Online reading assignment: Milky Way history, big bang clues (NC 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.
"The big bang."

"The 'top-down' hypothesis of how the Milky Way galaxy was formed, and the big bang theory since both explain theories of how things came to be."

"I like how when we look at the stars we could be looking at a star that's possibly already dead."

"Watching the video about how astronomers measure the distance in light stars to a star was very interesting, it was a question I had on my mind when we briefly started talking about lightyears in class. I am still genuinely curious how it the math goes down step by step."

"That we are basically made up of stuff from stars that went supernova; so we are made up of dead stars that gave us the materials to make other stars and planets and eventually would lead to life using metals like iron, calcium, carbon, oxygen, and nitrogen that help to form the basic building blocks of life that would eventually lead to us."

"Learning about galaxies was pretty interesting, but it takes on a whole new layer of intrigue when we're talking about our own galaxy. Very cool."

"I found it interesting that the universe isn't finite but that it is infinite and that the universe may have a starting date meaning that there was a certain time that it didn't exist until it did."

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

"One thing I found interesting was the finite speed of light. It turns out that we have a time-machine of sorts to actually see the universe as it was in the past."

"It's comforting knowing that the galaxy is pretty much responsible for polluting itself. Humans haven't totally ruined everything. And the Milky Way is essentially a disgusting extra smog day in Los Angeles. Eeek! I also appreciated learning how light years are calculated and found it completely mind-blowing that I have looked at what a galaxy [Andromeda] looked like 25.4 million years ago. This is one thing that I wrote down at the beginning of the semester that I wanted to learn."

"The big bang theory because you always hear people say it, but I never knew what it actually was."

"I really like the Zen Pencils comic strip because it involves life in the universe."

"How everything in general is pretty much made up of metals/dirt, which sorta (not really) debunks my 'space is mystical' thing."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"I need a bit more clarification on the big bang theory, other than that everything was pretty straightforward."

"I was tripping out on that video that talked about why the space is black, so is it black because when we look at space we are actually looking at space in the past? Please go over this a bit."

"It is puzzling that we don't know if there is a true edge of the universe. And what happens if the universe has an edge? How does that affect our understanding of the universe?"

"Light years are a concept that continue to confuse me."

"Look-back time. And how do you calculate how far another galaxy is?"

"The 'gaps' between galaxies."

"Does hydrogen turn into the metals and how?"

"I am not understanding the differences between a halo and a disk as it refers to the Milky Way's different formations. They both seem the same to me."

"Trying to grasp the concept with an open mind as an infinite anything is hard to think of as well as that at one time there were no stars or anything is just hard to wrap my mind around."

"The Hubble law."

"The Hubble law, which sounded interesting, also kind of lost me a little."

Indicate how the amount of these elements in the universe have changed over time.
(Only correct responses shown.)
Hydrogen: decreased [33%]
Metals (elements heavier than hydrogen and helium): increased [73%]

The outermost layers of __________ are more abundant in metals (elements heavier than hydrogen and helium).
extremely old stars that formed a long time ago.  ***** [5]
young stars that formed very recently.  ********* [9]
(There is a tie.)  [0]
(Neither, as stars cannot have metals.)  [0]
(Unsure/guessing/lost/help!)  * [1]

Indicate what produced these elements.
(Only correct responses shown.)
Hydrogen in the sun's core: the very early universe [67%]
Helium in the sun's core: the sun [40%]
Carbon in your body: another star, in the past [40%]
Calcium in your bones: another star, in the past [53%]
Iron in your blood: another star, in the past [53%]
Gold and silver from mines: another star, in the past [33%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Is there an actual answer to what caused the big bang?" (Not yet, but asking what caused the big bang might be like asking "why does time run forward?" or "why isn't gravity both attractive and repulsive?")

"Will we learn more about the big bang theory?" (Yes, after the second midterm.)

"Could you please go over the difference between a halo and a disk as it refers to the Milky Way?" (Here's a visual explainer from the European Space Agency.)

"I really enjoyed this reading."

"I love this class!"

"We're coming up nearer and nearer to the end, I can't wait to see what else you have in store." (You'll see.)

"If the universe wasn't infinite, then would could be beyond it?" (If it turns out that the universe wasn't infinite, then if you started traveling outwards, you wouldn't keep going and going, but after a long time you would eventually return back to your starting point.)

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