10/11/16 Exam Study Guide
Elem Astronomy-Solar System 1307
Professor Hector Noriega
Terms to know:
1. Kepler’s First Law: Planets have elliptical orbits with the sun at one focus.
2. Kepler’s Second Law: Planets speed up in their orbits as they approach the sun, and slow down as they recede from it. (Planets carry out equal distance in equal time).
3. Kepler’s Third Law: A smaller orbit means it orbits around the sun in a shorter amount of time. Mass does not matter. Don't forget about the age old question of The cell membranes are compost of what?
4. Eccentricity: The measure of how ovular an object is. (circular=less eccentric; ovular=more eccentric)
5. The Four Conic Section: Resulted from cutting a cone at 4 different angles (circle; ellipse; parabola; hyperbola)
6. Retrograde: the apparent backward motion of the planets caused by the Earth passing them and creating the illusion of a planet moving backwards.
7. Light: 300 000 km/sec, has frequency, wavelength, energy, and is part of the spectrum of light.
8. Dark Matter: is nonvisible, does not reflect or radiate light, and is not directly detectable.
9. Law of Refraction: When light passes from one medium to another with a different density, light is bent, or refracted.
10. Law of Reflection: Light will reflect off a surface at the same angle it hit the surface. We also discuss several other topics like What is the ability of the nervous system to change and adapt throughout life?
11. Photon: A particle of light
12. Duality of light: it is the wave-particle composition of light. 13. Spectrum of Light: All forms of light, including the visible light spectrum. Ranges from: gamma rays (highest energy), x-rays, visible light, microwaves, radio waves (least energy).
14. Black Body: A perfect emitter of light.
15. Black Body Curve: it is the graph of an objects energy output in relation versus its wavelength, showing the peak emission and peak wavelength. The graph allows us to see that temperature affects color and luminosity.
16. Peak Emission: The highest point of the black body curve. If the point is higher on the graph it means it is bigger and brighter.
17. Peak Wavelength: It is the wavelength given off at the peak emission of the black body curve. It is used to determine the color of the star (Left means more blue; right means more red.)
18. Stefan-Boltzman Law: Luminosity depends on an objects T
surface area (A), and its temperature
19. Properties of Telescopes: a. Light gathering power We also discuss several other topics like What is the smallest functional unit of force development control?
Don't forget about the age old question of What are the countries that are members of the tripartite pact?
b. Angular resolution (more detail) c. Magnification
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20. Aperture: The diameter of a telescope
21. Convex Lenses: Curved pieces that allow for light to be refracted and concentrated to a single point, but causes chromatic aberration.
22. Chromatic Aberration: A blurry image resulting from multiple focus points created by using a curved lens to refract light. 23. Mirror Lenses: Curved mirrors that reflect light to create a clear image and avoided chromatic aberration. These are used by modern telescopes.
24. Joseph Faunhofer: He identified dark lines in the solar spectrum, which were named Faunhofer lines (absorption lines). These black lines indicate trapped/absorbed light in the atmosphere.
25. Spectral Lines: Used to identify elements in stars, because each element gives off its own spectral line when excited. 26. NGT: New generation telescopes. The largest telescopes of modern times.
27. Adaptive optics: A system that adapts to rapid changes in wave front by atmospheric turbulence. It can be controlled with pistons. If you want to learn more check out What is the meaning of introspectionists?
28. Pistons: Computer controlled actuators.
29. Doppler Effect: A change of color in light due to its approaching/receding movement. This causes blue-shift or redshift in the spectral lines.
30. Blue Shift: light waves are being compressed as an object moves, which means it is approaching.
31. Red-Shift: light waves are being stretched as an object moves, which means it is moving further away (receding). If you want to learn more check out What is the study of how the allocation of resources affects economic well-being?
Facts to know:
∙ Is composed of particles and waves
∙ Light is finite, not infinite! It has a speed of 300,000 km/sec. ∙ All light travels at the same speed (Gamma rays, visible light, radio waves).
∙ Blue has the most energy and highest frequency in the VISIBLE SPECTRUM, whereas red has the least energy and lowest frequency. ∙ It can be refracted (bent as it enters a new medium) or reflected off a surface (completely bounce off an object at its original angle).
∙ The bigger the star, the more energy it will emit which will thus make it brighter (the bigger the brighter).
∙ Low frequency is accompanied with the longest wavelength
∙ High frequency is accompanied with the shortest wavelength Black Body Curve:
∙ There is a relationship between temperature, color, and luminosity. A hot star will be blue (towards the left side of the graph) and a cool star will be red (towards the right side of the graph).
∙ The peak determines its luminosity and finds the temperature. The higher the point is on the graph, then the brighter it is (the bigger the star, the brighter it is).
∙ Each element produces its own spectral line combination, making it easier to determine the chemical composition of stars.
∙ The width of the lines indicates pressure conditions.
o Thick lines = high pressure = dwarf stars
o Thin lines = low pressure = giant stars
∙ Stars: shows a continuous spectrum with dark lines.
∙ Galaxy: shows a complex spectrum with several dark lines produced from millions of stars.
∙ Nebula: dark background with few bright lines.
∙ Planets: Shows same spectrum from the sun with extra dark lines produced from absorption in the planets’ atmosphere.
∙ Blue light has shorter wavelengths. As an object approaches, its wavelength is compressed, creating shorter wavelength, which causes it to become blue-shifted
∙ Red light has longer wavelengths. As an object moves further away, its wavelength is stretched out longer, which causes it to become red shifted.