Online reading assignment: the Milky Way (SLO campus)

Astronomy 210, spring semester 2016
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 Milky Way's shape, size and composition and spiral arm structure and formation.

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.
"Dark matter is interesting, this may or may not stem from my love of Futurama."

"hat the sun orbits around in Milky Way, this was interesting because the sun is usually seen as the center of the orbits."

"That we can calculate how far we are from the center of our galaxy. I never really wondered where we are situated in our galaxy before."

"I find dark matter interesting, mostly because we can't see it, but we can feel its effects."

"The traffic jam example explaining spiral arm formation was very interesting. I feel I learned a lot purely from that and the example made it much easier to understand."

"That a big chunk of our galaxy is made up of dark matter we can not see. I would think someone would have done a lot of research on dark matter by now to figure out what it is."

"It's interesting how much of the universe is dark matter and how so many people don't know and may not ever bother to know or care."

"How we figured out that our galaxy is shaped as a disk."

"How dark matter is like an unknown form of matter and yet, it's astonishing how it's still a problem today in astronomy."

"How stars in the Milky Way's spiral arms are being born, live for a short period, die continuously and then are reborn again, repeating."

"Learning about the Milky Way because I didn't really know anything about it before. I knew it was important before, but my non astronomy self just thought it was something cool to look for in the sky at night."

"The formation of stars in the spiral arms. The diagram is really cool in the textbooks as it shows how the stars are formed and then released out of the spiral orbit."

"That we are not 100% sure what the dark matter within the Milky Way is. This is interesting to me because most of matter could be made of of material we have not discovered."

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

"I don't understand how the location of globular clusters tells us how close/far we are from the center of our galaxy. It just doesn't make sense to me."

"I didn't understand the bad hair day question."

"I don't entirely understand what the Cepheid variable stars are and was hoping you could explain more in depth of those!"

"I'm confused still about how dim red dwarfs are related to dark matter (and MACHOs in general), I thought dark matter doesn't interact with light or other forms of light matter."

"ow does dark matter accumulate so much mass evenly in our galaxy - if there are different areas of mass "evenly" spread out, say, black holes, or dim red dwarfs, or more of the MACHO / WIMP analogies, wouldn't there still be areas where light wouldn't pass by?"

"The part about density waves was confusing to me. I didn't understand the cause and effect of gravitational interactions."

"I'm pretty confused on the way we can tell the size and shape of the Milky Way."

"I think it's confusing why we have all these theories about our galaxy but no one can prove them to be completely true. I feel with our technology we should have been able to do that by now."

"How we know about dark matter."

"I know that we are a disk-shaped galaxy, but how do we really know if we are a spiral galaxy or or not?"

"I thought the slide of gravity and orbits was confusing. If the outer orbits are not as quick as the inner orbit speed does that mean that most of the mass of the Milky Way is not at the center?"

"The self-sustaining star formation was a little confusing to me."

"I'm not sure if I fully understand the spiral arms concept. I think I mostly get it. The density waves cause the stars to keep forming in the spiral arms, but I guess what I don't understand is what those density waves even are?"

"Radio wave maps. What???"

"Gravity and orbits of different Milky Way models. It's little hard to tell which one is concentrated in the center and which one is the inner orbits have the same speed as the outer orbits. As I can see they are just a tiny bit different."

"Dark matter is confusing. I don't understand how something can exist, but you can't see it. It should be called invisible matter or something!"

In your experience, how much of the "Milky Way" (the band of faint stars across the celestial sphere) have you been able to see in the night sky?
As much as can be seen with the naked eye.  **************** [16]
Not very much.  *************** [15]
Barely seen it.  ********** [10]
(Never been able to see it.)  **** [4]
(Unsure/guessing/lost/help!)  ** [2]

Using the most powerful light-gathering optical telescopes in the darkest skies, __________ of the stars in our entire galaxy can be observed from Earth.
1%.  ********* [9]
5%.  [0]
10%.  ************************** [26]
50%.  *** [3]
100%.  * [1]
(Unsure/guessing/lost/help!)  ******** [8]

If you did not have access to a mirror while camping, what could you do to find out whether or not you're having a bad hair day?
"Use my phone's camera ;)"

"Look into a nearby meadow or stream and channel your inner Narcissus."

"Car window."

"ask your fellow campers."

"To be honest, who cares? I'd just leave my hair alone in a mess or wear a beanie."

"Nothing, because you are camping, and how your hair looks is not important."

"If you're worried about how your hair looks while you're camping then you aren't experiencing it and enjoying it as you should."

"Look at your shadow!"

"Physically touch your hair and try to visualize what it might look like based off what you normally want your hair to look like."

Look at PimpStar Rims (*.html) for cars, or MonkeyLectric Rims (*.html) for bikes. Briefly explain how they work.
"The wheels are lined with a lot of LED lights, which strobe in a pattern at a speed matched by the movement of the wheel, resulting in what appears to be a still, LED image."

"They use a strip of colored lights in the wheel. When the wheel is rotating, it appears like the entire wheel is colored."

"The rapidly blinking lights coordinate to create patterns when moving across our field of view."

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Did you buy the MonkeyLectric Rims specifically for this class? Will the multiple-choice portion of the midterm be composed of the same questions from the quizzes? Will we get a study guide for the final?" (Yes, yes, and yes.)

"I never go camping." (Then consider glamping.)

"Is this pink moon and green moon stuff real? On the 20th I heard it will be a green moon, and on the 22nd will be the pink moon." (I would hope that you have learned enough astronomy to determine whether stuff like this is true or not.)

"How do the PimpStar Rims know when they turn on a specific light? In other words, what mechanism is used to detect the location of the light?" (Probably an accelerometer sensor, the same way your phone knows whether it's right-side up, sideways, or upside-down.)

"No comment. (You just did.)

"Have you visited NASA?" (A few years back, I was the guest moderator for a NASA teaching education organization. #nasastrong #presenting #representing.)

"For some reason astronomy is a very abstract for me, and I have such troubles understanding any of it. Yet I still am so interested I wish I did not have so many units so I could really try and dedicate a lot of time to this class because it is very cool."

"I've failed every quiz, but I feel like I've learned a lot so that's good!"

"Do you have PimpStar Rims?" (Only on my bicycle. #theyseemerolling #theybehating)

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