20190508

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

Astronomy 210, spring 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, 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.
"Black holes."

"The theory of how we know what the Milky Way looks like is particularly interesting to me. Just how we can understand what our surroundings in the universe are based off of what we can see is pretty amazing."

"Learning about what the universe is made of and how everything formed."

"I found it really cool how you said that we are all made of stardust. It's a cool idea."

"I think overall the big bang is very interesting, it's fun to learn where we came from."

"That we can tell how old a star is based on how much metal there is, like if it's an old star it's metal-poor but if it's a new star it's metal-rich."

"I think it's cool we came from stars. 'Everything is made of stardust.'"

"All the different kind of metals."

"To know that we are all made up of matter that originated from the universe itself is absolutely wicked."

"That the universe started pretty much with only hydrogen because that is not a lot of variety."

"I like the idea that we are essentially made up of stardust because it connects my sense of self and body to the great unknown of space."

"To learn that newer stars will be more metal-rich. I thought it would be the other way around, with older stars being more metal-rich, because that was just the way my train of thought went."

"The Milky Way being built up from absorbing small galaxies over time, the YouTube simulation was pretty cool."

"Something that I thought was really cool and kind of messed with my mind is that if we are looking at a star that is 1,400 light years away we aren't looking at how it looks now. We are actually looking at how it looked 1,400 years ago."

"I thought it was really cool how in the TEDTalk it talked about how light years work and that it takes 8 minutes for sunlight to reach us so when we see it we see what the sun looked like 8 minutes ago. When we see the Big Dipper were actually seeing what it looked like 80 years ago."

"Kipling's 'The Elephant's Child' story, because I have never heard of any part of that story and it was intriguing."

"The big bang theory."

"The big bang section. It was interesting to learn about some of the things we think are true about it!"

"All of the matter here on Earth (and space) originally came from stars. Everyone is connected through old roots."

"I loved the videos from Minute Physics! I'd never heard of them before this course, and am very interested to check out more of their stuff!"

"The big bang theory is interesting to me. I find it interesting because it explains how life on Earth began."

"I found the entire presentation very interesting because we take so many classes about the history of Earth but I have never thought about the history of a galaxy."

"That the claim that there is 'no center of the universe' is an absolute, and is not possible to make that claim seeing as how we haven't found the boundaries of the universe, scientists just assume that it is boundless?"

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Black holes, still."

"How the universe began with just hydrogen. What created the hydrogen?"

"How did all of the metals get here?"

"The hydrogen/metals section. I skimmed through the section and couldn't find the answers to the questions below."

"Understanding the metallicity of stars is confusing to me. If stars are fussing hydrogen and run out of energy at iron then how are they 'metallistic?'"

"I found the production of elements to be kinda confusing."

"Monolithic collapse or how the Milky Way changed from spherical to flattened shape, was confusing to me."

"Light years, distances..."

"Lookback time seemed like an odd concept. Why are we looking into the past? Does it have to do with older stars?"

"So the night sky is dark but isn't? this was confusing to me because if the universe is forever expanding does that mean it will eventual all be bright and what would happen to the dark matter?"

"I want to go over more about the big bang."

"What is causing galaxies to move away from each other? I know, we are far from galaxies, but I am wondering how they are separating."

"Something I found interesting and confusing was the Hubble law and that everything is expanding."

"Learning about why galaxies move away or towards us was a bit confusing. I think I just need it explained in class to really grasp the idea."

"From the video 'Why is it Dark at Night,' I understand that it takes time for light to reach us as it travels through space. So are there places in the universe such as the earliest point where the big bang happened where space would be bright?"

"The Hubble constant. Is everything in space moving at the same speed?"

"The space between galaxies and how the space between galaxies actually expands. I have found half of this class to be confusing. My mind is much more in tune with art and music rather than science and math."

"The big bang was confusing."

"Nothing specifically."

"I still need to read this material."

"I'm honestly just kinda confused about all of it so some review would be helpful."

"I didn't find anything confusing enough to put in this box."

Indicate how the amount of these elements in the universe have changed over time.
(Only correct responses shown.)
Hydrogen: decreased [64%]
Metals (elements heavier than hydrogen and helium): increased [71%]

The outermost layers of __________ are more abundant in metals (elements heavier than hydrogen and helium).
extremely old stars that formed a long time ago.  ****** [6]
young stars that formed very recently.  ***************** [17]
(There is a tie.)  * [1]
(Neither, as stars cannot have metals.)  [0]
(Unsure/guessing/lost/help!)  **** [4]

Indicate what produced these elements.
(Only correct responses shown.)
Hydrogen in the sun's core: the very early universe [46%]
Helium in the sun's core: the sun [32%]
Carbon in your body: another star, in the past [43%]
Calcium in your bones: another star, in the past [46%]
Iron in your blood: another star, in the past [46%]
Gold and silver from mines: another star, in the past [50%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"I would love a little more lecture for this section as I didn't get a chance to read in detail yet."

"What are some of the reasons some people don't believe in the big bang?" (You don't have to believe in the big bang, you just have to understand how to interpret the evidence. Other people's interpretation may differ. Some other people may not bother even looking at the evidence.)

"Do you believe that the universe is infinite?" (Well, the universe is finite in the sense that because looking further out in space means that you are looking further back in time, and since time "began" at the start of the big bang about 14 billion years ago, then there is an edge in time to the observable universe, about 14 billion years out away from us in all directions. So I'll go with that.)

"If the universe started out with just hydrogen, who/what are the hydrogen's mommy and daddy? (The big bang. Well, actually just after the big bang (energy) cooled down enough for protons and electrons to form, which is what hydrogen is made of (one proton and one electron).)

"I couldn't figure out where gold and silver originate from, but I'd love to know." (Star poop. Gold and silver (and everything else heavier than helium) are by-products of stars consuming hydrogen for fusion, forming metals, and then exploding, casting all that stuff out the rest of the universe for new stars (and planets) to form. So basically, star poop.)

"Explain the Hubble law, thanks :)"

"I thought reading about the big bang was interesting because being raised Catholic I don't know a lot about it." (Interestingly enough, it was a Catholic priest (and scientist) who was the first to propose the big bang theory.)

"Please help."

"Very happy to have done better on the second midterm than the first."

"I killed the second midterm."

"Can we go over the final exam material every class in preparation for the final exam?" (We are doing that, in the sense that the last two weeks of the semester use all the concepts we've learned earlier.)

"How was your weekend?" (Mrs. P-dog and I celebrated Sinkhole de Mayo. How was your weekend?)

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