Bellwork What two properties effect the force of gravity?

The Sun: Our very own star

How did Helium Get Its Name? F r o m t h e S U N ! ! ! ! ! ! !

The sun is a large ball of mostly hydrogen and helium and is held together by gravity. It provides energy for photosynthesis, which releases oxygen into the atmosphere. The sun determines our survival on Earth 109 Earths would be required to fit across the Sun's disk, and its interior could hold over 1.3 million Earths.

Properties of the Sun

Structure of the Sun

Structure and Atmosphere of the Sun

Layers of the Sun

Structure Continued… 1.Core. The Sun's nuclear "furnace," where fusion reactions initially combine hydrogen atoms to produce helium, yielding energy in the process. The core contains about ½ of the sun’s mass

The Sun’s Appearance

The light seen in this sunrise was created in the core of the sun millions of years ago

2. Radiative Zone. Very dense, about 300,000 km thick. Energy moves through a surrounding envelope of gas toward the Sun's surface. It takes about 1 million years for one photon to reach the surface of the sun from the radiative zone.

3. Convective Zone: 200,000 km thick. Big "bubbles" of hot gas transport energy to the surface. Convection is defined as the transfer of heat by the circulation or movement of the heated parts of a liquid or gas.

4. Photosphere. The Sun's visible surface. Because of its high temperature, it glows yellow.

5. Sunspot: A magnetic "storm" on the Sun's surface, creates dark spots of cooler temperatures, which in turn can cause lower temperatures on Earth.

Sun Spots

6. Chromoshpere: a thin region below the corona only 30,000 km thick

The Photosphere and Chromosphere

This image of the solar 'chromosphere' was obtained on on 20 November 2006 by the Hinode solar observatory, and reveals the structure of the solar magnetic field rising vertically from a sunspot (an area of strong magnetic field), outward into the solar atmopshere. The chromosphere a thin 'layer' of solar atmosphere 'sandwiched' between the sun's visible surface (or photosphere) and its outer atmosphere (or corona). The chromosphere is the source of ultra violet radiation. (Credit: Hinode JAXA/NASA/PPARC)

Prominence

7. Corona: The Sun's outer atmosphere, which is heated by the magnetic field to millions of degrees.

Corona

Solar flares: regions of extremely high temperatures that send huge streams of electrically charged particles into the solar system cause by sun’s magnetic fields

How the Sun generates energy Fossil evidence along with radiometric dating support the theory that the sun has been shining for 4.6 billion years. How can something burn for this amount of time with no apparent decrease in energy output? Einstein explains: E=mc 2

The Sun’s Energy

Nuclear fusion: -Nuclei of small atoms combine to form a larger nucleus High temperature and high pressure in the core of the sun allows the normally repulsive positively charged hydrogen atoms to come together and fuse into helium. This reaction produces energy which takes millions of years to reach the sun’s surface and then only 8.3 minutes to reach Earth as light.