and form small globules. So it will be like a traditional chunder, but will come out in a straight line and hit whatever you were looking at, rather than curving to the floor. And it will be a hell of a mess to clean up.
Si
There’s a spewing scene in the film Apollo 13, IIRC.
A couple of Apollo astronauts suffered with space sickness, resulting on one occasion, so I read, in “small globules of vomit and diarrhoea” floating around the cabin.
Per ardua ad astra, indeed.
Once ejected from the mouth, there will be nothing in particular to cause it to break up, except maybe impact with the far side of the cabin. I think the violence/turbulence with which the vomitus is ejected from the mouth will be enough to cause it to break up into small globs immediately.
That sort of depends on the hurler - some people seem to aspirate as they vomit, which means the vomit gets blown out the mouth as an aerosol. Others projectile vomit as a continuous stream. Still others just vomit with limited force. YMMV.
Si
Which was filmed in a microgravity environment.
I don’t have a cite on-hand, but I’ve read that many astronauts who are prone to space sickness will pack some extra socks. Why? To stick in the bottom of sick bags, because otherwise, the vomit will bounce off the bottom of the inside of the bag, and hit you in the face. Which I’m sure just makes for an even more pleasant experience.
Thanks for the answers. I knew that liquids tended to go globular in orbit. At first I thought they’d just hurl out a big braille basketball, but then common sense kicked in and said that would require a little more control than the situation would provide.
BTW in orbit you don’t throw up, you throw out. 
What interests me is the equal and opposite force: how far backward/what acceleration will he have after a good session.
Also, since the spew is coming from his head, he must pick up some rotational force.
In space, no one can hear you barf.
I too wonder if a good reverse dinner would give you some kind of propulsion in a low Gravity enviornment.
Well, if it’s moving at any speed, air resistance should cause it to break up, though maybe not before reaching the wall.
Hopefully they’ll devise a porcelain airlock that you can hug and your ejectus will go off into space as the Comet Vomit.
I just read “Packing for Mars: The Curious Science of Life in the Void” by Mary Roach and she discusses that issue. Of course I can’t remember if there was actually a solution other than ‘don’t puke in space’. (There were some poop incidents mentioned that I will never be able to erase from my mind.)
If you’re in the ISS, you’d probably have to chase it around to clear it up. If you’re in a suit…eww.
I was a big fan of MTV’s the Wildboyz – basically, the guys from the movie Jackass decide to parody nature specials. In their last season, they went to Russia, took a ride on the zero-g plane, which everyone (except perhaps the Russians) calls the “Vomit Comet”. Steve-O spent most of that season inducing vomiting in himself, on purpose, so that episode failed to disappoint – if that’s what you’re looking for.
Ladies and gentlemen, we could be looking at the propulsion system for the first green spacecraft.
Or yellow, or brown, or multicolored, as the case may be.
Good Lord, what is that woman going to write about next…
You asked for it, you got it, sort of. With pukeback. Need those napkins on the bottom of the bag.