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

Astronomy 210, spring 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.
"That no low mass stars have died yet."

"The different kind of star deaths because they all die in different ways."

"Novas, because I was not aware of how exactly they happened till reading the presentation."

"I thought it was funny that the 'starving' stars were actually the ones that had more mass."

"How a hummer H2 has an mpg of 9.8 This is interesting to me, because i would try to never buy a car with a really low mpg."

"Black holes, because I had heard about them but never researched them or knew whether or not they really existed."

"Novas and supernovas, it is intriguing to understand what sparks them and what is actually happening scientifically."

"The different types of star explosions. I liked the analogies you gave us."

"I can't wait to learn more about black holes."

"A black hole's event horizon, because it is so difficult to contemplate that point of no return."

"I didn't know that you technically can't see a black hole, but I now get why they are called 'black holes' because they go on forever and ultimately objects are just falling into a black abyss."

"Finally! Learning how stars die because it has been something I've been curious ever since I was registered in this class."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"How can a star be older than the universe? How is anything older than the universe? That seems impossible. Isn't it already the oldest thing? Isn't the universe everything? How do people know?"

"The different types of evolutions of each the different stars."

"Black holes. An understanding of a black hole would be the highest level of knowledge in the universe. Could you please explain more how the low mass stars will live longer than the medium mass stars? I thought that the more mass a star has the more time it would take to die because of how big it is."

"The different types of supernova star explosions."

"I was a little thrown with the white dwarfs that explode and take their companion star down with them, and how we know what stars will do this, and why they are different than just any other star."

"Of the stellar remnants, how can a white dwarf be the largest but not the most massive? I didn't quite understand this."

"I understand how stars try to eat Helium after they run out of hydrogen, but the birth of a star trips me out."

"How the white-dwarf star takes hydrogen from its comparison star and then can explode."

"Literally almost everything, I'm kinda lost."

A Hummer H2 and a SmartCar ForTwo can travel the same distance with a full tank of gas. Briefly explain how this is possible.
"It's possible because the Hummer has a bigger gas tank, even though it gets less miles per gallon."

"The H2 has a bigger gas tank to start off with, while the SmartCar makes better use of its tiny gas tank with its beast mpg."

"They both use fuels differently to accomplish the same thing?"

"Different types of gasoline?"

"I'm not sure. I have no idea."

"Eh, what?"

Match the end-of-life stage with the corresponding main-sequence star.
(Only correct responses shown.)
Black hole: massive main sequence star [86%]
Neutron star: massive main sequence star [49%]
White dwarf: medium-mass main-sequence star [61%]
(No stellar remnant observed yet: low-mass main-sequence star [57%]

Match the type of explosion (if possible) with the corresponding main-sequence star.
(Only correct responses shown.)
Type II supernova: massive main sequence star: [84%]
Type Ia supernova: medium-mass main-sequence star [80%]
Nova: medium-mass main-sequence star [57%]
Low-mass main-sequence star: (no explosion possible) [65%]

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.  *** [3]
hours.  [0]
days.  ** [2]
a year.  [0]
many years.  ***** [5]
forever.  ********************************** [34]
(Unsure/guessing/lost/help!)  ***** [5]

The first rule of astronomy class is...
"Commit to the KEEP word tags?"

"Go to astronomy class."

"Pluto is not a planet."

"I can't remember."

"Happy faces :) :) :) :) :)"

"Go to class."

"Look at the stars."

"You do not talk about astrology?"

"Draw smiley faces when lost on exams."

"To always call you p-dog."

"The word 'hella' is a real astronomy word."

"Study a lot."

"Don't talk about astronomy class. Or is it always talk about astronomy class? Damn, I messed up the one rule!"

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Have you ever eaten out of a tub of mayonnaise because you were hungry and too lazy to go to the store?" (Mrs. P-dog would not allow that.)

"Any advice to get through the next few weeks?" (Stay the course. #squadgoals)

"Are we having another study session before the next exam?" (Yes.)

Would you jump into a black hole? Because I'd definitely consider it. I'd just want to know where it goes."

"No comment." (You just did.)

"Will our final have multiple choice questions from the previous two midterms?" (Yes, and also from the last quiz.)

"Can I get an A in the class?"


"How do you see an object (hypothetically) spiraling around a black hole forever if black holes have swallowed and collided with objects?" (It's already happened, but the light that we see from around the black hole is "held back" such that we only see it happen very slowly, stretched out over time.)

"Will all the stars/planets/matter in space eventually be sucked into black holes?" (No, they only significantly warp space-time in their immediate vicinity, like every other object with mass.)

"Not sure what the first rule of astronomy class is..."

"How was your spring break? (It was awesome--Mrs. P-dog and I went to Joshua Tree National Park.)

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