Notes 14-1 Observing the solar system. Chapter Preview Questions 1.What is the sun and where is it within the solar system? a. a planet; at the center

Notes 14-1Observing the solar system

Chapter Preview Questions

• 1. What is the sun and where is it within the solar system?

• a. a planet; at the center of the system• b. a planet; at the outer edge of the system• c. a star; at the center of the system• d. a star; at the outer edge of the system


• 1. What is the sun and where is it within the solar system?

• a. a planet; at the center of the system• b. a planet; at the outer edge of the system• c. a star; at the center of the system• d. a star; at the outer edge of the system


• 2. Which four planets are closest to the sun?

• a. Mercury, Venus, Earth, Mars• b. Mercury, Earth, Pluto, Neptune• c. Jupiter, Saturn, Uranus, Neptune• d. Mercury, Earth, Mars, Jupiter


• 2. Which four planets are closest to the sun?

• a. Mercury, Venus, Earth, Mars• b. Mercury, Earth, Pluto, Neptune• c. Jupiter, Saturn, Uranus, Neptune• d. Mercury, Earth, Mars, Jupiter


3. What are some general characteristics of Jupiter • and Saturn? • a. small, rocky, many moons• b. large, ringed, many moons• c. large, rocky, no atmospheres• d. small, thick atmospheres


3. What are some general characteristics of Jupiter • and Saturn? • a. small, rocky, many moons• b. large, ringed, many moons• c. large, rocky, no atmospheres• d. small, thick atmospheres


• 4. What makes life as we know it possible on Earth? • a. rocky surface, one moon, water vapor• b. ice, suitable temperatures, thick air• c. rocky surface, water in three states, thin air• d. liquid water, suitable temperatures • and atmosphere


• 4. What makes life as we know it possible on Earth? • a. rocky surface, one moon, water vapor• b. ice, suitable temperatures, thick air• c. rocky surface, water in three states, thin air• d. liquid water, suitable temperatures • and atmosphere

Geocentric System

• In a geocentric system, Earth is at the center of the revolving planets and stars.

Ptolemy’s Model

• 140 AD• Geocentric model• Thought plants moved on small circles that

move on bigger circles

Heliocentric System

• In a heliocentric system, Earth and the other planets revolve around the sun.

Copernicus

• 1542• Worked out the arrangement of the known

planets and how they move around the sun

Galileo

• 1600s• Used a newly invented telescope to make

discoveries that support the heliocentric model.

Tycho Brahe

• Late 1500’s• Made observations about the positions of the

planets without using a telescope

Kepler

• Used Tycho Brahe’s data to develop 3 laws that describe the motions of the planets

• 1) The orbit of each planet is an ellipse (elongated circle)

• 2) Planets move faster when close to sun, and slower when further from sun

• 3) Planets that are closer to the sun orbit the sun faster

Elliptical Orbit

The solar system

• In Galileo’s time, Mercury, Venus, Earth, Mars, Jupiter, Saturn were discovered

• Since then, Uranus, Neptune, Pluto, moons, etc. have been discovered

• Today, we know that the solar system consists of the sun, the planets, their moons, and other small objects that orbit the sun

Measuring Distances in Solar System

• Unit = Astronomical Unit (AU)• 1 AU = ~150 million km (distance = Earth’s

average distance from sun)

The Sun and Planets• Shown below are the average

distances of each planet from the sun.

Exploring solar system

• Telescopes on Earth and in space• Astronauts to moon/ space• Moons and planets do not produce their own

light, but rather they reflect the sun’s light

Planet Speed Versus Distance• Johannes Kepler

discovered a relationship between the speed of a planet and its distance from the sun. Use the graph to discover what Kepler learned.

Planet Speed Versus Distance

– About 30 km/s

• Reading Graphs:

– According to the graph, what is Earth’s average speed?


– Mercury; Mercury

• Interpreting Data:

– Which is closer to the sun, Mercury or Mars? Which moves faster?


– Planets that are closer to the sun move faster.

• Drawing Conclusions:

– What is the general relationship between a planet’s speed and its average distance from the sun?


– Uranus’s speed is less than that of Jupiter because Uranus is farther from the sun than Jupiter.

• Predicting:

– The planet Uranus is about 2,900 million km from the sun. Predict whether its speed is greater or less than Jupiter's speed. Explain your answer.

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Notes 14-1 Observing the solar system. Chapter Preview Questions 1.What is the sun and where is it within the solar system? a. a planet; at the center