18.1

• Atmosphere


  The envelope of gas that surrounds Earth, held together by Earth's gravity, which makes Earth "livable" by regulating solar energy which drives all life processes on Earth
• Atmosphere


  • It gives us warm, gives us oxygen to breathe, and it is where weather happens
  • It keeps the overall temperature fairly steady, especially between night and day
• Meteorology


  The branch of Earth Science which deals with the study of the atmosphere and its corresponding weather patterns
• Meteorologists


  People who study the atmosphere
• PAGASA


  The Philippine agency that deals with climate and weather, providing flood and typhoon warnings, public weather forecasts and advisories, meteorological, astronomical, climatological and other specialized information and services primarily for the protection of life and property and in support of economic, productivity and sustainable development
• Roles of the Atmosphere on Earth

  • Animals breathe in oxygen through respiration, plants use carbon dioxide through photosynthesis
  • The nitrogen and oxygen gases make it possible for energy to move such as sound
  • The atmosphere shields Earth from the harmful effects of ultraviolet radiation (UV) emitted by the Sun
  • The atmosphere keeps the temperature of Earth at a suitable range through greenhouse effect
  • The state of the atmosphere also dictates weather patterns on Earth, the energy of the wind drives propellers, sailboats and windmills and it also creates waves and ocean currents
• Ozone layer


  Protects us from the Sun's UV rays
• Composition of Earth's atmosphere


  • Nitrogen (78%)
  • Oxygen (21%)
  • Water vapor, carbon dioxide, ozone, argon, neon, helium, hydrogen, dust particles, and chlorofluorocarbons (1%)
• Layers of the atmosphere


  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere
  • Exosphere
• Temperature gradient


  The changing temperature in the layers of the atmosphere, as one increases altitude from one layer to the other, temperature changes across the layers
• Troposphere


  • It has the highest density and greatest air pressure
  • It provides oxygen that we can breathe, keeps Earth at a livable temperature and allows for weather to occur, making it a very important part of the atmosphere
  • It is the layer where rain, tropical storms, hurricanes, and thunder storms happen
  • As altitude increases, the temperature in the troposphere decreases
• Tropopause


  The boundary that separates the troposphere from the stratosphere, where the jet stream (air current of rapidly moving air) is found
• Stratosphere


  • Most volcanic dust accumulates in this layer
  • The ozone layer, which protects Earth from harmful sun rays, is found in this layer
  • There is less turbulence in this layer, so airplanes fly here instead of the troposphere as it is unstable
• Stratopause


  The boundary that separates the stratosphere from the mesosphere
• Mesosphere


  • It has no gases that absorb UV rays from the Sun, and is a very cold layer at -90°C
  • It has a thin layer of air enough to decelerate meteors entering Earth, adding friction to meteoroids producing the burning tail of shooting stars, and burning most meteor and asteroids before they reach the Earth's surface
• Mesopause


  The boundary that separates the mesosphere from the thermosphere
• Thermosphere


  • It is the biggest atmospheric layer, comparatively closer to the Sun and it absorbs a large amount of solar radiation
  • The ionosphere, a layer of charged gas particles in the thermosphere, bounces off radio waves from different parts of the world
• Aurora borealis, as viewed from outer space, is an effect of the interaction of our atmosphere with the solar flares
• Aurora borealis


  The aurora in the Northern Hemisphere
• Aurora australis


  The aurora in the Southern Hemisphere
• Karman line


  An invisible marker which serves as the boundary between Earth's atmosphere and outer space, named after Theodore von Kármán
• Low-Earth orbit (LEO)


  A satellite orbit characterized by its altitude, about 160 to 2000 km above Earth's surface, where the International Space Station (ISS) and the Philippines' first microsatellite DIWATA-1 are found
• Exosphere


  • It is the outermost layer, more than 700 km to 10,000 km from Earth's surface with no clear boundary, continuing into outer space