Partial Pressures within a Nebula?

[Thurlor]

I was just wondering if there were any theories regarding the 'atmospheric' pressures within nebulae. I assume they would be lower than most planet's yet greater tha vacuum.

[Dollan]

As far as I know, even the thickest portions of a nebula (which would be around condensing stars in young systems) are essentially vacuum. That, of course, changes as one enters "into" the condensing star, but at that point the heat and pressure would probably make atmospheric density a moot question.

I've often wondered this myself, though. But I'm pretty sure the sci fi trope of a starship emerging suddenly from a nebula is just that, sci fi. Presumably the ship would be visually detectable for some time prior to exiting.

Of course, I could be screwed in the head and completely wrong on this point!

...John...

[MKruer]

Someone once phrased it this way to me. "The densest parts of space (Nebula) have better vacuum then the best vacuum chambers on earth"

Desity of Space 1^-12 kg/m3
Desity of Air 1.29 kg/m3
Desity of Water 1034.32 kg/m3

[Thurlor]

Thanks, that clears that up.

So, I would be highly improbable for any chemical reactions to happen in said nebula? Am I right?

[selden]

Improbable, yes, but this just means that the rate is very, very low, not zero.

Very complex molecules have been detected in dust clouds in space.

[Scytale]

If portions of nebulae would have atmospheric densities, then they would probably exert gravitational pull and start to accrete more matter... they would eventually end up as stars or gas giants...

[delmarco]

Thanks, that clears that up.

So, I would be highly improbable for any chemical reactions to happen in said nebula? Am I right?

chemical reactions happen everyday, every minute in space, in nebulas, star cradles, etc...
the rates are slow, but the events are as widespread and vast as the entire region of universe (we are talking huge parking lot here with lots of little ants doing stuff, but because the lot is so vast we cant really see the ants or say that the ants are very active and busy...even though they are lots of ants, lots of very busy ants here and ants don't like to be labeled as "not-being-busy")

99% of the time the precursor catalyst for reactions are not related to density, gravity or partial pressures but through the will of an intellegent creator...

ha ha ha ha...jking.

actually electromagnetic fields and charge polarization (also account the quantum effects in a vaccuum) of adjacent regions inside the nebula can react and cook the stew that eventually becomes stuff we call stars and planets...

gravity and density and partial pressures usually follow up later on after the stew has been simmering and clumping together...
very complex for me to explain in detail, but i'm hungry now as I'm typing and aI want stew, so that will have to do.