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

Astronomy 210, spring semester 2017
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.
"Reading about stars dying. I often have conversations about that with my sisters when we're outside to see the stars (I know, it's weird, haha!) and so it was cool to become more educated about it."

"I really enjoyed the comparison of the Hummer H2 and the SmartCar. It was a really good example. I like it when you relate the subject to easier things to understand."

"The life and death of main sequence stars was very interesting as the process is much more difficult and complex than I originally believed. Instead of just dying out in a single path each star can die differently depending on its circumstances."

"The 'star-vation' analogy and how soon each type of star will give up on whats in the fridge and begin to die away."

"That white dwarfs are so much bigger than neutron stars because I've always associated the word 'dwarf' with small, but in this case it is not small when compared."

"I find the implosion or explosion of stars fascinating as a dying star can no longer produce its own energy and the outer layers of the core literally cave in, crushing the center space, and imploding the remnants the star carcass."

"Star deaths are important to Earthlings because MASSIVE stars create the atomic elements of which we are made of.....STARDUST......Ziggy we are one with you!"

"I found it interesting, well more along the lines of like how the textbook says 'astronomy is about us.' I like that it relates to you."

"It's cool that black holes are basically the death of certain large stars. I had never really made that connection before."

"The way they explained blackholes and how you can't 'see' them but you can 'feel' them."

"That black holes are actually not as 'powerful' as most people think. Most people think that they suck up everything. So its interesting that there is an actual point in the blackhole where things can not escape past and once you pass it there's no going back."

"The idea of seeing an object enter a black hole, and how it seems to take longer and longer for it to get to the bottom as time goes, making it an infinite amount of time to see it enter the black hole."

"Learning about black holes. It's insane that they can cause time to slow down in curved spacetime."

"I'm just excited to be learning about black holes finally."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"the different types of stars and their explosions."

"The heating and cooling of massive stars, depleting its fuel, and surrendering to death. I would just appreciate a recap on the layers and stages of dying stars."

"The whole concept about medium-mass stars, and their lifetimes and dying process confuses me. It just sounds superconfusing and it's a lot to remember. I just need to go over it a few times."

"It's confusing to me that when massive stars die they can turn into a lot of things. And that you don't really know when or what it will turn into another, like if it will be a neutron star or a black hole."

"The physics of black holes is confusing because they are black holes. They aren't exactly simple."

"While I am fascinated by black holes I'm still confused on why you would only feel it has been two months but from your friends watching you it could be forever. I feel like I may have the concept mixed up so a little bit of clarity on that subject would be helpful."

"Still get confused on the size, mass, and density scales and how they relate for stellar remnants. They just seem so backwards to me. How can a white dwarf be the largest star remnant but a neutron star and black hole be the most massive star remnants?"

"Black holes are so fascinating, but pretty confusing. Like whaaaaat?!"

"Most of it because I am behind on the reading for this homework."

"I was confused with most slides on the pictoquiz and didn't quite understand how the pictures had to do with stars."

"I am confused about the detection of black holes. How do we receive information back from something that only consumes?"

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 tank of the hummer H2 is much larger than the tank of the smart car. However, it uses the gas much less efficiently, so it takes that much more gas to go the same distance."

"A Hummer has a bigger tank but very low mpg while a smartcar has a tiny tank but better mpg."

"I suppose each tank has a fuel capacity that is proportional to the vehicle's consumption. Hummer probably has a 30-40 gallon tank and it guzzles, where a SmartCar's tank may be 7-8 gallons and it only sips."

"The Hummer has a larger gas tank."

Match the end-of-life stage with the corresponding main-sequence star.
(Only correct responses shown.)
Black hole: massive main sequence star [82%]
Neutron star: massive main sequence star [42%]
White dwarf: medium-mass main-sequence star [52%]
(No stellar remnant observed yet: low-mass main-sequence star [55%]

Match the type of explosion (if possible) with the corresponding main-sequence star.
(Only correct responses shown.)
Type II supernova: massive main sequence star: [85%]
Type Ia supernova: medium-mass main-sequence star [76%]
Nova: medium-mass main-sequence star [52%]
Low-mass main-sequence star: (no explosion possible) [55%]

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.  ****** [6]
hours.  [0]
days.  [0]
a year.  [0]
many years.  * [1]
forever.  ********************* [21]
(Unsure/guessing/lost/help!)  ***** [5]

The first rule of astronomy class is...
"Don't call it astrology."

"Bring snacks to this three hour long class."

"Peace is a lie. There is only passion. Or is it: there is no emotion, There is peace."

"Don't overthink astronomy?"

"Do the online homework?"

"Fluorine uranium carbon potassium bismuth technetium helium sulfur germanium thulium oxygen neon yttrium."

"Have fun."

"Ask questions?"

"Respect P-dog."

"Show up."

"COME TO EVERY CLASS!! its only once a week I mean c'monnnnnnn."

"Red dwarfs never die."

"Eat dinner before class."

"Know your planets and directions."

"Nothing moves faster than the speed of light?"

"Be prepared."

"What is the evidence?"

"Don't talk about astronomy class."

"What happens in astronomy class stays in astronomy class."

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Help, my brain is still on vacation!"

"Did you have a nice spring break? How was camping? Hopefully you were able to take a real and restful break!" (It was nice and relaxing, other than when Mrs. P-dog and I were channeling our inner pyromaniacs. How was yours?)

"Do you think it hurts a star to die?" (I would like to think that embracing your destiny is a positive experience.)

What causes a massive star to 'choose' between a black hole or a neutron star? Does it have to do with the fusion rate?" (It depends on how massive its core is--mass is destiny.)

"This reading assignment was very dense and I really found it interesting but exhausting."

"The GIFs and pictures for these presentations were on point."

"Why do we have two midterms?" (Well, if you rock out on both the first and second midterm, then you may not need to take the final.)

"What time and date is our final? (It's already listed on the course calendar.)

"I love this class. I keep talking to my friends and family about it and how easily you relate subjects to everyday life"

"You ROCK P-dog." (NO, YOU ROCK.)

"What is the first rule of astronomy class?"

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