Observing Projects
Use the Starry Night™ program to observe globular clusters, which contain some of the oldest stars in our universe. Display the Milky Way as seen from the center of a transparent Earth by selecting Favourites > Explorations > Milky Way center. Click on the Options tab and click on Stars > Globular Clusters and use the hand tool to move the view to explore the distribution of these old groups of stars around the galactic center. This distribution is that of a halo around the Galaxy, a situation matched by most galaxies. The age of these clusters is determined by examining the Hertzsprung-Russell diagrams of their stars and by determining the relative amounts of heavy elements compared to that of the lighter elements, hydrogen and helium. While these clusters contain the oldest stars still shining in our sky, there would have been older stars whose heavy-element content would have been less than that of globular cluster stars, the so-called Population III stars that have contributed to background radiation in space. Open the Find pane and locate and examine the following globular clusters, noting particularly their symmetry, another sign of their great age. (a) In each case, find the approximate angular diameter of the cluster: (i) M3; (ii) M12; (iii) M13. (b) In view of the expected conditions that would have been found in the universe at the time of recombination, 380,000 years after the Big Bang, how would these clusters have appeared to us in the unlikely event that we were present at this time?
Collaborative Exercises
The four fundamental forces of nature are the strong force, the weak force, the gravitational force, and the electromagnetic force. List four things at your school that rely on one of these fundamental forces, and explain how each thing is dependent on one of the fundamental forces.
Consider the following hypothetical scenario adapted from a daytime cable television talk show. Chris states that Pat borrowed Chris’s telescope without permission. Tyler purchased balloons and a new telescope eyepiece without telling Chris. Sean borrowed star maps from the library, with the library’s permission, but without telling Pat. Eventually, when the four met on Sunday evening, Chris was crying and speechless. Can you create a “grand unified theory” that explains this entire situation?
The Cosmic Connections: The History of the Universe figure shows the history of the universe in the form of a graph of the temperature versus the time after the Big Bang. Create a similar history of your class, starting with estimated outside temperature on the vertical axis and number of days since the beginning of the academic term on the horizontal axis. Include dates for major exams and assignments up through today. In different color ink, show your predictions for temperatures, days, and events from today until the end of the course.