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

Astronomy 210, spring semester 2018
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.
"the size of our galaxy and what little part of our solar system actually takes up in the Milky Way. It makes me wonder what other planets are out there that can sustain life."

"Interesting to think about our galaxy and how the Milky Way was formed. I thought and still think its crazy how everything is formed and how we came about."


"It is interesting when something very obvious occurs to me. For example, it makes sense to have the universe start with only hydrogen, because stars are formed with hydrogen, but it never occured to me before."

"The fact that all elements heavier than hydrogen came from a dying star. The fact that the very things necessary for life came from stars repeatedly dying and being born is a pretty mindblowing idea."

"I think it is awesome that we are composed of starstuff or dust. I still do not understand it completely but I like the sound of it."

"I think it's very interesting to claim that we are made up of stardust. It's a very funny-sounding way to think about it, but it does make sense because of the elements that are found all over Earth and in us."

"The short Neil deGrasse Tyson video. It was so soothing and magical; I really loved it."

"I enjoyed reading about how lookback time works when looking through a telescope, simply because the concept of time is so weird."

"I found it interesting that the universe has an edge when it comes to time and what we can look at it. This is interesting to me because its crazy to think that the universe is so huge that we can only look at back at it so far, so we really would have a hard time telling if the universe goes on forever or not."

"The video about the reason the the night sky is dark. The question 'Why is the sky dark at night' is a trivial question everyone thinks they know the answer to, but in fact the explanation given by the video gives an exact reason that covers the holes in the simple explanation 'because the sun has set.'"

"Learning more about the big bang was very cool! I've heard about the theory here and there throughout my life, but never really looked into it."

"That galaxies aren't expanding, just the space between them. This is interesting because it answered a queestion that I had about universal expansion."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Not that I found this confusing but I more of found this super-crazy and hard to grasp. Knowing that when we look at the farthest star we can see with the naked eye we are seeing it in its far past. Which this shows us a time machine sort of thing."

"Figuring out what produces some of the elements was confusing to me. Maybe I just missed some of it but I went over this a few times and couldn't find it. My computer's browser is also acting weird making this harder."

"In the presentation you mentioned that old stars are metal-poor and newer stars are metal-rich. This was confusing to me because my logic says that old stars have had more time to form more and more metal making them metal-rich, while new stars have had less time to form hydrogen into heavier metals making them iron-poor."

"I guess the concept that stars have created all heavy elements (metals) in the universe still blows my mind."

"I just don't understand how stars create metals. And how light-years are related to time travel. My brain hurts."

"The part that describes how the beginning of the universe was made up of just hydrogen before the first generation massive stars gathered this and fused other elements, is confusing to me. This is confusing to me because I still wonder where this hydrogen came from and where these massive 'first-generation' stars came from. This question seems to still remain unanswered."

"I find the explanation of the big bang both the most interesting and the most confusing concept introduced in the text. It makes sense, technically, but it's size and span, as well as trying to picture it as you're reading, is just incomprehensible."

"It's a little confusing to think that the universe is expanding but at the same time appears to run away."

"Although incredibly interesting, the big bang does confuse me a little, because my mind just cannot comprehend how the universe is always expanding and how everything around me comes from a star. Just wow."

"I was not necessarily confused by anything."

"In the lesson what I believed to be personally confusing is the whole big bang theory. I understand how it happened but what confuses me is how scientists and astronomers know it happened and what was life before it?"

"I haven't been able to read, finals preparation is killing me."

Indicate how the amount of these elements in the universe have changed over time.
(Only correct responses shown.)
Hydrogen: decreased [58%]
Metals (elements heavier than hydrogen and helium): increased [70%]

The outermost layers of __________ are more abundant in metals (elements heavier than hydrogen and helium).
extremely old stars that formed a long time ago.  ********* [9]
young stars that formed very recently.  ***************** [17]
(There is a tie.)  ** [2]
(Neither, as stars cannot have metals.)  * [1]
(Unsure/guessing/lost/help!)  **** [4]

Indicate what produced these elements.
(Only correct responses shown.)
Hydrogen in the sun's core: the very early universe [42%]
Helium in the sun's core: the sun [48%]
Carbon in your body: another star, in the past [36%]
Calcium in your bones: another star, in the past [39%]
Iron in your blood: another star, in the past [42%]
Gold and silver from mines: another star, in the past [30%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"The universe is CRAZY to think about. Yikes!"

"I never knew that the particles within us originated mostly from old stars. That's pretty amazing!"

"What do you think the coolest fact in astronomy is?" (That we're made of atoms that are the by-products of stars that fused hydrogen, before exploding. So we're made of stardust. Actually, starpoop..)

"Enjoying the class, just wish I was better at this stuff!" (How could you not be good at this stuff? You're made of starstuff. Or starpoop.)

"How could there be a big bang if there was no substance to explode on?" (Well, the "big bang" is actually a misrepresentation of the expanding space between galaxies; nobody knows what caused this. But it happened, and we'll go over the evidence for how it is going on even today.)

"Do you believe the big bang to be the cause of our universe?" (I think it's fair to say that I understand the evidence--and I think it's fair in this class to teach you and test your understanding of the evidence as well.)

"How many questions is our final going to be, and are you offering any more extra-credit?" (I don't think there's going to be more extra-credit. The Final Exam is just like a midterm: 10 multiple-choice questions and three short-answer questions, but comprehensive over the entire semester.)

"How hard is the final going to be, can we do a final project instead of a test?" (I don't think the Final Exam is going to be any more difficult than a midterm. If you really want to do a final project for astronomy, that's what astronomy lab is for.)

"I enjoy coming to this class."

"I find your presentation slides to be cool and helpful."

"I don't know anymore?"

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