Topic 1 – The seasons of the Earth1. Seasons of the year. (n.d.). Retrieved December 9, 2011, from the National Aeronautics and SpaceAdministration website: http://www-istp.gsfc.nasa.gov/stargaze/Sseasons.htmIf the Earth's axis were perpendicular to the ecliptic (Earth's orbital path around the Sun), the Sun's axis position relative to the Earth would always be halfway between the North Pole and the South Pole; its view from any point on Earth would be the same every day; and every point on Earth, except the poles, would be in shadow (night) half the time and in sunlight (day) half the time. Because the Earth's rotation axis is tilted from the perpendicular, the Earth experiences seasons. The spring equinox occurs around March 21 and the autumn equinox around September 22 and during this period the length of day and night is equal. The summer solstice occurs around June 21st and the winter solstice occurs around December 21st. The North Pole is tilted towards the Sun during the summer solstice and is pointed away from the Sun during the winter solstice (Seasons, n.d.).2. Astronomical theory of climate change. (n.d.). Retrieved December 9, 2011, from the NationalOceanic and Atmospheric Administration website: http://www.ncdc.noaa.gov/paleo/milankovitch.htmlMilutin Milankovitch, a Serbian astronomer, developed an astronomical theory that explains climate change. When the inclination of the Earth's axis changes, the gravity of the seasons changes; a greater degree of slope means hotter summers and colder winters, while a decrease in slope means cooler summers and warmer winters. As the Earth wobbles in orbit, the tilt can vary from 22 degrees to 25 degrees over a 41,000-year cycle. Currently the inclination is 23.5 degrees. More...... middle of paper...... for marine life. During an El Niño event, westerly winds at the western end of the basin allow warm water to flow eastward and trade winds weaken. The storm patch and atmospheric convection move with the warm water causing heavy rain and flooding along coastal areas of western South America. The thermocline (the boundary layer between warm surface water and deeper, colder water) deepens and cold water is not pushed up, which deprives marine life of needed nutrients. During a La Niña event, the trade winds become stronger and the warm pool shrinks, which results in colder, drier weather off the coast of America. Atmospheric convection is limited to the western end of the basin and heavy rain falls over Indonesia. Cold waters along the west coast of South America rise and nutrients are abundant for marine life (El Niño, n.d..).