20150415

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

Astronomy 210, spring semester 2015
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.
"Time dilation and curvature of spacetime, because I just saw interstellar and I could relate to what the slides were talking about it."

"It had not occurred to me that a Hummer could travel as far as a SmartCar, but the answer is almost self-explanatory."

"I honestly found everything about the death of stars super-interesting."

"I like how you compare a star's life with the cars. It really helps to understand things better. At first I thought they would be like cars, to later find out they're nothing like them."

"The lifetime of the stars was interesting because the low mass stars live the longest and none has ever died. I would think the larger stars would live longer."

"I found the Hummer and SmartCar question interesting because it actually made me stop and think."

"Spaghettification."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"I can't seem wrap my head around time dilation."

"I don't understand how two stars can be born at the same time but yet one lives way longer than the other."

"I'm not sure why some stars die faster than other, I get it has to do with mass but I don't understand why."

"The different types of explosions each star makes."

"Black holes."

"I found it confusing how smaller stars live longer. This was confusing because compared to planets, bigger planets' core stays warm longer, making it live longer, so I would have assumed it's the same for stars. Guess not!"

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 SmartCar has a better mileage per gallon and the hummer has a lower mileage per gallon than the SmartCar. Taking that into consideration, the Hummer can hold a bigger amount of gas that yields a certain amount of mileage traveled. The SmartCar being smaller, can hold less gas, but can travel further per gallon, thus they travel the same distance with a full tank of gas."

"One has a bigger gas tank than the other."

"Because they convert the gas at the same rate."

"I'm still completely lost and need help with this."

Match the end-of-life stage with the corresponding main-sequence star.
(Only correct responses shown.)
Black hole: massive main sequence star [85%]
Neutron star: massive main sequence star [50%]
White dwarf: medium-mass main-sequence star [56%]
(No stellar remnant observed yet: low-mass main-sequence star [47%]

Match the type of explosion (if possible) with the corresponding main-sequence star.
(Only correct responses shown.)
Type II supernova: massive main sequence star: [76%]
Type Ia supernova: medium-mass main-sequence star [79%]
Nova: medium-mass main-sequence star [50%]
Low-mass main-sequence star: (no explosion possible) [53%]

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.  **** [4]
hours.  * [1]
days.  * [1]
a year.  [0]
many years.  * [1]
forever.  ********************* [21]
(Unsure/guessing/lost/help!)  ****** [6]

The first rule of astronomy class is...
"'It’s a 'religion for intelligent atheists' (from The Theory of Everything)."

"Bring coffee and a snack."

"Show up with caffeine!"

"To call you 'P-dog.'"

"Reach for the stars!"

"'Be informed of and to abide by all student policies outlined in the Cuesta College Catalog, and deadlines in the Cuesta College Class Schedule.'"

"Everything is astronomy is HUGE."

"There are no stupid questions."

"Stars are the best ever, dont mess with black holes."

"Do your homework so you can pass! :)"

"Sci-fi films are not indicative the actual science behind astronomy."

"Come to class."

"The first rule of astronomy class is you have to like stars."

"Always expect the unexpected?"

"Never be late."

"Respect P-dog."

"I am not sure."

"Expand your knowledge. Make conclusions on scientific observations? I'm not sure."

"Have fun?"

"Don't talk about astronomy class."

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Talk about Interstellar and its credibility to be real or not?"

"I don't know what Stephen Hawking is talking about, and I have tried to read his book A Brief History of Time but it;s like eating soup with a fork."

"If your friends leaped into a black hole, would you leap too?" (Hey, someone's gotta watch them fall in.)

"Why do you grade so much more leniently than other teachers? It really makes learning this subject much more interesting! I appreciate it!" (Really? Some other students might have the complete opposite opinion about grading, but still, you're welcome.)

"If one entered a black hole, would their life expectancy grow larger than normal? or shorter?" (From that person's perspective, spaghettification would end their life pretty quickly. From the outside observers' perspective, the spaghettification process would look slowed down.)

"I loved all the visuals for the black holes!"

"Why do we see the sky as blue when space is black?" (The atmosphere scatters short wavelengths (blue) from sunlight. At night, the atmosphere is still there, but there is no sunlight to scatter, so it appears clear.)

"Have you ever watched the movie Event Horizon?" (Yes. I found it interesting because it was a stupid, yet very scary science fiction movie at the same time.)

"I loved all the visuals for the black holes!"

"Whats your favorite part of astronomy?" (This stuff.)

"What did you do for spring break? (Mainly just trying to keep up with Mrs. P-dog.)

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