Space Review

Which statement is true regarding measuring distances in space?

• The time taken for light to travel through our Solar System is longer than that for light to travel through the Milky Way.

• The Earth is one astronomical unit (AU) from the Sun.

• All of the terrestrial planets are more than one astronomical unit (AU) from the Sun.

• An astronomical unit (AU) is larger than a light year.

The sun is much larger than the moon. However, as viewed from Earth, the sun and moon appear to be the same size. Why do the sun and moon appear to be the same size when viewed from Earth?

• The moon is much denser than the sun.

• The moon is much hotter than the sun.

• The moon is much brighter than the sun.

• The moon is much closer to Earth than the sun.

Devyn is at the observatory and is examining a newly discovered star through a powerful telescope. She wants to find out how bright the star actually is. What information does she need to calculate the absolute magnitude of a star?

• Apparent magnitude and distance from Earth of the star

• Color and distance from Earth of the star

• Color and composition of the star

• Color and temperature of the star

The diameter of Saturn is nearly ten times that of Earth. However, the density of Saturn is much less than that of Earth. What is the reason for this?

• Earth is farther from the sun than Saturn.

• Saturn has a ring system.

• Saturn is a gaseous planet.

• Earth is hotter than Saturn.

In 1995, the Hubble Space Telescope photographed a tiny spot in the sky for a period of ten days; 342 exposures were placed together to create an image known as the Hubble Deep Field. Although the sample is tiny, it is representative of the universe, which looks similar in all directions. The image below shows a collection of billions of stars. The Hubble Deep Field shows at least 3,000 groups of these stars.

• Galaxy

• Moon

• Universe

• Solar System

One physical property of a star is apparent brightness (magnitude). Which of the following is used in determining the apparent brightness (magnitude) of a star?

• The number of times the star rotates

• The number of prominences the star makes

• The distance the star is from Earth

• The constellation the star is in

An astronomer uses a telescope to observe a star. She observes that the color of this star is similar to the color of the sun. Therefore, she infers that the star and the sun have similar sizes and surface temperatures. Using this information, what can the astronomer conclude about the star?

• The star is hotter than most other stars in our galaxy.

• The star is medium sized.

• The star is a white dwarf.

• The star is brighter than most other stars in our galaxy.

The Sun's energy and composition is provided by which of the following?

• The Sun's magnetic field

• The burning of fossil fuels within the Sun

• Solar power that produces electricity in the Sun

• The fusion of hydrogen into helium

Our solar system consists of eight planets. Each planet is classified as either a terrestrial planet or a gas giant planet. Which is a difference between these two types of planets?

• Gas giant planets have rockier crusts than terrestrial planets.

• Terrestrial planets are larger than gas giant planets.

• Gas giant planets are denser than terrestrial planets.

• Terrestrial planets have thinner atmospheres than gas giant planets.

Ricky examined a table that lists the characteristics of four stars. Which star would appear the dimmest from Earth’s surface?

• Star B

• Star D

• Star C

• Star A