Moody Descriptive Astronomy
About this set
Created by:
ramseycarr on February 15, 2011
Subjects:
Log in to favorite or report as inappropriate.
Order by
34 terms
Terms | Definitions |
|---|---|
 geocentric | centered on the earth |
| direct motion | The normal eastward movement of a planet against the background of distant stars. |
| retrograde motion | The apparent backward motion of a planet against the background of stars. |
| epicycle | In Ptolemy's geocentric solar system, the small circle on which a planet moved. |
| deferent | In Ptolemy's geocentric solar system, the large circle on which a planet's epicycle moved around the Earth. |
| heliocentric | Centered on the Sun. |
| inferior planet | A planet that is closer to the Sun than the Earth. |
| superior planet | a planet that is farther from the sun than the earth. |
| conjunction | When a planet lines up with the Sun in the sky. |
| greatest elongation | The point where an inferior planet is as far away from the Sun as it can be (as seen from the Earth). |
| opposition | The point where a superior planet is as far away from the Sun as it can be (as seen from the Earth). |
| perihelion | The point in its orbit where a planet is nearest the Sun. |
| aphelion | The point in its orbit where a planet is farthest from the Sun. |
| semimajor axis | Half of the longest diameter across an ellipse. |
| force | a push or a pull |
| mass | A measure of how an object resists accelerating when acted upon by a force. It is proportional the amount of matter in an object. |
| weight | the measure of the force of gravity on an object |
| gravity | the force of attraction between any two objects that have mass |
| acceleration | any change in speed or direction of an object |
| occam's razor | The philosophical stand that says a simpler explanation is more likely to be correct than a complicated one. |
| lagrangian points | Points of gravitational stability in the orbit of a planet. |
| synchronous rotation | When one side of a body always faces the planet it revolves around. |
| solar nebula | the material from which the solar system was formed. |
| Jovian planets | planets that are Jupiter-like |
| density | mass divided by volume |
| chondrite | The first rock-sized bodies that formed in the solar nebula from dust grains. |
| planetesimal | The larger bodies that formed early in the solar nebula that were chemically differentiated. |
| aurora | The light produced when particles from the sun collide with atmospheric molecules. |
| accretion | the process of acquiring material |
| chemical differentiation | The sinking of denser elements to the center of a young molten planet. |
| terrestrial planets | earth like planets |
| plate tectonics | The movement of the Earth's crustal plates riding on top of the mantle. |
| greenhouse affect | The trapping of heat by carbon dioxide or other gases in the Earth's atmosphere. |
| condensation temperature | The temperature at which a substance in the vacuum of space solidifies. |
First Time Here?
Welcome to Quizlet, a fun, free place to study. Try these flashcards, find others to study, or make your own.