Chapter 12- The Solar System

Question 1

Astronomy

Answer 1

The branch of science that involves observations and explanations of events and objects that occur beyond Earth and its atmosphere.

Question 2

Astronomer

Answer 2

A scientist who studies astronomy. (Sun, planets, galaxies, black holes)

Question 3

Rotation

Answer 3

The spinning of an object around an imaginary line called the axis.

Question 4

Revolution

Answer 4

The motion of an object around another object.

Question 5

Photoperiod

Answer 5

The number of hours of daylight between sunrise and sunset.

Question 6

Effects of Earth’s rotation

Answer 6

Axis tilted 23.5 degrees in the celestial sphere.

Rotates counterclockwise, from west towards east.

Question 7

Planet

Answer 7

Must orbit the Sun;
Must have enough gravity to form a round shape;
Must have cleared the neighborhood of its orbit of any other objects.

Question 8

Retrograde Motion

Answer 8

The apparent slowing, reversal, and then looping of a planet in its path across the sky, occurring because Earth travels around the Sun faster than some of the other planets (Mars, Jupiter, Saturn)

Question 9

Precession

Answer 9

Although the angle of the earth’s axis is constant, the direction of it slowly changes, changing the position of the North Celestial Pole. It traces a circle ever 26,000 years.

Question 10

Perihelion

Answer 10

The point at which the earth is closest to the Sun, occurring around January 3rd (northern hemisphere’s winter). Antarctica is colder than the Arctic during our summer, because the Antarctica is the farthest point to the Sun.

Question 11

Aphelion

Answer 11

The point which the earth is farthest from the Sun in the ellipse, occurring around July 4th.

Question 12

Constellations / Asterisms

Answer 12

88 different … are recognized today, one of the most impressive being Orion the hunter. Some other unofficial patterns are called … The major stars all have Arabic names.

Question 13

Celestial Sphere

Answer 13

An imaginary rotating sphere upon which lie all the objects in the universe.

Question 14

Celestial Equator

Answer 14

A circle on the celestial sphere; the extension of Earth’s equator projected into the universe.

Question 15

Plane of the ecliptic

Answer 15

The path the Sun takes through the sky marked against the 12 constellations of the zodiac. The angle between the ecliptic and celestial equator is 23.5 degrees.

Question 16

Equinox

Answer 16

The two dates when the Sun crosses the celestial equator, around March 21 and September 22, the number of hours above the horizon and below the horizon are equal.

Question 17

Solstice

Answer 17

The Sun reaches the highest and lowest positions in the sky when the earth is tilted toward or away from the sun. The summer … marks the first day of summer,longest photoperiod of the year.

Question 18

Circumpolar

Answer 18

The constellations that never disappear below the horizon as the Earth rotates. In canada, the three main … constellations are Ursa Minor, Ursa Major and Cassiopeia.