Space Vocabulary

Question 1

Orbit

Answer 1

The curved path of a celestial object or spacecraft around a star, planet, or moon, especially a periodic elliptical revolution.

Question 2

Solar System

Answer 2

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.

Question 3

Galaxy

Answer 3

A system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.

Question 4

Universe

Answer 4

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.

Question 5

Satellite

Answer 5

An artificial body placed in orbit around the earth or moon or another planet in order to collect information or for communication.

Question 6

Impact Crater

Answer 6

A crater on a planet or moon caused by the impact of a meteorite or other object, typically circular with a raised rim.

Question 7

Axis of Rotation

Answer 7

The straight line through all fixed points of a rotating rigid body around which all other points of the body move in circles.

Question 8

Revolution

Answer 8

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.

Question 9

Seasons

Answer 9

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.

Question 10

Equinox

Answer 10

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.

Question 11

Solstice

Answer 11

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.

Question 12

Mare

Answer 12

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.

Question 13

Eclipse

Answer 13

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.

Question 14

Umbra

Answer 14

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.

Question 15

Penumbra

Answer 15

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.

Question 16

Astronomical Unit

Answer 16

The mean distance between the Earth and the sun, about 98 million miles or 150 million kilometers. It is often abbreviated as AU.

Question 17

Ellipse

Answer 17

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.

Question 18

Terrestrial Planet

Answer 18

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.

Question 19

Gas Giants

Answer 19

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.

Question 20

Asteroid

Answer 20

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.

Question 21

Comet

Answer 21

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.

Question 22

Meteor

Answer 22

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.

Question 23

Meteorite

Answer 23

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.

Question 24

Geocentric

Answer 24

Having or representing the earth as the center, as in former astronomical systems.

Question 25

Heliocentric

Answer 25

Having or representing the sun as the center, as in the accepted astronomical model of the solar system.

Question 26

Gravity

Answer 26

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.

Question 27

Tide

Answer 27

Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth.

Question 28

Waxing

Answer 28

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.

Question 29

Waning

Answer 29

The moon at any time after full moon and before new moon (so called because its illuminated area is decreasing). Expand. Also called old moon. Compare waxing moon.

Question 30

Gibbous Moon

Answer 30

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.

Question 31

Crescent Moon

Answer 31

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.

Question 32

New Moon

Answer 32

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.

Question 33

Quarter Moon

Answer 33

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.