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

    How buoyant force and atmospheric pressure can be helpful in life ?

    How buoyant force and atmospheric pressure can be helpful in life ?
  2. W

    How Many Cylinders Are Needed to Fill a Hydrogen Balloon?

    Homework Statement A balloon whose volume is 500 m^3 is to be filled with hydrogen at atmospheric pressure (1.01x10^5 Pa). a. If the hydrogen is stored in cylinders of volume 2.5 m^3 at an absolute pressure of 35x10^5 Pa, how many cylinders are required? Assume temperature of hydrogen remains...
  3. A

    My essay on the atmospheric boundary layer

    3 pages double spaced. Can someone please comment on it before Sunday? That would be nice. Thanks! the file located at http://students.washington.edu/achen89/3_boundarylayer.doc . Please feel free to e-mail corrections to hemaalpha@gmail.com Human civilization (and biological phenomena) has...
  4. M

    Atmospheric Muon lifetime experiment

    OK, I'm currently in the process of designing an experiment to measure the rest lifetime of the muon, using a vertical stack of four flat scintillation detectors separated by lead plates, and coincidence electronics, Time-Amplitude converter, etc. to acquire data from the cosmic ray muons...
  5. B

    Atmospheric pressure and density.

    My question states: Given that the ground-level pressure of the Earth’s atmosphere is 1.033 *10^5 N m^−^2, calculate the mass of the atmosphere. If the ground-level atmospheric density is 1.293 kg m^−^3, calculate the scale height. For the first bit, I used P=nKT, assuming a temperature of...
  6. W

    Atmospheric methane as energy source?

    Is it possible to extract methane from the atmosphere to use as energy or hyrogen source? The advantages are obvious: clean, renewable, and global warming reducing. Is it theoretically feasible but not practical at the moment (like nuclear fussion power generation)? If so, I just wonder why...
  7. Z

    SL Atmospheric Pressure Calculation

    Im glad this website is here for help, cause physics is nuts, but i enjoy it. question is at 11km below sea level what is the pressure in atmosphere. now I've got the equation p=(h)(g)(d) ive got g=9.8 m/s d=1030kg/m3 (given to us) but the height is what is throwing me off, in...
  8. wolram

    UK Moon Sighting: Was the Halo Real or Atmospheric?

    Did anyone in the uk see the moon last night ? it was so bright, and seemed to have a three lobed halo surrounding it, is this just atmospherics ?
  9. B

    Estimating Atmospheric Masses Using the Barometric Equation

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  10. A

    Solve Atmospheric Pressure: Physics AP Edition

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  11. vincentm

    [astrogeology] measuring atmospheric density

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  12. P

    Atmospheric Pressure & Boiling Point: Exploring the Why

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  13. M

    Atmospheric Pressure determined by?

    What factors determine the pressure of a planet's atmosphere? For example: Mars has an atmospheric pressure that's much lower than Earth's. Well, o.k., that's a simplistic statement. Go high enough up in Earth's atmosphere and no doubt you can find a spot where the "atmospheric pressure" is...
  14. DaveC426913

    Tree height and atmospheric pressure

    I'm sure this has been asked uncountable times before. How can any tree be more than 32 feet tall?
  15. P

    Atmospheric Pressure: Why Does It Stay the Same?

    I always wondered :confused: When you are standing on an open area. the pressure exerted by atmosphere on your head is the total weight of the atmosphere column just above your head.Of course, divided by the area of your head. When you are inside a closed room! Even then the atmospheric...
  16. D

    Is the Speed of Light Affected by Atmospheric Conditions?

    Do photons travel at the speed of light (c) inside the Earth's atomphere? Or is friction a factor of their velocity. Ty
  17. G

    Atmospheric pressure at high altitude

    I was a bit surprised to find that the average recorded atmospheric pressures at such locations as Mexico City (2.2 km above sea level) are roughly equivalent to those *at* sea level, i.e. in the 99-102 kPa range. I find this a bit odd, since the air density at this location is just under 80%...
  18. W

    How Do Free Electrons Move in Response to Atmospheric Potential Changes?

    This question is giving me some difficulty. Under normal atmospheric conditions, the potential in the atmosphere near the Earth's surface rises 80 V for every metre of increased elevation. A) What direction will free electrons in the atmosphere move? B) Calculate the loss in electric...
  19. S

    How quickly does the Earth's atmosphere dissipate into space?

    Anyone have a link or direct info regarding the rate at which the Earth's atmosphere dissipates into space? I'm looking for both an estimate of the current rate as well as a model (time and mass dependencies). Thanks.
  20. H

    How atmospheric humidity is measured

    it is not a myth that on some days our hair seems to not want to cooperate with whatever style we've chosen (this is especially true for women's hair styles). meteorologists use an instrument known as a hair hygrometer to measure the humidity in the atmosphere, because human hair has been found...
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