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

Solar Nebula. 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. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun, i.e. Mercury, Venus, Earth, and Mars.

Question 7

pro grade rotation

Answer 7

prograde. (prō’grād’) 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. Compare retrograde.

Question 8

retrograde rotation

Answer 8

All eight planets in the Solar System orbit the Sun in the direction that the Sun is rotating, which is counterclockwise when viewed from above the Sun’s north pole. Six of the planets also rotate about their axis in this same direction. The exceptions—the planets with retrograde rotation—are Venus and Uranus.

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

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

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

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Answer 13

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Question 14

dghsdghs

Answer 14

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Question 15

sgfhfdg

Answer 15

dghfg

Question 16

dfnhdghn

Answer 16

ndfgf

Question 17

gnfdfg

Answer 17

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Question 18

rgdrth

Answer 18

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