# Tag Info

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Apart from all kind of factors such as absorbtion and thermal flows there is a fundamental reason for the temperature difference: potential vs kinetic energy. When a gasmolecule "falls" down it acquires kinetic energy, which is heat, so it is height against heat.

0

I don't get this. Surely if the sky is blue in the daytime because the blue light is preferentially scattered, colouring the whole sky blue, like white light in fog, this effect would be even more pronounced at sunset, when there is more atmosphere for the light to pass through and therefore more particles to concentrate the blue light.

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The answer is in the EM absorption/emission profile of the atmosphere with height. Visible wavelengths pass through the atmosphere unheeded, except for clouds. IR is somewhat absorbed by carbon dioxide. That same carbon dioxide emits IR radiation too, allowing it to cool. Atmospheric parcels at higher elevations have less intervening carbon dioxide between ...

0

As illustrated HERE on Astronomy SE, since the velocity of the meteor or comet nucleus is going to be about 40 km/s (essentially the escape velocity from the sun at at 1 AU) and the velocity of Earth is about 30 km/s, the relative velocity of the two can be anywhere from 10 km/s to 70 km/s (varying by a factor of 7) depending on the direction the object is ...

1

There would be no net movement of air in such a straw extending from the surface of the Earth to outer space. Perhaps you're thinking that the air at the bottom of the straw is being pushed into the straw with a pressure of 1 atmosphere (14.7 psi) while the top of the straw is at vacuum (0 psi) and so there is a net force pushing the air into outer space? ...

0

It couldn't be easier to answer this question. It's utterly commonplace in English that words have different meanings. When you, OP, say "clouds" you are almost certainly talking about "cumulus clouds" ... cartoon clouds. A key thing to know is the clouds you are seeing, the bottoms are typically about one or two kilometers off the ground. The tops are ...

2

You'd explain it the same way you'd explain it to a fifty year old person. What about this... "As you know, there are different colours ... red, green and so on. The air likes to bounce around these colours. Amazingly enough, the air most likes to bounce around blue. The other colours don't get bounced around as much ... they just go away. So when you ...

8

I would keep any explanation to a three year old in wholly immediate, phenomenological terms; let him do the following experiment. As you know, the blueness of the sky's orb is a mostly scattering rather than transmission phenomenon, but this is probably too much detail. I think you need to keep the explanation along the lines of "stuff changes the light ...

2

None better than a local university can answer this question with their statement: A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line ...

2

What... on... earth??? Clouds come in various sizes and are fractal in size. It would be very difficult to answer the question "what is the average cloud diameter in the above picture", and even harder if it were an animated video with clouds constantly growing, shrinking, splitting, merging, changing shape, disappearing and forming anew, with fuzzy ...

8

I don't know if they are 200 feet or 2 miles across Clouds are fractal. Cloud particles can be a few dozens of micrometres, and big tropical cyclones can be thousands of kms across. That's a range of more than 10 orders of magnitude! That's why clouds are a pain to represent in models — it is simply impossible to have a physics-based model of a cloud ...

3

An easier answer: Suppose we get 3cm of rain fall over an area of one square kilometer. The mass of water (which came from the cloud) is about 30,000 tonnes

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How big are clouds? When I look up into the sky I have no frame of reference, so I don't know if they are 200 feet or 2 miles across. An old astronomy based system, that I learned as a kid in the scouts, is to use your hands and arms as a rough guide measure, specifically by making your hand into a fist, then putting your arm as forward outwards as far ...

6

The nature of a cloud makes answering this question a bit difficult. Clouds can have various sizes ranging from the size of a football field to that of a city, with thicknesses ranging from from a dozen to several hundreds of feet. The difficulty arises when considering what is 'a' cloud.. If, for example, the picture shows a single cloud, it's radius ...

0

You could use the Buoyancy Frequency, $N$, as a measure of stratification and stability. $N$ is defined as: $N^2 = \Large\frac{g}{\theta} \frac{d\theta}{dz}$ Where $\theta$ is the potential temperature. With some variations in answers here and there. The term $\Large \frac{d\theta}{dz}$ is a measure of convective stability with negative values representing ...

8

No, it would not be sucked off, for the same reason that the earth has an atmosphere to begin with: gravity. No, for the same reason that Jupiter doesn't have a noticeable pull on you: the strength gravity decreases with the inverse square of distance. No, Gravity is too strong. Your misconception seems to be coming from the idea of a vacuum and a straw. ...

27

Has Musk done his homework? With regard to the basic idea of using nuclear weapons to release CO2 and thereby warm Mars, no, he hasn't. I suspect this was either Bored Elon Musk speaking, or perhaps the Elon Musk who didn't quite deny being a super villain ( 1-900-MHA-HAHA Elon Musk?) in that interview with Colbert. CO2's enthalpy of sublimation is ...

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