What is Atmospheric: Definition and 270 Discussions

An atmosphere (from the greek words ἀτμός (atmos), meaning 'vapour', and σφαῖρα (sphaira), meaning 'ball' or 'sphere') is a layer or a set of layers of gases surrounding a planet or other material body, that is held in place by the gravity of that body. An atmosphere is more likely to be retained if the gravity it is subject to is high and the temperature of the atmosphere is low.
The atmosphere of Earth is composed of nitrogen (about 78%), oxygen (about 21%), argon (about 0.9%), carbon dioxide (0.04%) and other gases in trace amounts. Oxygen is used by most organisms for respiration; nitrogen is fixed by bacteria and lightning to produce ammonia used in the construction of nucleotides and amino acids; and carbon dioxide is used by plants, algae and cyanobacteria for photosynthesis. The atmosphere helps to protect living organisms from genetic damage by solar ultraviolet radiation, solar wind and cosmic rays. The current composition of the Earth's atmosphere is the product of billions of years of biochemical modification of the paleoatmosphere by living organisms.
A stellar atmosphere is the outer region of a star and typically includes the portion above the opaque photosphere. Stars with sufficiently low temperatures may have outer atmospheres with compound molecules.

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  1. C

    Software that models atmospheric hypersonic flight

    Hi, I would like to model various projectiles and capsules being fired at hypersonic speeds by a coilgun or equivalent mass driver. Does anyone know of any programs that could simulate a launch or at least parts of the flight? (ie. setting the atmospheric density for a given region, calculating...
  2. S

    Can Gas Giants' Atmospheres Be Ignited? Exploring the Possibilities

    Hi, quick question for you guys. I was having a discussion the other day with a friend of mine, about whether it was possible to ignite the atmosphere of a planet, specifically gas giants; considering many are made of flammable gasses and compounds (hydrogen, methane etc...). I would have...
  3. O

    Understanding the Water Pump: Gravity and Atmospheric Pressure

    Hello. I saw this video: ... it is about water pump. I want to know how it works. First straw is above the water surface, second is below the water surface. To the straw below the water surface goes watter because force of gravity act on it. This is why air column increases and makes it...
  4. S

    Calculating Air Temp Increase from Atmospheric to 3 Bar Pressure

    How to calculate the raise in temperature of air when it's pressurized by a piston type air pump from atmospheric pressure to 3 bar(gauge pressure) ?
  5. Nostalgia00

    Atmospheric Transmittance Venus?

    Hi guys this is my first post! I've been trying to find a plot of the atmospheric transmittance of Venus but I've had no luck. I'm particularly interested in the C-band transmittance. Thanks for any information you have!
  6. A

    Algorithms for atmospheric water balance method

    Hi I want to estimate divergence of water vapor flux in atmosphere with NCEP/NCAR data I have the equations for that and i want the algorithms to implement it for NCEP/NCAR data. I have a paper with algorithms for ECMWF data. Can i take this? or it required new algorithms for my data
  7. O

    Atmospheric pressure - questions

    Hello. I have two simple questions. 1) I don't understand atmospheric force. I read that it occurs by heaviness of air column and it act perpendicular to any surface. I can't imagine it. Where is the air column in experiment with glass and papper? Why the atmospheric force act...
  8. electronicsguy

    Why does atmospheric pressure not keep liquids inside upside down cups?

    If I hold the top end of a straw filled with water, the water stays in the straw which is due to the atmospheric pressure. How come this effect is not seen in upside down cups? Should the atmospheric pressure keep the liquid inside it within the cup since the other end is closed? Also, the...
  9. A

    Atmospheric Emission: Climate Change, CO2 & Quantum Chemistry

    A friend is a quantum chemist. He is in agreement that climate change is bad (he feels the primary problems with CO2 is ocean acidification). Anyway he states there is no credible research showing that atmospheric CO2 re-emits radiation to the planet. His belief is that the intersection of IR...
  10. H

    How can you anticipate when to add the atmospheric pressure?

    Homework Statement There are certain problems involving pressure where you are required to add the atmospheric pressure to solve the problems, i have done some problems where i work everything out but get the answer wrong because i did not add the atmospheric pressure. How can i overcome this...
  11. A

    Atmospheric physics / geophysics.

    I'm a 2nd year applied physics student in university and I'm wondering if anyone has advice on careers in atmospheric physics / geophysics. Although it is controversial I would like to go into the field of research of climate control by injecting volcanic ash into the atmosphere. Does...
  12. O

    Does Interstellar Gas Affect Atmospheric Seeing in Ground-Based Observations?

    This is probably a stupid question, but it has been bugging me. We are severely limited in ground based observations due to atmospheric seeing effects distorting the image. Why then are we not concerned by the vast amounts of gas/planets/etc in the line of path to our source that should also...
  13. T

    MHB Finding the Altitude at a Given Air Pressure

    Atmospheric pressure decreases as altitude increases. The pressure can be approximated by the formula P(h) = 101.33(0.9639)^\frac{h}{1000} where P is pressure in kilopascals and h is height in feet. a) What is the pressure at sea level (0 feet)? b) At what altitude will the air pressure be...
  14. M

    Drift speed of an electron in normal atmospheric conditions

    Homework Statement How fast would a electric arc be when it ionizes through normal, unpressured air between say, two electrodes? Not the same as lightning as it is hypothetically from an artificial source. Homework Equations How would one calculate (please include your formula's and which...
  15. chasrob

    Atmospheric Extinction: How Deep Can 20/15 Vision See?

    Let's say that you are aboard the ISS looking out a port hole. Far above the atmosphere, how deep should someone of say, 20/15 vision be able to see with the naked eye? 12th or 13th mag.? I read where, in 1944 during the war blackout, amateur astronomers were able to pick out 8th mag. stars...
  16. R

    Pressure vessel exploding within an atmospheric chamber

    I am currently investigating pressure test safety with my current employer. Currently we test pressure vessels inside steel test containers, see attached pdf. At the moment Boyles law is used to calculate the resultant pressure increase inside the steel container if the pressure vessel was to...
  17. leviterande

    Is it possible to glow-discharge air at atmospheric pressure?

    Hi, I know air can be made ionized and glow at low atmospehres like in vacuum tubes at high voltages. But is it possible to somehow make a glow discharge(not corona discharge out of leaking sharp edges) at atmospheric pressures?. Except of Ionization radiation- I haven't heared or read of...
  18. rshreyas

    Generate Electricity from Atmospheric Pressure

    can we produce electricity from atmospheric pressure...if yes, please suggest any processes or methods by which we can generate electricity from atmospheric pressure..
  19. V

    Atmospheric Pressure Question?

    Homework Statement A scuba diver can withstand pressures up to 4 atmospheres without risk of getting the bends. Homework Equations What is the maximum safe diving depth? The Attempt at a Solution 4 atmospheric pressure = 40 meters down in water. Thus the maximum safe diving depth...
  20. C

    Methane and CO2 atmospheric lifetime math problem

    Homework Statement On a per-molecule basis, methane is 26 times more effective as an infrared absorber than is CO2. Calculate the corresponding ratio on a per-unit-mass basis, and compare it with the 20-year GWP for methane. What's the reason for any discrepncy you find? (CO2 atmospheric...
  21. S

    How Does Turbulent Mixing Affect Atmospheric Pressure with Altitude?

    In the absence of turbulent mixing, the partial pressure of each constituent of air would fall off with height above sea level in Earth's atmosphere as Pi=P0ie−Migz/RT where Pi is the partial pressure at the height z, P0i is the partial pressure of component i at sea level, g is the acceleration...
  22. B

    How do gasses in a bottle have the atmospheric pressure

    when you close a bottle , why doesn't it collapse on itself ? shouldn't it since the pressure outside the bottle is greater than the pressure inside i know this is not the case , but how do gasses inside the bottle have the same pressure as the atmospheric ?
  23. S

    Normal Force and Atmospheric Pressure

    1. Suppose a cube of mass m is lying at rest on a horizontal surface. The area of one face of the cube is A. For the equlibrium of cube no net force acts on it. If we consider the vertical direction then the contact force N should be equal to the force due to gravity plus the force due to...
  24. tjej

    Atmospheric railway versus conventional railway

    There is a new automated people mover (APM) opening in Porto Alegre, Brazil called Aeromovel; it is built using atmospheric railway principles (see http://www.copa2014.gov.br/en/noticia/100-national-technology-aeromovel-reaches-its-final-construction-stages-porto-alegre) The vehicles runs...
  25. Y

    Atmospheric Pressure and Mercury in a Test Tube

    The problem statement Recently I came across this problem and couldn't understand it. I know that in situation 1, the length of the specific place will be decreased; In situation 2, it will be increased. Can someone help me here? Thanks first!
  26. W

    Idea about Mars atmospheric loss

    Mars current atmosphere is 0.006 bar. It is theorized that the atmosphere was thicker in the past possibly thicker than Earths 1 bar atmosphere. There are many processes that could have done this such as having no magnetic field, lack of geological activity, a planetoid crashing into it and...
  27. D

    Fluids Problem - Atmospheric Tank Pressure Vent

    Homework Statement Theres a atmospheric tank with a goose neck vent on the top and also an inlet pipe [a diameter 2 inch schedule 40] on the top. There is a compressed air line [from a 50 psi compressor] going into the inlet. The pressure inside the tank should not be above 2 psi. Size the...
  28. J

    Does atmospheric pressure affect the saturated vapor pressure ?

    When the Clausius-Clapeyron equation for saturation vapor pressure over liquid water is derived via the Carnot cycle, it is usually assumed that there is only gaseous water above the liquid. The other atmospheric gases are neglected. However, in common settings (lake, glass of water...), the...
  29. S

    Vapor pressure and atmospheric pressure

    the book says vapor pressure is independent of atmospheric pressure, if that is the case then why must the vapor pressure of a liquid be equal to the atmopheric pressure for it boils. I pictured atmospheric pressure as a column of air sitting above a liquid and therefore pushing down the gas...
  30. F

    Atmospheric stoichiochemistry: what mass of oxygen gas is produced?

    Homework Statement Oxgyen gas generated in the thermal decomposition of potassium chlorate is collected over water. At 24 C and an atmospheric pressure of 762 mm Hg ((101.6 kPa), the volume of gas collected is 0.128 L. The vapor pressure of water is 22.4 torr (2.98 kPa). What mass of oxygen is...
  31. F

    Atmospheric Stoichiochemistry: what mass of CO2 is produced?

    I have two problems actually: Problem 1 Homework Statement What mass of carbon dioxide can be produced at a temperature of 1500 *C and an atmospheric pressure of 92.5 kPa, if 15.5 L of acetylene gas is burned at STP? Homework Equations PV = nRT P1V1/T1 = P2V2/T2The Attempt at a Solution...
  32. I

    Comparing Atmospheric Pressure to Explosion Force

    Is there any way, crude as it may be, to find an equivalency between the pressure exerted on an object from layers of atmosphere and the force or energy put on an object from an explosion? I'm trying to categorize the durability of certain things and I've gotten to a point where instead of...
  33. I

    Vacuum, atmospheric pressure and constant gravitational acceleration

    This isn't home work, just a curiosity question and I'm obviously under qualified to find the answer. Looking to approximate how the amount of of vacuum in inches of Hg negate the affects of atmospheric pressure in regards to acceleration. We all remember when David Scott let loose the...
  34. J

    Atmospheric eddies, waves etc: definitions

    Hi all. I'm reading up on types of atmospheric motion, and when discussing the meridional transport of various properties, the motion is generally split into three components: 1. Mean meridional circulation 2. Transient eddies 3. Stationary waves However, depending on what book...
  35. denjay

    Atmospheric Carbon Sequestration?

    I recently saw a documentary about our energy usage and how we derive our energy. Obviously it was a pessimistic viewpoint but I think it might actually be true (It's called Blind Spot, I recommend it). One thing about it that spoke to me was that people don't worry about climate change because...
  36. R

    Modeling Atmospheric Re-entry & Determing Optimal Re-entry Parameters

    I'm taking a course in adaptive neural networks and became interested in trying to see if I can use neural networks to find the optimum values for the control parameters in atmospheric re-entry in order to reach a specified target on Earth. I've come across a paper that discusses this and goes...
  37. R

    Simple experiment to measure atmospheric Oxygen

    I am doing a biology project in which I needed to measure the O2 in the test chamber to determine how much activity I had. The Oxygen sensor I bought on eBay was long expired and useless. O2 instruments were at least $120 used. So I began looking for a simple cheap solution to do it with common...
  38. S

    Understanding Hurricane Warnings & Damage Potential Along the Gulf Coast

    Assume that Hurricane Don forms into a category 1 hurricane and is positioned in the Gulf of Mexico as shown in the figure below. The 24 hour forecast is for Don to make landfall at the Texas/Louisiana border in 24 hours as a category 2 storm. (The states of Texas and Louisiana are labeled with...
  39. C

    What is the role of atmospheric refraction in a sunset?

    Homework Statement Explain, with the relevant equations and a clearly labeled figure, what is actually happening as you view a sunset. Make sure to include a clearly labeled ray diagram for full credit. Homework Equations n1sin(θ1) = n2sinθ2 1/f = 1/o + 1/i The Attempt at a...
  40. M

    Why is atmospheric pressure the same indoors?

    Hi, apologies in advance as I feel stupid for asking this, but believe me I tried googling. The typical explanation for atmospheric pressure is that there is a column of air sitting on us, creating a pressure of 101 kPa. But what if there's a ceiling above us? Now only a few feet of molecules...
  41. E

    Could an Atmospheric Siphon Create a Self-Sustaining Effect?

    While I'm at it I might as well ask your help on another question that has been bugging me for a while. Let's hypothesize a huge "straw" a hundred metres or more in diameter. One end of this straw is at sea level. The other end is at 10,000 metres in altitude. It's obvious that the air...
  42. M

    Atmospheric pressure effect on simple mechanisms

    Please see attachment. Will be happy to receive comments/responses on the doubts raised. Murali
  43. T

    Atmospheric Physics: Max Env. Lapse Rate of Unsaturated Air Layer

    Homework Statement Consider a layer of unsaturated air on Earth, 2000 m thick, whose base is at a height of 4000 m above sea level. The layer sinks and is compressed till its base is at 350 m and its top is at 1650 m. If the layer now provides a subsidence inversion, calculate the maximum...
  44. F

    Separate water vapor from atmospheric air

    There is a simple method to separate the water vapor from the atmospheric air, however, in the form of gas and not of condensed water?
  45. C

    Hypothetical flying and gliding animals of planets with higher atmospheric pressure

    How would they look like? Being more specific and less speculative: would higher atmospheric pressure (ex. 5 atm) mean that it is easier to fly/glide because lower wingspan would allow to achieve the same lift? Or it would be actually harder, because denser atmosphere would mean higher drag...
  46. C

    Why Does Θ-Dependence Vary with Neutrino Energy in Monte Carlo Simulations?

    Hi I've been asked to give "A physical explanation of why the Θ-dependence of multi-GeV Monte Carlo data is qualitatively different from the sub-GeV data." i.e why is the monte carlo simulated data peaked around Cos(theta) = 0 for high energy neutrinos but not low energy ones. I'm not sure...
  47. R

    Atmospheric pressure and the spring constant

    Homework Statement I already found A, but I keep getting wrong answers for B. A cylinder is fitted with a piston, beneath which is a spring, as in the drawing. The cylinder is open to the air at the top. Friction is absent. The spring constant of the spring is 4300 N/m. The piston has a...
  48. K

    Atmospheric pressure to gas pressure in the apparatus

    Homework Statement If the atmospheric pressure is 745 mm Hg, what is the gas pressure in the apparatus in atm? (Hint: the gas pressure is not equal to atmospheric pressure. Which is greater Pgas or Patm?) Be careful with your units, 10.2 cm is equal to 102 mm Homework Equations...
  49. A

    Atmospheric Pressure Above the Sea Level

    Homework Statement The atmospheric pressure deceases exponentially with height. At 5.5 km, the pressure is half that at sea level. At what height is the pressure one eighth that of sea level? Homework Equations All I can think of is Pat=ρgh I know 1 atm=101325 Pa=101.325 kPa and that this is...
  50. A

    Limitations to the practical use of atmospheric electricity?

    "In fine weather, the electric potential increases with altitude at about 30 volts per foot (100 V/m)...." what hinders its practical application as a source of power, as a battery?
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