Gaseous layer around a planet, dwarf planet, or a star.
2
votes
2answers
28 views
Penetration of light in the atmosphere
While I was considering an answer to this question, I wondered how much light that enters the atmosphere reaches the ground without colliding with air molecules—if any. I've taken a good bit of ...
1
vote
1answer
58 views
Has martian sunset same spectra than this earthly bluish-violet sunset?
Has martian sunset same spectra than this earthly bluish-violet sunset?
What about sunset on Mercury?
0
votes
2answers
110 views
How can anything be hotter than the Sun?
I've heard that if a space shuttle enters the atmosphere from a bad angle its surface will become so hot that it will be hotter than the surface of the Sun.
How can that be? It seems to an uneducated ...
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
171 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 ...
2
votes
1answer
148 views
What if Felix Baumgartner went the other way?
How much harder would it have been for Felix to use some powered sled and head for the ISS when he stepped out of his capsule? He was already above most of the atmosphere.
BTW, Is that capsule still ...
1
vote
2answers
179 views
Is it possible to calculate atmospheric pressure if given temperature (F) and elevation?
I am working on a report at work and need to determine the atmospheric pressure for small intervals over a 24 hour period. Searching Google, I've found charts which give a base pressure of 14.65 psia ...
5
votes
3answers
207 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 ...
2
votes
1answer
78 views
Sensors for Greenhouse Study
A group and I have the opportunity to design a payload that will be sent up some 100,000 ft (~ 30 km) into the atmosphere for approximately 3 hours. In our design, we were going to include gas sensors ...
1
vote
1answer
66 views
Equations for the two-plane model of the greenhouse effect
I'm trying to understand this "toy model" of the greenhouse effect.
http://www.realclimate.org/index.php/archives/2007/04/learning-from-a-simple-model
The model predicts the surface temperature of ...
3
votes
0answers
35 views
Special conditions at layer F2 ionosphere
I saw this graph about the electrons density in different altitudes and difference between night and day, the difference between the 2 electron densities (day and night) decreases till 300 Km (F2 ...
0
votes
0answers
33 views
Term for “atmospheric ricochet” due to wrong “angle-of-attack”
I watched "Apollo 13" yesterday, and they had the "angle-of-attack" problem that had to be manually solved, to prevent the ship from "ricochet[ing] off the atmosphere like a rock skipping off a pond".
...
2
votes
1answer
133 views
What is the cause of orange sky glow?
I live in the Netherlands and recently I have been seeing an orange glow in the sky at night, in the northwestern direction. What is the cause of this? And why is it in the northwestern direction (I ...
2
votes
0answers
24 views
Surface UV exposure with cooler star
If the sun's surface was ~ 4000K (and earth closer to compensate), the UV component of the radiation would be less. However, UV makes ozone via photolysis of oxygen. Also, the stratosphere would ...
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 ...
2
votes
2answers
157 views
Minimum size of an asteroid to actually impact earth
From what I understand, an object entering the atmosphere will start to burn up from the tremendous resistance of the atmosphere. Presumably, for asteroids under a certain size, they will burn up ...
1
vote
1answer
83 views
Is the Earth's atmosphere a Faraday cage?
X-ray telescopes are required to be above the atmosphere as the atmosphere blocks EM waves with wavelengths < UV . Does this mean that the Earth's atmosphere can be thought of as a Faraday cage ...
9
votes
1answer
333 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 ...
14
votes
2answers
274 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 ...
1
vote
0answers
61 views
What is the critical mass of a planet to have an atmosphere like Earth's?
Small planets/orbits like Moon cannot have atmosphere because of their masses. They don't have enough gravity to hold an atmosphere. Then what is the critical mass that makes enough gravity to keep an ...
5
votes
1answer
264 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 ...
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 ...
3
votes
1answer
70 views
image distortion when taking a picture from space
I'm trying to understand if there is a distortion of an image taken from space (i.e. from a satellite), and if there is, then how to model it mathematically (depending on the angle in which we take ...
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 ...
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.
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 ...
2
votes
1answer
80 views
How far does typical view of clouds/atmosphere extend?
The specific "sub questions" I'm asking are:
When you are looking at clouds just on the horizon, how far away would they be?
How wide (in km) is that total field of vision at roughly cloud height.
...
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 ...
4
votes
2answers
291 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 ...
0
votes
1answer
307 views
Atmospheric Escape of Gas Molecules
Most of the Bodies and Objects in space are likely to have an atmosphere. Since the space is empty, the gases in atmosphere should have either dissolved or emptied into space. But, Why doesn't this ...
1
vote
2answers
122 views
Height of the atmosphere - conflicting answers
Okay. I have two ways of working out the height of the atmosphere from pressure, and they give different answers. Could someone please explain which one is wrong and why? (assuming the density is ...
0
votes
2answers
100 views
Atmosphere above huge fire areas (e.g., “fire ocean”)? [closed]
My question is more about climate sciences, but I hope that it is still related to physics.
What would be possible atmospheric conditions for planet with some kind of "fire" ocean?
I had some ...
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 ...
0
votes
2answers
92 views
Is a photovoltaic cell on an artificial satellite the same construction as one used on Earth's surface?
Just what the title states.
Are photovoltaic cell arrays on a satellite the same that are used within Earth, or is there some difference in their construction given the differing environment in which ...
1
vote
2answers
109 views
During an Ice Age, would someone at moderate latitude get a sunburn/suntan on a sunny day?
Let's say you live at a moderate (temperate, in today's terms) latitude during the last glacial maximum. You're probably in some kind of steppe or taiga biome, even though you're at 40 degrees north, ...
0
votes
1answer
79 views
Can atmospheric hydrogen be collected for use?
Just what the title states.
Free hydrogen accumulates in the exosphere. At high altitudes there are large volumes of open space between molecules - which would be a hindrance to collection.
Would ...
1
vote
3answers
229 views
Would the rate of ascent of an indestructible balloon increase as function of it's altitude?
Assume a balloon filled with Hydrogen, fitted with a perfect valve, and capable of enduring vacuum (that is to say, it would retain it's shape and so well insulated that the extremes of temperature at ...
2
votes
2answers
108 views
If I lift a submerged hose over 35 feet above the water's surface, what's in the top foot?
I've been arguing with a friend about the whole "perfect vacuum" concept. He and I agree that the most powerful vacuum pump in the world couldn't pump water more than ~34 feet above the surface of a ...
0
votes
2answers
154 views
Why is the atmosphere transparent in the visible spectrum?
One of the great coincidences in physics is that the Sun happens to shine most brightly at exactly the wavelengths our eyes can see; it's an easy explanation that our eyes evolved to make the most out ...
21
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 ...
2
votes
2answers
952 views
If blue light has a higher energy than red light, why does it scatter more?
As $E=hf=\frac{hc}{\lambda}$, blue light - with a smaller wavelength - should have a higher energy. However, it is the case that blue light scatters the most. Why is it that higher energy rays scatter ...
0
votes
2answers
640 views
Why the pressure of atmosphere doesn't crush you when you e.g. walk outside?
Why the pressure of atmosphere doesn't crush you when you e.g. walk outside? I mean the density of air is $1.26 kg/m^3$, so with $100 km$ above us, it exerts much pressure on you when you walk ...
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, ...
-2
votes
1answer
184 views
For how long can we make an air balloon stay flying via remotely controlled heat system?
I wonder how a function $$f=f(h, m_{\mathrm empty}, V_{max}, T_{h}), $$ with the top height $h$, the empty mass $m$, the maximum volume $V_{max}$, and the temperature of the heater $T_{h}$ would look ...
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 ...
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 ...
5
votes
2answers
193 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 ...
1
vote
3answers
426 views
Long-Life High Altitude Balloon
Normally high-altitude balloon experiments end with the balloon popping and the payload falling back down to be reclaimed.
But if a second balloon was attached to the payload, one which was only ...
3
votes
1answer
135 views
Keeping air in a well
Let's say I've got an Earth-like planet with no atmosphere: it's just a barren ball of rock. I want to live there, but I don't like domes, so instead I'm just going to dig a big hole and let gravity ...
2
votes
3answers
451 views
Electromagnetic wave reflection vs. light reflection
Related: x-ray interaction with atmosphere
I know that electromagnetic waves of particular frequencies reflect from the ionosphere. And the light (which from one perspective is an electromagnetic ...
