Gaseous layer around a planet, dwarf planet, or a star.
1
vote
2answers
237 views
Atmospheric pressure inside a rigid vessel
On a macroscopic scale one can explain the atmospheric pressure by the weight of the column of air over a given small area.
If you enclose this air in rigid vessel (for example by pressing together ...
1
vote
2answers
437 views
Altering Venus rotational speed to match Earth's via weather manipulation
Venus rotates approximately 6.5 km an hour Earth rotates approximately 1650 km/h how fast could we speed up Venus's rotation via only weather manipulation ( maybe a giant fractal lens between Venus ...
3
votes
2answers
321 views
x-ray interaction with atmosphere
Why x-ray are stopped by atmosphere while they are more energetic than UV or IR?
They certainly interact with atmosphere but I can't understand which phenomenon stop them.
0
votes
3answers
163 views
Lightning Power?
What is the power source of a lightning? It doesn't consume fuel, nor an atomic fission/fusion, but it discharges a large amount of energy. Is it feasible to create an artificial lightning using the ...
4
votes
1answer
103 views
Why does air contain $Ar$ specifically?
Air consists roughly of $N_2$, $O_2$ and $Ar$.
Why is $Ar$ the relatively common noble gas compound and not for example the lighter ones $He$ or $Ne$?
1
vote
2answers
176 views
Global warming and planetary thermodynamics
To a first approximation, the earth currently radiates out as low frequency thermal radiation the same amount of energy as it absorbs as high frequency solar radiation. (This ignores energy generated ...
-1
votes
2answers
159 views
Is the Earth air-tight, and does that make plastic bags redundant?
Honestly though, is the Earth considered air-tight in the sense that its gases don't escape?
I'm sure every physicist who reads this is going to tear their hairs out, but the extent of my knowledge ...
4
votes
1answer
213 views
Do atmospheric physics prevent hot air balloons from ascending over 60,000ft?
I was reading the altitude records for hot air balloons on Wikipedia, and noted that the max hot air balloon altitude was about 60,000ft. It didn't really say if there was a reason why. I know that ...
5
votes
1answer
70 views
What is the physical origin of scintillation?
The twinkling of stars, or scintillation, occurs because the optical path length of the atmosphere varies in both space and time due to turbulence.
This means that when the wavefront from a distant ...
2
votes
0answers
74 views
Jupiter: Zonal Jets in opposite directions
I recently read that the Great Red Spot arises from the shear instability of zonal flow from zonal jets travelling in opposite directions.
Is there any reason why such zonal jets travel in opposite ...
2
votes
2answers
1k views
Pressure at a given altitude?
I am trying to find out the pressure at a given altitude but have been disappointed to find the following equation does not work at all: (h = height in meters)
Where
sea level standard ...
7
votes
2answers
473 views
What determines the apparent radius of the rainbow?
Let's say I know how to compute the apparent radius of a rainbow from the viewpoint of the observer: take a photo of the scene, measure the distance to a known reference object, and its dimensions. ...
6
votes
1answer
473 views
What does the Rayleigh Phase Function tell us
I am working on some radiative transfer equations, and struggling as I'm fairly new to this field. I have read about the Rayleigh Phase Function which is:
$P(\theta) = \frac{3}{4}(1 + cos^2 \theta)$
...
0
votes
1answer
172 views
what is the relationship of sound volume to atmospheric pressure?
what is the relationship of sound volume to atmospheric pressure? if I was in a plane with a cabin pressure equal to 8000 feet would the volume drop be noticable?
2
votes
1answer
9 views
How can we be sure that liquid iron/titanium droplets can form around particulates on hot Jupiters - just as they do on Earth and Venus?
I know that we have some solar system analogs. But is there a limit to it?
3
votes
1answer
17 views
Is CO2 really a potent greenhouse gas for planets around M dwarfs?
The thing with global warming is that it absorbs infrared (IR) radiation from the planet and reradiates much of it back to the planet (whereas the Sun's peak flux is in the visible region, that is ...
3
votes
3answers
121 views
Are there convective movements similar to those in clouds everywhere in the atmosphere?
I heard there were powerful convective movements in clouds which were responsible for increasing the size of water droplets or ice crystals. My question is: do the same movements appear outside of ...
3
votes
1answer
13 views
For the long-term evolution of atmosphere/orbit, when is perihelion more important than mean distance?
When we want to figure out the long-term evolution of a planet's atmosphere/orbit, when is perihelion more important than mean distance?
E.g. some processes (like Jeans Escape and escape of ...
3
votes
2answers
83 views
Assuming that the Sun wouldn't evolve into a red giant, how long would the Earth's atmosphere last?
It's not going to last forever - Jeans Escape is going to eventually act on the atmosphere after trillions of trillions of years: see http://faculty.washington.edu/dcatling/Catling2009_SciAm.pdf
0
votes
1answer
169 views
range of infrared light
I notice in the EMS chart that only half of the IR range will travel through the earth's atmosphere. So in the range of frequencies that penetrate the atmosphere what frequency travels farthest?
6
votes
2answers
250 views
Is apparent horizon curvature lesser due to refraction of light in the atmosphere?
I have encountered this claim while searching for sources answering " Can we see the curvature of earth from the top of world's tallest building? ".
Wikipedia article on horizon claims (with no ...
5
votes
5answers
34 views
Which current big Earth-based telescopes are equipped with adaptive optics?
I know only that the VLT is equipped with adaptive optics (AO) to bypass atmospheric distortion. Is it the only one, or have other telescopes been build with AO in the optical and infrared spectrum?
2
votes
1answer
216 views
Hail stones in summer?
This has always puzzled me. Yesterday (in London) it started hailing despite it being about $20^oC$. A couple of years ago I experienced hail in Sicily when it was about $35^oC$ in the shade!. How is ...
5
votes
3answers
233 views
Why is the surface of Venus so hot?
Whenever I have seen Venus described, its high surface temperature is attributed to an intense greenhouse effect. This seems to make sense, as its atmosphere is roughly 96% CO2. But on Earth, the ...
1
vote
1answer
1k views
Ascent rate and size of balloon
I am part of a school project, Project Stratos to send a balloon to the edge of space (the closer side :P) and was wondering how you would work out the accent rate of a large balloon (roughly 1m^3 of ...
8
votes
3answers
1k views
What would happen if the polar ice caps of Mars melted?
My dad told me that Mars' polar ice caps are made of H2O and CO2. If they melt, would it add an atmosphere to Mars and allow life?
6
votes
1answer
30 views
Refraction and scattered light for NLCs
For helping with judging NLC candidates (are they NLC or not) I have a set of formulas to calculate the minimum altitude (in km) of the candidate given an observed altitude (in degrees) of the ...
13
votes
3answers
209 views
Why don't more rocky planets/moons have appreciable atmospheres?
It seems obvious why mercury has no atmosphere, given its proximity to the sun--but yet Venus is also fairly close, and has an extremely dense atmosphere. Titan is a large moon with an atmosphere ...
8
votes
3answers
306 views
Extended sound of thunder
Why does the sound of thunder last several seconds even when lightning lasts for only fraction of a second?
10
votes
5answers
9k views
Why does the road look like it's wet on hot days?
Often, I'll be driving down the road on a summer day, and as I look ahead toward the horizon, I notice that the road looks like there's a puddle of water on it, or that it was somehow wet. Of course, ...
0
votes
1answer
372 views
Uses and interpretation of the 'Bowen Ratio' ($B_o=SH/LE$)
The Bowen Ratio is the ratio of sensible heat flux to latent heat flux, so presumably it gives some information about the relative importance of these processes. But it is not clear how this ...
5
votes
2answers
2k views
The Density of Clouds
Clouds are made up of tiny water or ice droplets, depending on temperature. This implies that cloud density is greater than that of dry air. Why don't clouds sink through their surrounding atmosphere ...
10
votes
2answers
277 views
Is this a weather phenomenon or an instrumental artifact?
The radar image of the midwest provided by Weatherunderground at 10:30 PM Central time, May 8 2011 has odd patterns.
Are these patterns real? Perhaps caused by large scale convection over cities? Or ...
4
votes
3answers
187 views
stability of hypothetical lunar atmosphere
Assume that by some means, the moon could be given an atmosphere, of the same density and pressure at the surface as the earth's. Obviously in a stable atmosphere there are temperature variations from ...
5
votes
4answers
4k views
How does carbon dioxide or water vapour absorb thermal infra red radiation from the sun?
We are all told at school water vapour and carbon dioxide are the top two greenhouse gases, and that they absorb thermal infra red radiation, trap heat and warm up the Earth. My question is how do ...
3
votes
3answers
260 views
Ozone Hole in the South Pole
Perhaps this should be a chemistry question, but it seems to have physics attributes. There's a perennial ozone "hole" around the south pole created by destruction from Cl based chemicals like CFCs. ...
5
votes
3answers
903 views
Why don't different air masses mix immediately?
In meteorology, the atmosphere is considered to be divided into air masses, regions of relatively uniform temperature and humidity with fronts on their borders. But why doesn't the air from different ...
15
votes
9answers
2k views
Why do space crafts take off with rockets instead of just ascending like an aircraft until they reach space?
I guess it's not a very educated question, but I never quite understood why spacecrafts have to shoot up and can't just reach space by simply continuing an upwards ascent like an airplane.
5
votes
1answer
385 views
Estimating hydrogen loss by Jeans escape
I'm looking at Jeans (thermal) escape of hydrogen from the early Earth's atmosphere. I understand how to calculate the rate in (g cm^-2 s^-1) using the number density, average particle velocity, and ...
4
votes
3answers
4k views
How can I calculate Vapor Pressure Deficit from Temperature and Relative Humidity?
I have a series of measurements of temperature and relative humidity (RH), together with mosquito capture data. Because mosquitoes are sensitive to desiccation, it's reasonable that RH may be useful ...
5
votes
1answer
329 views
Mean optical depth in plane parallel atmospheres
I have the second edition of Houghton's "The Physics of Atmospheres". In section 2.2 he says one can do simple radiative transfer calculations in a plane parallel atmosphere by assuming that there ...
5
votes
5answers
629 views
What would ACTUALLY happen to a person jettisoned into space?
[insert obligatory statement of my lack of knowledge in physics]
Alright, so we have all seen the movies where someone gets blasted out of the airlock on their starship, or their suit decompresses ...
6
votes
5answers
1k views
How come gas molecules don't settle down?
If the earth's gravity exerts a net downward gravitational force on all air molecules, how come the molecules don't eventually lose their momentum and all settle down? How is the atmosphere is still ...
9
votes
4answers
2k views
Why can't CO2 mix back with the liquid after a soda bottle has been shaken?
If you shake a soda bottle before opening it, and then open it, you get the fizz.
That is the compressed CO2 releasing to the atmosphere which is at comparatively low pressure value.
Two questions ...
29
votes
8answers
9k views
Why does the atmosphere rotate along with the earth?
I was reading somewhere about a really cheap way of travelling: using balloons to get ourselves away from the surface of the earth. The idea held that because the earth rotates, we should be able to ...
0
votes
2answers
406 views
Would weighing scales show a negative weight if placed in a vacuum?
The weighing scales in my kitchen are currently showing 0 Kg. However, there is a column of air between the scales and the ceiling that is presumably exerting pressure on them. If I were to place ...
3
votes
2answers
531 views
logarithmic wind speed profile
Under some atmospheric stability condition, over flat terrain, it has been observed for a while that the ratio between wind speed at height $h_1$ above the earth and the wind speed at height $h_0$ is ...
2
votes
2answers
503 views
Can extra-solar gamma rays reach the Earth's surface?
Can gamma rays of high enough energy entering our planet's atmosphere reach the surface (50% probability)?
Or, in other words, is there a window for extremely high-energy gamma rays like for the ...
10
votes
2answers
281 views
How are the northern lights produced?
Although I've never seen it myself, I hear the northern lights are a sight to be seen! I know they're related to the Earth's magnetic field but I don't know much more about them. What is the physical ...
