Earth - Chapter 8 Test Review

What is the orbital period for a planet whose orbit has a semimajor axis of 4 AU?

• 2 years

• 4 years

• 8 years

• 16 years

Which of the following is NOT one of Kepler's Laws of Motion for orbiting bodies?

• An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

• A planet orbits the Sun in an ellipse, with the Sun at one focus of the ellipse.

• A line connecting a planet to the Sun sweeps out equal areas in equal time intervals.

• P²=a³, where P is the orbital period of the planet in years and a is the average distance of the planet from the Sun in astronomical units (AU).

Which is the most important factor in determining how long a star will live?

• color

• temperature

• composition

• mass

Elements heavier than iron

• were created during the Big Bang.

• are created in the supernova explosions of high-mass stars.

• are created by nuclear reactions in stars.

• can only be created in a lab.

Planets are believed to form

• at the same time as the stars they orbit.

• millions of years after the stars they orbit.

• only around stars just like the Sun.

• around every star in the universe.

Where did the heavy elements that make up the bulk of Earth originate?

• supernova

• meteorites

• Big Bang

• the Sun

What is thought to be the age of the eight planets in our solar system relative to each other?

• The inner planets formed together first and the outer planets formed together later.

• The outer planets formed together first and the inner planets formed together later.

• They all formed at approximately the same time.

• They formed sequentially from Neptune inward to Mercury.

Which of these statements about Kepler's Laws is true?

• A planet moves most rapidly when its orbit takes it closest to the Sun.

• The time that is required for a planet to complete an orbit is proportional to the square of its radius.

• Planets orbit clockwise around the Sun.

• Planets travel in circular orbits.

The planets in our solar system are thought to have come from

• clumps of rocky material that exist between the stars.

• the same cloud of gas and dust in which the Sun formed.

• a cloud of gas in the Orion Nebula.

• a supernova (they were flung out into space by the explosion).

Imagine you are searching for dense and rocky planets in a newly discovered planetary system. Based on what you know about our solar system, where would you most likely find this type of planet?

• very far from the central star.

• close to the central star.

• in circular orbits.

• in regions with lots of moons.