Online reading assignment: atmosphere problems, Earth, the moon, Mercury (SLO 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.
"The practice of 'sidereal tracking' to keep telescopes pointed towards whichever celestial object as the Earth turns on its axis. The calculations and equipment to constantly keep up with the tiny adjustments have to be very accurate and precise which is incredible."

"I found the enormous telescopes built on mountain tops to be the most interesting. I know how much energy goes into residential and commercial projects in cities. Projects of such scale, with totally custom materials and equipment, in locations so secluded are extraordinarily impressive."

"Our atmosphere blocks out most electromagnetic radiation, allowing the things below it, such as us humans, to not be harmed by gamma rays, x-rays, and some radio waves. This is personally interesting because I find it fascinating how much nature naturally helps us out."

"I found atmospheric turbulence to be very interesting. I never realized there was such a thing. I especially liked the comparison of looking at an image from under water and the distortion if there is movement in the water. Fascinating that clarity in our sky is effected much in the same manner through atmospherical turbulence."

"I found it interesting that volcanoes over time and still today have contributed a massive amount of our greenhouse gases present today."

"I loved your analogy of gravy for plate tectonics. It was pretty funny but the way you described it made a lot of sense and actually helped me out. And you're right, heating up gravy in the microwave is just wrong!"

"I think it's so cool that at one point long ago there might have been an ocean on Mars. I mean, it's crazy how over time a planet can lose so much of its internal heat that it changes so drastically! Imagine if at one point there was life on Mars and things were swimming in the ocean--the idea of life outside of Earth is so fascinating."

"Studying the planet Mercury, I honestly had no clue what this planet looked like and how similar it looks to the moon!"

"I found Mercury to be very interesting considering it being a 'one-plate' planet. Knowing how earth was formed with plate tectonics, you might assume that other terrestrial planets might be similar, but Mercury is considered the "one-plate" planet. I found it interesting how Mercury actually has a bigger core than Earth, but looks very similar to our moon, and yet our moon has a smaller core than Earth."

"I found the large-impact hypothesis to be very interesting and a unique way to look at how the Earth and the moon could have possibly formed together at the same time."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"The concept of adaptive optics was kind of confusing. First off, why is the it necessary to have the technique of adaptive optics and what is the process that achieves that."

"Using two separate telescopes to get a more powerful resolution by them working together."

"I don't understand how airborne telescopes are practical. Wouldn't it be very expensive to merely stabilize it, as to not blur everything?"

"The histories of the moon and Mercury."

"This section was the most confusing for me so far. The plate tectonics, greenhouse gases and geological activity were tricky. The only background I have with learning about these things is what I learned in elementary school, so I feel a bit lost. After reading through it a few times, it seems to be clicking more--but I still feel a bit rusty."

A large modern optical telescope in outer space would have images with better __________ than a comparable ground-based telescope.
brightness.   ** [2]
resolution.   **************** [16]
magnification.   * [1]
(None of the above choices.)   [0]
(Two of the above choices.)   ****** [6]
(All of the above choices.)   *********** [11]
(Unsure/guessing/lost/help!)   * [1]

Stars to appear to "twinkle" in the night sky because of...
"With changes in movement and constant turbulence of the atmosphere, our view of the stars are distorted causing a 'twinkling' stars."

"I have no idea... This is what I am confused about."

"The force of gravity from other celestial objects?"


Identify how carbon dioxide enters and how it is taken out of Earth's atmosphere.
(Only correct responses shown.)
Enters atmosphere from: volcanoes [49%]
Taken out of atmosphere by: oceans [46%]

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) [43%]
Flat lava plains: middle [25%]
Craters on top of flat lava plains: youngest (formed most recently) [41%]

Identify the oldest (longest ago) to the youngest (most recent) features on Mercury.
(Only correct responses shown.)
Large crater basins: oldest (formed longest ago) [41%]
Lava-filled lowlands: middle [38%]
Long curving ridges: youngest (formed most recently) [46%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Would an infrared telescope work well on the ground if you were somewhere higher up, or is it only for higher altitudes?" (Because Earth's atmosphere blocks a lot of that type of light, going higher (where the air is thinner) helps, an infrared telescope on a mountain would be better than at sea level, but would not be able to see as much infrared light going higher, as with an airborne or space-borne telescope, )

"Are there many other theories on the origin of the moon?" (Yes, but they've all been disproven, and the large-impact hypothesis is the theory that is best supported by analysis of rocks brought back from the moon by Apollo mission astronauts.)

"I am confused by the moon's smooth low-lands, formally knowns as its mare, being ancient lava flow, for me, I can't imagine the moon having lava flow. Is it different type of lava than on Earth or did the moon have active volcanoes?" (It's a slightly different type of lava, but yes, the moon had active volcanic eruptions (typically welling up from vents and cracks in the surface, rather than from mountainous volcanoes).)

"How can we identify older or younger features on a distant planet without visiting the planet?" (By counting the density of impact craters (old areas) with smooth plains (new areas). Since we've confirmed this method on the moon's surface, we can apply this to determine the ages of many areas on Mercury, Venus, and Mars.)

"Do you see the shape of a dinosaur on the moon like I do?" (Not really, but I see a rabbit, but some people see a man's face or a woman's profile in the moon.)

"Where have you seen the darkest sky with the brightest stars/planets/constellations?" (Lots of places.)

"The textbook says that the preferred direction of motion in the solar system is counterclockwise and all planets revolve around the sun in that direction, except for Venus and Uranus. What does that mean? Why not those planets?" (Their contrary behavior suggests that they experienced extraordinary impacts in their pasts that altered their rotational motion.)

"Your slides are really fun and interesting but this textbook is so hard to read, not because the information is confusing but because the chapters are so dense and the subject matter is dry. I guess I'm using this textbook to complain...sorry." (#sorrynotsorry)

"How long have you used the format of combining a textbook with online blog information?" (It's been a work in progress over the past five years or so.)

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