Space Flashcards
Orbit
the curved path of a celestial object or spacecraft around a star, planet, or moon, especially a periodic elliptical revolution
Solar system
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
Galaxy
all existing matter and space considered as a whole
Satellite
an artificial body placed in orbit around the earth or moon or another planet in order to collect information or for communication
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 action of rotating around an axis or center
Season
each of the four divisions of the year (spring, summer, autumn, and winter) marked by particular weather patterns and daylight hours, resulting from the earth’s changing position with regard to the sun
Equinox
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)
Solstice
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
Mare
The lunar maria are large, dark, basaltic plains on Earth’s Moon, formed by ancient volcanic eruptions
Eclipse
the total or partial obscuring of one celestial body by another
Umbra
The umbra is the innermost and darkest part of a shadow, where the light source is completely blocked by the occluding body
Penumbra
During a partial lunar eclipse, a portion of the Moon’s disk remains within the penumbra of Earth’s shadow while the rest is darkened by the umbra.
Astronomical unit
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
Terrestrial planet
A terrestrial planet, telluric planet, or rocky planet is a planet that is composed primarily of silicate rocks or metals
Gas giant
a large planet of relatively low density consisting predominantly of hydrogen and helium, such as Jupiter, Saturn, Uranus, or Neptune
Ellipsis
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.
Asteroid
a small rocky body orbiting the sun
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
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
Gravity
the force that attracts a body toward the center of the earth, or toward any other physical body having mass
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
the moon at any time after new moon and before full moon, so called because its illuminated area is increasing
Wanning
the moon at any time after full moon and before new moon
Gibbous moon
The definition of gibbous refers to a moon in between a half-moon but less than a full moon, or something that protrudes or creates an obvious bulge
Crescent moon
The Waxing Crescent phase begins the part of the lunar cycle when the Moon is visible at night
Full moon
The full moon is the lunar phase when the Moon appears fully illuminated from Earth’s perspective.
New moon
In astronomy, the new moon is the first lunar phase, when the Moon and Sun have the same ecliptic longitude
Quarter moon
half of the Moon’s visible portion is lit up during a quarter moon.
Perihelion
The word “perihelion” stems from the Ancient Greek words “peri”, meaning “near”, and “helios”, meaning “the Sun
Aphelion
Aphelion” derives from the preposition “apo”, meaning “away, off, apart
