Discovering the Milky Way Galaxy

Who were the astronomers that began to count and map out the stars in the night sky in a methodical and three-dimensional manner?

• Henrietta Leavitt and Harlow Shapley

• Edwin Hubble and Albert Einstein

• Sir William Herschel and Caroline Herschel

• Galileo Galilei and Nicolaus Copernicus

What did Henrietta Leavitt discover that was crucial for understanding the size of the Milky Way?

• The theory of relativity

• The concept of a heliocentric solar system

• The period-luminosity relation

• The existence of black holes

What is the period of pulsation for a Cepheid variable star?

• 1 to 60 days

• 12 to 24 hours

• 1 to 10 years

• 30 to 90 days

Where do Cepheid variable stars lie on the H-R diagram?

• Red Giant Branch

• Instability Strip

• White Dwarf Region

• Main Sequence

What did Harlow Shapley prove about the Milky Way Galaxy?

• It is a small collection of stars

• Its center is near the Sun

• It is a gigantic disk of stars

• It is the only galaxy in the universe

What is the proper motion of a star?

• The rate at which a star moves across the sky

• The brightness of a star

• The temperature of a star

• The distance of a star from Earth

What did early astronomers believe about the position of the Sun in the galaxy?

• It was at the edge of the galaxy

• It was outside the galaxy

• It was at the center of the galaxy

• It was in a different galaxy

What is the period of pulsation for RR Lyrae variable stars?

• 1 to 60 days

• 30 to 90 days

• 1 to 10 years

• 12 to 24 hours

What did the discovery of the period-luminosity relation allow astronomers to do?

• Measure the temperature of stars

• Identify new planets

• Calculate the distance to star clusters

• Determine the age of the universe

What did Harlow Shapley's discoveries lead to regarding our understanding of the universe?

• The universe is shrinking

• The universe is static and unchanging

• There are many galaxies beyond the Milky Way

• The universe is a single galaxy