Space Flashcards
the curved path, usually elliptical, described by a planet, satellite, spaceship, etc., around a celestial body, as the sun.
Orbit
the sun together with all the planets and other bodies that revolve around it.
Solar System
a large system of stars held together by mutual gravitation and isolated from similar systems by vast regions of space.
Galaxy
everything that exists in, on and around the Earth
Universe
Astronomy. a natural body that revolves around a planet; a moon.
Satellite
A crater on a planet or moon caused by the impact of a meteorite or other object.
Impact crater
the line about which a rotating body, such as the earth, turns.
Axis of rotation
the orbiting of one heavenly body around another.
Revolution
one of the four periods of the year (spring, summer, autumn, and winter), beginning astronomically at an equinox or solstice, but geographically at different dates in different climates.
Season
the time when the sun crosses the plane of the earth’s equator, making night and day of approximately equal length all over the earth and occurring about March 21 (vernal equinox or spring equinox) and September 22 (autumnal equinox)
Equinox
either of the two points in the ecliptic farthest from the equator.
Solstice
any of the several large, dark plains on the moon and Mars: Galileo believed that the lunar features were seas when he first saw them through a telescope.
Mare
the obscuration of the light of the moon by the intervention of the earth between it and the sun (lunar eclipse) or the obscuration of the light of the sun by the intervention of the moon between it and a point on the earth (solar eclipse)
Eclipse
the complete or perfect shadow of an opaque body, as a planet, where the direct light from the source of illumination is completely cut off
Umbra
the partial or imperfect shadow outside the complete shadow of an opaque body, as a planet, where the light from the source of illumination is only partly cut off.
Penumbra
a unit of length, equal to the mean distance of the earth from the sun: approximately 93 million miles (150 million km). Abbreviation: AU
Astronomical Unit (AU),
Typical equation: ( x 2/ a 2) + ( y 2/ b 2) = 1. If a = b the ellipse is a circle.
Ellipse
inner planet
Terrestrial Planet
giant star
Gas Giant
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.
Asteroid
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.
Comet
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.
Meteor
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.
Meteorite
measured from or considered in relation to the center of the earth.
Geocentric
measured from or considered in relation to the center of the sun.
Heliocentric
the force that attracts a body toward the center of the earth, or toward any other physical body having mass. For most purposes Newton’s laws of gravity apply, with minor modifications to take the general theory of relativity into account.
Gravity
the periodic rise and fall of the waters of the ocean and its inlets, produced by the attraction of the moon and sun, and occurring about every 12 hours. 2. the inflow, outflow, or current of water at any given place resulting from the waves of tides.
Tide
the moon at any time after new moon and before full moon, so called because its illuminated area is increasing. Compare waning moon. Origin of waxing moon Expand.
Waxing
the moon at any time after full moon and before new moon (so called because its illuminated area is decreasing). Also called old moon. Cf. waxing moon.
Wanig
It’s easy to see a waxing gibbous moon in the daytime because, at this phase of the moon, a large fraction of the moon’s day side is facing our way. … Any moon that appears more than half lighted but less than full is called a gibbous moon. The word gibbous comes from a root word that means hump-backed
Gibbous Moon
A crescent is a thin, curved shape that’s thicker in the middle and tapers to thin points at each end, like the little sliver of moon you might notice in the sky. Crescent was first used to describe the shape of the waxing, or growing moon, and if you listen closely you can hear its similarity to increase.
Crescent Moon
the phase of the moon in which its whole disk is illuminated.
the time when the moon’s whole disk is illuminated.
Full 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
New Moon
Third Quarter. The moon is one-half illuminated by the sun. Occurs when the moon’s illumination is decreasing, Waning Crescent. The moon is less than one-half illuminated by the sun but less than one quarter illuminated.
Quarter Moon
