Unit 4 Review: Hierarchy of the Universe

Name a celestial body found within our solar system.

• Sun

• Andromeda Galaxy

• Alpha Centauri

• Betelgeuse

Which is the smallest?

• the solar system

• Jupiter

• Milky Way Galaxy

• Sun

A Galaxy is made of:

• stars, gas, and dust

• only stars

• only gas

• only dust

How are a galaxy and a nebula related?

• Some galaxies are found inside of a single nebula.

• A galaxy from the gas and dust of a single nebula.

• Many nebulae are found inside of a single galaxy.

• Nebulae and galaxies combine to form stars.

A light-year is a unit of measurement used to describe what?

• Time

• Distance

• Speed

• Brightness

Why do scientists use light-years instead of Astronomical Units to measure the distances between stars?

• The speed of sound is too slow.

• Telescopes can measure only in light years.

• Distant stars can only be seen if there is light.

• The smaller numbers that result from measuring with larger units are easier to use.

Which distance is the greatest?

• Distance across the Milky Way galaxy.

• distance to the Jupiter.

• the verge of the solar system.

• distance to another near galaxy.

What does gravity do inside of nebulae?

• The gravity pulls the gas and dust apart, leading to the formation of a larger nebula.

• The gravitational pull between the gas and dust matter leads to the formation of new galaxies.

• The gravitational pull between the gas and dust matter leads to the formation of new stars and planets.

Gravity is important for keeping planets in orbit around stars because:

• it provides the necessary force to keep planets in a stable orbit.

• it repels planets away from stars.

• it has no effect on planetary orbits.

• it only affects the rotation of planets.

Why couldn’t astronomers detect planets before modern telescopes were discovered?

• The planets are much closer than the stars they orbit.

• The planets are much farther than the stars they orbit.

• The planets are much smaller than the stars they orbit.