A ________________ is a huge mass made of very hot gases (____________________ and ____________________) which produces energy through ________ ___________ process, and then emits such energy in the form of radiation

StarHydrogen Helium

Nuclear Fusion

What is the closest star to Earth?

SUNProxima Centauri is the next closest at 4.2 light years away

What is the sun made of?

73% ___________________

25%____________________

Hydrogen

Helium

Is it a big star?

No, it is an average (medium) size star

CORE

RADIATIVE

CONVECTIVE

PHOTOSPHERE

CHROMOSPHERE

CORONA

http://www.windows.ucar.edu/tour/link=/sun/Solar_interior/Sun_layers/Convection_zone/sun_conv_big_jpg_image.html

The Sun’s Interior

Core:__________ has a tremendously high temperature and pressure. The temperature is roughly 15 million °C. Here is where nuclear fusion occurs, turning four hydrogen nuclei into a single helium nucleus plus a LOT of energy.

http://www.windows.ucar.edu/tour/link=/sun/Solar_interior/Sun_layers/Convection_zone/sun_conv_big_jpg_image.html

The Sun’s Interior

Radiative Zone:_____________________emits radiation. that spreads outwards. The temperature ranges from 15 million °C to one million °C. It may take photons of radiation millions of years to pass through the radiative zone, as they gradually make their way out

http://www.windows.ucar.edu/tour/link=/sun/Solar_interior/Sun_layers/Convection_zone/sun_conv_big_jpg_image.html

The Sun’s Interior

Convective Zone:____________________ the photons continue to travel outwards via convection (towards lower temperature and pressure). The temperature ranges from one million °C to 6,000 °C.

Outer Layers of the Sun Photosphere

Chromosphere

Corona

Photosphere________________: Surface of the sun (lower atmosphere)

• Consists of a layer of glowing gas (300 miles thick) which radiates most of the _____________ we see.

• The temperature is about 5,500 °C

• It has a thick grainy texture consisting of numerous, relatively small, bright markings called ____________.

light

granules

____________ are cool, dark spots on the surface. They are much bigger than the Earth. They occur in a 11-year cycles.

Sunspots

http://www.enchantedlearning.com/subjects/astronomy/sun/sunspots.shtml

http://zebu.uoregon.edu/~soper/Sun/chromosphere.html

________________ is the layer above the photosphere.

•It is a very thin layer that appears reddish in color

• Temperatures ranging from 6,000 °C (at lower altitudes) to 50,000 °C (at higher altitudes).

•This layer is a few thousand miles thick.

________________ is the layer above the chromosphere.

•The corona extends for millions of miles

•Temperatures are tremendous, reaching one million °C.

Chromosphere

Corona

Solar flare_______________ is a magnetic storm which includes a sudden, rapid, and intense variation in brightness. Radiation is emitted across almost the entire electromagnetic spectrum.

Solar Prominence_______________________ is an arc of gas that erupts from the surface of the Sun. They form magnetic loops that hold relatively cool, dense gas suspended above the surface of the Sun.

Solar Wind

The top of the corona is constantly flowing into space, where it becomes _________ ____________.Solar wind

How do we know what elements are in the sun and other stars?

By using spectroscopy

Spectroscopy______________: the study of the spectrum of luminous beams and began back in the 19th century.

• Separates various components of beams of light, different wavelength

• Figures out the chemical composition of stars

http://www.enchantedlearning.com/subjects/astronomy/

• Spectrum shows absorption lines (absorbs that wavelength of light)

• These lines show what elements are in the stars (spectral types).