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 runaway planets (Venus and Mars), jovian planets (Jupiter, Saturn, Uranus and Neptune), and the dwarf planets (and the International Astronomy Union classification scheme).
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 thought the reasons for all the differences between the planets are really interesting. Like a planet's distance from the sun, how big it is, its atmospheric composition, it's core temperature, and how geologically active it is."
"Learning about the greenhouse cycle is very interesting for me. Larger planets putting out more greenhouse gas while smaller planets release less makes sense because of the mass of the planet and capacity to outgas. Also that because the strength of gravity on larger planets the greenhouse gases stay together is quite interesting."
"How important mass in relation to a planet's atmosphere and core heat is."
"That there is such a thing as 'frustrated volcanos' on Venus. Perfect GIF animation example btw..."
"I thought it was cool how Mars used to have oceans on its surface. This interests me because the astronomers were able to figure that out."
"The fact that there is hidden water on Mars! Maybe someday astronauts will find evidence that proves the planet was once hospitable."
"I enjoyed re-learning key aspects and characteristics of the planets and finding out new information about them that I hadn't known before."
"The 'bad' greenhouse effect was interesting, I never really knew before that too much could be bad in something like that."
"I find the runaway greenhouse effects of Venus and Mars very interesting. To me, Venus is especially interesting because it seems like it's the worst case scenario apocalyptic wasteland planet. In short, it's 'metal.' Very cool."
"How Jupiter has active weather patterns because it is seen with the colors of the planet."
"I found it interesting that if you took a boat onto Jupiter that you would never actually float, you would continuously sink with the gases just getting thicker and thicker. You would eventually start to sink into a liquid type substance but you would never actually hit a liquid. This is interesting because at first, I thought of putting a houseboat on Jupiter."
"Learning about the different planets and their similarities or slight differences. I also liked learning about what actually makes a planet, a planet. Having a reason behind why things are the way that they are."
"The IAU classification scheme was really interesting. Makes sense why Pluto is no longer considered a planet."
"The reason of why Pluto isn't a planet anymore. I've known that it was a dwarf planet, but I never understood it fully until now."
Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Never heard of a Cornish hen before. Is that weird or is that just me?"
"The self-maintenance of our Earth versus other planets like Venus and Mars; I think I just need some more explanation."
"I think it's weird that there is water on Mars. I guess I just don't imagine other planets having atmospheres like Earth does so when I think about water on other planets it seems like there would be water in space and that's weird. But when I think about it I guess it makes sense."
"The whole variety of greenhouse effects on different planets is a bit hard to keep track of. I'll probably forget each planet's particular greenhouse effect by tomorrow."
"Something I found confusing was how Venus has so much carbon dioxide. Is all of the water vapor of Venus gone out of atmosphere, or is it still in atmosphere and it is just too hot to condense?"
"Reading about the volcanic resurfacing on Venus was interesting and confusing. How would we be able to figure out how many eruption cycles Venus has had and are we able to predict the future eruptions?"
"I was curious to know if Earth will slowly become more hostile in the future alike Venus and mars. The textbook did not touch on the possibility but introduced the idea that Venus and Mars both were more habitable in the beginning."
"I found a little bit confusing reading about Jupiter's complex atmosphere and the belt-zone circulation."
"I find the jovian planets confusing in that they have no surface and are liquid. Just giant balls of liquid floating in space. Perhaps not so confusing, more strange."
"Whether Neptune or Uranus is the coldest planet. You would think that Neptune would be chillier because it's farthest from the sun, but Uranus has calmer weather patterns."
"I feel like I understood most of the things covered in this chapter, but I guess I don't quite get why Uranus is colder than Neptune. I read the explanation from your blog post, but I guess I just don't understand why its orbit is so tilted. What made it like that? Why isn't Uranus the same temperature as Neptune?"
"I would like more explanation on ice giants because I am having trouble understanding what causes them to be the way they are. More on the Cooper Cooler™ effect?"
"Being able to define a planet and what that is exactly. I understand it, but it's still kind of confusing to me."
"What made scientists change the classifications of a planet? Why did the IAU make Pluto a dwarf planet?"
Identify the relative amounts of these characteristics for Venus, compared to Earth. (Only correct responses shown.)
Interior core heat, today: about the same as Earth [55%]
Geologic activity, today: less than Earth [71%]
Volcanic outgassing, up until now: about the same as Earth [58%]
Heat from the sun: more than Earth [87%]
Amount of atmosphere, today: more than Earth [77%]
Identify the relative amounts of these characteristics for Mars, compared to Earth. (Only correct responses shown.)
Interior core heat, today: less than Earth [94%]
Geologic activity, today: less than Earth [87%]
Volcanic outgassing, up until now: less than Earth [77%]
Heat from the sun: less than Earth [94%]
Amount of atmosphere, today: less than Earth [94%]
Which jovian planet has the coolest interior temperatures?
Jupiter (most massive).  Saturn (most prominent rings). **  Uranus (least active weather patterns). ********************  Neptune (farthest from the sun). *********  (Unsure/guessing/lost/help!) 
I believe Pluto should be a planet.
Strongly disagree. **  Disagree. *******  Neutral. ***********  Agree. ******  Strongly Agree. ***** 
Briefly explain your answer to the previous question (whether Pluto should be a planet).
"If pluto were to be included as a planet, it would create argument to include tons of other planets like Eris that fit the plutos qualifications for planethood sometimes better than pluto (its bigger)."
"I think any planet-type object in our solar system should be a planet, but what do I know?"
"It seems funny that in 2006 we lost a planet. We went from nine planets to eight planets. Pluto is still a planet but is in another class called dwarf planet due to its size. In my opinion we need to restore the solar system to its former nine-planet glory."
"I do not have enough information to support a claim on whether or not Pluto should a planet. I am not very familiar with the subject. "
"It's orbit is affected by other planets and does not dominate its own orbit."
"Because, although Pluto has two of the three requirements for a celestial body to be called a planet (namely, (1) it has an orbit around the sun; (2) it is massive enough to be rounded by its own gravity); it doesn't have the third requirement: it hasn't cleared its own orbit path around the sun (it's not gravitationally dominant)."
"Pluto deserves to be a planet ."
"Scientifically I understand why Pluto is considered a dwarf planet instead of a planet, however my nostalgia on remembering Pluto as a planet as a kid gives me a slight bias."
"It is what it is."
"I think that Pluto is an interesting subject, but I'm not really emotionally attached to it. I understand the scientific community's reasons for changing its classification. I do believe that Eris, Ceres and company could all be classified as planets in addition if the accepted classification had been different. I don't have very strong opinions on the subject one way or the other, and I don't think that Pluto's planethood--or lack therof--should detract from our interest in it."
"I always knew Pluto as a planet so I would have to let it stay as a planet for my nostalgia."
"Does it really hurt to just call Pluto a planet? Pluto was always considered a planet when I was a kid, it was taught to me that way. I'll never accept Pluto as anything other than a planet, that deserves to be called one just as much as the other planets!!"
"I can understand why the IAU classified Pluto as dwarf planet because it is so similar in size to other objects in the Kuiper Belt. Some of these ice-body objects have their own moons too, so they are practically Pluto. Most people think of planets as larger than Earth and Pluto is itty bitty in comparison to the other planets in our solar system."
"Honestly, it's more of an emotional planet, because I went through elementary school with it being a part of our solar system (and it was my favorite planet, other than Earth, with Jupiter as my second) and then it was just taken out. Technically and scientifically I understand that it is a dwarf planet, but I'd still like it to be a part of our solar system."
"I actually went neutral since astronomers know why it does not reach the standards of a planet."
"Ever since I was little everyone said Pluto wasnt considered a planet. Till this day I don't care if it follows the definition of a planet, all I care about is that Pluto is still up there next to all the other planets so It should be one just cause its there."
"Classification is important in the sciences. knowing exactly what an object is can put data into context. Arguing over how to classify something is a waste of time and distracts from some of the dwarf-planet's interesting features and traits."
"Pluto orbits the sun and it also has a round shape. This gives it two out of three yes's plus it was already a planet so it should get to be a planet again."
"A planet to clear its orbital may have some relevance to the proximity to the sun when they formed and the Kuiper belt shows the result when a planet doesn't have that proximity. possibly to be defined Kuiper planets."
"I would say so because it was deemed a planet earlier but at the same time their are other planets that had better qualifications than Pluto but were not deemed planets."
"Pluto passes two of the three IAU qualifications. I don't think Pluto has a strong enough gravity to pull in or eject another object like a moon for example. Therefore it cannot be considered a planet despite its rounded shape and rocky characteristics."
"I defer to the IAU on such."
"I believe Pluto should be a planet because it orbits the sun and has an atmosphere when close to the sun."
"Human nature tends to cause us to want bring everything together into a family. This leads to feelings of hurt when a member of the family is dismissed. We often view the planets as our 'solar system family,'" therefore, by excluding a member, the family unit is seen as having been torn apart which tears at heartstrings. Bring Pluto back, he's cute."
"I do think that since Pluto didn't meet all the criteria to be a planet, it shouldn't be called one. It still doesn't make my heart hurt any less that they took it out though."
"I understand why it's not a planet but it does have its own moons. why does it depend so greatly on the planet's size if its considered a planet or not? just because Pluto is a dwarf makes it that much less of a planet?"
"According to the textbook, Pluto isn't considered a jovian or terrestrial plant. It also states that 'an object must be large enough to dominate and gravitationally clear its orbital region or more, or all, other objects.' So according to these standards Pluto maybe cannot be a planet."
"Pluto is classified as a dwarf, so I guess it shouldn't be a planet. However, that was due to recent updates in what classifies a planet and what doesn't, hence why Pluto was considered a planet for more than 70 years."
"Using the current system it doesn't meet the criteria. The classification system may change, and since it is too far for me to realistically visit, it doesn’t affect me that much so I don’t have a lot of emotional investment."
"Pluto should not be classified as a planet because it has little mass and does not dominate its orbit. Similar objects have been found in the Kuiper belt, so it doesn't live up to IAU's planet standards. Poor Pluto."
"After reading the part in the book about Pluto it shouldn't be a planet, it wasn't able to push other things out its orbit with its gravitational pull."
Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"I'm relieved to have a break from spatial reasoning, it's obviously not my strong point."
"The concept that a planet needs to be geologically active in order to maintain its habitability is fascinating, and somewhat debatable. Couldn't a greenhouse dome provide conditions on a geologically inactive planet that would make habitation possible?" (Yes, especially since it's not possible to terraform Mars.)
"How come Mars is being investigated for habitability and not Venus?" (There has been some speculation on what would be required to terraform Venus, but Carl Sagan conceded that it is probably too far gone.)
"Venus is pretty stinking hot if our probes can only last a few hours on its surface... Venus is the 'hot lava' game in real life!"
"'Jovian' is a cool word. Really rolls off the tongue, unless I am saying it wrong?"
"Saturn's rings are made of ice particle/chunks. Theoretically, could that be a good water source when/if we become an interplanetary species? Or are there more accessible water sources in solar system?" (Maybe, but Saturn's moons (along with some of Jupiter's moons) have water ice as well.)
"More about the other planets that could have been planets."
"Is it likely that the junk in the asteroid belt or Kuiper belt could attract and become a planet in a few billion years, or is the way planet-making period in this solar system over?" (The asteroid belt will keep on as distributed debris, because of Jupiter's disruptive gravitational influence. Similarly for the Kuiper belt, due to all of the jovian planets.)
"Do you think Pluto should be a planet?" (Eh. It is what it is.)