Approximately how old is our solar system?

About 6,000 years old About 65 million years old About 4.6 billion years old About 13.8 billion years old

What was the original cloud of gas and dust that formed our solar system called?

A solar nebula A comet cloud A protoplanet A pulsar

What force caused the solar nebula to collapse and form the solar system?

Magnetism Gravity Nuclear energy from the Sun Solar wind

What did the center of the collapsing solar nebula eventually become?

Jupiter The asteroid belt The Sun Earth

What are planetesimals?

Tiny stars that circle the Sun Small rocky or icy bodies that clumped together in the early solar system and eventually built up into planets Moons of Jupiter Fragments of exploded stars

Why did only rocky planets form in the inner solar system near the Sun?

Rocky material is lighter and drifted toward the Sun The Sun's gravity only attracted rocks It was too hot for ice and gases to condense, so only rocky and metallic materials could survive there Gas giants formed first and pushed rocky material inward

What is the nebular hypothesis?

The theory that planets were captured by the Sun from other stars The idea that the solar system has always existed The scientific explanation that the solar system formed from a rotating cloud of gas and dust that collapsed under its own gravity The hypothesis that the Sun and planets formed from a black hole explosion

How do scientists know the age of the solar system?

By counting the rings inside the Sun By radioactive dating of meteorites and Moon rocks By measuring how far the planets have moved from the Sun By timing how long it takes light from the Sun to reach Earth

What was the leftover disk of material around the young Sun called?

A supernova remnant An accretion black hole A protoplanetary disk A stellar corona

Which event is thought to have possibly triggered the collapse of the solar nebula?

A collision between two other galaxies A shockwave from a nearby supernova explosion A giant asteroid hitting the nebula The gravitational pull of a passing black hole

Which of the following best describes the process by which planets grew from the protoplanetary disk?

The Sun ejected blobs of hot gas that cooled into planets Dust grains stuck together into pebbles, pebbles grew into planetesimals, and repeated collisions built up full-sized planets Planets formed instantly when the nebula collapsed All planets were once part of another star that exploded