Phases Of The Moon Flashcards
(34 cards)
the curved path of a celestial object or spacecraft around a star, planet, or moon, especially a periodic elliptical revolution.
Orbit
the collection of eight planets and their moons in orbit around the sun, together with smaller bodies in the form of asteroids, meteoroids, and comets.
Solar system
a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.
Galaxy
all existing matter and space considered as a whole; the cosmos. The universe is believed to be at least 10 billion light years in diameter and contains a vast number of galaxies; it has been expanding since its creation in the Big Bang about 13 billion years ago.
Universe
a celestial body orbiting the earth or another planet.
Satellite
a crater on a planet or moon caused by the impact of a meteorite or other object, typically circular with a raised rim.
Impact crater
the straight line through all fixed points of a rotating rigid body around which all other points of the body move in circles.
Axis of rotation
an instance of revolving.
Revolution
each of the four divisions of the year (spring, summer, autumn, and winter) marked by particular weather patterns and daylight hours, resulting from the earthβs changing position with regard to the sun.
Season
the time or date (twice each year) at which the sun crosses the celestial equator, when day and night are of equal length (about September 22 and March 20).
Equinox
either of the two times in the year, the summer solstice and the winter solstice, when the sun reaches its highest or lowest point in the sky at noon, marked by the longest and shortest days.
Solstice
large, dark, basaltic plains on Earthβs Moon, formed by ancient volcanic eruptions. They were dubbed maria, Latin for βseasβ, by early astronomers who mistook them for actual seas.
Mare
an obscuring of the light from one celestial body by the passage of another between it and the observer or between it and its source of illumination.
Eclipse
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.
Umbra
the shadow cast by the earth or moon over an area experiencing a partial eclipse.
Penumbra
a unit of measurement equal to 149.6 million kilometers, the mean distance from the center of the earth to the center of the sun.
Astronomical unit
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 that does not intersect the base.
Ellipse
is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun, i.e. Mercury, Venus, Earth, and Mars.
Terrestrial planet
a large planet of relatively low density consisting predominantly of hydrogen and helium, such as Jupiter, Saturn, Uranus, or Neptune.
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 βtailβ of gas and dust particles pointing away from the sun.
Comet
a small body of matter from outer space that enters the earthβs atmosphere, becoming incandescent as a result of friction and appearing as a streak of light.
Meteor
a meteor that survives its passage through the earthβs 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
having or representing the earth as the center, as in former astronomical systems.
Geoneric