Astronomy Study Guide - Astronomy Test #2 Study Guide...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Astronomy Test #2 Study Guide Important Terms 1. Absorption Line Spectrum : A Spectrum in which certain wavelengths are darker than adjacent wavelengths. The missing light is absorbed by atoms or molecules between the source and the observer. 55.1 2. Accretion Theory: Accretion means the collecting of additional material. Accretion disks arise when material is being transferred from one celestial object to another. Accretion disks are relatively flat sheets of gas and dust surrounding a newborn star, a black hole, or any massive object growing in size by attracting materials. The Accretion Theory is one theory scientist have for the formation the moon in which dust and material left over from the formation of the earth collided and stuck together to form the moon. 3. Achromatic Doublet: Dual lenses that are used to minimize chromatic aberration. Usually bring two wavelengths (typically red and blue) into focus on the same plane. 4. Albedo: Albedo is the term used to measure the amount of light an object reflects. 5. Apogee: The point of an orbit that is most distant from the center. 6. Arecibo Observatory: A very sensitive radio telescope located in Puerto Rico. 7. Bohr Model: First theory of a hydrogen atom to explain the observed spectral lines. This model rests on three ideas: that there is a state of lowest energy for the electron, that there is a maximum energy beyond which the electron is no longer bound to the nucleus, and that within these two energies the electron can only exist in the certain energy levels. 21.3 8. Capture Theory: Theory that states the moon formed elsewhere in the solar system and by chance got caught in the earth’s gravitational field and was pulled into orbit. 9. Cassegrain Telescope: A type of reflecting telescope in which incoming light hits the primary mirror and is then reflected upward toward the prime focus, where a secondary mirror reflects the light back down through a small hole in the main mirror into a detector or eyepiece. 28.2 10. Catadioptric Telescope: Telescope designed to combine specifically shaped mirrors and lenses to allow very fast focal rations (when used at the prime focus), while controlling coma and astigmatism.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
11. Chromatic Aberration: Caused by a lens having a different refractive index for different wavelengths of light. Chromatic Aberration is corrected with an Achromatic Doublet. 12. Continuous Spectrum: A Spectrum with neither dark absorption nor bright emission lines. The intensity of the radiation in such a spectrum changes smoothly from one wavelength to the next. 24.3 13. Core, Mantle, Crust: Core: The innermost, usually hot, region of a planet. 32.1 Mantle: The outer part of a rock planed immediately below the crust and outside the metallic core. 35.1 Crust: The Solid Surface of a planet, moon, or other solid body. 35.1 14. Crater: A circular pit, generally with a raised rim and sometimes with a central peak. A crater can be formed by the impact of a solid body, such as an asteroid,
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/10/2010 for the course PHY 107 taught by Professor Worek during the Spring '08 term at Community College of Allegheny County.

Page1 / 7

Astronomy Study Guide - Astronomy Test #2 Study Guide...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online