Studying the Sun Ch. 24

The Study of Light Electromagnetic Radiation  Electromagnetic radiation includes gamma rays, X-rays, ultraviolet light, visible light, infrared radiation, microwaves, and radio waves.  The electromagnetic spectrum is the arrangement of electromagnetic radiation according to wavelength.

Electromagnetic Spectrum Makes no sense without caption in book

a spectroscope is used to measure different compositions and temperatures separates light into different colors Hydrogen and Helium are most abundant elements in stars

spectrum of a star tells astronomers about its motion Sun Spectrum

Doppler effect: apparent shift in the wavelength of light emitted by a light source moving toward or away from the observer In astronomy, the Doppler effect is used to determine whether a star or other body in space is moving away from or toward Earth.

The Doppler Effect Makes no sense without caption in book

blue shift: light waves appear to have shorter wavelengths as the star moves toward the Earth (spectrum shifted toward blue end) red shift: light waves appear to have longer wavelengths as the star moves away from the Earth (spectrum shifted toward red end)

A. Core Structure of the Sun the temperature at the core is 15,000,000°C it is made up entirely of gas the sun is fueled by nuclear fusion in this process, hydrogen atoms are fused to make helium atoms

B. Radiation Zone: the temperature in the radiation zone is 2,500,000°C C. Convection Zone: the temperature in the convection zone is 1,000,000 °C

Atmosphere of the Sun A. Photosphere the temperature in the photosphere is 6,000 °C it is considered the surface of the sun it appears yellow in color

B. Chromosphere the temperature in the chromosphere is 4,000 °C it appears reddish in color

Corona the temperature in the corona is 2,000,000°C it can only be seen during a total solar eclipse

Structure of the Sun Makes no sense without caption in book

Solar Activity Sunspots: cool, dark areas of the sun that appear darker than the surrounding areas number of sunspots varies according to an average 11-year cycle temperature drops and solar activity slow at site

Sunspots Makes no sense without caption in book

Prominences: cloud of glowing gases that arches high above the sun’s surface caused by the sun’s magnetic field

Solar Prominence Makes no sense without caption in book

Solar Flare: sudden outward eruption of electrically charged atomic particles may interfere with phone, TV, and radio reception

Solar Wind: electrically charged atomic particles that stream out into space from holes in the corona as particles fly past the Earth, they interact with our magnetic field and upper atmosphere causing auroras

Why is the sun so important to Earth? Sun’s energy is produced by nuclear fusion (like that of an atomic bomb). The reaction which takes place is a nuclear fusion of hydrogen to helium and this releases the sun’s energy in the form of gamma rays. Gamma rays are absorbed and re-emitted at a lower and lower temperature and by the time it reaches the surface of the sun the majority of it is in the form of visible light, but it also emits heat and radiation.

The Sun’s Visible Light The visible light, solar radiation, and heat released by the Sun travels to Earth at the speed of light and reaches Earth in a little over 8 minutes. This energy from the sun enters our atmosphere where it is either absorbed or reflected back into space. That which is absorbed heats the Earth and also allows for the process photosynthesis to occur (the basis of the food chain). This process turns solar energy into chemical energy and allows life to exist on Earth.

Why doesn’t solar radiation hurt organisms on Earth? The solar radiation that reaches Earth is deflected around Earth due to its magnetic field. The interaction between the solar radiation and Earth’s magnetic field produce the Auroral Lights (Northern Light or Aurora Borealis).

The Sun’s Movement The Sun is in constant motion in the solar system and universe. The sun has a barycenter: which is a center of mass between it and any other planet or celestial body. It is being pulled by the planets as they orbit it. The Sun has a barycenter with all of the planets and celestial bodies which orbit it and these bodies slightly move the Sun from the barycenter of the solar system.

Picture of Sun’s Center of Mass based on position of planets