Science Galaxy Flashcards
Revolution
Motion of one object around another
Season
Patterns of temperature changes and other weather trends over the course of a year
Equinox
Sunlight shines equally on the northern and Southern Hemispheres
Mare
Today a dark area on the Moon is still Called a lunar mare
Eclipse
An eclipse occurs when a shadow makes the Sun or the Moon seem to grow dark
Umbra
The umbra is the darkest part
Penumbra
Around it is a spreading cone of lighter shadow called the penumbra
Astronomical unit
Earths average distance from the Sun
Ellipse
A shape of each orbit is an ellipse-a flattened circle or oval
Terrestrial planet
Mercury, Venus, Earth,and Mars the four planets closet to the Sun
Gas giants
Jupiter, Saturn, Uranus, and Neptune are made mainly of hydrogen, helium, and other gases
Asteroid
Small, solid, rocky bodies that orbit close to the Sun
Comet
An object that produces a coma
Meteor
The particles and the air around them become hot enough to glow, producing brief strikes of light
Meteorite
A space object that reaches Earths surface
Orbit
The path of an object on space as it moves around another object because of gravity
Solar System
The Sun, Planets, and various small bodies make up the solar system
Galaxy
A group of millions or billions of stars held together by their own gravity
Universe
Everything space and all the matter and energy in it
Satellite
An object that orbits a more massive object
Impact crater
When an object strikes the surface of a larger object in space it explodes and leaves behind a round pit
Axis of rotation
Earth rotates around an imaginary line running through its center
Gravity
The force that objects exert on each other because of their mass
Geocentric
having or representing the earth as the center, as in former astronomical systems.
Heliocentric
having or representing the sun as the center, as in the accepted astronomical model of the solar system
Tide
the alternate rising and falling of the sea, usually twice in each lunar day at a particular place, due to the attraction of the moon and sun
Waxing
cover or treat (something) with wax or a similar substance, typically to polish or protect it.
Waning
have a progressively smaller part of its visible surface illuminated, so that it appears to decrease in size
Gibbous moon
having the observable illuminated part greater than a semicircle and less than a circle.
Crescent moon
the curved sickle shape of the waxing or waning moon.
Full moon
the phase of the moon in which its whole disk is illuminated
New moon
the phase of the moon when it is in conjunction with the sun and invisible from earth, or shortly thereafter when it appears as a slender crescent
Quarter moon
The moon is one-half illuminated by the sun
