Report, edit, etc...Posted by Do-0dan on 2007-01-07 at 20:58:48
I don't think that there's any barrier between empty space and the gases in the atmosphere, so why don't gases continue to expand beyond the current size of the earth(the solid earth + the atmosphere)?
I'm pretty sure it's not due to gravity because easily go up and only come down when they condense.
I'm pretty sure it's not due to gravity because easily go up and only come down when they condense.
Report, edit, etc...Posted by Doodan on 2007-01-07 at 21:33:28
They stay because of gravity. It's all about density. Air basically "floats" on top of solids and liquids, just as liquids "float" on most solids, and a few solids float on liquids. The most dense stuff is closest to the core, and the least dense goes outward for many thousands of miles. Lighter air such as hydrogen and helium naturally goes to the outermost regions of the atmosphere, while heavy air like radon stays close to the ground.
Interesting note: When we fall through the air, we are basically sinking in it. Just as water prevents something from reaching any high speeds while it sinks in it, air resistance prevents you from accelerating faster and faster like you would if you were falling in a vacuum.
Interesting note: When we fall through the air, we are basically sinking in it. Just as water prevents something from reaching any high speeds while it sinks in it, air resistance prevents you from accelerating faster and faster like you would if you were falling in a vacuum.
Report, edit, etc...Posted by Do-0dan on 2007-01-07 at 22:28:11
I don't think air has density. Air should have 0 density because density=mass/volume and the volume is the whole world which is extremely vast, so small #/big number = close to 0
So if it's about weight, then would that mean that gravity becomes stronger as its range increases?
So if it's about weight, then would that mean that gravity becomes stronger as its range increases?
Report, edit, etc...Posted by CheeZe on 2007-01-07 at 22:31:13
Umm.. air is actually pretty heavy. 1.2 kg/m^3 to be exact and it gets less dense as you go higher.
Report, edit, etc...Posted by Do-0dan on 2007-01-07 at 22:52:58
I'm confused...If air is that heavy, then why is it that I can jump?
An individual air molecule should be extremely light, so it should keep rising right? If so, then every individual molecule should float on to outer space...
An individual air molecule should be extremely light, so it should keep rising right? If so, then every individual molecule should float on to outer space...
Report, edit, etc...Posted by xmrxsiegecopx on 2007-01-07 at 22:55:27
Count all of the molecules of air in the world, add up their mass, and tell me that isn't heavy.
Report, edit, etc...Posted by CheeZe on 2007-01-07 at 22:56:38
QUOTE(Do-0dan @ Jan 7 2007, 10:52 PM)
I'm confused...If air is that heavy, then why is it that I can jump?
An individual air molecule should be extremely light, so it should keep rising right? If so, then every individual molecule should float on to outer space...
[right][snapback]611257[/snapback][/right]
An individual air molecule should be extremely light, so it should keep rising right? If so, then every individual molecule should float on to outer space...
[right][snapback]611257[/snapback][/right]
Explain how that even makes sense. You know how gravity works right? =/
Report, edit, etc...Posted by Felagund on 2007-01-07 at 22:56:43
Air isn't that dense.
Random question concerning science... after all the stars burn out, won't the planets continue to generate some heat because of plate movement and the such?
*Edit* With density, don't think of it as lighter compounds floating, but heavier compounds sinking. If there were nothing beneath the air to support it, it would sink to the core of the Earth too.
Random question concerning science... after all the stars burn out, won't the planets continue to generate some heat because of plate movement and the such?
*Edit* With density, don't think of it as lighter compounds floating, but heavier compounds sinking. If there were nothing beneath the air to support it, it would sink to the core of the Earth too.
Report, edit, etc...Posted by Do-0dan on 2007-01-07 at 23:00:52
Does it sink or does it fill up the space, because if you create a vacuum in mid air then air will flow into that vacuum
Report, edit, etc...Posted by CheeZe on 2007-01-07 at 23:09:29
That's only under the assumption of no gravity. Earth pulls the air down. It makes sense because air gets less dense as you go higher because it's further from the earth. This is the equation that shows the force between two masses:
F is the magnitude of the (repulsive) gravitational force between the two point masses
G is the gravitational constant
m1 is the mass of the first point mass
m2 is the mass of the second point mass
r is the distance between the two point masses
QUOTE
F is the magnitude of the (repulsive) gravitational force between the two point masses
G is the gravitational constant
m1 is the mass of the first point mass
m2 is the mass of the second point mass
r is the distance between the two point masses
Report, edit, etc...Posted by Do-0dan on 2007-01-07 at 23:34:45
QUOTE(CheeZe @ Jan 7 2007, 10:09 PM)
That's only under the assumption of no gravity. Earth pulls the air down. It makes sense because air gets less dense as you go higher because it's further from the earth. This is the equation that shows the force between two masses:
[right][snapback]611266[/snapback][/right]
[right][snapback]611266[/snapback][/right]
You're saying that a vaccum within the atmosphere will never be filled? Density shouldn't matter in this discussion, only mass should since the volume stays the same. So since hydrogen is very light, would it escape our atmosphere and go into space?
Report, edit, etc...Posted by BeeR_KeG on 2007-01-08 at 00:23:00
Gravity has an effect on all particles, regardless of mass, volume or density.
An object with less mass requires less force in order to have the same reaction, in this case staying/escaping the Earth's gravitational pull.
You are confusing the terms of fluid(gases and liquids) buoyancy with gravity.
In order for any particle to escape Earth's gravitational field, it would have to have a force greater than the force the Earth exerts on the object and in a vector in the exact opposite direction.
An object with less mass requires less force in order to have the same reaction, in this case staying/escaping the Earth's gravitational pull.
You are confusing the terms of fluid(gases and liquids) buoyancy with gravity.
In order for any particle to escape Earth's gravitational field, it would have to have a force greater than the force the Earth exerts on the object and in a vector in the exact opposite direction.
Report, edit, etc...Posted by DT_Battlekruser on 2007-01-08 at 00:37:22
Remember, the force of gravity is proportional to the mass of an object. Ignoring other particles, the resultant force of the earth on a hydrogen atom will cause the same acceleration as the resultant force of the earth on 100 megaton block of iron.
The only reason you hear about some particles being "light" enough to escape the atmosphere (which some are) is because the vector forces from chemical reactions and the displacement with respect to the movement of the earth are constant regardless of mass, so very light elements such as elemental hydrogen can relatively easily be propelled out of the atmosphere. This is why on planets such as Venus, when radiated greenhouse energy breaks down H[sub]2[/sub]O, it likes to recombine with elemental sulfur to make sulfuric acid (H[sub]2[/sub]SO[sub]4[/sub]) and free up elemental hydrogen which escapes the atmosphere and leaves the clouds of sulfuric acid and carbon dioxide that remain on Venus.
Oh and BeeR, gravity has no effect on massless particles
The only reason you hear about some particles being "light" enough to escape the atmosphere (which some are) is because the vector forces from chemical reactions and the displacement with respect to the movement of the earth are constant regardless of mass, so very light elements such as elemental hydrogen can relatively easily be propelled out of the atmosphere. This is why on planets such as Venus, when radiated greenhouse energy breaks down H[sub]2[/sub]O, it likes to recombine with elemental sulfur to make sulfuric acid (H[sub]2[/sub]SO[sub]4[/sub]) and free up elemental hydrogen which escapes the atmosphere and leaves the clouds of sulfuric acid and carbon dioxide that remain on Venus.
Oh and BeeR, gravity has no effect on massless particles
Report, edit, etc...Posted by Doodan on 2007-01-08 at 01:29:38
QUOTE(Do-0dan @ Jan 7 2007, 10:52 PM)
I'm confused...If air is that heavy, then why is it that I can jump?
An individual air molecule should be extremely light, so it should keep rising right? If so, then every individual molecule should float on to outer space...
[right][snapback]611257[/snapback][/right]
An individual air molecule should be extremely light, so it should keep rising right? If so, then every individual molecule should float on to outer space...
[right][snapback]611257[/snapback][/right]
I'm not sure about the exact number, but I think that at sea level, there's around 20 pounds of air pressure per square inch. That means that on every square inch of our bodies, about 20 pounds of air is pushing against it. Our bodies are built to withstand and live under that pressure. Ever see those shows about creatures that live like 2,000 feet beneath the ocean? Their bodies are designed so that they can live normally under the tremendous water pressure at that depth. I doubt they notice it at all.
Report, edit, etc...Posted by Do-0dan on 2007-01-08 at 19:49:16
I hope I don't anger anyone for my stupidity, but if I understand this correctly, then a certain force is required for any mass to escape the atmosphere, or negate the force of gravity. Now since all gases in the atmosphere have the same pressure (1 atm or lower depending on altitude), then they have the same force because pressure = force/area, and area is the same for all of the gases (the atmosphere of the Earth). Therefore, if hydrogen gas is able to escape the Earth, then shouldn't every other gas be able to? This situation should be an all or nothing deal... Here are some smilies to calm your anger from reading this: 
Do the gases receive the required force from going through an endothermic reaction within the atmosphere?
Do the gases receive the required force from going through an endothermic reaction within the atmosphere?
Report, edit, etc...Posted by DT_Battlekruser on 2007-01-09 at 01:44:14
Since heating of all gasses is even from solar radiation (and energy re-radiated by the Earth), the forces applied from that heating are equal. Therefore an force that would naturally push a gas out of the atmosphere is equal for all particles, regardless of mass. Gravity, meanwhile, has a force proportional to the mass of the affected particle. The smaller the particle, the less gravitational force to be overcome, hence the greater ease with which it escapes the atmosphere.
Report, edit, etc...Posted by MasterJohnny on 2007-01-09 at 01:59:58
so if you were to add air on the moon would its gravity make it stay there?
Report, edit, etc...Posted by Doodan on 2007-01-09 at 02:07:26
Don't think so. The bigger the planet, the more atmosphere it tends to have. Just look at Jupiter and Saturn. ;p
Besides, I think any appreciable atmosphere the moon did manage to acquire would be stripped away by the earth's gravity.
Besides, I think any appreciable atmosphere the moon did manage to acquire would be stripped away by the earth's gravity.
Report, edit, etc...Posted by DT_Battlekruser on 2007-01-09 at 02:44:51
The more massive an object, the more gravitational pull it has. As Doodan said, the Moon does not have enough mass to generate a gravitational field strong enough to retain a significant atmosphere, plus if it had a thin atmosphere, Earth's gravity would attract it too.
Report, edit, etc...Posted by Gradius on 2007-01-09 at 14:54:54
If you landed on one of the gas giants like Jupiter you would sink really fast and the pressure would crush you.
Report, edit, etc...Posted by Lithium on 2007-01-09 at 20:21:40
The pressure wouldnt crush you before the gravity crushes you in the instant you enter the atmosphere. Jupiter's gravity is significantly larger than that of Earth's.
Report, edit, etc...Posted by Rantent on 2007-01-09 at 20:26:48
QUOTE
I don't think that there's any barrier between empty space and the gases in the atmosphere, so why don't gases continue to expand beyond the current size of the earth(the solid earth + the atmosphere)?
The answer to this is quite a bit more complex then simply "gravity."Now I don't claim to know exactly what happens but I'll give you what I have learned over the years.
Atoms and molecules are always moving. This movement creates pressure, volume, and tempurature. (Among other things.) When you heat up atoms, they move more energetically. This increase of kinetic energy allows them to overcome some of the force of gravity. This is what allows heat to rise. The question is, why doesn't any particle become so energized that it breaks it's gravitational connection with the world completely, flying away into space.
If you think about it, the higher particles would only become more and more energized, because a great deal of our energy comes from the sun, and hits the topmost particles first.
The reason they do not simply leave the pull of the earth is because when you increase an atom's energy, you are not onyl increasing the movement of the atom as a whole, but the constituent particles (nucleons, and electrons.) At some point, these particles become so energized that they break apart. This breacking apart creates a mass of ions in the upper atmospheres, which are then harnessed by the polarity of the earth, into magnetic rings, known as the van allen belts.
Thats why even the highly charged particles don't escape, sorry I couldn't elaborate.
Report, edit, etc...Posted by green_meklar on 2007-01-10 at 10:51:25
QUOTE
The pressure wouldnt crush you before the gravity crushes you in the instant you enter the atmosphere.
??? How does that work? So long as you aren't on or in some kind of relatively dense medium (i.e., about 500 times denser than our atmosphere at sea level) or have reached terminal velocity, it hardly matters how much gravity there is, because you're still accelerating downwards and for the most part you won't feel it. I suspect the pressure on Jupiter would crush you before the gravity would.
Report, edit, etc...Posted by DT_Battlekruser on 2007-01-10 at 21:07:30
QUOTE(green_meklar @ Jan 10 2007, 07:51 AM)
??? How does that work? So long as you aren't on or in some kind of relatively dense medium (i.e., about 500 times denser than our atmosphere at sea level) or have reached terminal velocity, it hardly matters how much gravity there is, because you're still accelerating downwards and for the most part you won't feel it. I suspect the pressure on Jupiter would crush you before the gravity would.
[right][snapback]611989[/snapback][/right]
[right][snapback]611989[/snapback][/right]
Gravity can't crush you all by itself. Even if you were being sucked into a black hole, gravity doesn't crush you. The only reason you think about gravity crushing you is if you are pinned against a surface, such as the solid surface of a rock planet. The pressure of Jupiter's atmosphere would crush you as you fell to the center of Jupiter or until you met gas more dense than your body.
QUOTE
If you think about it, the higher particles would only become more and more energized, because a great deal of our energy comes from the sun, and hits the topmost particles first.
Because the Earth re-radiates energy, particles don't just keep getting more energized as they rise.
Report, edit, etc...Posted by Do-0dan on 2007-01-10 at 21:21:36
QUOTE(Rantent @ Jan 9 2007, 07:26 PM)
The answer to this is quite a bit more complex then simply "gravity."
Now I don't claim to know exactly what happens but I'll give you what I have learned over the years.
Atoms and molecules are always moving. This movement creates pressure, volume, and tempurature. (Among other things.) When you heat up atoms, they move more energetically. This increase of kinetic energy allows them to overcome some of the force of gravity. This is what allows heat to rise. The question is, why doesn't any particle become so energized that it breaks it's gravitational connection with the world completely, flying away into space.
If you think about it, the higher particles would only become more and more energized, because a great deal of our energy comes from the sun, and hits the topmost particles first.
The reason they do not simply leave the pull of the earth is because when you increase an atom's energy, you are not onyl increasing the movement of the atom as a whole, but the constituent particles (nucleons, and electrons.) At some point, these particles become so energized that they break apart. This breacking apart creates a mass of ions in the upper atmospheres, which are then harnessed by the polarity of the earth, into magnetic rings, known as the van allen belts.
Thats why even the highly charged particles don't escape, sorry I couldn't elaborate.
[right][snapback]611828[/snapback][/right]
Now I don't claim to know exactly what happens but I'll give you what I have learned over the years.
Atoms and molecules are always moving. This movement creates pressure, volume, and tempurature. (Among other things.) When you heat up atoms, they move more energetically. This increase of kinetic energy allows them to overcome some of the force of gravity. This is what allows heat to rise. The question is, why doesn't any particle become so energized that it breaks it's gravitational connection with the world completely, flying away into space.
If you think about it, the higher particles would only become more and more energized, because a great deal of our energy comes from the sun, and hits the topmost particles first.
The reason they do not simply leave the pull of the earth is because when you increase an atom's energy, you are not onyl increasing the movement of the atom as a whole, but the constituent particles (nucleons, and electrons.) At some point, these particles become so energized that they break apart. This breacking apart creates a mass of ions in the upper atmospheres, which are then harnessed by the polarity of the earth, into magnetic rings, known as the van allen belts.
Thats why even the highly charged particles don't escape, sorry I couldn't elaborate.
[right][snapback]611828[/snapback][/right]
Wow..Never would have figured out that last part by myself. Thanks for the explanation
