The Universe and Galaxies

What statement describes galaxies?

• They are similar in size to our solar system.

• They contain one star and thousands of planets.

• They are spherical in shape and usually smaller than our solar system.

• They contain billions of stars and are significantly larger than our solar system.

What statement about the size of the universe is true?

• Most astronomers believe the universe is expanding in size.

• Most astronomers believe the universe is shrinking in size.

• Most astronomers believe the universe is remaining the same size.

• Most astronomers believe the universe is shrinking and expanding in a cyclic pattern.

Which unit is commonly used to express distance between stars and galaxies?

• astronomical units (AU)

• kilometers (km)

• lightyears (LY)

• nanometers (nm)

Which is the correct sequence from largest to smallest?

• Universe, Milky Way, Solar System

• Milky Way, Universe, Solar System

• Solar System, Milky Way, Universe

• Universe, Solar System, Milky Way

Which statement is believed by most scientists about the age of our solar system?

• The universe is the same age as our Solar System.

• The universe is older than our Solar System.

• Our Solar System is older than the universe.

• Our Solar System is about 4.6 million years old.

What components best define a galaxy?

• gas, dust, and billions of stars

• meteors, comets, and asteroids

• planets, moons, and a single star

• ice, rock, and dust

Examine the table showing different galaxies in the universe. Why do scientists use light years (ly) as a unit of measurement?

• Traditional units such as kilometer would give extremely large values.

• The unit of light year directly relates to the number of stars found in galaxies.

• Galaxies are only able to be measured if they produce light.

• A common unit allows easier communication between scientists in different countries.

Which type of galaxy is shown in the image?

• elliptical galaxy

• irregular galaxy

• lenticular galaxy

• spiral galaxy

What will be the position of the sun on the galaxy?

• at the center of the galaxy

• at the spiral edge of the galaxy

• in a spiral arm about one-third of the way from the center of the galaxy

• in a spiral arm about two-thirds of the way from the center of the galaxy

Which shape should a student choose to describe the milky way galaxy?

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