Space Vocabulary 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
A system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.
Universe
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.
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.
Axis of Rotation
The straight line through all fixed points of a rotating rigid body around which all other points of the body move in circles.
Revolution
The movement of one object around a center or another object, a forceful overthrow of a government by the people or any sudden or grand change. An example of revolution is movement of the earth around the sun.
Seasons
One of the four natural divisions of the year, spring, summer, fall, and winter, in the North and South Temperate zones. Each season, beginning astronomically at an equinox or solstice, is characterized by specific meteorological or climatic conditions.
Equinox
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) or, either of the equinoctial points.
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 /ˈmɑːriə/ (singular: mare /ˈmɑːreɪ/) are large, dark, basaltic plains on Earth’s Moon, formed by ancient volcanic eruptions. They were dubbed maria, Latin for “seas”, by early astronomers who mistook them for actual seas.
Eclipse
The partial or total blocking of light of one celestial object by another. An eclipse of the Sun or Moon occurs when the Earth, Moon, and Sun are aligned. ◇ In a solar eclipse the Moon comes between the Sun and Earth.
Umbra
The umbra (Latin for “shadow”) is the innermost and darkest part of a shadow, where the light source is completely blocked by the occluding body. … An observer in the umbra experiences a total eclipse.
Penumbra
A partial shadow between regions of full shadow (the umbra) and full illumination, especially as cast by Earth, the Moon, or another body during an eclipse. 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
The mean distance between the Earth and the sun, about 98 million miles or 150 million kilometers. It is often abbreviated as AU.
Ellipse
An ellipse is defined as the locus of all points such that the sum of the distances from two foci to any point on the ellipse is a constant. Below we see the elliptical orbit of a planet, P, with the Sun, S, at one of the foci.
Terrestrial Planet
A terrestrial planet, telluric planet, or rocky planet is a planet that 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.
Gas Giants
A large, massive, low-density planet composed primarily of hydrogen, helium, methane, and ammonia in either gaseous or liquid state. Gas giants have swirling atmospheres primarily of hydrogen and helium, with no well-defined planetary surface; they are assumed to have rocky cores. … Also called Jovian planet.
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.
Geocentric
Having or representing the earth as the center, as in former astronomical systems.
