Space Flashcards
Orbit
the circular or elliptical path of an object as it revolves around another object
Solar System
a 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 crater on a planet or moon caused by the impact of a meteorite or other object, typically circular with a raised rim.
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
DescriptionThe lunar maria are large, dark, basaltic plains on Earth’s Moon, formed by ancient volcanic eruptions.
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.
Penumbra
the partially shaded outer region of the shadow cast by an opaque object.
Astronomical Unit
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
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.
Terrestrial Planet
a planet having a compact rocky surface like the Earth’s; the four innermost planets in the solar system
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 object made of rock or metal that orbits the sun
Comet
a body of ice and dust that travels in a long narrow orbit around the sun
Meteor
a streak of light in the sky that forms when a piece of rock from space burns up in Earth’s atmosphere (related term: shooting star)
Meteorite
a piece of rock or metal from space that strikes Earth’s surface
Geocentric
having the Earth as the center
Heliocentric
having the sun as the center
Gravity
a force that exists between any two objects that have mass (related word: gravitational)
Tide
the regular fluctuation of sea water driven by the gravitational pull of the Moon and Sun on Earth’s oceans and other large bodies of water
Waxing
A waxing moon is any phase of the moon during the lunar cycle between the new moon and the full moon. A waxing moon is one that is getting larger each night.
Wannig
Waning is the opposite, or decreasing after a full moon, and is always illuminated on the left.
Gibbous Moon
The definition of gibbous refers to a moon in between a half-moon but less than a full moon
Crescent Moon
A crescent is a thin, curved shape that’s thicker in the middle and tapers to thin points at each end
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
A quarter moon occurs when we see the Moon half illuminated by the Sun, and half enshrouded in darkness.
Perihelion
the point in the orbit of a solar system body when it is closest to the Sun
Aphelion
the point in the orbit of a planet or other orbiting body where it is farthest from the Sun or the body around which it revolves
