Post on 26-Dec-2015
Chapter Two Highlights
Origin of our universe & solar system
GeologicTime Shape & orientation of
the Earth relative to the Sun
Mapping and location systems
Navigation The Water Cycle
Beginnings Origin of the universe
– Big Bang model
– Stars, galaxies, and clusters
– Wilkinson Microwave Anisotropy Probe - 380,000 years post BB
– Hubble Space Telescope (HST)
Origin of our solar system
– Collapse of a rotating interstellar cloud
– Accretion to form planets
Earth OriginsEarth Origins Big Bang !!!!Big Bang !!!!
– 13 bya 13 bya
– extremely hotextremely hot
– subsequent formation of ~100 million subsequent formation of ~100 million
galaxies with ~100-200 million stars galaxies with ~100-200 million stars
eacheach
– Milky Way is our Milky Way is our spiralspiral galaxy galaxy
( ( galaktosgalaktos = milk ) = milk )
A spiral galaxy structurally similar to the Milky Way Galaxy. 56,000 light years in diameter and 62 million years away.
A spiral galaxy structurally similar to the Milky Way Galaxy. 56,000 light years in diameter and 62 million years away.
Earth OriginsEarth Origins Planetary Accretion TheoryPlanetary Accretion Theory
– 5 bya 5 bya
– solar nebula (swirling dust cloud) from solar nebula (swirling dust cloud) from
a a supernovasupernova
• ~75% H, 23% He, 2% other stuff ~75% H, 23% He, 2% other stuff
– most material drawn to center to form most material drawn to center to form
protosun protosun
– rest rest accretesaccretes to form to form planetsplanets
Origin of the Solar System and Earth
Cloud of gas and space dust (nebula) began to contract about 4.53 billion years ago.
The Nebular Hypothesis
Hubble Space Telescope image of solar nebula similar in size to ours. Obscuring dust cloud across center.
Hubble Space Telescope image of solar nebula similar in size to ours. Obscuring dust cloud across center.
First image of a “possible” planet outside of our solar system.
First image of a “possible” planet outside of our solar system.
Water in the S0lar System
Extraterrestrial oceans – Liquid oceans on Jupiter’s moons,
Europa and Callisto Early planet Earth
– Separation of dense and lighter compounds through repeated melting and solidifying layered system, ocean, and atmosphere
– No free oxygen until photosynthetic organisms evolved
Mars shows erosional and depositional features that suggest the presence of running water in the past.
Mars shows erosional and depositional features that suggest the presence of running water in the past.
Origin of the Oceans Age of Earth: approximately 4 billion years
Water from interior of Earth
– Mantle
– Gas that escape volcanoes is 70% water vapor
– 4 billion years at current rate 100 times the volume of the oceans
Water from outer space
– 10 million comets enter the atmosphere each year
– Layer of water 0.0025 mm deep added each year
– 4 billion years at current rate 2 to 3 times the volume of the oceans
Age and Time
Age of Earth – History of estimates
• Bible 10/23/4004 B.C. , cooling time, rate of addition of salt in oceans by rivers, radiometric dating
– Radiometric dating 4.5-4.6 billion years Geologic time
– Eons, eras, periods, epochs
– Important events Natural time periods
– Time required for Earth to complete one orbit around the Sun
– Length of day and seasons– Lunar month– Solar day– Sidereal day
Shape of Earth
Gravity – Earth is nearly spherical
Spin – Earth bulges at equator
Distribution of continents– Slightly pear shaped
Topographic relief – Minor compared to planet’s size
Location Systems Latitude and longitude
– Latitudes (or parallels) are parallel to the equator
– Longitudes (or meridians) are formed at right angles to the latitude lines
• Prime meridian and international date line
– Great Circle– Nautical mile (1 minute of arc at the
equator) Chart projections
– Distorted images of Earth’s curved surface
– Projection types: cylindric, conic, and tangent
Location Systems
Measuring latitude
– North Star, Polaris Longitude and time
– Use of clocks to record the time the Sun is at its zenith
– Greenwich Mean Time (GMT) or Universal Time
Modern Navigational Techniques
Radar (radio detecting and ranging)
Loran (long-range navigation) Satellite navigation system Global Positioning System (GPS) Shipboard computers
– Electronic atlas• Surface charts
• Bathymetry
• Continuous tracking of ship’s position
Earth: The Water Planet
Water on Earth’s surface– Effect of seasons
– Effects length of day
– 71% of Earth’s surface is covered by water, while 29% of the surface area is land
Hydrologic cycle– Evaporation, transpiration, and
sublimation
– Precipitation, rain, and snow
Earth: The Water Planet
Reservoirs and residence time– Large reservoirs long residence time
– Small reservoirs short residence time
Distribution of land and water – Northern Hemisphere (land)
– Southern Hemisphere (water) Oceans Hypsographic curve
Geography of the oceans
Earth’s oceans:
Cover 70.8% of Earth’s surface
Are interconnected (“world ocean”)
Have huge size and volume (as a
reservoir, contain 97% of Earth’s water)