The Earth in Space

http://static.theurbn.com/wp-content/uploads/2010/12/earth-from-space-western.jpg

http://www.windows2universe.org/the_universe/images/galaxies/m31_small.gif

http://starchild.gsfc.nasa.gov/Images/StarChild/solar_system_level1/solar_system.gif

The Earth is the 3rd planet from the sun. About 4.54 billion years ago it was formed. Everything in our solar system rotates around the sun.
"The immediate galactic neighbourhood of the Solar System is known as the Local Interstellar Cloud or Local Fluff, an area of denser cloud in an otherwise sparse region known as the Local Bubble, an hourglass-shaped cavity in the interstellar medium roughly 300 light years across. The bubble is suffused with high-temperature plasma that suggests it is the product of several recent supernovae.^[105]
There are relatively few stars within ten light years (95 trillion km) of the Sun. The closest is the triple star system Alpha Centauri, which is about 4.4 light years away."  (1)



Big Bang Theory: The big bang theory states that a very long time ago there was nothing. then this big "bang" came and it ecxpanded and cooled going from very small and hot to the size and temp of our current universe. It contunes to expand and cool. They say there was no actual explosion, only expansion. This is why galaxies appear to be moving away from us. "the abundance of the "light elements" Hydrogen and Helium found in the observable universe are thought to support the Big Bang model of origins."   (2)
How old is the universe:
"Until recently, astronomers estimated that the Big Bang occurred between 12 and 14 billion years ago. To put this in perspective, the Solar System is thought to be 4.5 billion years old and humans have existed as a genus for only a few million years. Astronomers estimate the age of the universe in two ways: 1) by looking for the oldest stars; and 2) by measuring the rate of expansion of the universe and extrapolating back to the Big Bang; just as crime detectives can trace the origin of a bullet from the holes in a wall." Life cycle of a star depends on its mass. High mass stars are brighter and low mass stars are dimmer. A star like the sun has enough fuel to burn for about 9 billion years, a star twice as big can burn for about 800 million years.   (3)



1. http://en.wikipedia.org/wiki/solar_system , Wikipedia, November 17th, 2011 , Wikimedia Foundation inc
2. http://big-bang-theory.com/ , allaboutscience.org, 2002-2011
3. http://map.gsfc.nasa.gov/universe/uni_age.html , NASA.com, Britt Griswold, 07-19-2010

The Water Cycle

http://en.wikipedia.org/wiki/File:HydrologicalCycle1.png


This process has many steps. Precipitaion- condensed water vapor that falls to earth. Canopy interception- precipitation that is intercepted by plant foliage and evaporates back to the atmosphere. Snowmelt- Runoff produced by melting snow. Runoff- The way water moves across land. Infiltration- The flow of water into the ground. Subsurface flow- Flow of water underground. Evaporation- Transformation of water from liquid to gas. Sublimation- Change from solid water to water vapor.  Advection- The movement of water through the atmosphere. Condensation- Transformation of water vapor to liquid water in the air. Transpiration- Release of water vapor from plants and soil into the air.
   (1)

Rivers and Streams:
There are 3 main types of streams. Ephemeral-Streams regularly exist for short periods of time. Intermittent-streams flow at different times of the year when there is enough water. Perennial- streams that flow year-round. (2)
When humans build things it effects rivers and streams because building materals get dumped into the water, things may block the flow and pollutants get thrown in killing all life in and around the water. The highest threat levels are in the United States and Europe.  Globally between 10,000 and 20,000 aquatic species are at risk because of how bad humans treat wetland. The worlds least affected rivers were the ones farthest away from populated areas. (4)
http://www.epa.gov/bioiweb1/aquatic/rivers_and_streams.html

http://photos1.blogger.com/blogger2/3514/4365/1600/RiverTransport.jpg

"Here we focus on the local hydrologic cycle for a watershed. The important factors are precipitation, evapotranspiration, overland flow, infiltration, groundwater flow and stream flow, along with special manifestations of each referred to, respectively, as baseflow (groundwater flow into streams), runoff (different authors use different definitions) and subsea flow (deep groundwater flow directly into the adjacent ocean or estuaries). The following notation will be used to represent the associated watershed components:" (3)

Components of Local Water Cycle P = Precipitation Qswi = Surface water in (e.g. stream flow into the watershed, and overland flow that enters directly) Gin = Groundwater flow in Qswo = Surface water out (e.g. stream flow, and overland flow that exits independently of streams) ET = Evapotranspiration Gout = Groundwater flow outDS/Dt = Change in the volume of water in storage (S) per unit time

http://www.brown.edu/Courses/GE0158/web2_revised/dennis/basic.html






1. http://en.wikipedia.org/wiki/water_cycle, wikipedia, Nov. 21, 2011, Wikimedia Foundation inc
2. http://www.epa.gov/bioiweb1/aquatic/rivers_and_streams.html , U.S. Environmental Protection Agency, March 7, 2011
3. http://www.brown.edu/Courses/GE0158/web2_revised/dennis/basic.html ,THe hydrologic cycle, Dennis Wong, John F. Hermance
4. http://www.guardian.co.uk/environment/2010/sep/29/human-impact-world-rivers-water-security , Theguardian, 2011,