# Tag Info

44

The atmosphere rotates along with the Earth for the same reason you do. Force isn't needed to make something go. That's a basic law of physics - that a thing that's moving will just keep moving if there's no force on it. Force is needed either to make something change its speed, or to make its motion point in a new direction. A force can do both or just ...

26

The atmosphere of the Earth is mainly composed of nitrogen (N2, 78%) and oxygen (O2, 21%) molecules, which together make up about 99% of its total volume. The remaining 1% contains all sorts of other stuff like argon, water and carbon dioxide, but let's ignore those for now. As you probably know, the oxygen we breathe is produced by plants from water and ...

16

Friction AKA wind resistance. You must have tried to stand in a strong wind or stuck you hand out the window of a traveling vehicle. From that you can feel the force that moving air exerts on objects in its way, and by Newton's law of reaction things in the way exert an equal force tending to move the air up to speed with the ground near it. Even if the ...

16

Yes, helium can leave the Earth, and yes, we will run out of helium, but because of different reasons. When you buy a helium balloon and its contents get released, this helium goes into the atmosphere. It isn't gone, and it could in principle be purified out of normal air. However, the total amount of helium in the atmosphere is so small it is ...

15

There are at least two reasons: the air layer adjacent to the Earth surface is dragged with it (being at rest with it). air viscosity -- it could be thought as a friction between different air layers. Upper layers are carried along by underlying layers. If the air were to stop suddenly it would result in ~1500 km/h wind speed. For comparison Hurricane ...

15

I doubt if anyone has come up with a complete explanation, but some laboratory simulations have created similar patterns. They happen if the central and surrounding areas in a flat, circular disk of fluid have different velocities. Emily Lakdawalla at The Planetary Society covers it at this site. She also explains how other patterns (triangles & ...

13

If you were to surround the atmosphere by an adiabatic envelope and allow it to come to equilibrium, it probably would settle into such a state. However, the atmosphere is not a static place. It is actively mixed due to heating of the ground by the sun, and by cooling of the upper atmosphere by radiation into space. This makes the surface air less dense than ...

11

If we accept that the system (the Earth's atmosphere in this case) is chaotic and adopt the usual definitions of a chaotic system, e.g. one by Edward Lorenz Chaos: When the present determines the future, but the approximate present does not approximately determine the future. we immediately see the answer to your question. The small (impossible to ...

8

Temperature generally gets cooler as you go higher in altitude (which is one reason why you have snow on mountain peaks long after it has melted away in the foothills). Hail develops in thunderstorms. A thunderstorm ~BY DEFINITION~ is a storm which has developed through the freezing layer. So think about this: If you see lightning or hear thunder from ...

8

I can't point to a definitive reference, but my recollection is that thunderstorms are associated with a lower layer of warm air rising rapidly through an upper layer of cold air. It's the rapid vertical transport that generates the static charge and hence the lightening. In winter it's rare to get these atmospheric conditions. So it's not that there's ...

7

From the Wikipedia article:(My emphasis) Some people thought that the ozone hole should be above the sources of CFCs. However, CFCs are well mixed globally in the troposphere and the stratosphere. The reason for occurrence of the ozone hole above Antarctica is not because there are more CFCs concentrated but because the low temperatures help form polar ...

7

According to Ahrens R. The bases of cumulus cloud can be estimated quite easily when the surface air temperature and dew point are known. If the air is not too windy, we can assume that entrainment of air will not change the characteristics of a rising thermal. Since the rising air cools at the dry adiabatic rate of about 10°C per 1000 m, and ...

6

Look at ensemble forecasts. Although they do not exactly give confidence intervals, they do give the same kind of information you would use a confidence interval for. Weather is chaotic. So are the models. If initial conditions change slightly, outcome changes dramatically. Therefore, models are typically run a number of times, for example, ten runs. ...

6

I would guess the answer is the rather boring one that there are only a small number of common gaseous elements and because all the planets formed from the same dust cloud they all have a similar set of elements. There are obvious differences that have straightforward explanations. For example small planets can't hold on to hydrogen and helium while the ...

5

In general, yes the updrafts also occur in warm dry air, as a result of heating on the ground which produces hyrdostatic instability in the atmosphere. As the updrafts go higher, they cool adiabatically and may, if they go high enough and if there is enough moisture in the air, cool enough to condense water vapor and form clouds. However there can also be ...

5

Analysis for Jesus's molecule usage: Our breathing rate changes a lot, but on average its about 1 breath every five seconds, or 12 breaths a minute, or 720 breaths an hour, or 17280 breaths a day or 6,307,200 breaths a year, and if we live for 32 years that gives us 201,830,400 breaths in his lifetime. How many atoms? multiply 2.02e8 total ...

5

It might affect climate, but not on the time scale of a month, and does not significantly affect the weather. The fact that the moon exists may significantly stabilise the inclination of the Earth relative to the Sun. This, in turn, affects climate in the long run. The debate is ongoing. For example, see long term axial tilt (Wikipedia): The Moon has ...

5

In the moist air of the clouds, the water condenses on dust particles. At the altitude where this happens, it is usually below the freezing point of water, so it quickly freezes. If winds and updrafts keep these particles of ice in the moist air, they collect more water. Eventually, the weight of the ice particles overcome the updrafts and fall to the ...

4

Logarithmic profile for wind speed regards the bottom part of atmospheric boundary layer (say, about the bottom 100 m, on a boundary layer about 1000 m high). It can be deducted doing some non obvious but reasonable assumptions. A) Vertical flux of horizontal momentum due to turbulence must be uniform in the lowest part of the atmosphere. Let's consider a ...

4

Propagation of very energetic photons through medium looks like this. The photon enter the medium, at some point it scatters off an electron or creates an electron-positron pair in a coulomb field, the initial energy distributed between the two daughter particles. Each of these particles then "splits" again, and so on, and as a result an electromagnetic ...

4

I found a reference through Google Books, Very high energy gamma-ray astronomy by Trevor Weekes, which says that the atmosphere is essentially opaque to high-energy gamma rays, equivalent to a meter-thick wall of lead. We are able to do gamma-ray astronomy with ground-based telescopes by detecting the decay products of the gamma rays' interactions with ...

4

From [The ASCE Standardized Reference Evapotranspiration Equation]1 Given T is temperature in degrees Celsius, and RH is relative humidity: Saturation Vapor Pressure (es) = 0.6108 * exp(17.27 * T / (T + 237.3)) Actual Vapor Pressure (ea) = RH / 100 * es Vapor Pressure Deficit = ea - es Why this is a meaningful measurement: "The strain under which ...

4

I would not claim to understand what precisely is going on here, but other things remnaining constant, mathematically you have: $$\lim_{L \rightarrow 0} \quad p_0 \cdot \left(1 - \frac{L \cdot h}{T_0} \right)^\frac{g \cdot M}{R \cdot L} = p_0 \cdot \exp \left( - \frac{ h \cdot g \cdot M}{T_0 \cdot R} \right)$$

4

The greenhouse effect is well-established science, and experiments that demonstrate the effect on a lab scale are common to the point that they are often presented in science fairs. When I say "greenhouse effect" in this context, I'm referring to the radiative trapping of heat by absorption of outgoing radiation by gases. As has been pointed out on Physics ...

4

The mechanism by which lightning is produced is complex and imperfectly understood, but we know moisture is important in two respects: Heat is released when water vapor in the air condenses into liquid drops, and this heat helps provide energy to the thunderstorm. Interactions between supercooled liquid water droplets and ice crystals in the upper ...

4

Cumulous clouds form when the atmosphere gets unstable. For incompressible liquids, "unstable" means a high density liquid "water" is balancing precariously on a low density liquid "oil" (ignore surface tension). If a little bit of the lower density liquid rises, it will act like a "bubble", and will be pushed upward. The updraft will cause a positive ...

4

This is quite humorous. In an 1883 offical US military publication, "Weather Proverbs" by 1st Lt. Dunwoody, at page 107 it is stated "When coffee bubbles collect in the centre of the cup expect fair weather. When they adhere to the cup, forming a ring, expect rain." This is the converse of the lifehack proverb! In 1997 Dave Thurlow, using a grant ...

4

Since Helium is so light it can actually escape into outer space. See here. Most of the helium we use comes from radioactive particles decaying underground. Yes, we can run out, and yes, it will make everything awful.

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