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

Astronomy 210, fall semester 2019
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 Neil deGrasse Tyson's "The Most Astounding Fact" 2008 interview for TIME magazine, a TED-talk video explanation of measuring extreme distances, and Minute Physics video explanations of Olbers' paradox and the expanding universe.

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.
"What I found quite interesting is how many compounds/things today come from stars in the past. I've never thought about that."

"That the calcium in our bones, carbon in our body and iron in our blood were all formed from a past star...like, what???"

"That for stars such as Deneb when we do see them we're looking at their past form, not its current state."

"The concept of light-years and seeing stars, planets, and galaxies as they were so many years ago is really crazy to think about and super-cool. So basically, hypothetically, if the sun were to go out, we would have a nice 8-ish minutes before freezing to death."

"The concept of space and time is fascinating. One fact from the 'light seconds, light years, light centuries' video that I thought was cool: the Big Dipper appears to us the way it looked 80 years ago, because it took that long for light to travel to Earth."

"That we can use type Ia supernovae to tell how far away something is from us in space. I didn't realize that supernovae were brighter than their galaxies."

"The universe having finite age, but not a finite size."

"To think that there isn't an edge to our universe, and I could see why a lot of people go along with the misconception that there is a 'center to the universe.' There is no center, and it appears to be that the space between galaxies continue to expand over time. We're on the grow!"

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"I'm kind of confused on how the amounts of elements changed over time, but other than that I'm good."

"I'm confused by what each thing produces which element and things of that sort; it's just a lot to take in and it's confusing me."

"I'm confused about the production of elements. I think I might need to learn about it in person to truly grasp the concept."

"The monolithic collapse and bottom-up models are slightly confusing because they are both theories about the formation of the Milky Way. I have a feeling I may or may not mix them up."

"Why the universe keeps expanding and why do younger stars have more metal than older stars? Will the universe stop expanding? Since older stars fuse elements heavier than helium, shouldn't they have more metal?"

"How does the universe continually expand? How is there no limit or will there ever be a limit?"

"How the universe is infinite. It's crazy trying to wrap my head around that. How can it have no end? It just never ends? It's mind-blowing, really."

"The age and 'boundary' of the universe, and how it is determined. I think the human brain isn't evolved enough to grasp such complex (and almost metaphysical) topics, so things can start seeming very counter-intuitive. I am looking forward to our in-class discussion to clarify the topic."

Indicate how the amount of these elements in the universe have changed over time.
(Only correct responses shown.)
Hydrogen: decreased [65%]
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.  **** [4]
young stars that formed very recently.  **************** [16]
(There is a tie.)  [0]
(Neither, as stars cannot have metals.)  [0]
(Unsure/guessing/lost/help!)  [0]

Indicate what produced these elements.
(Only correct responses shown.)
Hydrogen in the sun's core: the very early universe [45%]
Helium in the sun's core: the sun [40%]
Carbon in your body: another star, in the past [65%]
Calcium in your bones: another star, in the past [50%]
Iron in your blood: another star, in the past [75%]
Gold and silver from mines: another star, in the past [45%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"At first there is nothing...bada bing bada boom...now the universe exists!"

"Thank you for giving us a constant supply of astronomy comics."

"This class has put me in an existential crisis."

"How is it even possible that the big bang occurred?" (I don't think we can ever answer 'why the big bang occurred,' but we are certainly able to answer 'how do we know the big bang occurred?')

"Will the final cover the last few chapters we are going over?" (Yes, along with the last quiz.)

"Do we have more than one Hubble telescope in space right now?" (The Hubble Space Telescope is designed to observe visible light; all the other space telescopes are designed to observe in different wavelengths (such as x-ray, infrared, etc.) that would be blocked by Earth's atmosphere.)

"Headline: 'Swiss Deny Dairy Product Influence on Moon Composition.'"

"How close are we to seeing the big bang?" (We see its after-effects everywhere around us.)

"If humans are made from stardust, then are there aliens also made from stardust?" (Yes, unless those aliens are made up only of hydrogen.)

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