Online reading assignment: history of atoms, Earth, the moon, Mercury (SLO campus)

Astronomy 210, spring semester 2013
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 history of atoms, 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.

"I found the greenhouse effect to be interesting because I was able to visualize the concept since I know what a greenhouse is; plants can grow with the heat from the sunlight. I thought it was cool that it was also considered the 'parked car effect' since sunlight heats up a car, but the heat gets trapped."

"That the universe is in us..."

"How similar Earth is to the moon and nearby planets. Although entirely different, it's interesting seeing the similarities."

"I found it interesting how the moon is almost all crust with a smaller core than it thought it should have considering its size."

"After Earth formed and it was cooling the oceans formed which started dissolving carbon dioxide and removing it from the atmosphere it then reacted with dissolved compounds in the water to form limestone and other mineral sediments. I find this interesting because I have never thought about how these things were created and it is a very easy concept to understand and I guess I was just surprised by the information."

"The fact that volcanoes put carbon dioxide in our atmosphere but that oceans absorb a lot of it so it doesn't pollute our atmosphere too much."

"What was interesting to me was the history of atoms in our body. For example, atoms heavier than iron such as iodine were created by rapid nuclear reactions that only occur during supernova explosions. I found this really cool and interesting because I never knew this until now and I was always curious about what people were made of."

"I think it's interesting that if the moon and Mercury had formed in the same manner as Earth, then they would be expected to have the same size cores as Earth."

"I really liked the cute little comic strip!! I like the poetic appeal to it. I love Earth! :D"

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

"The greenhouse effect was a little confusing, maybe just a little clarification."

"That the universe is in us..."

"It's not really confusing, but when the book says that all this stuff happened and everything is constantly changing, it's a little hard to grasp that. We live for 100 years at the most, while it takes years and years for a planet to form, for example. It's crazy."

"How certain theories apply to how planets were formed and how it is known."

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

"We are made of matter from the first 3 min of our universe?" (Only if you are primarily made of hydrogen, with a sprinkling of deuterium, helium, and lithium thrown in.)

"Is the reading suggesting that some or all moons are formed from high impact events?" (Only Earth and the moon, and Mercury.)

"I thought there were eight quizzes total and three would be dropped. It says there are only seven on the schedule though. I remember you mentioning this early on in the semester but I must have forgot." ("Quiz 8" is credit fir taking the educational research surveys in class.)

"I was recently told by a friend that the static that you can hear in between radio stations has something to do with the big bang. Do you know? " (About 1% or so of that static.)

"Do we need to know all the other planets rotations and angles that are exceptions to the natural rotation pattern in the solar system?" (Only that they are all more or less the same, except for the notably tilted-over axis of Uranus.)

"Neil deGrasse Tyson is the bee's knees, one of my favorite people to listen to/watch. Have you heard of the Joe Rogan Experience podcast? He interviews him in #310, free on iTunes [also on YouTube] if you ever want to kill 2.5 hrs in a long drive. Really entertaining to listen to his down-to-earth caliber as a hardcore astrophysicist!" (Neil is da man.)

Online reading assignment: history of atoms, Earth, the moon, Mercury (NC campus)

Astronomy 210, spring semester 2013
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 history of atoms, 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 moon and Mercury look alike in color and are covered with impacted craters. but different because Mercury has a larger core than the moon."

"I found the formation of Earth interesting and the process of the evolution of the atmosphere."

"The greenhouse effect. I didn't really understand it until now but the car example made it very clear."

"I found the comic strip interesting because Neil deGrasse Tyson is awesome. It was really cool the way he put things in perspective."

"We are a part of the universe. This is interesting, because: science."

"Learning about the origins of our atoms is amazing. Just thinking that stars made the iron in our bodies is amazing!"

"I had heard about the 'large-impact hypothesis' theory about the creation of the moon, but I didn't know that it produced lower density rock on the moon and also affected the rotation of Earth."

"That Mercury is only 40 percent larger than Earth's moon, and that it can't keep a permanent atmosphere. It sounds cool."

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

"I found plate tectonics confusing and the separation of plates on Earth."

"I kind of couldn't tell which feature on the moon was the youngest. Any advice on how I could tell which features are the youngest/oldest?"

"Mercury and the moon because i didn't know they were alike at all."

"Nothing was too confusing, it's weird because when you, P-dog, explain it in class is when I start to question things."

"The text seems to say that Venus would not have had its severe greenhouse affect if it had been able to retain water in an ocean and trap excess carbon there, but Venus was too close to the sun and couldn't keep its water. Is it really that simple? I thought that Venus was also in a habitable zone like Earth."

"What I found confusing in the assigned textbook reading is that they consider the moon as planet-like just because it's two-thirds the size of Mercury, and it is similar to Earth, Mercury, Venus, and Mars. Since they had said the moon was a natural satellite."

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

"I never really know what to write here, so hi. I like how you teach, you're funny!" (Okay. Funny: ha ha, or funny: weird?)

"I was listening to Neil deGrasse Tyson and he was talking about antimatter. He said that if aliens came to us (assuming that they hadn't touch the ground yet) he wouldn't shake their hand. He would throw something to them to make sure that we are the same matter." (Neil is da man. Incoming!)

"How much water could comets have actually carried to Earth? It seems like it could only be a small amount." (The specific amount of water from cometary impacts, compared to the amount of water outgassed from Earth's volcanoes is still being investigated. In any case, most of Earth's atmosphere is thought to have been outgassed from its volcanoes.)

Astronomy quiz question: Venus' lack of plate tectonics

Astronomy 210 Quiz 7, fall semester 2012
Cuesta College, San Luis Obispo, CA

Lack of __________ on Venus' surface may be evidence it does not have plate tectonics.
(A) volcanic activity.
(B) sedimentary rocks.
(C) widespread faults and folded mountain ranges.
(D) oceans.

Correct answer: (C)

Plate tectonics ("continental drift") on Earth results in characteristic midocean rifts (where new crust is formed from the mantle) and subduction zones (where older crust is folded back down into the mantle), but also results in faults, where crustal plates move laterally past each other, and folded mountain ranges, where crustal plates are compressed and crumpled up. Lack of these features indicates that Venus does not have plate tectonics as does Earth.

Section 70158
Exam code: quiz07sEcn
(A) : 6 students
(B) : 0 students
(C) : 26 students
(D) : 2 students

Success level: 73% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.33

Online reading assignment: history of atoms, Earth, the moon, Mercury (NC campus)

Astronomy 210, fall semester 2012
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 history of atoms, 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.

"By the time the universe was three minutes old, the protons, neutrons and electrons in your body had come into existence."

"The comic strip was awesome! I love it when art and school can be combined so well. It made me feel very small, but in a good way if that makes sense. It was a bamf way to get me to learn astronomy. Thinking about the universe being within us is calming in a way."

"Earth's atmosphere is one of my favorite things to read about because I'm extremely interested in global warming and learning about what effects our atmosphere."

"Not all greenhouse gases are bad."

"How we can tell what features on the moon are older and younger just by looking at the it."

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

"The fact that Earth has evolved over millions of years--and it eventually evolved to support life. Why has this not happened in any other terrestrial planet? It's always been weird to me that the universe is so vast, yet, we still do not have any definitive evidence to show that other life exists. I find this odd and confusing."

"Plate tectonics--although I found this to be interesting I still found it to be confusing and think I only understood the basic concept of what the continental drift is."

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

"Wow, Earth has it all figured out. Volcanoes emit carbon dioxide, the atmosphere traps it which in turn keeps us warm, and oceans reabsorb the carbon dioxide to be recycled back into the volcanoes." (Yes, if nothing goes wrong.)

"John F. Podojil: 'Teaching is not a profession; it's a passion. Without passion for your subject and a desire for your students to learn and be the best in the world, then we have failed as a teacher and failure is not an option.' Not many teachers are passionate for what they teach, and simply from your lectures and explanations of things you can tell you teach from your heart and with passion... Thank you." (You're welcome. And it is certainly hard not to be excited about teaching a bamf subject like astronomy.)

Presentation: no place like home

Our planet--Earth--totally rocks. 'Nuff said. (Video link: "All Alone in the Night - Time-lapse footage of the Earth as seen from the ISS.")

What better reason than to understand how it works? You all are caretakers for our planet, so let's make sure to read the owner's manual.

In this presentation we will look in-depth at key features of Earth, in order to "contrast and compare" it with the other terrestrial planets in subsequent presentations.

First, mass.

Let's line up the planets left-to-right from most massive (Earth) to the least massive (Mercury). Earth's moon is not a planet, but we'll include it as a bonus, for it is very similar (yet very different) than Mercury, which will be discussed in the subsequent presentation. What evidence is there that Earth is currently the most geologically active? What evidence is there that Mercury and the moon are the least geologically active today? We have drilled in towards the core of Earth, and yes, it's pretty hot down in there, but we haven't drilled into the rest of these terrestrial planets (and the moon)--what does their lack of geological activity tell us about the temperatures of their cores? Note that core temperatures correlate with geological activity, such that the planets are also lined up left-to-right from hottest core (Earth) to the coldest cores (Mercury, and the moon).

Why do massive planets have hotter cores than less-massive planets? The terrestrial planets are subject to the "turkey/cornish hen effect." Suppose a turkey and a cornish are both taken out of the oven, where they were at the same temperature. Allowed to cool off on the counter for an hour, the interior of the turkey is still steaming when you cut into it, while the cornish hen (being much smaller) has cooled off considerably. All else being equal, large things cool off more slowly than small things. Earth has a hotter core than any of the other terrestrial planets because it is the most massive, and this allows it to maintain its current volcanic and tectonic plate motion activity, compared to the dormant or dead geological activity on the smaller terrestrial planets.

Remember that when compared to all the other terrestrial planets...Earth is pretty damn hot.

Second, plate tectonics.

This is often referred to as "continental drift" for obvious reasons, but the crust under the ocean is also moving around, and being continuously built and destroyed at various locations in order to shift the positions of the continents around. While we're still on the Thanksgiving food theme, what food do you think of when you watch these continents drift? (Video link: "Plate tectonics animation.")

Continental drift (or plate tectonics) reminds me of...gravy. Specifically the skin that forms on gravy, the day after Thanksgiving, where you pull it out of the refrigerator, and slowly warm it back up on a stove, because microwaving your gravy is just wrong. As the gravy gradually warms up, convection currents form, circulating below the gravy skin, pulling sections apart at certain places where warm gravy rises, or drawing together sections at certain places where cool gravy sinks. The next day after Thanksgiving, try this out for yourself, and imagine that we are just living on floating sections of gravy skin.

Midocean rises (or rifts) are where plates are separating away from each other, due to hot rising magma below the crust. This is where new crust is made.

Regions where cool sinking magma below the crust draws plates towards each other, such that they crumple up, forming mountain ranges; or where one plate subducts below the other, such that sinking plate is gradually destroyed.

In the first subsequent in-class activity, you will delve deeper into these tectonic plate motion regions, and also compare the relative ages of different regions of crust.

Third, the greenhouse effect.

Building a greenhouse for plants requires a transparent material such as glass or plastic to let sunlight through, keeping the plants toasty. Our atmosphere is just a big greenhouse, but instead of glass or plastic, certain gases have similar properties, such as carbon dioxide, but also water vapor and methane.

More specifically, a greenhouse material or gas is only transparent to visible light, which passes through and warms up objects below. These warmed objects will emit infrared light, which a greenhouse material or gas is actually opaque to, preventing it from passing through. So a greenhouse material or gas is a one-way street for the sun's energy, letting it through in the form of visible light, but trapping it in the form of infrared.

Earth enjoys a "good" greenhouse effect, as without greenhouse gases it would actually a little too far away from the sun to receive and trap enough energy to be comfortably warm. So a little greenhouse effect can be a good thing.

However, it is possible for there to be too much of a good thing, where the greenhouse effect traps too much of the sun's energy. Here firefighters are called to open up a car with a child locked inside, who is in danger of experiencing too much greenhouse effect, where visible light from the sun passes through the glass windows, warms the interior, which emits infrared, and if a lot of the infrared is prevented from escaping, the interior becomes too warm.

The primary source of greenhouse gases in our atmosphere? Turns out to be volcanic activity, which over time has spewed out vast amounts of carbon dioxide, and that other greenhouse gas: water vapor. And this still continues today.

But the amount of greenhouse gases in our atmosphere is controlled by our oceans, which not only collects the water vapor from volcanic activity, but also absorbs the carbon dioxide.

Think about opening a can of soda or pop, and letting it sit out for a long while. It will become flat, such that most of the trapped carbon dioxide escapes out to the atmosphere. (Thank you for contributing to global warming.) But it won't become completely flat, as there will always be some carbon dioxide in there, as water has a certain affinity for small amounts of carbon dioxide. If you were set out a pan of pure, distilled water exposed to air, due to its affinity for carbon dioxide the pan of water would actually take in a small amount from the atmosphere.

Now consider the vast of amount of water in Earth's oceans, which will soak up carbon dioxide from the atmosphere. It doesn't stop there, as the carbon dioxide in the oceans (through processes we don't have time to elaborate on further) will filter down and be trapped in sedimentary rock. And due to plate tectonics, this rock will eventually be subjected back down into Earth's mantle, conveniently recycling both carbon dioxide and water. So this natural process will control the amount of greenhouse gases present in the atmosphere...

...as long as it is not overwhelmed by man-made sources of greenhouse gases!

This carbon cycle is an involved process you will analyze in another subsequent in-class activity, along with comparing how this cycle went awry for the other terrestrial planets Venus and Mars. You should be able to fill in the first page of this in-class activity by now, and complete the remaining two pages after the subsequent presentation on the runaway planets, Venus and Mars.

Astronomy quiz question: Venus' lack of plate tectonics

Astronomy 210 Quiz 7, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

Evidence that Venus does not have plate tectonics is:
(A) runaway greenhouse effect.
(B) no venusquakes detected by landers.
(C) no subduction zones nor midocean rises.
(D) no oceans.

Correct answer: (C)

Since the main features of plate tectonics are subduction zones and midocean rises, the lack of subduction zones and midocean rises on Venus is evidence of its lack of plate tectonics.

Section 70158
(A) : 6 students
(B) : 5 students
(C) : 29 students
(D) : 4 students

"Success level": 69% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.67

Astronomy quiz question: cause of plate tectonics

Astronomy 210 Quiz 7, Fall Semester 2008
Cuesta College, San Luis Obispo, CA

[4.0 points.] What causes Earth's plate tectonics?
(A) Convection currents underneath the crust.
(B) Tidal forces from the moon.
(C) Gradual slowing rotation.
(D) Asteroid impacts that cracked the crust.

Section 70160
(A) : 28 students
(B) : 1 student
(C) : 0 students
(D) : 1 student

Correct answer: (A)

Lateral mantle flow below pulls the crust in certain directions; hot, rising magma produces new crust formation at midocean rifts; while cool, sinking magma occurs at subduction zones.

"Difficulty level": 94% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.13

Section 70158
(A) : 59 students
(B) : 4 students
(C) : 4 students
(D) : 1 student

"Difficulty level": 88% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.33