Online reading assignment: medium-mass stars, massive stars, neutron stars and black holes, keep-quit-start resolutions (NC campus)

Astronomy 210, spring semester 2014
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 the evolution of medium-mass stars, massive stars, neutron stars and black holes, and keep-quit-start mid-semester resolutions.

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 black holes interesting because...its a black hole! If something is fast enough it can get away from its gravitational pull but if it isn't it just gets pulled into it!"

"The comparison of the two cars. It is interesting to think about how although one gets much better mileage, they both go the same distance."

"A low mass star will actually last much longer than a high mass star due to its fusion rate, I always thought it would be the other way around."

"I found the death of stars very interesting because they need that energy so much so that they will steal hydrogen from neighboring stars and cause them both to die...they are so selfish. they are like I'M TAKING YOU DOWN WITH ME!"

"Nuclear fusion. I am fascinated by the process happening within these stars, just because it's awesome and powerful beyond belief."

"I thought it was interesting that massive stars can either become a black hole or a neuron star after they die."

"I found time dilation interesting because is seems that with enough curvature of space, like that of a black holes, time could come to a complete stop. Makes me think of time as relative. Just depends on whether or not you're experiencing life inside a black hole or out."

"I knew stars 'died' but didn't know what actually caused their deaths."

"That everything that is heavier than iron was produced in a supernova. I find that interesting."

"It was interesting to learn the death of medium-mass stars. I didn't know some of the stars took so one to die and others were way faster."

I really liked reading about the black holes. I think it's super cool how there is a point of no return basically where you cannot outdo the pull which is the 'event horizon.'"

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Also black holes...I understand the concept of the gravitational force, but I didn't quite grasp the space-time curvature."

"Black holes are also really confusing and its hard for me to wrap my brain around it. Where does the light go and is anything existent behind it?"

"I found the black hole stuff confusing. I just dont get it at all"

"The event horizon of black holes. I am going back in the reading to try and straighten out the concept in my mind."

"How are black holes the most dense compact object?"

"Black holes. Stretching bodies. Falling into it forever. Weird."

Found density of a black hole hard to understand. How can something so small become so dense? Reading about it makes sense but just hard to conceive of in actual life."

I think it's confusing how black holes work and how the event horizon affects time."

"It was kinda confusing how the hummer and smart car both has the same range. But I think I see how that works. Pretty cool."

"I didn't understand what mass a black hole would be."

A Hummer H2 and a SmartCar ForTwo can travel the same distance with a full tank of gas. Briefly explain how this is possible.
"The Hummer H2 has a bigger fuel tank and wastes a lot of gas while the SmartCar has a little fuel tank but saves a lot of gas, so they both can travel the same distance."

"While the SmartCar has better mileage, it has a smaller tank and the difference comes out that they can both go the same distance on a tank of gas. One will just cost a lot more..."

"They can start off at a full tank of gas, but you may need to fill up that Hummer more often...or they are both on a trailer being pulled! ;)"

Match the end-of-life stage with the corresponding main-sequence star.
(Only correct responses shown.)
Black hole: massive main sequence star [71%]
Neutron star: massive main sequence star [33%]
White dwarf: medium-mass main-sequence star [58%]
(No stellar remnant observed yet: low-mass main-sequence star [42%]

Match the type of explosion (if possible) with the corresponding main-sequence star.
(Only correct responses shown.)
Type II supernova: massive main sequence star: [88%]
Type Ia supernova: medium-mass main-sequence star [58%]
Nova: medium-mass main-sequence star [63%]
Low-mass main-sequence star: (no explosion possible) [54%]

If you were to leap into a black hole, your friends would typically watch you falling in for __________ before you entered the event horizon.
seconds.  * [1]
hours.  * [1]
days.  [0]
a year.  * [1]
many years.  *** [3]
forever.  ********** [10]
(Unsure/guessing/lost/help!)  ********* [9]

The first rule of astronomy class is...
"...do your homework!"

"...read the book!"

"...everything is awesome! Everything is cool when you're part of a team!"

"...show up to class ready to learn and have a good attitude. At least that seemed like a good general rule to follow. Is this a trick question?"

"...uh, why are you called P-dog?"

"...don't show up late to the party."

"...dude, do not jump in black holes, that's dangerous."

"....you don't talk about astronomy class."

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Spacetime continuums freak me out, also they leave me inclined to believe in time travel."

"What are the chances of the Milky Way galaxy being sucked into a black hole?" (None, unless you are in the very tiny fraction of the galaxy that is already extremely close to the black hole to begin with, and wind up colliding with other stuff to slow down your orbital speed around the black hole. Otherwise, you're safe.)

"I'm sorry this weekend has kept me busy--I am so tired, and this will never happen again."

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