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The Sun is the most unique object in the Solar System, and a fair example of the most ubiquitous objects in the Milky Way: it is a star. Analysis of sunlight reveals that the Sun is made mostly of the elements Hydrogen & Helium, with just traces of other elements. The Sun maintains its high internal temperature by thermonuclear fusion.
Topics:
Reading:
| Ch. 2-3 | Einstein showed that light sometimes behaves as particles and sometimes as waves |
| Ch. 2 | DISCOVERING SPECTRA (p. 46) |
| Ch. 2-18 | Each chemical element produces its own unique set of spectral lines |
| Ch. 2-21 | Spectral lines occur when an electron jumps from one energy level to another |
| Ch. 7 | The Sun (p. 149) |
| Ch. 7 | THE SUN'S ATMOSPHERE (p. 150) |
| Ch. 7-1 | The photosphere is the visible layer of the Sun |
| Ch. 7 | THE ACTIVE SUN (p. 153) |
| Ch. 7-4 | Sunspots reveal the solar cycle and the Sun's rotation |
| Ch. 7-5 | The Sun's magnetic field creates sunspots |
| Ch. 7 | THE SUN'S INTERIOR (p. 159) |
| Ch. 7-7 | Thermonuclear reactions in the core of the Sun produce its energy |
| Ch. 7-8 | Solar models describe how energy escapes from the Sun's core |
Web Resources:
A thought-experiment: if we could transport a pint of gas from the center of the Sun to Earth, what would happen?
One of the largest eruptions ever observed is shown in this image. This huge arch is created by gas flowing along magnetic field lines.
A close-up of a large group of sunspots. These cool regions result when powerful magnetic fields prevent convection from transporting heat from the solar interior.
This image, taken using ultra-violet light, shows gas at temperatures of 1,500,000°K. Such gas reveals the inner part of the Sun's magnetic field.
The solar corona is a thin envelope of very hot gas gas surrounding the Sun. It becomes visible during a solar eclipse when the Moon blocks out the Sun's disk. The long streamers of the corona follow the Sun's magnetic field.
Sun and inner atmosphere, imaged using ultra-violet light.
Homework 8: Spectral Lines, due 10/23.
Quiz 8: Sun and Planets, given 10/18.
Last modified: October 18, 2001
http://www.ifa.hawaii.edu/~barnes/ast110/ts.html
