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2.  Largest object in our solar system  Makes up 99% of mass in our solar system  Density similar to the gas giants  Inner part of the sun is very dense and made of plasma

3.  Lowest layer of atmosphere is the photosphere (visible surface-most of the light emitted comes from here)  Chromosphere- above photosphere; appears red  Corona-top layer of atmosphere  Gas continues to flow outward at high speeds and forms solar wind  Particles are deflected when they reach earth and it creates auroras.

5.  Features of the Sun can change over time  Sunspots-dark spots on the surface of the photosphere  Actually very bright but appear darker because they are cooler  Last two months

6.  Sunspots change regularly reaching a maximum number every 11.2 years  The Sun’s magnetic pole switches so that the north pole becomes the south and vice versa.  Solar cycle starts with fewest sunspots and ends with maximum; poles switch and the same cycle continues  Total cycle = 22.4 years

7.  Violent eruptions of particles and radiation from the surface are called solar flares  These particles can interfere with communication and damage satellites  Solar cycle impacts Earth  In the 1600’s there were no sunspots- known as the “Little Ice Age”

8.  In the core fusion occurs  Fusion is the combining of nuclei  Fission is the opposite  In the core, Hydrogen fuses to make helium and mass is converted to energy to fuel the Sun

9.  Radiative zone lies above the core; particles are continually gaining energy  Above this is the convective zone; gas carries energy the rest of the way to the surface  Eventually that energy reaches us

10.  73.4% hydrogen  25% Helium  Less than 2% of C, N, O, Ne, Mg, Si, S, Ca, and Fe  Similar composition to the gas giants suggesting that the Sun and gas giants represent the composition of the interstellar cloud that they were formed from

11.  Visible light arranged according to wavelengths  Can use to identify elements  3 types:  Continuous: ◦ No breaks in the colors ◦ Comes from a glowing solid or compressed gas  Absorption: ◦ Non compressed gas ◦ See bright lines at certain wavelengths ◦ Depends on element  Emission: ◦ See dark bands caused by absorption of light by elements