1.
Astronomy
and Cosmology
What is the difference between astronomy and cosmology? Cosmology is a branch of astronomy that studies origin, structure, and space-time relationships of the universe.
The Early Greeks (and Phoenicians, Egyptians) named the stars in 88 patterns called constellations. Astronomers were the “stellar” scientists at this time. About 300 BC, an observatory was built in Alexandria, Egypt.
Who are the most important astronomers and what did they discover? Copernicus is recognized as the father of astronomy because he theorized the earth rotates on its own axis and travels around a fixed point, the sun. In 1609, Galileo Galilei was the first to see Jupiter’s moons with the first telescope and supported Copernicus’ theory against current doctrine. He also showed that the stars are further away than the planets. Kepler developed the principles of planetary motion, especially elliptical orbits such that the square of the period is related to the cube of the radii of orbit. Einstein provided the framework of light and energy in a relativistic relationship. Einstein‘s theory is that light travels at constant speed and time travels at different rates (but always forward). Einstein’s twin paradox: if a space traveler makes a round trip somewhere near the speed of light, then the traveler will have aged less than the stay at home twin. He also suggested space-time bends around massive objects like black holes. Stephen Hawkings (who suffers from multiple sclerosis and is partially paralyzed) expanded Einstein’s universe and attempted to unify astrophysics using gravity relationships around black holes, which are located at the centers of galaxies and are so dense, not even light can escape their gravity.
Telescopes. The optical telescopes (with reflecting mirrors and/or refracting lens) have been the mainstay of astronomy for hundreds of years. Newer telescopes collect radiation from the full electromagnetic spectrum (radio waves, x-rays, gamma rays, ultra violet, visible light, cosmic rays). The Hubble Space Telescope (HST), with mirrors only 2.4 m diameter, went into orbit around the earth in 1990 and provided clear pictures of the universe 3X better and further than any telescope before its time. Its view is unobstructed by atmosphere and light pollution. The HST uses several types of imaging and sensing devices. It has been repaired and recommissioned to work until 2010. New land-based telescopes are using large micro-manipulated mirrors to improve on the HST imagery.
What are the most important
facts to know about the universe? Our Milky Way Galaxy, a spiral galaxy, contains
over 200 billion stars, and spans 100,000 light years. Galaxies can be spiral,
elliptical, or irregular. Light travels at 300,000 m/s. A light-year is the
distance light travels in one earth year. Our solar system is 30,000 light
years away from the center of the Milky Way galaxy. Galaxies are clustered into
groups called super clusters, and these are parts of constellations. On a
moonless night away from city lights you can see a band of whitish light, which
is the disc of the Milky Way due to the large quantity of stars we cannot see
individually. There are over 100 billion galaxies, each containing over a
billion stars. Carl Sagan coined “billions and billions and billions” of stars.
A light-year is the distance light travels in a year. Galaxies are separated by
millions of light years. SETI is the search for extraterrestrial intelligence.
Galaxies form most of the visible mass of the universe and there is black mass,
which we cannot see. Astronomers have recently discovered planets orbiting
other stars.
Polaris, the north star, looks like it is always above the north pole from anywhere on the northern hemisphere. This explains why early sea explorers were able to navigate out of site of land and develop trade routes essential to development of western civilization.
What are some important
events with people in space? Chuck Yeager broke the sound barrier in the X-15,
the Russian Sputnik was first in space in 1957, Yuri Gagarin was the first man
in space in 1961, Alan Sheppard was the first American in space, John Glenn was
the first to orbit Earth and also the oldest person in space, Neil Armstrong
was first on the moon in 1969, and Sally Ride was the first woman in space.
Russia built the first space station (Mir). Russian cosmonauts hold many of the
space records, esp. longevity.
2.
Big
bang theory and expansion of the universe proposed by Edwin Hubble
10 to 20 billion years ago the universe was
as small as your fist (no space or time)
10-32 seconds after the “big bang”
initial expansion at greater than the speed of light
Existence of quark soup, 6 types of subatomic
particles, building blocks of protons and neutrons
In 1 second “big freeze” occurred when
particles came together started formation of atoms (nucleosynthesis) reducing
temperature from 10 billion to 1 billion degrees, H and He start to form
300,000 years after the big bang light and
matter separated
1 billion years after the big bang the first
galaxies form
Currently, universe is expanding, but
expansion is slowing (future expansion or collapse?) Open, flat, and closed
universes are speculated outcomes of future expansion/collapse. Doppler affect
with light used to measure movement away or toward us. Doppler effect is a
shift in frequency of electromagnetic radiation when the observer or source are
moving relative to each other. Older parts of universe are expanding away from
us at faster rate than near parts. We know this by the larger red shift in
light spectrum from older parts of universe.
Radiation from big bang is still detectable.
3.
Parallax
Parallax shift is the apparent movement of objects against each other, or a background. Parallax is a method used to measure distances to planets and stars. We use parallax with our bifocal vision to determine distances by comparing the L and R eye images. Move your finger or pencil 20 to 40 cm away from your face and look at it and background with right, left and then both eyes open. The closer the object, the greater the parallax shift. Astronomers use the star view from 6-month intervals when the earth is on opposite sides of orbit around sun. Uses trigonometry by measuring angles to point source from 2 locations (e.g. 2 eyes or 2 locations of earth’s orbit). Early astronomers used parallax to determine that planets orbit the sun rather than the earth. The largest parallax shift for the nearest star is less than 1 arc second (diameter of a dime at 1 mile distance) = 1 parsec away = 3.26 light years. Galileo tried to use parallax in 1609 to determine star distances but found his telescope was not able to observe the small shifts in parallax. The first star parallax was measured in 1838 independently by 3 scientists. Hendersen’s meridian circle was the most practical and popular. Photography was introduced in 1888.
4.
Stars
– life cycles - how visual, radio and X-ray telescopes collect data
We collect data on stars using visual, radio, and X-ray telescopes.
Stars start as nebula, a clump of gas (mostly H and He) and dust to coalesce into a prostar. When critical mass reached, then fusion begins (H combines into He).
Most are in binary systems (2 or more suns)
and are in “main sequence”. Main sequence of star life (90% of stars) is large
blue sun, smaller yellow sun (our sun is a G2 star). When H is used up and only
He left, star swells into red giant whose core collapse into a white dwarf
(outer material blown away in supernova), becoming a dead star (neutrons only)
or black hole. Supergiant– extra large star (300 times size of our sun) that is
short-lived. The Hertzsprung-Russel Diagram shows relationship of absolute
magnitude, luminosity, and star temperature. Stars have different colors
(related to temperature) and their brightness, compared to our sun, is its
luminosity. Surface temperatures range form 2,800 (red stars) to 28,000 degrees
C (blue stars).
Some stars pulsate = Cepheid Variables e.g. Polaris (North Star)
Quasars are oldest objects in universe and are near edge of universe, 12 billion light years away, they give off radio waves and more energy than 100 galaxies combined
Inside the star heavier elements get created through fusion.
5.
Composition
of the sun and nuclear energy generation
Fusion is nuclear transformation; primarily 2
H become 1 He, releases energy
Temperature at the core is 15 million degrees
C and at the outer layer only 2 million degrees C and at the surface the
temperature drops to 6000 degrees C.
It takes 1 million years for energy to escape
the sun core to reach its surface
Sunspots – dark spots on sun surface, cooler
than other areas of sun
Solar flares – outbursts of light and energy
Solar wind – emission of subatomic particles,
mostly protons, and cause the comets tails to point away from the sun
7 layers: He core, radiative zone, convective
zone, photosphere, chromosphere and corona
Energy enters the earth system primarily as
soar radiation and eventually escapes as heat. Sun energy (not earth core heat)
is the primary source of energy and heat on the surface of the earth. Sun
energy reaching earth – 34% reflected,
42% heating, 23% evaporation, 1% waves and wind, 0.023% photosynthesis, energy
cycles through earth’s biogeochemical systems
6.
Solar
system formation and material composition
Planets formed 4.6 billion years ago. Heavier
metals ended up nearer the sun, condensing to form rocky planets consisting of
iron, silicon, magnesium, sulfur, aluminum, calcium and nickel. Heavy metals
sank to the cores and light materials went to the surface. The early atmospheres
of the inner planets blew away with solar wind. 500 million years ago, solar
system was in its current form.
The planets, comets, asteroids, dust and
gases orbit the sun in ellipses, but earth’s ellipse looks more like a circle.
Radial orbital distances of planets, asteroids, and comets are sometimes
measured in astronomical units (AU), the radial distance of earth’s orbit.
Mercury’s magnetic field is 1% as strong as earth’s. It is a rock planet composed mostly of iron and nickel. It has a thin atmosphere of H, He, K, and S compounds.
Venus is the closest planet to earth and has similar size and
composition. It has a CO2 atmosphere. Its surface has volcanic
activity and is pot marked with craters.
Earth has a high content of radioactive uranium, thorium and potassium so its interior is hot, even after cooling for over 4 billion years.
Mars is 1/3 the size of earth and is composed of iron and iron
sulfides. The outer surface is oxidized (rusted) and looks red. Its magnetic
field is too weak to measure. The Pathfinder landed there in 1997. Mars may
have had primitive life on it 3 billion years ago, but is unlivable now.
Jupiter is composed mostly of H and He gas and is larger than all the other planets combined. The Great Red Spot is a giant cyclone storm at least 2 times the size of earth. In 1994, a large comet crashed into Jupiter.
Saturn is a large gas planet composed of H and He. It has a magnetic
field 1000X stronger than earth. The A and B rings are actually thousands of
rings with ice and ice-covered particles.
Uranus and Neptune are both gas planets and look blue because of their
methane gas atmospheres.
Pluto is a tiny low-density planet composed mostly of nitrogen.
The 4 inner planets have different atmospheres in depth and composition. Earth is the only one with a substation amount of oxygen. Remember the greenhouse effect and global warming. Why does Venus have the highest temperature and not Mercury? It’s the gas.
The main dark shadow of solar eclipse =
umbra, the lighter part of shadow = penumbra.
Nebula theory – solar system formed at same
time from a gas cloud
99% of the gas became the sun and fusion
started
7.
Planetary
exploration
SETI – search for extraterrestrial intelligence
Pioneer and Voyager were early interplanetary explorations. Magellan probe mapped Venus. Pathfinder robot landed on Mars in 1997, 2 probes in 2000 were destroyed
8.
Asteroids
and their impact on planets, especially recent one being currently studied (vs.
comets)
Comets are made of dust, loose rock, frozen
water, methane, and ammonia. There is a large spherical cloud of comets outside
of Pluto, the Oort Cloud. They have elliptical orbits around the sun and
eventually lose all their material (vaporize). Comet tails always point away
from the sun due to solar wind (particles expanding away from sun).
Meteors burn up in the atmosphere, meteorites
hit the ground (-ite means rock). Pea size meteors impact earth at the rate of
10 per hour. Meteors burn up in about 1 sec leaving a fiery streak (shooting
star). Most of our atmospheric dust is attributed to space debris.
What materials are asteroids made of? Rock,
metal (iron and nickel). Asteroids are from 100 feet to several miles diameter.
Most are located in the asteroid belt between Mars and Jupiter about 245 to 580
million km from sun, but also many in orbits around sun closer or farther than
earth and some pass through earth’s orbit (e.g. Apollo, Amor and Athens Group).
Over 1000 asteroids > 1 km diameter cross earth’s orbit.
Where did they come from? Broken up planet is
one hypothesis
What size of asteroid can do real harm to the
Earth? 1 mile wide
What asteroid is currently being probed by
NASA? 433 Eros (also Gaspra, Ida, and Mathilde) is being studied by the NEAR
probe (Near Earth Asteroid Rendezvous). Eros has a 50% chance of hitting the
earth in next 100 million years.
Asteroids hit Earth all the time; most are
small and burn up in the atmosphere. The last large one was 2,000 years ago and
left a ¾ mile wide crater in Arizona.
Asteroid collisions leave craters seen on the
moon surface
There are over 1000 asteroids over a Km wide
that cross Earth’s path and one of these hit the earth every 300,000 years on
average
The 5 mass extinctions recorded in the fossil
record are being attributed to asteroid hits, esp. the dinosaur extinction 65
million years ago.
9.
Earth
development over last 6 billion years (change in composition and structure)
First million years there were many volcanoes
spewing lava, ash, and water (created oceans). One theory of ocean development
is that water came from ice comets.
Earth has a solid inner core (3,500 km thick)
mostly Fe and Ni due to high pressure. Mantle (3,500 km thick) is like silly
putty, solid but plastic and moving like a liquid. Crust is only 60 km.
Blue green algae fossils found in rock 3
billion years old. Living Xenophile bacteria found in deep rock mining cores
today. Early life believed to be formed from self-replicating molecules in
primordial soup with UV sunlight and lightning providing energy.
Continents were all connected as one,
Pangaea, and then drifted into 2 continents, Gondwanaland and Laurasia. These
in turn broke up into our present 6 continents.
Earth’s earliest atmosphere (H and He similar
to other planets) was swept away by solar wind since these gases were so light.
Volcanoes spewed water vapor, CO2, methane and nitrogen gases. As
earth crust cooled, water condensed forming rain and filling the oceans. The CO2
dissolved into the water (chemical buffering) leaving mostly N2 in the air. One
small source of O2 was the breakup of H2O by UV light.
The major source was life forms (cyanobacteria) broke up CO2 into C
and O2, keeping the carbon and releasing the oxygen (a waste
product). Carbon now cycles through the biogeochemical spheres.
1.
Ocean
floor – magnetic patterns, age, topography
Midocean ridges, largest mountain ranges in
the world, represent 20% of earth surface, are sites of seafloor spreading at
rift zones. N and S poles reverse as evidenced by changing polarity of rock near
rifts. Magnetic poles shift every so often, about every 30,000 years evidenced
by the polarity shifts in the mid ocean ridges. Midocean ridges cover over 80%
of the Pacific Ocean floor and rise less than 5,000 feet.
Ocean crust moves and circulates back into
mantle (subduction) under continents and is much younger and denser than the
continental plates. Ocean crusts are no older than 160 million years.
Abyssal plains are incredibly flat features.
When ocean plates collide, volcanoes emerge
at the boundary and form island arcs (e.g. Japan)
Rift zones occur at sea floor spreading are
where hot mantle oozes out and separates ocean plates
SONAR – sound navigation and ranging is used
to determine seafloor depth, speed of sound in water is 1500 m/s (faster than
speed of sound in air)
2.
Plate
tectonics and plate boundaries
Asthenosphere is under the lithosphere and it is plastic like and flows
with convection currents
Continental drift proposed by Wegner in 1912
supported by fossil evidence and rock formations. The major mountain ranges of
the world were lifted from sea level by continental plate convergence.
Crust (continental and oceanic) and upper
layer of mantle = lithosphere, is solid
Mantle below lithosphere is liquid and has
cycling currents
The plates are: Eurasian, Indoaustralian,
Philippine, Juan de Fuca, Pacific (the largest), No. American, So. American,
Nazca, African, Scotia, and Antarctic
3 kinds of boundaries: divergent (apart),
convergent (together), and transform (horizontal shift)
Ocean plates are much younger and more dense
(basalt rock) than continental plates (andesite and granite rock), so when they
collide, the ocean plate goes under the continental plate (subduction) and
melts back into the mantle
3.
Rock
formation and composition
Hardness, luster (light reflection), streak (color), cleavage, and fracture can classify rocks. Mohs rock hardness scale: 1-10. Rocks with higher numbers can scratch rocks with lower numbers.
Fossils are found in sedimentary rock. Only
the hard parts remain identifiable so early life forms in the Precambrian and
Cambrian periods are hard to determine.
Age of rocks is determined by radioactive
dating (atoms of different elements s break apart at different rates so half
lives can be from seconds to millions of years). Ages of rock can also be
determined by the layering, erosion, and faulting in cliffs and road cuts.
Minerals form crystalline structures from
cooling magma or evaporating water
Crystal shapes: tetragonal, hexagonal,
orthorhombic, monoclinic, triclinic
4.
Earthquakes
and S and P waves
3 fault types: normal (down and away),
reverse (collide and raise), and strike slip (horizontal)
Richter scale measures amplitude and it is
logarithmic (1 pt = 10X increase). 1-3 not felt, 3-5 felt with little to no
damage, 6 slight damage, 7-8 major damage, 9-10 massive. The less used Mercali
Scale is a 12-point scale (I to XII) based on amount of damage a quake causes.
Epicenter is the focus or focal point of the
break
Prepare for earthquakes – retrofit,
flashlights, cell phones, water, food, AM radio, wrench for gas valve, shoes
near bed, first aid kits, fire extinguishers, strap water heaters, blankets,
tools, brace cabinets and bookshelves, medications and extra eyeglasses,
disaster plan, place to meet, contact person outside are for communications.
Most of the building damage during the 1906 San Francisco quake was caused by
fire (sparks around broken gas valves) while most of human injury was caused by
falling collapsing buildings. Our 1989 Loma Prieta Quake (7.2 on Richter Scale)
was most destructive to structures sitting on “fluid” like landfill and marshy
soils. A 5.0 size quake similar to the one that hit Napa in 2000 can occur
anytime, anywhere in the Bay Area.
Underwater quakes can cause massive ocean
waves, tsunami, over 100 ft. (30 m) high.
The San Andreas Fault is a transform fault
that has crept 350 miles in the last 20 million years. The San Francisco
peninsula used to be in the Monterey Bay.
5.
Two
types of volcanoes (some say 3) – location and properties
Volcanoes occur at plate boundaries and hot spots (e.g. Hawaii). Pacific Ring of Fire has most of the world’s active volcanoes (over 1500)
Orienteering is a sport participants find and
“ring” a series of hidden electronic stations in the wilderness using only a
compass and a topographic map with station locations. Fastest time wins. O’
maps contain more details than standard topo maps including ditches, fences,
cliff faces, fields.
GPS – global position system, uses series of
satellites to find 3 dimensional position on earth surface (e.g. NorthStar GPS
system in Cadillacs), can contain multiple layers of information (e.g.
landform, streets, buildings, customers), GIS tasks include data input and
manipulation, query and analysis, and visualization (graphics). Military and
surveyor GPS systems can pinpoint location within 3 cm.
GPS – geographical information systems, takes
numerical data and creates visual maps (e.g. weather maps), developed by
military (department of defense or DOD), need at least 3 satellites in view of
receiver and prefer at least 5. Most ocean going vessels have GPS systems
(global positioning systems) for navigation.
1.
Solar
radiation provides all the energy for all processes on the earth surface and in
the atmosphere
Solar radiation enters Earth’s atmosphere and about 35% is reflected back into space, 42% heats the air, water, and land, 20-30% goes to the hydrologic cycle (water), 1% goes to wind and wave action. Only 0.023% of the sun’s energy goes into photosynthesis. Over 60% is reradiated from the earth as IR light. Absorbed UV light heats the atmosphere, ocean and land. Cities are warmer during the day than the countryside due to greater absorption of heat by cement and asphalt and reduced transpiration by plants.
2.
Circulation
patterns in the atmosphere and distribution of heat, relation to Earth’s
rotation
Wind belts are general wind patterns around
the globe
3 major wind cells: Hadley (0-30 latitudes
near equator), Ferrel (30-60 latitudes), Polar (60-90)
Doldrums are calm windless areas near
equator.
Jet streams at top of troposphere between
wind cells (95-180 km/h wind rivers from east to west in North America used by
jet pilots)
The equator rotates at over 1000 mph and the
upper latitudes at less than half this rate causing the Coriolis effect, which
influences circulation patterns with air and water moving from poles to equator
and then west along equator. This general pattern sets up the other current
patterns.
Land heats and cools faster than ocean so get breezes shifting on a day-night (diurnal) pattern. During day land heats and air moves out to sea (land breeze), during the night the sea cools slowly so air moves to land (sea breeze).
Hot air has more water holding capacity than
cool air
3.
Reading
weather maps
Color indicates temperature (brighter colors are hot, blue and purple are cool)
Weather stations measure pressure, wind
speed, temperature, humidity, and rainfall. Each weather station (data
collection point) is designated on weather maps by a “station model”, circles
with symbols around it representing their data. Barometers measure air pressure
in millibars (760 mbar = 1 atmospheric pressure at sea level). Thermometers
measure air temperature (C, F, K). Anemometers measure wind speed. Dew point
hygrometers measure relative humidity (% of total capacity). Rain gauges
measure rainfall.
Relative humidity is the amount of water
vapor actually in the air compared to the amount it can hold (saturation =
100%). Water condenses above 100% relative humidity and forms clouds or rain.
Clouds can indicate local fronts. Cloud types include stratus (flat), and
cumulus (puffy) and can occur at low, mid (alto), or high (cirrus) altitudes.
Clouds are made of condensed water vapor when relative humidity is greater than
100%.
High pressure zones (H) are from dense air
masses expanding and causing wind. Low pressure zones (L) are from less dense
air mass. Thick lines indicate pressure fronts with triangular points (low
pressure front) or circles (high pressure front).
Isotherms are lines connecting 2 points of
equal temperature.
Isobars are lines connecting 2 points of
equal pressure.
Computer models represent raw data from
weather stations and satellites using GIS computer mapping programs to generate
the moving images presented by the weatherperson on TV.
4.
Atmosphere
composition and temperature inversions
Mars and Venus both have high concentrations
of CO2 and little or no O2. Mars has very little water
vapor. Venus has sulfuric acid clouds which destroys any probes sent into the
atmosphere. Earth also had a CO2 atmosphere, but the biotic life on
earth transformed the atmosphere and buffers the atmosphere from drastic change.
Oceanic phytoplankton (not rainforest) is the
major gas exchanger on earth. Plankton produces over 70% of the oxygen we
breath. Atmospheric CO2 has changed over time and may be the cause
(or result) of the ice age cycles and is currently an intense area of
scientific investigation.
Atmosphere is 78% N, 21%O, 1% Ar, 0.03% CO2,
0-4% water, trace of Ne, He, CH4, Kr, Xe, H. Water is the only
substance that exists as a gas, liquid, and solid in the atmosphere. Most of
the dust in the atmosphere comes from outer space. The small amount of CO2,
in the air is considered to be a limiting factor for plant growth in the most
efficient glasshouse operations so CO2 gas is added to the
glasshouse atmosphere.
Atmosphere layers – troposphere,
stratosphere, mesosphere, thermosphere, and exosphere. These layers are
primarily differentiated by temperature inversions caused by differences in how
each layer absorbs the sun’s light energy. As altitude increases, the
temperature decreases in the troposphere, increases in the stratosphere, and
decreases in the mesosphere. Troposphere contains 75% of all the gases in the
atmosphere. All our weather happens in the troposphere. The stratosphere has the ozone layer which
collects UV light energy and warms this gas layer. The ionosphere is a layer of
ions in the upper atmosphere (200 mi., crossing both mesosphere and
thermosphere) that reflects radio waves. Thermosphere temperature increases due
do lower density of gas (fewer molecules) collecting lots of sun energy so
temperature increases with altitude. The exosphere contains only H and He at
low densities and loses molecules to space.
Gravity keeps the gases from blowing away so
gas density is greater near the surface. At sea level it is 760 millibars (= 1
atmosphere =10 N/m). Air pressure decreases with altitude. Greater density and
temperature increase pressure (greater number of collisions).
Smog is caused by dust and nitrous and
sulfuric oxides. Smog has 2 forms, photochemical brown smog formed by light
reactions and sulfurous smog formed from burning fossil fuels. In LA, Beijing,
Mexico City, and Bakersfield, smog can be trapped by ocean wind, mountains, and
atmosphere inversion layer, increasing its concentration to critical levels.
Sulfur dioxide from coal burning plants or
nitrous oxides from car exhaust combine with moisture in the air forming
sulfuric and nitric acids, which enter the atmosphere and concentrate in water
vapor. “Acid rain” has destroyed many forests. An acid has a low pH (high
amount of H ions).
Fog (cloud) on ground is caused by air
temperature inversions.
5.
Greenhouse
effect and global warming
On Earth, solar radiation comes into the
atmosphere mainly as visible light and UV light. Atmospheric gases trap the
radiation as heat and act like an insulation layer. The main greenhouse gases
are water vapor, carbon dioxide, methane, nitrous oxides, and
chlorofluorocarbons. CO2 is the most important. The greenhouse
effect from CO2 (and other atmospheric components) warms our planet
about 35°C. Global warming is the
increase in temperature we are now experiencing. Many scientists believe the
increase of fossil fuel combustion has caused this warming through the
greenhouse effect. Some scientists believe it will lead to our inevitable doom.
On Venus, the CO2 is thick and
traps most of the incoming heat creating a greenhouse effect making it the
hottest planet in the solar system (460°C). Venus also has 15 km
thick clouds of sulfuric acid.
On Mars, the thin atmosphere does not
adequately buffer the temperature which then swings into extremes, but even the
high temperatures are too cold for life. The ice caps at the poles are frozen
CO2.
6.
Ozone,
UV, cancer, CFCs
Trace amounts of ozone (O3) are in
a diffuse layer in lower stratosphere. Ozone is blue and has a strong odor while
oxygen is colorless and is odorless. Out of every 100 million molecules I the
air, 2 million are oxygen and 3 are ozone. Much of sunlight is in the UV
electromagnetic spectrum with a shorter wavelength than blue and violet light
and occurs in 3 bands, UVA, UVB, and UVC. Ozone absorbs most of the UV light
(UVB and UVC, not UVA) from the sun and protects organic chemicals (including
all living organisms) from UV light degradation. UV radiation can cause burns,
skin cancer, cataracts (in eye), suppression of the immune system, premature
aging of the skin. Melanoma skin cancer has doubled in the last 20 years. A 1%
decrease in ozone will cause more than a million cases of cancer.
Ozone contributes to the greenhouse affect
but is minor compared to CO2.
Chlorofluorocarbons (e.g. Freon refrigerant)
are gas molecules that contain chlorine, fluorine and carbon atoms. They rise
to the ozone layer where UV light breaks them into atoms. Chlorine reacts with
ozone to form oxygen molecules (O2). A single chlorine atom can
attack over a million ozone molecules. Without ozone, the UV light will damage
DNA, our genetic code, and cause cancer.
The ozone layer is becoming less dense over
Antarctica and is referred to as the “ozone hole”
7.
Distribution
of rainforests and deserts – latitudinal bands, global patterns in weather
Deserts and rainforests tend to occur in the
tropics and subtropics. They are separated by mountain ranges, which can cause
a rain shadow effect. Rain shadows occur in the coastal and Sierra Nevada Mountains
in California.
Deserts get created by high heat (tropical
latitudes), mountain barriers from rain, wind patterns.
8.
Climate
(long term weather) is the result of energy transfers in and out of the
atmosphere.
Climate is determined by temperature, precipitation, latitude, altitude, topography and close water bodies. Proximity of water bodies tends to moderate the climate (fewer, less drastic swings)
3 major zones are: polar (pole to 60° latitude), temperate (60° to 30° latitude), and tropical (30° to the equator). Also
marine vs. continental climate patterns.
The ocean has a greater impact on continental
climate than previously believed. Ocean temperature and currents are now
receiving more scientific attention.
Climates change due to drifting continents, sun
output (sun spots), distance to sun, ocean currents
6 major climate regimes: Mediterranean,
marine west coast, moist continental, moist subtropical, desert, and steppe
Land and water have different heat capacities
which creates day-night wind patterns on coasts
Large bodies of water moderate local climate
Earth axis, rotation, and orbit around sun
influences seasons
Cold fronts are less dense than warm air
masses so cold slips under warm raising the warm air and cooling it producing
raining cumulus clouds
Warm fronts rise over cold air masses so
water condenses out of the rising air mass
Occluded fronts are when warm and cold air
meet and remain stationary, causing heavy rain
Hurricanes, Indian name meaning “big wind”,
are large, severe tropical storms in the Atlantic and Gulf of Mexico. Typhoons
are over the Pacific. Cyclones are over the Indian Ocean. Winds over 74 mph,
eyes of 6-60 miles, total center diameter up to 300 miles, total storm diameter
up to 2,000 mi. Warmer ocean water temperature is linked to storm severity.
Storm strength measure by Saffir-Simpson Scale (0-5). Hurricane Andrew hit
Florida with $20 billion damage in 1992.
Tornado prediction is difficult since they
happen quickly and unexpectedly. Many are associated with sever thunderstorms.
Winds up to 500 mph but only last for about 20 minutes. Funnel creates very low
pressure causing windows to burst out. Greatest occurrence of tornadoes is in
the Mississippi Valley (Midwestern US). Storm strength measured by Fujita-Maker
Scale (0-5). Satellite systems detect flashes of lightning whose patterns are
good predictors. Tornado “watches” indicate potential for occurrence and
“warnings” indicate a tornado has formed.
Flooding and flash floods can strike without
warning since rain in another location is causing the buildup of surface water
that accumulates in gullies and dry riverbeds. Floods can follow widespread,
heavy rain especially when soil is saturated. Floods can also occur due to deep
snow cover, full reservoirs, and high river and stream levels. Since water adds
buoyancy to cars, only 2 feet of water is needed to turn cars into boats.
Insurance companies traditionally do not
normally cover injury and damage due to “Acts of God” which includes all of the
severe natural disasters: hurricanes, tornadoes, earthquakes, and floods.
Special insurance, usually expensive, must be purchased separate from
homeowner’s policies.
1.
Carbon,
nitrogen, oxygen, and water cycles
C, H, O, N, and P are the main elements of life.
Also S, K, Cl, Mg, Fe, Na play major roles.
C, H, O, N, and P all cycle through living
beings, atmosphere, water, and rocks (biogeochemical cycles). They are all
linked and integrated into our biosphere.
The reservoirs of C: in the atmosphere as CO2,
in living organisms as carbohydrates and other biochemicals, in soil as organic
matter, in ocean water as carbonic acids, and in rock layers as coal, methane
gas, oil, peat. Sunlight and photosynthesis drives the carbon cycle.
The reservoirs of N include the atmosphere as
N2 and nitrous oxides, living organisms as proteins, and DNA, in
soil as organic matter. Nitrifying bacteria in the soil can oxidize N2
(gas in atmosphere) to NO2 and NO3, which can be reduced
to NH3 used by plants.
Water cycles (hydrologic cycle) from the
ocean to air vapor to precipitation as rain and snow washing down to streams
and underground aquifers and eventually returning to the ocean.
Oxygen is part of all the above cycles:
carbon, nitrogen, phosphorous, and water cycles.
2.
Circulation
patterns of the ocean and distribution of heat, relation to Earth’s rotation
Vertical currents from the cold water to the
warmer surface (upwelling) are essential for marine life since this circulates
the nutrients which tend to drift downward to the bottom with dead organic
material (detritus, marine snow). Upwelling feeds over half of the fish within
1/10 of the ocean surface.
Currents flow at 2.5 to 4.5 mph. Surface
currents (top 300-600 ft.) are moved by wind. Deeper currents are moved by
differences in density (temperature, salinity) and are therefore called density
currents.
2 tides per 24 hr. period (2 bulges on
opposite sides of the earth). Spring tides (maximum change) when sun, moon, and
earth lined up in a line, neap tides (least change) when moon, earth, and sun
at right angle. The moon is more important than the sun in creating tides since
it is closer.
Pressure in the deep sea can be 1000 times
greater than surface water.
Long shore currents run parallel to the shore.
Water is warmer at lower latitudes (closer to
equator). Warm water moves to poles and then sinks as it cools and goes back to
equator. Deep water tends to be cold, 34-39°F (1-4 degrees C).
Surface waves caused by wind. Top of wave is
the crest, bottom is trough, and distance between waves is the wave length.
3.
Ocean
water – properties, chemistry, layering, vertical and horizontal currents
Ions are: Cl- (55%), Na+
(30%), S (8%) in various forms, Mg+ (4%), Ca+ (1%), and K+
(1%). These salts come from the erosion of rocks on land. Salinity increases
when the ocean water evaporates and salinity decreases when atmospheric air
precipitates. Rivers also bring fresh water to the oceans, lowering salinity at
river mouths.
Seawater freezes at –1.9°C. (pure water freezes at 0°C).
Objects in water displace an equal volume
(when objects sink) or weight (when object float) so that they are “buoyed” up
(less impact from gravity).
Different wavelengths of light penetrate to
different depths. This is why water is blue.
The ocean is not an infinite unchanging body
and is being polluted and modified by civilization.
4.
Distribution
of marine life – patterns with depth and topography
Phytoplankton (photosynthetic bacteria) in the open ocean zone provide
over 70% of our oxygen through photosynthesis. Zooplankton (animal bacteria
less than 2 micron or 2/1000 mm) eat the phytoplankton
and are the herbivore base of the animal food web in the ocean.
Bioluminescence is used by many sea creatures in the deep ocean (abyssal and nektonic zones) by many sea creatures
5.
ENSO
cycle (El Niño, La Nina)
La Nina (little girl) is a cooling of the
ocean-atmosphere in the tropical Pacific.
Heat expands water like air, just not as
much. Hot water is less dense and “larger” than cold water. Due to this
expansion with heat, ocean water temperature can be estimated from the change
in ocean height by satellites (TOPEX, Poseidon run by NASA-) using RADAR
altimeters JPL (can measure 3 cm changes) and moored Atlas buoys (1 m changes).
Satellite and buoy data are analyzed by the NOAA (National Oceanic and
Atmospheric Administration).
El Niño and La Niña both influence our local
climate (storms, flooding, length of seasons).
ENSO (El Nino Southern Oscillation) is the
wide scale fluctuation of temperature of the tropical Pacific Ocean due to
shifts in ocean currents. ENSO has caused droughts in India, Indonesia,
Australia, and the Philippines and caused flooding in Peru, Ecuador, and California.
It is blamed for the Mississippi flood in 1993.
1.
Natural
resources
Land – mountains (Coast and Sierra Nevada Ranges, Mt. Whitney, Mt. Lassen, Mt. Shasta are volcanic), desert (Mojave Desert, Death Valley, Imperial), valleys (Central, Salinas, Napa and Sonoma, and Imperial Valleys)
Coast – natural bays (San Francisco, San Diego, San Pedro, Monterey, Humboldt), sanctuaries (Monterey Bay is largest on west coast), estuaries, fish and animal wild life
Water – rain patterns, fresh water, water
policies determine land use and $$$ in western US. Hetch Hetchy Dam
controversial. Lake Tahoe, made by glaciers, is the deepest mountain lake and
never freezes. Sonoma Lake is a major local resource for potable water. Snow
pack in mountains provides most of the fresh water for California, which keeps
rivers flowing year round.
River systems: Sacramento and San Joaquin
Rivers both flow to SF Delta, Eel and Russian Rivers provide most of the local
potable water.
Forests – Coast Ranges and Sierra Nevada,
variety of species esp. coast and sequoia redwoods
Animal life – abundance of Charismatic mega
fauna (bear, deer, lion, condors, eagles)
Plant life – 30% of 5,000 native plant
species occur only in CA (endemic)
Geothermal energy at the Geysers near
Cloverdale. Santa Rosa will pump waster water to it.
Government organizations: Natural Resources
Conservation Service, Forest Service, Bureau of Land Management, Water and
Power Resources Service, National Park Service, Fish and Wild Life Service,
Army Corps of Engineers
“Green” civic organizations: Green Peace,
Sierra Club, Save the Redwoods League, California Conservation Council, Nature
Conservancy.
2.
Natural
hazards, location and geological origins
Earthquakes – main faults in Bay Area are:
Hayward-Rogers Creek, San Andreas, and Calaveras
Floods and flash floods – occur during heavy
rainfall and ground is saturated. Where do they tend to occur? Petaluma has
been flooded in the downtown area and in the Payran area.
Fires – set by lighting and pyromaniacs.
Large amount of “fuel” around homes caused the Oakland fire to get out of hand
and burn several hundred homes. Forestry officials set “preventative” and
“maintenance” fires to reduce fuel. Forest and range fires can travel at 30 mph
and can not be outrun. Forest firefighters can get trapped and die of smoke
inhalation before they become crispy critters. Thick fuel, drought, and hot
weather combined create high fire danger.
Volcanoes – active sites near Mt. Lassen, Mt.
Shasta
Snow blizzards – what do you do if caught in
one in the mountains?
Rock, land, snow and mudslides – result from
too much rain. Many houses on hills are vulnerable.
Drought – less rain than usual creating a
resource limitation.
Tornadoes – yes we do have them in California
Geysers and hot springs
Sinkholes – occasionally a house sinks into
deep pit
La Brea tar pits contain remains of
dinosaurs.
Abandoned mine shafts
Allergies – Petaluma was known by the Indians
and is currently known at the hospitals as the “land of sickness” due to its
allergy producing pollen and winds. May and June are high season for sufferers.
3.
Economically
important resources
Agriculture – CA has dry climate, variety of
soils, fresh water. Over 250 crops. Main produce is meat, milk, cotton, grapes,
vegetables, fruit, and nuts. California leads the world in many crops.
Fisheries – freshwater: salmon, trout, bass;
ocean: tuna, swordfish, salmon, halibut, abalone, mussels, shrimp, crab
Lumber – redwood, pine and fir used for
building, harder woods for furniture and cabinets
Water – 10% of runoff is used in urban areas,
42% is used for agriculture, Colorado River controlled by Glenn Canyon and
Hoover Dams which provide energy, water and flood control for Arizona and
Southern California.
Oil – off shore oil in Santa Barbara is
controversial
(What happened to the gold and silver mines?)
4.
Sources
of fresh water and its distribution
Total world supply of fresh water is 326 million cubic miles. Only 3,100 cubic miles of water is in the atmosphere as water vapor or clouds at any one time = 1 inch of rain over the entire world. Less than 1 percent of fresh water is drinkable without filtration.
Water source, transport, purification, use,
treatment and wastewater use are major local issues in Petaluma. Our city
council is currently spending millions of dollars on fresh water sources
(County Water District controversy), flood control and drainage (Pyran St.),
water shed (Laferty Ranch) and a new wastewater treatment plant. Also, the
Petaluma River (and marshland) and Basin needs continuous maintenance of
dredging and environmental cleanup. Water will limit our growth and be our
biggest local issue and economic factor for several years.
The biggest contamination to the watershed
system (rivers, creeks and drainage
ditches) is sediment from erosion and runoff, which fills up low spots and
water then erodes new channels and floods. The local fish populations have
declined 90% since 1940 because of sediment buildup.
Water can also be polluted by farm chemicals
(fertilizers and pesticides) either directly, from water surface runoff, or
from erosion of contaminated soil. The Mississippi receives a huge influx of
atrazine (a corn herbicide, most used pesticide) and N every year at springtime
creating a “dead zone” in the Gulf of Mexico.
Fertilizers (esp. N) and chemicals (esp.
Phosphorous containing detergents) entering water bodies causes algae blooms
that deprive the water of oxygen killing the fish and destroying the food web.
Road waste and oils enter the gutter systems and contaminate local waters.
Fresh water is purified before it is potable (useable for cooking and drinking).
Recycled water (from waster treatment plants) can be used as irrigation for orchards and vineyards, mixing cement, filling landscape ponds, irrigating dairy crops, and golf courses. (1987 Clean Water act)
The Colorado River, which supplies LA and much of the Southwestern US with water, is “harder” than most water sources and contains high concentrations of Ca and Mg ions. Soft water contains more Na ions. Water hardness influences our use of household chemicals including soaps and shampoos.
Snow pack in the Sierra Nevada is intensely
measured because it acts as our water reservoir and can cause major flooding.
What is the Hetch Hetchy Project? What is the
current controversy? Folsom Lake is manmade. Why was it created?
State Agencies involved: California State
Water Project, California Dept. of Water Resources, water districts,
Reclamation Board, Department of Fish and Game, Resources Agency, others
Recent law: “Safe Drinking Water, Clean
Water, Watershed Protection And Flood Protection Act”
EPA enforces environmental regulations,
including all “clean” water laws.
1.
Nuclear
Fission and power plants
Uranium is mined and
purified to obtain high-grade material. In the core of reactors, Uranium is
bombarded with neutrons, which starts a self-sustaining chain reaction. Uranium
splits into smaller atoms generating a lot of energy. This energy heats water and the steam generated then turns large
magnet turbines that in turn generate electricity. The nuclear waste is
extremely hazardous for over 10,000 years and its storage is highly
controversial. The current plan of disposal is deep burial in salt mines in a
mountain in Nevada.
2.
Other
natural sources of electrical energy are: fossil fuel (oil, gas, coal, peat),
hydroelectric (dams), geothermal (steam fields), wind (turbines), tides.
Wind energy is the fastest growing source today due to high, unpredictable fuel costs. Energy from burning crops (e.g. corn) is renewable, but too expensive in today’s market.