SPACE SCIENCE – 2ND QUARTER NOTES
STRUCTURE OF THE ATMOSPHERE
 The ATMOSPHERE is the envelope of gases that surrounds our planet.
o It supplies Oxygen to breather
o It protects us from meteors and cosmic rays
o It helps regulate temperature
o Planets without an atmosphere like Earth’s can’t sustain life
 The creation of the atmosphere was a direct act of God (Gen. 1:6-9)
o After sin entered the world, the atmosphere may have changed, but we’re not sure exactly how
 The atmosphere can be divided into TWO LAYERS BASED ON COMPOSITION or FOUR LAYERS BASED ON
TEMPERATURE
 In addition, there are several unique layers to our atmosphere
Atmospheric Chemical Elements
 Oxygen – if the air was pure oxygen or even more than 25% oxygen, fires would burn out of control
o Our oxygen level is 21%, so about the most that is reasonable (Design)
 Nitrogen – the chief function of this gas is to dilute the oxygen
o It is relatively INERT – meaning it doesn’t react much
o 78% - again by DESIGN
Composition Layers:
 Homosphere – gases are evenly mixed
o This mixture goes to about 50 miles above the earth
 Heterosphere – gases divide based on density, with heavier closest to earth’s surface
o The lighter gases extend all the way into space
o The gases in order from closest to the earth are: nitrogen, oxygen, helium, and hydrogen
Temperature Layers
 TROPOSPHERE – this is the lowest layer and is the weather layer.
o Temperature decreases with increasing altitude (about 3.5 degrees F for every 1000 feet) until just
under 7 miles in altitude (about 35,000 feet)
o This drop in temperature is called the LAPSE RATE and stops getting colder at about -67 degrees F
o Warm air at the bottom tends to rise and cold air at the top tends to sink
o Rising warm air causes clouds to form and brings rain
o Sinking cool air brings fair weather
 STRATOSPHERE – extends out to about 30 miles (160,000 feet)
o Temperature varies from -67 F at the boundary with the Troposphere and actually GETS WARMER to
about 32 F at the top!
o Free of clouds and significant dust
o Aircraft flying long distances often fly in this layer
o Some winds can travel up to 300 mi/hr in this zone and move from west to east – called the JET STREAM
 Pilots use the Jet Stream to increase their speed and save fuel
 Flying AGAINST the Jet Stream can obviously do the opposite
 MESOSPHERE – is the next layer outward and extends up to 50 miles out (250,000 feet)
o Its temperature decreases with altitude and has the coldest temperatures in the atmosphere at -130 F at
its top edge
 THERMOSPHERE – the uppermost temperature layer
o Though atoms and molecules are heated to high temperatures, they are so far apart it might not feel hot
o
Since radiant energy is unfiltered in this level, in the daytime spacecraft traveling in this level DO
become hot
o The thermosphere extends out to about almost a million feet in altitude
 EXOSPHERE – there is no distinct boundary between the atmosphere and space, but this layer is a transition
zone
o Gravity is so little that gases in this area can escape into space.
Special Layers
 OZONE LAYER – this is actually part of the upper Stratosphere
o Ozone is actually THREE oxygen atoms (instead of the two in normal “breathable” oxygen)
o It absorbs ultraviolet radiation and shields the earth from its effects
o The presence of ozone is why the Stratosphere warms (absorbing solar radiation)
o A hole over the South Pole has caused concern that man-made chemicals threaten the Ozone Layer
 IONOSPHERE – the sun’s radiation in the Thermosphere causes atoms and molecules to lose electrons
o These electrically-charged atoms are called ions.
o These ions reflect radio waves that allow us to communicate with other around the world.
 MAGNETOSPHERE – composed of protons and electrons from the sun that have become trapped in the earth’s
magnetic field
 Sometimes these particles escape into the lower atmosphere and give off beautiful colored light
called the Aurora Borealis (near the North Pole) or the Aurora Australis (near the South Pole)
ENERGY IN THE ATMOSPHERE
 Almost all the energy on the earth comes from the sun.
 ONLY ABOUT HALF of the radiant energy that falls on the earth actually makes it to the surface
o Clouds and particles in the atmosphere can reflect almost a third of the radiant energy
o Up to almost 20% is absorbed by the same
 Remember: the Ozone Layer filters out most of the Ultraviolet rays
 The radiation absorbed by the earth’s surface warms the earth and then is emitted as Infrared radiation.
o The earth warms the air indirectly after the sun warms the earth – this is called the GREENHOUSE
EFFECT
o Water vapor and carbon dioxide are called Greenhouse Gases because they trap infrared rays
Conduction and Convection:
 When heat is transferred by DIRECT CONTACT with another substance, that’s called CONDUCTION
 When heated air transfers energy to another location because of air movement, that’s called CONVECTION
WEATHER
 The study of the atmosphere (especially the Troposphere) is called meteorology.
 The condition of the atmosphere at any given time is called the weather.
 A description of the weather may include ALL of the following:
o Temperature – humans can only tolerate a small range of temperatures
o Atmospheric Pressure – the gases in our atmosphere have a weight (because of gravity) and put
pressure on the surface of the earth and everything there.
 Warm and cool air have different densities and therefore exert different pressures
o Humidity – the amount of moisture in the air compared with the maximum amount it will hold at a given
temperature is called the Relative Humidity
 Warmer air can hold more water vapor than cool air
 Relative Humidity affects comfort
o
o
Wind Speed and Direction
 Wind direction is determined by the direction FROM WHICH IT IS COMING
 A wind from west to east is considered a west or westerly wind
 Wind increases the rate of evaporation, so temperatures seem cooler
 In cold weather, wind makes things less comfortable and is expressed as WIND CHILL
Precipitation – is any form of water that falls to the earth’s surface from the sky
 Rain, snow, hail, sleet
ATMOSPHERIC WATER – Chapter 10
CHANGES OF STATE (PHASE)
 Most water enters the atmosphere as water vapor by evaporation from the oceans
 Water can exist in three STATES or PHASES: solid, liquid, gas
o Ice, water, water vapor
 The change from a solid to a liquid is called MELTING; the reverse is called FREEZING
 The change from a liquid to a gas is called VAPORIZATION and can occur by BOILING or by EVAPORATION
o What’s the difference between them? One is at the boiling point and the other is at a lower
temperature
 The change from a gas to a liquid is called CONDENSATION
 Sometimes, things can change from a solid directly to a gas and that’s called SUBLIMATION



Since water can exist in the atmosphere in any of its 3 states, how does that work?
o As WATER VAPOR, water is felt in the air as humidity.
o When it is a solid or liquid, it appears as clouds (and often precipitation)
A CLOUD is a mass of water droplets or ice crystals suspended in the air
As warm, humid air rises, it cools off and causes the water vapor (humidity) to condense as tiny droplets –
sometimes as ice crystals
o When planes fly high they sometimes have to use de-icing equipment to prevent ice from forming on
the wings
BASIC CLOUD TYPES:
 STRATUS clouds form in layers or sheets
 CUMULUS clouds are puffy and piled up
 CIRRUS clouds are thin, high, and wispy
 NIMBUS clouds are dark and gray and may bring rain or snow
See VIDEO:


With all the water IN the atmosphere, how do we get it out??
o DEW – when the air is calm and it gets cool at night, dew can form (remember Gideon – Judges 6?)
 Warm air holds more moisture (humidity) than cool air, so overnight as air cools, it can’t hold as
much moisture, so it forms on things that are cool
o FROST – if temperatures are cold enough to make things freeze, frost can form.
 If it’s cold enough, water vapor SUBLIMES right into a solid (ice crystals) instead of condensing
as water first.
PRECIPITATION refers to ALL forms of water falling from the atmosphere
o The VERTICAL movement of air causes cloud formation by CONVECTION
 Remember hot air rises and then cools, causing clouds and precipitation
o


Air movement OVER MOUNTAINS causes air to cool as it rises.
 The windward side gets more precipitation (Vail vs Denver)
o When two AIR MASSES collide, the cooler one wedges the other higher and causes cooling
All liquid water precipitation is called RAIN, but there are two types have special names:
o DRIZZLE is small droplets of rain falling slowly
o FREEZING RAIN is super-cooled water that falls as liquid but freezes on contact – part of an ICE STORM
Solid precipitation has several forms:
o SNOW forms when water vapor sublimates directly into ice crystals
o SLEET is small rounded ice pellets
o HAIL is large ice pellets that fall during severe thunderstorms
AIR MOVEMENT IN THE ATMOSPHERE
Chapter 11
 Our weather changes because air is always moving
 AIR MASSES are huge chunks of air covering thousands of square miles and expanding up into the atmosphere
many miles
o Air masses take on the humidity and temperature of their SOURCE REGION.
o There are FIVE kinds of air masses possible:
 CONTINENTAL MASSES that form over land and MARITIME MASSES that form over oceans
 ARCTIC (extremely cold areas), POLAR (cool or cold areas), and TROPICAL (warm or hot areas.)
 Possible combinations are: cA, cP, cT, mP, mT (for a total of 5) – mA virtually NEVER forms, so
has been dropped from the list
 SEE VIDEO
o ???What kind of weather might each air mass bring to different parts of the country during different
seasons??
o Air masses are called WARM or COLD depending on their temperature compared with the surface over
which they are passing.
WINDS – three factors determine wind flow and direction:
 Horizontal atmospheric pressure differences
o COLD AIR masses have more dense air and so have HIGHER PRESSURE
 Coriolis effect
 Friction
o Winds experience friction like fluids (air is considered a fluid)
o Uneven terrain and buildings increase friction
o Higher level winds aren’t affected as much as surface winds
 Local winds are created by local temperature differences:
o Sea and Land breezes are created by different surface temps
 Remember cool air sinks and warm air rises.
 Cool air rushes in to take the place of rising warm air
o Valley and Mountain breezes work the same as mountains warm and cool faster than wooded valleys