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

Astronomy 210, spring semester 2013
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, and on 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.

"I really liked the section that talked about the end of the sun (and Earth), it sounds awesome but incredibly unfortunate. Thank god I wont be there."

"I found it interesting which stars live the longest and how they all eventually die. The red dwarfs live the longest and if you are smaller then you live longer."

"I found the type II supernova bounce very interesting. I think its very interesting that all of the energy/motion takes effect in the outer layer (smaller ball)."

"I found it interesting how if close-pair binary stars are born at the same time, the one that dies off first will gather hydrogen from its neighboring star and depending on how fast it gathers the energy, will determine how it's ending will be."

"What I found interesting was the fate of the sun and the end of the earth section. It's amazing how the sun fuses hydrogen into helium and becoming more luminous, but also scary that in five billion years the sun will end the world."

"The difference between the nova and a type Ia supernova."

"Everything I've been taught about black holes from movies and TV shows were false."

"Everything was interesting! The whole death of stars subjects is my favorite so far!"

"I didn't even know black holes actually existed. I thought they are more of a made up concept."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.

"After reading about black holes I have a basic understanding of what they are, but what confused me was the concept of someone falling into a black hole and what it would look like to a viewer. Time dilation is discussed but this didn't click with me. I get the person if supposedly falling slowly but I need to hear another explanation maybe."

"How an explosion happens with stars, because it doesn't seem possible."

"I think all of it is confusing in my opinion."

A Hummer H2 and a SmartCar ForTwo will travel the same distance with a full tank of gas. Briefly explain how this is possible.

"A Hummer has a huge gas tank, but gets almost no miles to the gallon, while a SmartCar has a tiny gas tank and can get a large amount of miles per gallon."

"The size of the tank and the miles per gallon of the vehicles are inversely proportional."

Briefly explain the difference between a nova and a type Ia supernova.

"Nova is a star exploding, a type la supernova is a big star exploding."

"A nova is an explosion on a white dwarf and can occur many times, whereas a type Ia destroys the star completely leaving behind nothing. Both occur due to nuclear reactions happening on the star."

"A white dwarf stealing hydrogen from a companion star slowly is a nova, and a type Ia supernova is when it steals hydrogen quickly."

"A nova is an old star flaring up or a violent explosion involving a white dwarf, whereas a type la supernova occurs when a white dwarf in a binary system receives enough mass to exceed a certain limit and then collapses."

The first rule of astronomy class is...

"Don't talk about astronomy class." (5 responses.)

"Don't talk about/never trust astrology." (2 responses.)

"To pass astronomy class."

"Cheeseburgers for all."

"Respect/call you P-dog!" (3 responses.)

"Probably do the reading."

"Go to class." (2 responses.)

"You are part of the universe and not just an observer."

"Don't be tardy for the party?"

"Don't fall into a black hole?"

"I have no idea..." (2 responses.)

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.

"What is the ring around the moon on some nights, it also happens sometimes with the sun?" (Ice crystals in the sky can cause a halo around the moon or sun.)

"Can we have a short class because it's almost spring break?" (I'm not sure Wednesday night qualifies as "almost" spring break.)

"Explain black holes the best you can. This topic is so cool. Thanks P-dog." (Imma try. Imma try real hard.)

"You should show us the Astronomy Picture of the Day at the beginning of the class period instead of a cartoon. (You should make the Astronomy Picture of the Day website your homepage in your browser. Just saying.)