Earth

Our Beautiful Home

Vital Statistics• Mass = 6.0 x 1024 kg (1 M)• Radius = 6378 km (1R)• Average density = 5520 kg/m3

• Tilt = 23.5o

• Revolution = 365.26 days• Distance from sun = 1.496 x 108 km (1AU)• Magnetic field present• Atmosphere = 78% N2

and 21% O2 (and other trace gases)

• 71% water• Albedo = 0.37 (37% of sunlight reflected back into

space)• Tav = 13 - 15oC• 1 moon

The Spheres

Atmosphere

Average atmospheric pressure at sea level is 14.7 pounds per square inch!

Greenhouse Effect

• Greenhouse gases:– CO2

– CH4

– NOx

– H2O

The Ozone Layer

Hydrosphere

• All the Earth’s water:– Oceans– Ground water– Streams– Lakes– Air– Soil– Cryosphere

Lithosphere

Crust Composition

Plate Tectonics

• Motions of large segments (plates) of the Earth’s surface caused by convective motions in the underlying mantle

• Earthquakes

• Formation of volcanoes

• Continental drifts

Biosphere

• Sum of all ecosystems

• Connects spheres together

• Cycling of materials

The Carbon CycleCellular Respiration:

C6H12O6 + 6O2 --> 6 CO2 + 6H2O + NRG

Photosynthesis: 6 CO2 + 6 H2O + solar NRG --> C6H12O6 + 6O2

The Nitrogen Cycle

The Phosphate Cycle

Earth’s Layers

Interesting Fact: Magnetic Field sometimes flips (last oneoccurred 600,000 yrs ago

Solar wind particles sometimes leak through magnetic fields near the poles, colliding with gases in the upper atmosphere

Revolution and Rotation

• Earth’s revolution and rotation– Counterclockwise (looking down from North Pole)

• Tilt– Seasons

• Orbit– Elliptical– Sun at a focus

Our Moon

• Mass = 7.35 x 1022 kg

• Radius = 1738 km

• Density = 3340 kg/m3

• Cycle of Lunar Phases = 29.5 days

Origin of the Moon

• The prevailing theory is that a large object smashed into Earth ejecting debris into space which collected to form the moon

Orbit of the Moon

• Inclined about 5 degrees from Earth/Sun orbit

• Rotation – 27.5 days

• Revolution – 27.5 days• What is the consequence of this?• Synchronous rotation

Phases of the Moon

http://www.classzone.com/books/earth_science/terc/content/visualizations/es2503/es2503page01.cfm

Eclipses

• Solar Eclipse:• http://www.classzone.com/books/earth_science

/terc/content/visualizations/es2505/es2505page01.cfm

• Lunar Eclipse:• http://www.classzone.com/books/earth_science

/terc/content/visualizations/es2504/es2504page01.cfm

Eclipse Vocabulary

• Umbra – area of total shadow

• Penumbra – area of partial shadow

• Annular – eclipse does not cover the entire area of the Sun

• Total - eclipse covers the entire area of the Sun

Calendar of solar eclipses

• http://sunearth.gsfc.nasa.gov/eclipse/eclipse.html

Tides

• An ocean tide refers to the cyclic rise and fall of seawater.

• Caused by slight variations in gravitational attraction between the Earth, the Moon, and the Sun

• Tides are periodic primarily because of the of the Earth's rotation.

• http://museum.gov.ns.ca/fossils/protect/tideanim.htm

The Bay of Fundy

• The highest tides occur near Wolfville, Nova Scotia. • The water level at high tide can be as much as 16 meters higher

than at low tide. • Small Atlantic tides drive the Bay of Fundy/Gulf of Maine system

near resonance to produce the huge tides. • High tides happen every 12 hours and 25 minutes • Near mid-tide at Cape Split, one may hear the "voice of the

Moon" in the form of the roar emitted by turbulent tidal currents. • At mid-tide, the flow in Minas Cannel north of Blomidon equals

the combined flow of all the rivers and streams on Earth! • Nova Scotia bends when the tide comes in! As 14 billion tonnes

(14 cubic kilometers) of sea water flow into Minas Basin twice daily, the Nova Scotia countryside actually tilts slightly under the immense load!

Spring tide

• Sun, Moon, and Earth are aligned

• Sun and Moon create tides in the same direction

• Highest• Occur every new

and full Moon

Neap tide

• Sun and Moon are at right angles

• First and Third Quarter

• Gravitational forces compete

• Tidal distortion is the least pronounced