Re: Why is Space a Vacuum
 

Gases such as oxygen exist in nebula's due to the nova's or supernova's that created the nebula's. During the final years of a star's life, progressively 'heavier' elements are combined via fusion to create even more, "heavier" elements. That is to say, at first hydrogen is fused to form helium. Then, once the hydrogen supply becomes a little short, the helium at the core of the star begins to fuse together to form other elements. Through this chain of events, the "heavy" elements are formed, elements like oxygen, lithium, etc.

So when the star goes nova, those elements are dispersed into interstellar space, forming a nebula. However, these nebulae are constantly expanding due to the forces that created them in the first place. So eventually, the elements that form them are dispersed until the elements are spread as evenly as possible.

So basically, what a vacuum is is all the atoms that form the universe trying to spread themselves as evenly as possible throughout the universe, trying to create a uniform pressure. So the gas escaping from the tank is simply trying to equalize its internal pressure with the pressure of space. However, the pressure of space is very low, and space is so huge, so the tank becomes virtually empty, except for a few molecules that remain.

Also, gravity does overcome the drive to equalize pressure on both large and small scales. Planets on the small scale, and galaxies on the large. And galaxy clusters and superclusters if you want to go that far.

But I've probably confused you enough already, so I'll stop there. http://forum.shrapnelgames.com/images/icons/icon7.gif

Re: Why is Space a Vacuum
 

The densest nebulae have about 10,000 molecules per cm^3.
The air we breathe has 10^19.

If they get too dense or cool, then they'll collapse into star clusters.

Re: Why is Space a Vacuum
 

Fully understand the vacuum is because there is a lack of any heavier elements hydrogen and helium making up 99.999% of the volume of interstellar space.

Re: Why is Space a Vacuum
 

Umm... invert that number and then divide some really huge exponentials into it and you have a more accurate number on the volume of space taken up by hydrogen and helium. http://forum.shrapnelgames.com/images/icons/icon12.gif Now, the vast majority of matter is made of those 2 elements, but the vast majority of space is empty.

Re: Why is Space a Vacuum
 

<font size="2" face="sans-serif, arial, verdana">ah, that explains it. so, if you froze something to near 0 kelvin, you could compact it alot?

Re: Why is Space a Vacuum
 

<font size="2" face="sans-serif, arial, verdana">Fyron is correct..if this was true, letting oxygen out into space and then lighting a match would result in an explosion. It doesn't.

Hydrogen and helium make up the majority of elements because they are the simplest and take the least mass. For every, oh, carbon atom you could have TWELVE hydrogen atoms. For the metals and heavy radioactive elements, it gets even worse.

EDIT: and yes, things near 0K can be more compact. Note the can. Because as you compact them you decrease the volume and increase the pressure. The result of -that- is an increase in heat.

[ January 28, 2004, 05:13: Message edited by: Phoenix-D ]

Re: Why is Space a Vacuum
 

<font size="2" face="sans-serif, arial, verdana">Yes, because the molecules would not hardly be moving at all. And what P-D said. http://forum.shrapnelgames.com/images/icons/icon12.gif The increase in heat from compacting stuff comes from the increase in the kinetic energy transfered per unit area/volume, hence increased pressure. Same amount of energy, just in a smaller area/volume. But then the increased heat causes the molecules to move faster, so they get away from each other and decrease the volume again, unless you keep them trapped. http://forum.shrapnelgames.com/images/icons/icon7.gif Keep in mind that temperature is a measure of the average root mean square velocity of the molecules in a given volume, which is a direct result of their average kinetic energy.

[ January 28, 2004, 05:22: Message edited by: Imperator Fyron ]

Re: Why is Space a Vacuum
 

Ok the reason I brought this up was A) I honestly did not understand the nature of space as a vacuum, that being explained now, and thank you all, I move on to my other thought.

Nebula's are basically gasses being held in place by a gravitational force or other. These nebula can be pretty much any gas combination. So to turn this toward an SEIV topic, would it be possible to make a component that could use the inherent gasses of a nebula and convert them into energy for a ship or say stationary Starbase where a Q-reactor was not present?

The idea I have in mind is to make nebula system even more of a strategic asset then they currently are.

If you could mine a nebula for resources and use those resources for production or supply generation depending upon the component used, then nebula systems become far more useful in a game. You would want to protect them from nebula busters or other.

That being said, why not consider the possibility of mining the entrance to a black hole. We all know that matter is pulled into a black hole and super compacted to extremely dense material, so why can we not mine that material? Of course this would require a means to remain neutrally buoyant against the gravitational event horizon of a gravity well, and components to mine for resources at an accelerated rate. The cost would be high, but the pay off would be well worth it.

Also, as a twist to the normal use of a nebula, have breathable ones where you could establish colonies similar to ring worlds, but more along the lines of platforms or rafts that a colony can be built upon. So long as the nebula was breathable gas, IE hydrogen, oxygen, etc it could support a limited number of these colonies.

What about randomly forming nebula? Basically from what I recall from the discovery channel, a nebula is could be formed when a star explodes and the gasses within it are released. There is still enough density from the Stars core to keep the ever expanding gasses held together via gravity, thus creating a nebula. Kind of like a big bag of sun gasses held together and prevented from dissipating by what was left of the stars core and its gravity. So a nebula is formed, why can it not be used as a source for material or a home for a race that can live off of the gasses contained within?

These were just some thoughts I had about trying to make nebula a more useful part of the game.

Edit: Spelling error, thanks Narf for pointing it out. http://forum.shrapnelgames.com/images/icons/icon7.gif I owe you one.

[ January 28, 2004, 07:06: Message edited by: Atrocities ]

Re: Why is Space a Vacuum
 

Mining black holes is propably Last thing mankind ever learns to do, if ever. As we know, black holes are virtually everLasting (but not practically. There are few events caused by laws of quantum mechanics, which result that even black holes will lose mass and vanish in time and I am not talking about millions of years, but 10^90 years) and nothing can escape from there.

However, even if we could extract some material from a singularity, I doubt it could be of any use. Basically it is assumed that it consists of only protons and neutrons which would combine combounds with the nearby matter (atoms, electrons, neutrons, other protons) at the very same moment they would be taken off from the high gravity area. However this is interesting theoretical discussion

[ January 28, 2004, 07:50: Message edited by: Karibu ]

Re: Why is Space a Vacuum
 

<font size="2" face="sans-serif, arial, verdana">Also known as ramscoops.

The element mix you'll find is essentially pure hydrogen with a tad of helium mixed in. Fly through at high speed, and scoop up those 10,000 molecules per cm^3
You'll have to sweep 3x10^17 cubic meters before you've got 1 gram of hydrogen though, so you need a big scoop.

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And the densities of nebulae are so very low, only "none" races could consider it breathable.
Plus, there are no convenient ways to move around, since the material is so very thin, and there aren't even any stars around to sail by.

Black holes are a bad idea to mine for matter.
Jupiter would be uneconomical to pull material up from.
Stars are much worse, and hotter too. Solar wind is too thin to bother with.
Neutron stars, well your digging equipment would be compacted into neutronium and join the star, and the gravity is much worse.
Black holes are insanely bad.

They do evaporate, though, and emit radiation like a blackbody. As they get smaller, their effective temperature goes up and they emit more, and shrink faster until boom.

In the Last second of its existence, according to theory IIRC, it will lose 1000 tons of mass as energy. Enough to sterilize the entire solar system from anywhere nearby.

Any decent sized hole has an effective temperature lower than the surrounding universe, and will just pull in photons and stray atoms to grow.
Eventually, as space expands, the surroundings will approach emptyness, and the huge hole will begin to evaporate.

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The scale of time you are talking about is many millions of years.
If the race is waiting for nebulae to form randomly, they'd be an incredibly ancient race.

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PS:
Fun trumps all! If it would be fun to play, go ahead and do it!