Nebular Theory & Kepler Review

The theory that explains the formation of the solar system is called ____.

• Nebulis Theory
• Nebular Theory
• Big Bang Theory
• Big Nebulan Theory

How much of the nebula matter became the Sun?

• 33%
• 66%
• 99%
• 77%

What caused the nebula to collapse and start spinning?

• Supernova
• Asteroid collision
• Big Bang
• Nearby star exploded

How long ago did the solar system begin to form?

• 5 billion years ago
• 50 million years ago
• 5 million years ago
• 50 billion years ago

What is the period of rotation?

• How long it takes a planet to orbit the sun
• How fast a planet orbits the sun
• How fast a planet spins
• How elliptical a planet's orbit is

What is  the period of revolution?

• How long it takes a planet to orbit the sun
• How long it takes a planet to spin around
• How fast a planet spins
• How elliptical a planet's orbit is

What would happen if the Earth's inertia "quit working"?

• We would float off into space
• Sun's gravity would push us into space
• We would smash into Mars
• Sun's gravity would pull us in to it

Which two forces keep the planets in orbit around the sun?

• inertia & momentum
• gravity & inertia
• inertia & velocity
• gravity & velocity

When a planet is closest to the sun in it's orbit, it is called ____.

• perihelion
• aphelion
• parahelical
• aphahelical

What is the shape of a planet's orbit?

• circular
• elliptical
• spherical
• round