Measuring Distance in Space

A light-year is a measure of -

• time.

• distance.

• speed.

• velocity.

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CCSS.HSN.Q.A.1

How are objects located on the celestial sphere?

• longitude and latitude

• declination and parallax

• declination and righ ascension

• left ascension and right ascension

Approximately how many astronomical units are equivalent to one light-year?

• 63,000 AU

• 150,000 AU

• 300,000 AU

• 150,000 million AU

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CCSS.HSN.Q.A.1

How do scientists define an astronomical unit?

• the distance between Earth and the moon

• the distance between Earth and the Sun

• the distance from one end of the solar system to the other

• the distance from one end of the Milky Way galaxy to the other

An astronomical unit is equivalent to ______________.

• 150,000 miles

• 150,000 kilometers

• 150 million miles

• 150 million kilometers

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CCSS.5.MD.A.1

Which of the following models is most similar to the celestial sphere?

• Place an overturned glass bowl on a table, and place a piece of paper on top of the bowl. Use a marker to draw stars on the paper. The glass bowl represents Earth and the paper represents the celestial sphere.

• Place a marble on a table, and place an overturned glass bowl over the marble. Use a marker to draw stars on the surface of the glass bowl. The marble represents Earth and the bowl represents the celestial sphere.

• Place a marble on a table, and place an overturned coffee mug over the marble. Use a marker to draw stars on the surface of the mug. The marble represents Earth and the mug represents the celestial sphere.

• Place a marble on a table, and place an overturned glass bowl over the marble. Place a smaller marble on top of the glass bowl. The smaller marble represents Earth, the larger marble represents the Sun, and the bowl represents the celestial sphere.

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CCSS.HSG.MG.A.1

What is necessary to calculate a star's distance from Earth?

• the parallax angle

• the position of the star observed twice, six months apart

• the distance between the two points of observation

• all of the above

How do light-years help astronomers to determine the ages of distant objects in space?

• To calculate an object's age in years, astronomers must first know the object's distance from Earth in light-years.

• To calculate an object's distance from Earth in light-years, astronomers must first know the object's age in years.

• Light in space travels approximately 9.5 trillion km per year. Therefore, an object's distance from Earth in light-years is equivalent to the object's age in years.

• Light in space travels approximately 9.5 trillion km per year. Therefore, the images that astronomers see of distant objects actually show what those objects looked like long ago.

A star is located approximately 500 million light-years from Earth. Can a student determine the star's distance by calculating its parallax angle?

• No. Parallax cannot be used to calculate the distances of objects more than approximately 300 light-years away.

• Yes. Parallax enables astronomers to calculate the distances of objects fewer than 1 billion light-years away.

• The student cannot use the parallax angle alone to determine the star's distance; the student must also know the star's age.

• The student cannot use the parallax angle alone to determine the star's distance; the student must also know the star's size.

What is parallax?

• the average distance between a celestial object and Earth

• the angle formed by Earth and two celestial bodies located in different directions from Earth

• the apparent difference in the position of an object when viewed at the same time each year

• the apparent difference in the position of an object when viewed from different lines of sight