Explain atmospherics to me as if I was an inquisitive child.

[ivan astikov]

I know, I know! I could use google and look for a children's encyclopedic account, but I'm asking you.

I know you lot too well and I'm sure one of you is acquainted with a meteorologist somewhere online.

So, I want to know:

a) What it is made up of.
b) Why do we have one.
and c) Does the lower atmosphere(the bit that seems to affect us most) rotate along with the Earth, within its outer membrane(I'm assuming there is one), or does it actually have a braking effect on the speed of Earth's rotation?

Yes, I'm a very nosy child!

[Glazer]

a) The atmosphere is made of air. Air is a mixture of several gasses. Mostly nitrogen (80%), oxygen (18%) and small amounts of carbon dioxide, argon, neon and various others.

b)The earth formed with lots of molecular nitrogen. N². This nitrogen does not chemically combine with other elements because it is already bonded with itself. Molecular nitrogen is a gas and is lighter than rocks and water so it floats on top creating an atmosphere. Vulcanism and evaporation add gasses to the atmosphere and plants convert carbon dioxide to oxygen.

c) Yes the lower (and upper) atmosphere rotates with the earth. But there is no outer membrane the atmosphere just gets thinner and thinner until there is no atmosphere to speak of. The atmosphere does not slow down the earths rotation because space has no drag. (Ok maybe a tiny little bit due to solar wind and the moons tidal effects.)

[ivan astikov]

Answers 1 and 2 are clear enough, but if 3 is correct, how come there aren't 1,000mph headwinds if you fly the opposite way the planet is rotating?

[Glazer]

For the same reason that you don't drive 3600 MPH when driving east. Your moving relative to the earth not the entire universe. If you look at your motion as separate from the earth it would look ;ike your going in little circles going in bigger circles going in even bigger circles.

Unless you leave earths orbit you can consider the earth to be stationary. And all your motion relitive to it.

[Jaglavak]

Motion of the atmosphere: The atmosphere spins right along with the Earth. However, large scale north-south movement of air and water create significant Coreolis forces. The fancy way to say it is, in a rotating frame of reference ya gotta account for conservation of angular momentum.

Another way of looking at it is from a viewpoint directly above the north pole. A chunk of air at the equator will have an angular momentum of Mass x Velocity x Radius. Now consider the same chunk of air after if flows up to the 60th parallel. Angular momentum = Theoretically unchanged = Same mass x Half the radius x Twice the velocity. This effect guides ocean streams and jetstreams. In reality the moving air smacks into the air that's already there, converting angular momentum into nifty vortexes & cyclones & stuff.


Basic atmospheric processes:

Consider a chunk of air at sea level. If the air drifts upward, the work to get that done comes from adiabatic sorta-isentropic expansion of the air. In other words, air swaps internal energy for altitude. The internal energy comes from cooling and expansion. This is the primary cause of temperature variations in the troposphere and a main player in most weather patterns. See lapse rate.

Evaporation soaking up heat and rain releasing heat is the other main player in weather patterns.


All this is driven by temperature differences created by the sun. However, human industrial waste heat has reached an astounding 1/100th of 1% of solar heating across the planet. Future generations will have to take that into account - if they're lucky.

[Jaglavak]

Oh yeah; the latest theories say the Earth was smacked by a Mars-sized sister planet a few billion years ago. This blew away the oceans and atmosphere, melted the entire surface, and created the Moon and asteroid belt.

The replacement atmosphere and oceans happened from volcanism and probably comet splats. Comets formed waaaaay out in the Oort cloud, which preserved the low melting point stuff we need for life. Mainly O2 snow, N2 snow, and ice.

Atmosphere and oceans are both slowly evaporating away into space. In just a couple billion years this planet will be one big dust ball. Or rather, it would except for the inevitable massive government program to move the Earth away from the expanding sun and drop in some fresh comets. Riddled with fraud and cost overruns, of course.

[Glazer]

Motion of the atmosphere: The atmosphere spins right along with the Earth. However, large scale north-south movement of air and water create significant Coreolis forces. The fancy way to say it is, in a rotating frame of reference ya gotta account for conservation of angular momentum.

Another way of looking at it is from a viewpoint directly above the north pole. A chunk of air at the equator will have an angular momentum of Mass x Velocity x Radius. Now consider the same chunk of air after if flows up to the 60th parallel. Angular momentum = Theoretically unchanged = Same mass x Half the radius x Twice the velocity. This effect guides ocean streams and jetstreams. In reality the moving air smacks into the air that's already there, converting angular momentum into nifty vortexes & cyclones & stuff.


Basic atmospheric processes:

Consider a chunk of air at sea level. If the air drifts upward, the work to get that done comes from adiabatic sorta-isentropic expansion of the air. In other words, air swaps internal energy for altitude. The internal energy comes from cooling and expansion. This is the primary cause of temperature variations in the troposphere and a main player in most weather patterns. See lapse rate.

Evaporation soaking up heat and rain releasing heat is the other main player in weather patterns.


All this is driven by temperature differences created by the sun. However, human industrial waste heat has reached an astounding 1/100th of 1% of solar heating across the planet. Future generations will have to take that into account - if they're lucky.

This is the explanation you give a child? Clearly you overestimate our Mr. Nasty Cough.

[Jaglavak]

Well, I assumed the little rugger can understand basic English. Oh, and vector mechanics in a non-Newtonian frame of reference.

OK a precocious child.

[Jaglavak]

Or rather, it would except for the inevitable massive government program to move the Earth away from the expanding sun and drop in some fresh comets. Riddled with fraud and cost overruns, of course.

.... and bitterly opposed by the Oort Cloud Society, dedicated to preserving the asture beauty of the outer solar system for any future intelligent races that may evolve.