Astro 001 Exam 4 UPDATED QUESTIONS
AND CORRECT ANSWERS
What are the differences between open star clusters and globular star clusters? - CORRECT
ANSWER Open clusters are less concentrated, younger, and have fewer stars
Which of the following is false? - CORRECT ANSWER A nova is more luminous than
a supernova
What kind of gas cloud can collapse & form stars? - CORRECT ANSWER The gas
cloud must have a mass that exceeds the Jeans mass so that gravity overcomes the internal
pressure in the cloud
What is the mass of the black hole at the center of the Milky Way? - CORRECT
ANSWER 4 million solar masses
How do you measure the mass of the super massive black hole at the center of the Milky
Way? - CORRECT ANSWER Look at the orbits of nearby stars & apply Kepler's 3rd
law
About how long does it take light to cross the Milky Way galaxy? - CORRECT
ANSWER About 100,000 years
What does our galaxy look like? - CORRECT ANSWER All the above; large disk with
spiral arms & relatively flat & thin, clouds of dust & gas in spiral arms, old yellow stars
found at center bulge, old stars & globular clusters located in spherical halo
Why do stars in the halo have almost no heavy elements i.e. C, N, O? - CORRECT
ANSWER Halo stars formed before these elements were made
Where do stars form in the galaxy today? - CORRECT ANSWER In the disk
AND CORRECT ANSWERS
What are the differences between open star clusters and globular star clusters? - CORRECT
ANSWER Open clusters are less concentrated, younger, and have fewer stars
Which of the following is false? - CORRECT ANSWER A nova is more luminous than
a supernova
What kind of gas cloud can collapse & form stars? - CORRECT ANSWER The gas
cloud must have a mass that exceeds the Jeans mass so that gravity overcomes the internal
pressure in the cloud
What is the mass of the black hole at the center of the Milky Way? - CORRECT
ANSWER 4 million solar masses
How do you measure the mass of the super massive black hole at the center of the Milky
Way? - CORRECT ANSWER Look at the orbits of nearby stars & apply Kepler's 3rd
law
About how long does it take light to cross the Milky Way galaxy? - CORRECT
ANSWER About 100,000 years
What does our galaxy look like? - CORRECT ANSWER All the above; large disk with
spiral arms & relatively flat & thin, clouds of dust & gas in spiral arms, old yellow stars
found at center bulge, old stars & globular clusters located in spherical halo
Why do stars in the halo have almost no heavy elements i.e. C, N, O? - CORRECT
ANSWER Halo stars formed before these elements were made
Where do stars form in the galaxy today? - CORRECT ANSWER In the disk
