Online reading assignment: atmosphere problems, Earth, the moon, Mercury (NC campus)

Astronomy 210, spring semester 2017
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 problems caused by the atmosphere for telescope observing, Earth, and the impacted worlds: the moon, and Mercury.

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.
"Something interesting form the slide was the way the twinkled stars actually look. This seemed interesting because I've never actually looked up how a star looked like before this class."

Why stars twinkle. I found it interesting because of how all the air that it goes through, it distorts it and our eyes see the 'twinkle' effect."

"I really liked the analogy that compared turbulence distorting the astronomical views to being underwater and having the ripples disrupt your view of the surface. It's a really interesting concept, and the analogy made it easy to understand."

"The visible light spectrum is interesting to me, its crazy to think there are colors on the electromagnetic spectrum we as humans cannot see."

"The fact that the stars 'twinkle' because of the atmosphere, I always thought it was the stars actually twinkling. Like how our sun flares, I thought maybe other stars flared as well."

"I was interested to learn that the ocean plays a role in removing carbon dioxide from our atmosphere. I thought plants were the main filter."

"I found it interesting that the moon and mercury are similar with their craters and being mostly airless. I found it extremely interesting that neither of them have an atmosphere therefore unable to inhabit life."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"The section about the different telescopes was confusing, I hope we won't be tested on them and what they do!"

"I could not find where in the textbook it talked about oldest and youngest features on the moon."

"For some reason, I can't seem to grasp the concepts of the features on the moon and Mercury. The terminology is different in the questions and the readings, and I am finding it difficult to establish a timeline for the formation of the features."

A large modern optical telescope in outer space would have images with better __________ than a comparable ground-based telescope.
brightness.   ** [2]
resolution.   ****** [6]
magnification.   [0]
(None of the above choices.)   [0]
(Two of the above choices.)   ***** [5]
(All of the above choices.)   **** [4]
(Unsure/guessing/lost/help!)   *** [3]

Stars to appear to "twinkle" in the night sky because of...
"the atmosphere is disrupted as we look up at the stars and we are at the bottom so is easier for things to get distorted. The twinkles are from our atmosphere not being calm."

"When the light from the stars comes through the atmosphere, different temperatures, densities and winds make it look like they twinkle."

"The turbulence of the atmosphere."

Identify how carbon dioxide enters and how it is taken out of Earth's atmosphere.
(Only correct responses shown.)
Enters atmosphere from: volcanoes [50%]
Taken out of atmosphere by: oceans [65%]

Identify the oldest (longest ago) to the youngest (most recent) features on the moon.
(Only correct responses shown.)
Craters partially filled in with flat lava plains: oldest (formed longest ago) [30%]
Flat lava plains: middle [20%]
Craters on top of flat lava plains: youngest (formed most recently) [55%]

Identify the oldest (longest ago) to the youngest (most recent) features on Mercury.
(Only correct responses shown.)
Large crater basins: oldest (formed longest ago) [40%]
Lava-filled lowlands: middle [45%]
Long curving ridges: youngest (formed most recently) [55%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"If the atmosphere is what makes stars appear to twinkle, then why don't planets also twinkle? Doesn't the atmosphere's turbulence also affect them?" (The planets do twinkle, but it's not as noticeable. The stars are basically points of light, and 'twinkling' a point of light will make it noticeably distorted. Planets are large enough to be a small disk of light, and 'twinkling' a disk would only distort its edges, so the effect on its brightness is not as noticeable.)

"Is it that we don't have the technology for telescopes to overcome the opacity of the atmosphere, or is that a problem that can't be resolved aside from using telescopes on high mountains, or up in space?" (Can't stop the atmosphere from stopping the types of light that it stops. #neverstopstopping)

"How does visible light pass through glass to heat up objects such as plants, but the infrared light that comes from the plant doesn't escape the glass? Is the plant producing the infrared?" (Everything that is warmed-up will have an infrared glow, (unless it's super-hot like a light bulb or the sun, then it will emit visible light, or smoking-hot like an emitting ultraviolet or x-ray light. It turns out that the atoms in glass don't absorb visible light (letting it pass through), but absorbs and re-emits infrared light (blocking it). Interestingly the atoms in a plastic garbage bag will absorb and re-emit visible light (blocking it), but doesn't absorb infrared light (letting it pass through!)).

"Do we have to do group work every class? Or could solo work at least be an option?"

"Could we maybe try groups of two instead of three during class? I feel that it would be easier for me to work with one other person versus working with two others." (I'll think about it. Initially I'm assigning you to work in groups of three, according to recent astronomy education research, but I'm willing to adapt and experiment. You're also encouraged to print out your own individual copies of the in-class activities from the course website.)

"Did we skip Chapter 5? Am I behind in the reading?" (Yes, and no. Chapter 5 covers the sun, which the textbook groups together with the planets (because that's our solar system); but we'll do the planets first, and then cover the sun later with the rest of the stars (because the sun is just a star).)

"I was curious to know why you are teaching astronomy, when physics is your passion? (You're a great teacher, I was just curious as to why.)" (Astronomy is physics. However, an astronomy textbook is what you get when you take out everything that is awesome from the field of physics. Everything that is left over--well, that's what physics is.)

"The large-impact hypothesis seems like a lot of guesswork. Is there actual evidence to prove that's what happened, or is it just a theory that makes sense?" (Yes, and yes. It is the only theory that is consistent with the lunar rock samples gathered by Apollo astronauts, and it is the only theory that is not refuted by those same rocks.)

"If the greenhouse effect is causing the atmosphere to warm up, then how could we prevent global warming besides reducing our carbon footprint?" (There are some elaborate schemes that involve taking the carbon dioxide from the air and making dry ice (solid carbon dioxide), and then injecting this as a slurry deep underground, speeding up what the oceans, sedimentation, and tectonic plate subduction does. Or we could just lay off producing as much carbon dioxide (and other greenhouse gases) as we do and letting Earth slowly catch up and take care of itself over a long time. Either choice is very expensive and costly.)

"I am confused about how to identify the oldest to youngest features on the moon. What do these features look like and how do I categorize them? The material in the book was slightly confusing. Also there was a lot of information in the slides and in Chapters 4 and 6! I will definitely need to catch up on some more reading..."

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