Online reading assignment: medium-mass stars, massive stars, neutron stars and black holes (SLO campus)

Astronomy 210, fall semester 2016
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.

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.
"To know the Hummer2 and the SmartCar ForTwo could get as far on a full tank of gas. But since stars are not like stars, I think it is interesting that we have yet to see any little stars die we can only predict that they do. This just raises so many questions for me."

"That no low-mass stars have died...ever. Pretty crazy."

"How a white dwarf can pull hydrogen from a neighboring star and explode after some time."

"Supernovas! I've been waiting for this all semester!"

"Star deaths, in general. I didn't realize that different stars died different ways. For example, I thought all stars could turn into novas, not just stars in binary systems. I never understood the process before."

"How black holes can't be seen."

"The fact that we are made up of atoms from a dead star. I thought this was interesting because we wouldn't exist if stars didn't die."

"Everything. Stars and black holes are so mindbendingly fascinating I just want to talk about it all for hours. I find black kholes interesting because they're so unknown and so mysterious. It's fun to think of different possibilities and theories of where black holes lead to."

"The fact that black holes don't only effect matter and light but also space-time. Wrapping your head around space-time concepts always takes your mind far from familiar territory and experiences so that's always interesting."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"That no low mass stars have died yet."

"Just exactly how expansion cooling works as a concept."

"How a white dwarf can steal hydrogen from another star."

"Understanding the relationship between the explosions that different mass stars give off when they die."

"What's the difference between a type Ia supernova and a type II supernova?"

"That pulsars give off pulses of radio waves? Not sure what this means. Like they regularly give them off in a rhythm?"

"Black holes as a whole."

"The thought of space being curved blows my mind."

A Hummer H2 and a SmartCar ForTwo can travel the same distance with a full tank of gas. Briefly explain how this is possible.
"Because the H2 has a much larger gas tank than the SmartCar ForTwo which compensates for the lower mpg and therefore they could travel the same distance on a full tank of gas."

"The miles per gallon is better on the smart car of course so that's why it can go far, and the hummer has a big tank to make up for it horrible mileage."

"They travel within the same range?"

Match the end-of-life stage with the corresponding main-sequence star.
(Only correct responses shown.)
Black hole: massive main sequence star [70%]
Neutron star: massive main sequence star [63%]
White dwarf: medium-mass main-sequence star [70%]
(No stellar remnant observed yet: low-mass main-sequence star [67%]

Match the type of explosion (if possible) with the corresponding main-sequence star.
(Only correct responses shown.)
Type II supernova: massive main sequence star: [77%]
Type Ia supernova: medium-mass main-sequence star [73%]
Nova: medium-mass main-sequence star [67%]
Low-mass main-sequence star: (no explosion possible) [70%]

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.  [0]
many years.  **** [4]
forever.  ******************** [20]
(Unsure/guessing/lost/help!)  **** [4]

The first rule of astronomy class is...
"Show up to class."

"Have fun!"

"Ask questions!"

"P-dog knows best."

"Everything dies."

"To know why you're here in the first place."

"Bring your starwheel and try not to cry."

"I'm not sure, I skimmed over this. But I will have read it thoroughly before class tomorrow."

"You do not talk about astronomy class."

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"I need help studying better for these quizzes what else can I do to help myself?" (See me during office hours. We'll go through your individual case and break it down for you.)

"Where does the event horizon of a black hole lead to?" (No one knows. Except people that have already gone inside. But they're still in there, have no way of signaling us, and also they're most likely very dead.)

"Wouldn't your friends not be able to see you if you jumped into a black hole? Wouldn't the light be drawn into the black hole because of it's incredible gravity strength?" (Your "friends" would be able to watch you circle closer and closer in towards the event horizon surrounding the black hole, slower and slower. You (or whatever is left of you after spaghettification) will definitely enter the event horizon after some time, but the light from you at the moment you entered the event horizon would would never reach your audience.)

"I must refuse your invite to a 'Donner Party.' No, thank you!"

"Astronomy family dinners should be a thing during this class because it falls right at dinner time and I slowly die of hunger every Wednesday evening and never have enough time to eat before this class. :)" (We could make it a Donner dinner party.)

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