Space Vocabulary Flashcards
Orbit
the circular or elliptical path of an object as it revolves around another object
Solar system
system of objects that revolve around a star
Galaxy
a group of solar systems, dust, and gas held together by gravity; our solar system is part of the Milky Way galaxy
Universe
everything that exists in, on and around the Earth
Satellite
a natural or artificial object that revolves around another object in space
Impact crater
a large, circular pit in the surface of a planet or other body in space usually formed when two bodies in space collide
Rotation
the spinning of a celestial body, such as a planet, around an axis
Revolution
the orbiting of an object around another object
Season
a period of the year determined by the position of Earth as it revolves around the sun
Equinox
the twice-a-year occurrence during which Earth’s axis is perpendicular (at a 90 angle) to a line joining the Sun and Earth’s center
Solstice
the twice-a-year occurrence during which the Sun appears at the highest point in the sky as seen from the North or South pole
Mare
having to do with the moon or moon cycles
Eclipse
an event whereby one astronomical body passes between two other astronomical bodies
Umbra
the fully shaded inner region of a shadow cast by an opaque object, especially the area on the earth or moon experiencing the total phase of an eclipse.
Astronomical unit(AU)
the mean distance from the center of the Earth to the center of the sun (about 149.6 million kilometers); used to measure distances in the solar system
Penumbra
the partially shaded outer region of the shadow cast by an opaque object.
Ellipse
a regular oval shape, traced by a point moving in a plane so that the sum of its distances from two other points (the foci) is constant, or resulting when a cone is cut by an oblique plane which does not intersect the base.
Terresrtial
of, on, or relating to the earth.
Planet
a celestial body moving in an elliptical orbit around a star
Gas giant
a large planet of relatively low density consisting predominantly of hydrogen and helium, such as Jupiter, Saturn, Uranus, or Neptune.
Asteroid
a small rocky body orbiting the sun. Large numbers of these, ranging in size from nearly 600 miles (1,000 km) across (Ceres) to dust particles, are found (as the asteroid belt ) especially between the orbits of Mars and Jupiter, though some have more eccentric orbits, and a few pass close to the earth or enter the atmosphere as meteors.
Comet
a celestial object consisting of a nucleus of ice and dust and, when near the sun, a “tail” of gas and dust particles pointing away from the sun.
Meteor
a small body of matter from outer space that enters the earth’s atmosphere, becoming incandescent as a result of friction and appearing as a streak of light.
Meteorite
a meteor that survives its passage through the earth’s atmosphere such that part of it strikes the ground. More than 90 percent of meteorites are of rock, while the remainder consist wholly or partly of iron and nickel.
