Online reading assignment: Milky Way history, big bang clues (SLO campus)

Astronomy 210, fall semester 2015
Cuesta College, San Luis Obispo, CA

Students have a weekly online reading assignment (hosted by SurveyMonkey.com), where they answer questions based on reading their textbook, material covered in previous lectures, opinion questions, and/or asking (anonymous) questions or making (anonymous) comments. Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect. Selected results/questions/comments are addressed by the instructor at the start of the following lecture.

The following questions were asked on reading textbook chapters and previewing presentations on the history of the Milky Way and big bang clues, a comic strip adaptation of of Neil deGrasse Tyson's "The Most Astounding Fact" 2008 interview for TIME magazine, and Minute Physics' video explanation of Olbers' paradox.

Selected/edited responses are given below.

Describe something you found interesting from the assigned textbook reading or presentation preview, and explain why this was personally interesting for you.
"I like the idea that when you're looking at a star that's light years away, the star could look completely different, or could be dead already."

"Learning about metals and how they came from stars was cool! That was personally the most interesting thing for no good reason. :)"

"The fact that the big bang was not created with a center that it was created everywhere. I thought this was interesting because that was always what I thought it started from."

"I enjoyed the explanation of look-back time and how we are not seeing the edge of space but the edge of time."

"The part about the edge of space was really interesting to me. I have always wondered about infinity and if the universe had an end so it was interesting reading about it and how the universe has a finite age."

"That the universe is not infinite and has an edge in all directions. i though this was interesting b/c i just thought space was never ending and it went on and on."

"We see the star Deneb 1,400 years in the past. That seems so crazy to me that you can look at something with your naked eye and actually be looking at something from the past."

"I enjoyed reading about the Milky Way, and the history behind it. Also how the universe started out with only hydrogen, and stars gathered this to form metals."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Look-back time was confusing b/c reading something doesn't mean that i understand. i will need more explanation on this."

"Something I found confusing was the edge of time and how when we see an edge it is an edge of time and not an edge of space. That seems hard for me to wrap my head around."

"Why the night sky is dark. I was not able to put it together while reading."

"I'm having a hard time with the metal poor or metal rich categories as I think I may be mixing up the disk or halo."

"I found the part of the look-back time was confusing. I've heard the part that the stars we see are really much older than that what we see from the naked eye, but its hard to comprehend that a star I'm looking at in the sky is really from 1,400 years ago."

"If the universe is finite, what's beyond the universe? I guess I just didn't get the gaps and edges thing yet."

"If the universe is expanding, shouldn't things not be moving at the same speed."

Indicate how the amount of these elements in the universe have changed over time.
(Only correct responses shown.)
Hydrogen: decreased [52%]
Metals (elements heavier than hydrogen and helium): increased [81%]

The outermost layers of __________ are more abundant in metals (elements heavier than hydrogen and helium).
extremely old stars that formed a long time ago.  *** [3]
young stars that formed very recently.  ******************* [19]
(There is a tie.)  [0]
(Neither, as stars cannot have metals.)  * [1]
(Unsure/guessing/lost/help!)  **** [4]

Indicate what produced these elements.
(Only correct responses shown.)
Helium in the sun's core: the sun [37%]
Carbon in your body: another star, in the past [52%]
Calcium in your bones: another star, in the past [56%]
Iron in your blood: another star, in the past [59%]
Gold and silver from mines: another star, in the past [56%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"If when we are looking at stars through telescopes we are looking back in time at how they were millions of years ago, is it possible that they no longer exist at this exact point in time and that we are just seeing them as they were in the past?" (Yes.)

"Are there essays on the final?" (Yes, just like the midterms.)

"Where did the original atoms come from that were involved in the big bang?" (Those atoms (primarily hydrogen) were converted from energy. Then subsequent generations of stars fused that hydrogen into every other type of atom listed in the periodic table.)

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