20200218

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

Astronomy 210, spring semester 2020
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.
"It's so cool to think about infrared light with longer wavelengths than visible versus ultraviolet with shorter wavelengths than visible light."

"How in a telescope's tube there can be a mirror at the back and the light can bounce back and forth inside the tube and project the image to the eyepiece. To be honest I found it interesting just as to the fact it's sort of simple, but also complex at the same time."

"I found that the "Keck in Motion" video was the interesting part for me because I personally thought it was cool on how they basically work together to find stuff out with the stars and how they move."

"I thought that light pollution was interesting. I was always wondering why telescopes are in the middle of nowhere, but I never looked into why they are so far away from civilization. The reason being light pollution makes complete sense and it makes me want to go to the middle of the desert somewhere at night and observe all the stars that I can't see in the city because of light pollution."

"After reading the textbook, I thought learning about light pollution was interesting because some places have more light pollution like big cities. This makes sense to me because I feel like people who live in the country enjoy looking up at the sky and soaking in its beauty. People who live in the cities might think the sky is pretty but may not think it's as pretty as people who live in areas with less light pollution because they are able to see more."

"I liked reading about sidereal tracking. I never thought about how telescopes would need to move continuously to continue to look at a certain point in space."

"What I found most interesting was the explanation for why stars appear to 'twinkle,' because stars don't actually twinkle but due to turbulence in Earth's atmosphere."

"It was very interesting to hear about different places where telescopes are placed."

"That the planets and the sun both start from a nebula."

"That we are capable of finding data on the formations, compositions, and histories of other planets despite there not being any humans that set foot on any of them."

"That the ocean absorbs the CO2 in the atmosphere and filters it down to be trapped in sedimentary rocks. You only hear that plants use CO2 in photosynthesis but never that the ocean could use it to make rocks. I found that really interesting."

"I did not know how hot Earth's core is compared to other terrestrial planet cores in our solar system."

"I thought the geological structures of Mercury being so similar to those of the moon to be very interesting."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"The big interferometer in the presentation slides, I was just confused in its entirety and how it works."

"The textbook's explanation of how carbon dioxide is removed by oceans."

"The creation of Earth's secondary atmosphere, because of the steps it took to create it--I wasn't familiar with carbon dioxide being soluble in water which helped remove CO2 from the atmosphere."

"The history of the planets seemed to confuse me more than most of the reading. It just seemed like a blob of information to me and it was really hard to try to remember which fact was relative to which planet."

"I was confused on the features for the moon, the reading wasn't very specific."

"I still don't completely understand which craters are older or younger when it comes to the moon and Mercury. It's just not making sense to me."

"The large impact hypothesis for the moon's origin."

A large modern optical telescope in outer space would have images with better __________ than a comparable ground-based telescope.
brightness.   ******** [8]
resolution.   ************ [12]
magnification.   **** [4]
(Unsure/guessing/lost/help!)   *** [3]

Stars to appear to "twinkle" in the night sky because of...
"The twinkles are caused by turbulence in Earth's atmosphere. A star near the horizon will twinkle more than a star overhead."

"The light from the star travels through our atmosphere and by the time the light gets to earth its path will have bounced around a bit."

"The stars twinkle in the night sky because of the effects of our atmosphere. When starlight enters our atmosphere it is affected by winds in the atmosphere and by areas with different temperatures and densities."

"The way our atmosphere is."

Identify how carbon dioxide enters and how it is taken out of Earth's atmosphere.
(Only correct responses shown.)
Enters atmosphere from: volcanoes [48%]
Taken out of atmosphere by: oceans [52%]

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) [37%]
Flat lava plains: middle [26%]
Craters on top of flat lava plains: youngest (formed most recently) [44%]

Identify the oldest (longest ago) to the youngest (most recent) features on Mercury.
(Only correct responses shown.)
Large crater basins: oldest (formed longest ago) [56%]
Lava-filled lowlands: middle [41%]
Long curving ridges: youngest (formed most recently) [56%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Telescopes are pretty rad."

"How did science first figure out stars twinkle because of our atmosphere?" (The amount of twinkling is noticeably related to how windy it is. Less wind = less twinkling.)

"After doing the reading, what struck me the most was how there's atmospheric turbulence. The presentation talks how to solve this problem by placing the telescope as high as possible, where the thin air is. My question how do they know where the thin air is?" (Basically the higher up in elevation you are, the thinner the air--if you've driven or hiked up a high enough mountain, you may be literally "out of breath" because there is less oxygen up there for your lungs to take in. Also, yes, there would be less twinkling because there is less atmosphere up there.)

"Can a core of a planet reach the same intense heat of the sun?" (No. While Earth's core is pretty hot, the core of the sun is hella hot.)

"I'm completely lost on memorizing the terrain and the order it comes in, is there any shortcuts to remembering?"

"How can you tell which crater is younger and older and in the middle? Would smooth areas be considered youngest because it looks seemingly untouched since the planet formed?" (We'll go into further detail on this in class.)

"Can the moon die?" (It's already dead.)

"In the readings it is said that a large-scale collision may not have been responsible for Mercury's larger than expected iron core. It then just moves to the next stage of Mercury's expected history. Were no other theories developed on the planet's creation?" (There are many theories for Mercury's formation, but until a probe can land on its surface and analyze its rocks, then there really isn't much evidence to go on right now, and the limited evidence we have from looking at its surface from above is somewhat contradictory.)

"What's the oldest planet in our solar system?" (They're all the same age, in that they all formed at the same time as the sun from the same nebula. However, their surfaces will be different ages, because we think of rocks as "old" or "new" depending on how long it's been since they first hardened from being molten lava.)

"Will we have any opportunities for extra-credit? And when?" (Yes, typically in class just before/after each midterm, which is when most of you really need some extra-credit points.)

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