Ch Nine Vocab Flashcards
Astronomical unit
The average distance between earth and the sun
Solar system
It includes the sun, the planets, and other small objects; made up of smaller systems
Light minute
The distance light travels in one minute
Terrestrial planet
One of the highly densest planets nearest to the sun
Period Of rotation
The amount of time it takes an object to rotate once
Period of revolution
The amount of time an object takes to orbit the sun
Prograde rotation
The counterclockwise spin of a planet or moon
Retrograde rotation
The clockwise spin of a planet or moon
Greenhouse effect
The warming of the surface and lower atmosphere of the earth that occurs when water vapor, carbon dioxide, and other gases absorb and radiate thermal energy
Gas giant
A planet that has a deep, massive atmosphere, such as Jupiter, Saturn, Uranus, and Neptune
Dwarf planet
A body that does not fit all of the conditions for it to be considered as a planet
Satellite
A natural or artificial body that revolves around a planet
Luna
Another name for Earth’s moon
Comet
A small body of ice, rock, and cosmic dust that follows an elliptical orbit around the sun and that gives off gas and dust in the form of a tale as it passes close to the sun
Ellipses
Circles that are somewhat stretched out of shape
