Bell ringer (write the questions) Arrange the following list of objects found in space from largest to smallest: solar system, moon, universe, planet, Sun, galaxy. Compare and Contrast: terrestrial planets and gas giants. List the planets in order as you move away from the sun. Start the list with the Sun. Circle the terrestrial planets. SQUARE the gas giants.

Formation and development of stars All stars start off as a nebula A contracting cloud of gas and dust with enough mass to form a star is called a protostar Nebula

What unit of measure do we use to measure the solar system? Distances between objects in the solar system are so large that they are not easy to measure using m or Km. Astronomical Unit One astronomical unit = the average distance measured from the center of the sun to the center of earth about 150,000,000 Kilometers.

What unit of measure do we use to measure Galaxies? Distances to stars are so large that meters are not practical. Light year The distance that light travels in one year. About 9.46 trillion kilometers

SC.8.5.3 Distinguish the hierarchical relationships b/t planets & other astronomical bodies relative to solar system, galaxy & Universe, including distance, size & composition

Bell ringer Complete the following star formation timeline : Nebula----------____________-------------Star 2. What do scientist look at in order to differentiate stars? 3. What in an astronomical unit? When do scientist use this unit of measure? 4. When do scientist use light years as a unit of measurements?

The Sun Composed mostly of Hydrogen (75%) & helium (25%) 4.6 Billion years old Surface temperature = 5,500 degrees Cel. Core Temperature = 15,000,000 degrees Cel.

Structure of the SUN Corona: atmosphere Photosphere: visible surface Chromosphere: middle layer Convective Zone: convection Radiative Zone: Radiation Core: Nuclear fusion This Photo by Unknown Author is licensed under CC BY-SA

The SUN’s ENERGY Nuclear Fusion: When 2 or more atoms fuse to form another atom. In the Sun’s core The Sun’s Fuel : 2 hydrogen atoms become 1 helium atom Using Einstein’s formula, scientists are able to explain how the Sun produces so much energy

The Sun’s Energy Energy is Transferred to the Sun’s surface Radiation Waves in the Radiative Zone Convection in the Convection Zone

Sun’s ROTATION This Photo by Unknown Author is licensed under CC BY-SA

SOLAR ACTIVITY Sun Spots: dark areas that are cooler than the area surrounding them Solar Flares: Explosions that extend outward Prominences: Explosions the loop out and return to the Sun’s surface