Do Now 12/9/09 What is the sun made of??? ON YOUR BLUE SHEET What is the sun made of??? Write down a couple of facts you know about our Sun

The Sun

Sunny Facts Sun is an ordinary star Center of our solar system making life possible on Earth An enormous ball of gas fusing hydrogen into helium in its core Energy produced travels outward through radiation and convection zone where it swirls and then emitted into space Sunny Facts

Photosphere is the lowest layer of sun’s atmosphere and where light is given off Temperature is about 6,000 K Chromosphere is above photosphere and 2,000 km thick Sun’s Atmosphere

Corona is between 2,000 km and 10,000 km above the photosphere Largest layer of the Sun’s atmosphere extending millions of km into space Temperatures reach as high as 2 million K Charged particles escape as solar wind Sun’s Atmosphere

Suns Processes Thermonuclear fusion: two or more atomic nuclei collide at a very high speed and join to form a new type of atomic nucleus. Radiation: energy that comes from a source and travels through some material or through space Convection: transfer of heat from one place to another by the movement of fluids

Using the diagram 1. Where in the sun does nuclear fusion occur? 2. What conditions in this part of the sun’s interior causes nuclear fusion to happen?

3. How does the energy produced by nuclear fusion escape the sun. 4 3. How does the energy produced by nuclear fusion escape the sun? 4. How does energy move through the sun’s radiative zone? 5. What function does the sun’s convective zone perform?

Surface Features Sunspots appear as dark areas on Sun because they are cooler Lasts days, weeks, or months Observing sunspots led to the discovery that the sun rotates on an axis

Surface Features Rotation at equator takes 25 days and at poles 33 days Sunspots are cyclical with maximum activity every 10 to 11 years

Magnetic fields at sunspots may cause Prominences on Sun’s surface Huge arched columns of gas blasted into space 600 km/s to 1,000 km/s At times violent eruptions at sunspots cause Solar Flares to shoot outward at high speeds Surface Features

Surface Features Coronal Mass Ejections (CME) occurs during maximum sunspot activity Appears as a halo around the sun High solar winds, Ultraviolet light and X-rays can reach Earth and cause problems with radio signals Ionized gas causes aurora on Earth at poles