Beyond Our World Pre-Test

The Kuiper Belt is an area beyond Neptune where small objects made of mostly rock and ice are orbiting the Sun. Which of the following best explains why the objects in the Kuiper Belt orbit the Sun?

• The objects are held in place by Neptune’s magnetic force.

• The objects are held in place by the Sun’s gravity.

• The objects have too much mass to overcome Neptune’s pull.

• The objects have too little speed to move on their own.

One of the important criteria in classifying an object as a planet is that the object is spherical. What makes an astronomical object become spherical?

• gravity

• electromagnetic force

• convection

• magnetic force

A galaxy includes billions of different objects. Which of the following objects in our galaxy is largest?

• asteroid

• meteor

• planet

• star

The closest star to Earth other than the Sun is Proxima Centauri. What is true about Proxima Centauri?.

• It is in a distant galaxy.

• It is in our solar system.

• It is in a different universe.

• It is in the Milky Way galaxy.

Marlee uses a telescope to observe a red star. What does its color tell her most directly about the star?

• the star's age

• the star's temperature

• the star's distance from the Earth

• the star's location relative to other stars

Liam notices a star in the sky that is brighter than any other star he sees. What is Liam noticing about the star?

• its composition

• its luminosity

• its apparent magnitude

• its absolute temperature

The graph compares the surface temperature and color of stars. What would be the color of a star that has a surface temperature of 20,000 K?

• blue

• blue-white

• yellow-red

• red

Isabel is using a telescope to view stars in the night sky over her house. Which of the following is an observation Isabel can make?

• The exact temperature of the stars.

• The absolute brightness of the stars.

• The surface composition of the stars.

• The apparent magnitude of the stars.

The way a star can be observed from Earth depends on several factors. Which of the following does NOT affect a star’s appearance from Earth?

• The number of planets orbiting the star

• The diameter of the star

• The distance of the star from Earth

• The luminosity of the star

The Sun has several layers. Which layer is most visible to an observer on Earth?

• core

• chromosphere

• radiation zone

• photosphere