Gaseous layer around a planet, dwarf planet, or a star.
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 ...
20
votes
2answers
2k views
Why is the sky not purple?
I realise the question of why this sky is blue is considered reasonably often here, one way or another. You can take that knowledge as given. What I'm wondering is, given that the spectrum of ...
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.
14
votes
2answers
272 views
How deep is the Great Red Spot?
The Great Red Spot (GRS) is a very persistent storm system that's easily visible through a telescope on the surface of Jupiter. But what is the three-dimensional structure of the GRS, and how deep ...
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 ...
12
votes
1answer
3k views
Did Felix Baumgartner produce a sonic boom during his jump?
I really got to thinking about this. The speed of sound is measured at 761.2 MPH at sea level. But how does this number change as air density decreases? The lack of air density is what allowed his ...
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, ...
10
votes
2answers
84 views
Why is Jupiter so sharply defined?
In photographs of Jupiter, the limb seems extremely definite. Being a gas giant, my naive self thinks that the atmosphere should have a more gradual cut off, creating a hazy effect similar to that on ...
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 ...
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 ...
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 ...
9
votes
1answer
330 views
Energy from man-made tornadoes
Peter Thiel just paid $300,000 to Canadian inventor Louis Michaud who is working to construct useful "man-made tornadoes" or "atmospheric vortex engines" which could be components of future power ...
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?
8
votes
1answer
242 views
What causes a ring-like image around light of the moon?
I just encountered an interesting image in sky.
As you can see in following images there was a ring-like image around light of the moon.
I don't know if it was clouds but it was looking like it is far ...
8
votes
2answers
1k views
Is there an upper frequency limit to ultrasound?
Wikipedia has this diagram of the acoustic frequency spectrum:
Is there an upper limit to the frequencies you can transmit through the air? Are they absorbed more and more at higher frequencies, ...
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?
8
votes
1answer
2k views
From how high could have Felix Baumgartner jumped without disintegrating like a shooting star?
Today Felix Baumgartner jumped from 39 kilometres high and reached the earth safely.
Just considering friction, from how high can a human jump?
I expect that from a certain height, he would have ...
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
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 ...
6
votes
2answers
150 views
Is it possible to use a balloon to float so high in the atmosphere that you can be gravitationally pulled towards a satellite?
A recent joke on the comedy panel show 8 out of 10 cats prompted this question. I'm pretty sure the answer's no, but hopefully someone can surprise me.
If you put a person in a balloon, such that ...
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 ...
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 ...
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:
$P(\theta) = \frac{3}{4}(1 + cos^2 \theta)$
...
5
votes
4answers
1k views
Why less temperature at high altitude
Why there is always cold at high altitudes. e.g. at peak of mountains. Also as we go high from see level, temperature starts decreasing, so why is it.
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?
5
votes
3answers
297 views
Why is Titan able to maintain an atmosphere, and not Luna?
I just read stability of hypothetical lunar atmosphere. From the correct answer, i understand, the low escape velocity from Luna is part of the reason it is unable to retain an atmosphere.
Titan ...
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 ...
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 ...
5
votes
3answers
205 views
Can low-gravity planets sustain a breathable atmosphere?
If astronauts could deliver a large quantity of breathable air to somewhere with lower gravity, such as Earth's moon, would the air form an atmosphere, or would it float away and disappear? Is there a ...
5
votes
1answer
263 views
Why does the sun “shine brighter” some days?
Today, the sun seems extremely bright; more dazzling than usual, and even the roads seem to be brighter so it's not just when you look up in the sky. Is more light actually getting through (perhaps ...
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 ...
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 ...
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 ...
5
votes
2answers
192 views
Keeping air in a giant gravitationally-bound space balloon
Let's say a space-faring society wants to make a space station that has a large volume filled with air (or other gas), but no gravity. Using normal pressure tanks will require gathering an amount of ...
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 ...
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 ...
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 ...
4
votes
1answer
170 views
Can a hovering helicopter travel half the globe in 12 hours? [duplicate]
Suppose we have a helicopter that is able to stay stationary in flight for extended periods of time. If such a helicopter stayed at point A in the sky for 12 hours straight, would it reach the other ...
4
votes
2answers
283 views
What does the phrase “limb of the earth” or “atmospheric limb” mean?
What does the term limb of the earth (see this question, for example) or atmospheric limb mean? The phrase strikes me as very odd, since earth is nearly spherical. Do other planets with atmospheres ...
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 $Ne$?
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 ...
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 ...
4
votes
2answers
55 views
Attenuation mass-thickness for sunset light
We are able to look directly at the sun near sunset and sunrise, which clearly demonstrates the fact that our atmosphere attenuates visible light. Let's imagine it follows the typical attenuation ...
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 ...
4
votes
0answers
63 views
Atmospheric Circulation
What is the simplest simulatable model giving our rotating earth its 3 circulation cells (Hadley, Ferrel, Polar)?
The model should also show 1 circulation cell if the earth's rotation were stopped (or ...
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
4answers
1k views
Why the shape of rainbow is semicircular after rain why not the whole atmosphere is colorful?
I have a very simple question.
Everyone must have seen the rainbow after rain. According to the theory the rainbow is created due to the passing of sunlight from small drops of water in the ...
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
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 ...
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
