Chapter 21: Origins of Modern Astronomy

Question 1

Comets were believed to be what?

Answer 1

Bad omens and blamed of various disasters

Question 2

Ancient Greeks in Early History of Astronomy

Answer 2

• Used philosophical arguments to explain natural phenomena.
• Held incorrect geocentric view of universe.
• Used observational data

Question 3

What is “Earth-Centered” view?

Answer 3

earth was motionless sphere at the center of the universe; believed that sun and planets all revolve around the earth.

Question 4

What did Ancient Greeks believe about the stars?

Answer 4

They were on a “celestial sphere”

• transparent sphere, hollow
• they turn daily around the earth

Question 5

What is a Celestial Sphere?

Answer 5

Can be viewed as the sphere “ceiling” of the Earth were stars are located.

Question 6

What did the “Seven Wonders” include?

Answer 6

The Sun
The Moon
Mercury through Saturn

Question 7

What scientist concluded that the Earth is spherical?

Answer 7

Aristotle

because during an eclipse the shadow of the moon is curved.

Question 8

Who was the first Greek to profess a Sun-centered or heliocentric universe (aka.. the distance between the Earth from the sun and moon)?

Answer 8

Aristarchus

Question 9

What scientist concluded Earth was just another planet?

Answer 9

Nicolas Copernicus

He constructed a model of the solar system that put the Sun at the center.

Question 10

Who was Johannes Kepler?

Answer 10

• Ushered in new age of astronomy
• Planets revolve around the Sun
• Developed three laws of planetary motion

Question 11

The three laws of Planetary Motion?

Answer 11

1. Orbits of the planets are elliptical (oval)
2. Planets revolve around the Sun at varying speeds
3. Found a proportional relation between a planet’s orbital period and its distance to the Sun

Question 12

Who was Galileo Galilei?

Answer 12

Constructed an astronomical telescope in 1609.

Discoveries:

• Four moons of Jupiter
• Planets appeared as disks
• Sunspots- by tracking movement to determine how the Sun rotated.

Question 13

What scientist went blind in the later years of life because of staring at the Sun too much?

Answer 13

Galileo Galilei

Question 14

When the moon is viewed from the North Pole what way does the Earth orbit?

Answer 14

Counterclockwise

Question 15

Lunar phases are a consequence of?

Answer 15

1. The motion of the Moon

2. The sunlight that is reflected from its surface

Question 16

Shadow effects that were frist understood by the early Greeks, were called what?

Answer 16

Eclipses

Question 17

Two types of eclipses?

Answer 17

1) Solar Eclipse
- moon moves in line w/ Earth & Sun
- Can occur during new-moon phase

2) Lunar Eclipse
- Moon moves within shadow of Earth
- Only occurs during full-moon phase