Science Tip 10/27/10 What is at the center of our galaxy? Why don’t all the stars just fall into the black hole? What is emitted into “jets” as a result? What is meant by Galatic Cannibalism? -Turn in your video notes (after we talk about #4) - Get out your Stellar Evol & More worksheet

Science Tip 10/28/10 What are the 3 types of galaxies? Which galaxy is most mature? How do we know so much about the Sun? -Take out your Sun Objective notes

THE SUN Chapter 28

Layers of the Sun Core Radiative Zone Convective Zone Photosphere Chromosphere Corona

The Core At the Center of the Sun Makes up 10% of the sun’s total diameter of 1,300,000km. Temperature = 15,000,000oC Nuclear fusion is happening, Fusion of Hydrogen into Helium

Radiative Zone Zone surrounding the Core Temperature = 2,500,000oC Energy moves from atom to atom in the form of electromagnetic waves, or “Radiation”. This radiation process transfers energy through space.

Convection Zone Surrounds the Radiative Zone Temperature = 1,000,000oC Energy produces in the core move through this zone by “convection”. Convection is the transfer of energy by moving liquids or gases (in Suns case, Gas). Atoms of hot gas move outward and expand, they radiate and lose heat. Gas cools and sinks to the bottom of the convection zone. The gas then becomes heated again by the energy from the Radiative Zone and rise again. Thus continually transferring heat to the Sun’s surface.

Photosphere A.K.A. The Light Sphere Made of gases bubbling up from the convective zone. Temperature = 6,000oC Energy given off from the photosphere is in the form of Visible light. The visible light is what is seen from Earth Considered the Surface of the Sun.

Sunspots Cool, dark areas of gas within the photosphere. Caused by powerful magnetic fields. Slows down convection currents to the Photosphere, causing a cooling of certain areas of the surface.

Chromosphere Above the Photosphere A.K.A The Color Sphere A thin layer of gases that seems to glow with a reddish light. Temperature = 4,000oC to 50,000oC

Corona A.K.A. The Crown Blends into space. Huge cloud of gas heated by the sun’s magnetic field. Temperature = 2,000,000oC Thin layer, but prevents most atomic particles from the Sun from escaping into space. Sometimes these electrically charged particles find their way out as “solar wind” and flow to distant parts of the solar system. What do we call them when we see them here on Earth?? (Hint: You see them better up north!!)

AURORA BOREALIS