Astronomy college course/Star cluster quiz/Original version of this quiz

Study this version: http://en.wikipedia.org/w/index.php?title=Star_cluster&oldid=662839103

Quiz
{A grouping with 100 thousand stars would probably be a} - elliptical galaxy - dwarf galaxy - A-B association - open cluster + globular cluster {A grouping with a hundred stars is probably a} - elliptical galaxy - dwarf galaxy - A-B association + open cluster - globular cluster {I gravity is what holds stars in a cluster together, what is the most important process that causes them to spread apart?} + random motion - solar wind - magnetism - anti-gravity - supernovae {Members of an open cluster feel significant forces only due to gravitational interaction with each other} - True + False {Members of an open cluster feel significant forces from nearby giant molecular clouds} + True - False

{Members of a globular cluster tend to be} - young + old - of all ages {Members of a globular cluster tend to have} + low mass - high mass - a wide range of masses {In 1917, the astronomer Harlow Shapley was able to estimate the Sun's distance from the galactic centre using} - open clusters + goblular clusters - a combination of open and globular clusters {Most globular clusters that we see in the sky orbit _____ and have ______ orbits} - the center of the Milky way ... nearly circular + the center of the Milky way ... elliptic orbits - within the disk of the Milky way ... nearly circular - within the disk of the Milky way ... elliptic orbits {Many stars in a typical open cluster are nearly as old as the universe} - True + False {Many stars in a typical globular cluster are nearly as old as the universe} + True - False

{The number of globular clusters in the Milky way galaxy is about} - 1,500 +  150 -  15 thousand - 15 million {The location of open clusters can be described as} - uniformly distributed in a sphere centered at the Milky Way's center + in the spiral arms - between the spiral arms - uniformly distributed within the galactic disk {Stars can "evaporate" from a cluster. What does this mean?} - The gravitational attraction between stars evaporates the gas from stars - The solar wind from neighboring stars blows the atmosphere away + Close encounters between 3 or more cluster members gives one star enough speed to leave the cluster