Unit 12 Lesson 3 What Are Stars and Galaxies?

The sun is a medium-sized star, but it appears much larger than other stars. Why does the sun appear to be so large?

• The sun is hotter than other stars.

• The sun is affected by Earth’s gravity more than other stars are.

• The sun is much closer to Earth than other stars are.

• The sun produces more light than other stars.

Tags

NGSS.MS-ESS1-1

Unlike planets, stars make their own light and glow very brightly. Stars are made mostly of what material?

• very hot metal

• carbon and oxygen

• extremely hot rock

• glowing, hot gases

There are many different colors of stars. Which characteristic determines the color of a star?

• temperature

• distance from Earth

• actual brightness

• size and shape

A galaxy is composed of billions of stars held together by gravity. The illustration below shows one common type of galaxy.

What type of galaxy is shown in the illustration?

• barred spiral

• spiral

• spinning

• . elliptical

Tags

NGSS.MS-ESS1-2

The diagram below shows the Milky Way galaxy.

Which letter best shows the location of our solar system?

• W

• X

• Y

• Z

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NGSS.MS-ESS1-2

Some galaxies have symmetrical shapes. Other galaxies look jumbled.

What term do astronomers use to describe a galaxy such as the one shown in the illustration?

• barred spiral galaxy

• spiral galaxy

• irregular galaxy

• elliptical galaxy

Elliptical galaxies are brightest toward the center. Which of these statements best explains this observation?

• The stars are evenly distributed throughout the galaxy.

• The stars are spread throughout the galaxy in bands that look like the arms of spiral galaxies.

• Most of the stars are near the outside of the elliptical galaxy, with dust clouds in the center.

• The center is crowded with stars, and the number of stars decreases farther out.

Tags

NGSS.MS-ESS1-2

There are several types of galaxies. How do scientists classify galaxies?

• by size

• by number of stars

• by temperature

• by shape

Each of the images below shows two stars of the same color. Which picture and statement is correct?

• 
• 
• 
• 

All visible stars in the night sky are many times larger than Earth. Why do they look like tiny points of light?

• They are moving very fast.

• Most of the light from stars is absorbed by galaxies, so it does not reach Earth.

• The stars visible at night are located very far from Earth.

• The atmosphere blocks most of their light.