Solar System

Question 1

Nebula

Answer 1

a cloud of gas and dust in outer space, visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter

Question 2

Solar Nebula

Answer 2

Our solar system began forming within a concentration of interstellar dust and hydrogen gas called a molecular cloud. The cloud contracted under its own gravity and our proto-Sun formed in the hot dense center

Question 3

Nuclear Fusion

Answer 3

a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy

Question 4

Sunspot

Answer 4

a spot or patch appearing from time to time on the sun’s surface, appearing dark by contrast with its surroundings

Question 5

Astronomical Unit

Answer 5

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

Question 6

Terrestrial Planets

Answer 6

A terrestrial planet, telluric planet, or rocky planet is a planet that is composed primarily of silicate rocks or metals

Question 7

Prograde Rotation

Answer 7

Having a rotational or orbital movement that is the same as most bodies within a celestial system. In our solar system, prograde movement for both rotating and orbiting bodies is in a counterclockwise direction when viewed from a vantage point above the Earth’s north pole

Question 8

Retrograde Rotation

Answer 8

an APPARENT change in the movement of the planet through the sky. It is not REAL in that the planet does not physically start moving backwards in its orbit. It just appears to do so because of the relative positions of the planet and Earth and how they are moving around the Sun

Question 9

Gas Giant

Answer 9

a large planet of relatively low density consisting predominantly of hydrogen and helium, such as Jupiter, Saturn, Uranus, or Neptune

Question 10

Satellite

Answer 10

a celestial body orbiting the earth or another planet.

Question 11

Phase

Answer 11

a distinct period or stage in a process of change or forming part of something’s development.

Question 12

Eclipse

Answer 12

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

Question 13

Comet

Answer 13

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 14

Asteroid

Answer 14

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 15

Asteroid Belt

Answer 15

The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets

Question 16

Meteoroid

Answer 16

a small body moving in the solar system that would become a meteor if it entered the earth’s atmosphere

Question 17

Meteorite

Answer 17

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 18

Meteor

Answer 18

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