Chapter 3

Question 1

The Greeks

Answer 1

• Named “moving stars”, PLANETS from the Greek word meaning “wanderers”
• had a GEOMETRIC (geo for earth) view of the solar system- thought the earth was the center of revolving planets.

Question 2

Ptolemy’s view

Answer 2

He thought that as each planet revolved the earth they moved in different directions in big and little circles.

Question 3

Nicolaus Copernicus

Answer 3

• a polish astronomer
• in 1543 developed a HELIOCENTRIC (sun centered) view of the solar system which he explained the movements of the 6 known planets.

Question 4

Galileo Galilei

Answer 4

• made 2 discoveries to support the heliocentric view in the 1600’s
• saw 4 moons revolving around Jupiter
• observed that Venus appeared to go through phases like the Moon

Question 5

Tycho Brahe and Johannes Kepler

Answer 5

• Brahe made careful planetary observations in the late1500’s that Kepler, his assistant, analyzed in the early 1600’s.
• Kepler was the first person to determine that planets had elliptical orbits.

Question 6

Sun’s gravity

Answer 6

the most powerful force in the solar system

Question 7

Sun’s mass

Answer 7

99.8% of solar system mass

Question 8

Sun composition

Answer 8

Ball of glowing gas ¾ hydrogen, ¼ helium, very small amounts of other elements

Question 9

Sun facts

Answer 9

• The Sun rotates on its axis

* The Sun has an atmosphere

Question 10

Nuclear fusion

Answer 10

The Sun’s energy comes from nuclear fusion – under extremely high temperatures and pressure hydrogen atoms join together to form helium (mass is converted to energy)

Question 11

Three Parts of the Sun

Answer 11

1. Core
2. Radiation Zone
3. Convection Zone

Question 12

Sun’s Core

Answer 12

• central region
• temperature = 15 million degrees Celsius
• produces the energy

Question 13

Sun’s Radiation Zone

Answer 13

• middle layer
• Consists of very tightly packed gas where the energy from the core is transferred in the form of electromagnetic radiation

Question 14

Sun’s Convection Zone

Answer 14

outermost layer

•The gases travel in circular convection currents here

Question 15

The Sun’s Atmosphere

3 Layers

Answer 15

1. Photosphere
2. Chromosphere
3. Corona

Question 16

Photosphere

Answer 16

inner sphere
•Photos means “light” in Greek
•Gives off visible light

Question 17

Chromosphere

Answer 17

middle layer (color)
•Chroma means “color” in Greek
•Visible during solar eclipse (reddish color)

Question 18

Corona

Answer 18

outer layer
•Corona means “crown” in Latin
•Visible during solar eclipse (looks like a halo)
•Extends into space for millions of km
•Sends out a stream of electrically charged particles – solar wind, which on Earth is blocked by our magnetic field, except at the poles.

Question 19

Solar wind

Answer 19

Corona sends out a stream of electrically charged particles – solar wind, which on Earth is blocked by our magnetic field, except at the poles.
We see northern and southern lights.

Question 20

Sunspots

Answer 20

• areas of gas that are cooler than the gases around them in the photosphere
• Can be the larger than the size of the Earth
• Number of sunspots vary over a period of about 11 years.

Question 21

Prominences

Answer 21

reddish loops of gas that link pairs/groups of sunspots

Question 22

Comets

Answer 22

chunks of ice and dust whose orbits are usually very long, narrow ellipses

Question 23

Comet parts

Answer 23

•When close to the Sun, solar energy turns the ice into gas, releasing dust forming an outer layer called the coma.
•The inner layer is called the nucleus
The brightest part is the head which is made of the nucleus and the coma.
•Solar wind pushes the gas from the comet away from the Sun forming the tail (can be hundreds of millions of km long)
•Actually have 2 tails (one gas and one dust)
•Comet means “long-haired star” in Greek

Question 24

Edmond Halley

Answer 24

(1705) calculated orbits of 24 comets

Question 25

Asteroids

Answer 25

small rocky objects that orbit the Sun

most revolve around the Sun between the orbits of Mars and Jupiter (this region is known as the asteroid belt)

Question 26

Meteoroid

Answer 26

a chunk of rock or dust IN SPACE that usually comes from comets or asteroids

Question 27

Meteor

Answer 27

when a meteoroid enters the EATHS ATMOSPHERE friction makes it burn up and produce a streak of light.
SHOOTING STAR 💫

Question 28

Meteorites

Answer 28

when meteoroids are large enough to pass through the atmosphere and hit the EARTHS SURFACE