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Assuming absolutely no wind there will still be areas of turbulence, things will still be transferring heat to the air causing it to move, it doesn't take much motion for air to become turbulent because of its low viscosity. Viscosity will dampen any instability, so low viscosity means its easy for instability and turbulence to occur

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No. Atmospheric pressure is 14.7 lb/sq inch. That is, the air in a 1 inch square column from the ground to outer space weighs 14.7 lb. A 1 inch square column of water 32 feet tall also weighs 14.7 lb. A column as deep as the ocean weighs tons. This means there is several hundred times more water than atmosphere. If you heated the ocean until it boiled, ...

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The speed of a molecule is given by: $$V_{rms}=\sqrt{\frac{3k_BT}{m}}{\tag1}$$ with v in m/s, T in kelvins, and m is the molecule mass (kg). The most probable speed is 81.6% of the rms speed, and the mean speeds 92.1% (isotropic distribution of speeds). The mass of an oxygen molecule is $5.313\times 10^{-26}$ kg. This gives $v_{rms}$ a value of about ...

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Yes, the general process of losing gas molecules is possible. It's called atmospheric escape. The escape speed mechanism you mentioned is just one way in which it happens. Since lighter molecules move faster, they tend to be nearer the escape velocity. The Earth has lost (and continues to lose) hydrogen over the course of its history due to this. Oxygen is ...

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This presents the same problem as your previous question: Determine the number of days with North-East wind direction from the number of days with North and East wind direction? If we know the wind was from the North on $a$ days and from the North-East on $b$ days then there is no way to tell how many days the wind was from the NNE. The best you could do is ...

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Generally speaking there will be some correlation between wind directions. For example if on some specific day the wind blows from the North or East it is quite likely there was a North-East wind in the week or so around that day. By contrast if the wind is from the South-West on a particular day it is less likely there was a North-East wind in the week or ...

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I don't think it makes sense to talk about a temperature with regard to Aurora effects. It's an epiphenomenon. It's almost like asking "how fast is a car engine moving?" wholly dependent on your frame of reference. In this case the difficulty is using the term "temperature", which is too tied to perception to differentiate a purely physical answer.

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A quick google search for "aurora plasma temperature" brings up several interesting results, which seem fond of reporting temperatures in electron volts. That's entirely sensible, but probably not quite what you want. While we could do some math to convert those measurements to Kelvin, Rocket measurements of plasma densities and temperatures in visual aurora ...

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If you know when to expect it, light can be detected at the single photon level. For very long distances, the expected photon flux will be less than one per detector per unit time of your choice. Go look up the Lunar Laser Ranging Experiment, in which light was detected at this level. Also, the Lunar Laser Communication Demonstration, which allows high ...

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Infinity as long as you have a detector strong enough to detect it. Light keeps on travelling in a straight line forever as long as it doesn't bounce off some object. The problem with the lights you are talking about is that their intensity is really low and you can't resolve them because of the other stronger sources of lights you have around yourself. ...

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any flow is driven by pressure gradient, which must overcome the friction of flow through the tube. It's a very long way, hence huge pressure drop relative to the initial pressure gradient. No flow

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Assuming the tube is insulated along its whole length (which I think is the intent of the question although it's not stated), I think a flow in either direction is stable and sustaining, but there is no particular reason it will form in either direction if the initial conditions are that the air in the tube is still. It will then depend on the average air ...

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I think you've got the whole reason. We have good evidence that meteor showers are caused by lots of tiny pieces of fluffy comet detritus, which has no chance of reaching the ground; a bright bolide, however, is much more likely to have a substantial rocky or metallic mass.

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