|
Negative Pressure in Space?
Link |
by
on 2007-06-30 15:49:35 |
I know what the movies say about space and how air would be sucked out of a shuttle if it began to leak, and I also know that space is classified as a vacuum. My question is: does being in space actually apply negative pressure to a hollow object? And if so, what happens to air, water, etc. removed from hollow objects in the vacuum of space?  |
|
Re: Negative Pressure in Space?
Link |
by
on 2007-06-30 16:02:55 |
|
there is no meaning to "negative pressure". the lowest conceivable pressure is zero. pressure is the result of molecular collisions, millions of which take place at the surface of one drop of water every second. these collisions, each imparting a very small amount of force, cumulate to significance. when you sit in your computer chair, you are being bombarded by moving molecules of air from all sides. this bombardment creates measurable "air pressure". the more dense the air, the more molecules per cubic meter, the more molecules collide with your body every second. the less dense the air, conversely, the lower the pressure. a perfect vacuum is a region of space with zero matter present within it. the lowest pressure a body might experience is no pressure whatsoever, due to zero surrounding molecules colliding with it per second. this is (very nearly) the case for space-ship sized objects floating in space. in the absence of pressure, which is to say inside a vacuum, fluids will evaporate into gas, because there is no force (other than surface tension) holding the fluid together. the molecules of the fluid simply fly apart due to their thermal (internal) kinetic energy. this is why you need a space suit to go into space: you want your fluids to remain inside, and not to evaporate, flying all over the place. that would be bad times. 
|
|
Re: Negative Pressure in Space?
Link |
by
on 2007-06-30 18:00:10 |
|
By negative pressure, I meant the property of a vacuum that will effectively pull something apart, rather than let it drift apart, such as water, at zero pressure. But by the law of cohesion, wouldn't the water stay "together", or is this property only exhibited under the pressure of gravity? |
|
Re: Negative Pressure in Space?
Link |
by
on 2007-07-01 12:29:00 (edited 2007-07-01 12:29:55)
|
|
&uotthat is not "negative pressure". that is "outward force". at any significant temperature, cohesion would be overcome by the thermal kinetic force in the case of water in a vacuum. this is the same consideration as the "boiling point; of a liquid. a liquid's boiling point is determine by it's physical properties, namely, cohesion. at a certain internal kinetic energy level (see: heat), the force given by the collisions of the molecules of the liquid with each other overwhelms the force of cohesion, causing the liquid to boil and thereby turn into a gas. conversely, the cooling of a gas can lead to the cohesive force overwhelming the thermal force, resulting in condensation.
|
|
Re: Negative Pressure in Space?
Link |
by Honey's Lover
on 2007-07-01 12:31:32 (edited 2007-07-01 12:32:42)
|
|
"Truely you have a dizzying intelect" --The Dread Pirate Roberts just out of curiosity, what classes did you take
|
|
Re: Negative Pressure in Space?
Link |
by
on 2007-07-01 12:42:03 (edited 2007-07-02 18:03:10)
|
 Pirate gendou says Honey's Lover needs to sit down and shut up! 
|
|
Re: Negative Pressure in Space?
Link |
by
on 2007-07-01 17:57:29 |
|
Ah. Thanks for clearing that up, captain. |