The Sun & It’s Solar System

I. Safe Methods for Studying the Sun Spectroscope Solar Telescope Satellites

1. Spectroscope Chemical composition Temperature Internal Pressure

2. Solar Telescopes Projects a large image of the sun into a dark underground room Uses special glasses for viewing Ex. Kitt Peak National Observatory in AZ

3. Satellites SOHO (Solar and Heliospheric Observatory): Study Sun-Earth Connection, launched in 1996 YOHKOH Spacecraft (designed to study the Sun’s Corona, launched in 1991): ULYSSES in a polar orbit over the sun

Solar Max to Solar Minimum

B. Properties of the Sun Average size star Diameter = 1,380,000 Km Surface Temp = 55000C Interior Temp = 15,000,0000C

The Sun The Sun is a star All stars are a large ball of hot gas Main Sequence stars- Nuclear Fusion of Hydrogen gas

The Sun

The Core The source of the Sun’s Energy Where Nuclear Fusion fuels the Sun Can reach 15,000,000 degrees Celsius

Source of the Sun’s Energy E=mc2 Matter can be converted to energy & vice versa Fusion Reactions: Hydrogen that doesn’t become Helium becomes Energy 5 Billion years of fuel left in the sun Core is only place on sun where temp, density & pressure are all great enough to sustain nuclear fusion.

C. The Sun’s Atmosphere 3 Regions Photosphere Chromosphere Corona

1. Photosphere Apparent bright yellow surface of the sun Area of Sunspots Made of Granules Granules- the tops of individual columns of gases Gases rise from region below the photosphere

2. Chromosphere Above Photosphere Lower part of the outer atmosphere Seen only during a solar eclipse Colored Red by glowing Hydrogen Radiates mostly X-rays & UV Area of prominences

3. Corona Above Chromosphere So sparse in gas it would be considered a vacuum on Earth (low density) Seen during a total solar eclipse as a faint, pearly light

D. Solar Features Sunspots- Dark, cooler areas on the photosphere that occur in cycles Dark center called an umbra Lighter rim called penumbra Occur in pairs of opposite magnetic charge, like a bar magnet Appear to move from left to right across the photosphere

Filaments Filaments are large regions of very dense, cool gas, held in place by magnetic fields Found above the Chromosphere

2. Solar Prominences Huge loops of gas that connect different parts of sunspot regions A filament seen on edge. It appears brighter when seen this way.

3. Solar Flares Sudden eruption of heated hydrogen & energy around the area of a sunspot (a prominence that has exploded) Directly correlated to sunspot # (#of sunspots ,# of solar flares) Source of Solar wind bursts http://www.trschools.com/staff/g/cgirtain/flare1.mpg

4. Solar Wind Constant stream of electrically charged particles coming from the corona Given off in all directions

5. Coronal Holes Great tears in the Corona May extend halfway around the sun Do not close for several months Source of solar winds

6. Auroras Northern Lights = Aurora Borealis Particles of solar winds interacting with Earth's Magnetic Field & upper atmosphere Mostly occur in Earth's polar regions

7. Magnetic Storms When particles thrown out by coronal holes & solar flares are added to the constant solar winds Auroras may be seen at middle latitudes Compasses may read incorrectly Cellular & cordless telephone reception may be interrupted May interfere with radio frequencies

Sun Spots to Auroras

II. Observing the Solar System Solar System includes:     1. 8 Planets     2. Many Natural Satellites (moons)     3. Asteroids, Meteoroids, Comets

Solar System Cont’ All of the planets travel in elliptical orbits (paths around the sun) 5 planets can be seen without a telescope Mercury Venus Mars Jupiter Saturn Meteors can also be seen