Friday, September 30, 2011

Palomar Field Trip

I'd like to take the Ay20 class up for a VIP tour of Palomar Mountain sometime this term. Please fill out this poll to let me know your availability.

Tuesday, September 27, 2011

Introducing... Me!

Hi all!

I'm super excited to be the TA for this class. This is my first time as a TA. But I do have a couple prior teaching experiences. In particular, as an undergrad I spent a summer in China running technology summer camps for high school students there. That gave me the experience of being in front of a classroom. For me, a lot of the meaning of science comes from the impact it has on people, and so teaching is a crucial aspect of making science meaningful.

What do I want to get out of this class? I guess one of the things I want is to learn how to teach. Professor Johnson is a great person to learn from, because he's full of lots of creative ideas and lots of energy. I also want to share my love of science. It's so fun to interact with people who also get that thrill from learning to understand our universe. I also want to learn. When I signed up to TA this class, I didn't realize that would really be involved. But it turns out there's so many levels of understanding, and when you ask yourself, "How can I teach this?", you have to dive down a few levels below where you've been before.

I'm here to help you guys out. One major thing is if you have any suggestions or questions or concerns about the class, or about Professor Johnson, you should feel free to bring them up with me. The goal is that this way, nothing we see on the course evaluation forms at the end of term will be a surprise, since we'll already be working with you guys to implement your suggestions for the class while it's still going on.

See y'all bright and early tomorrow :)


Reading Assignment for Friday

Chapter 1 Carrol & Ostlie

And by "for Friday" I mean read this chapter before coming to class Friday. You never know when you might have to have a conversation with someone (for instance a TA or Prof) about the celestial sphere while hanging out in Cahill 219...

On Points and Posts

Please create your blogs and make your initial posts. Introduce yourself to the class, muse about something astronomical, ask a dumb question and try to answer it. Whatever you do, start writing and then continue writing.

Blog posts will typically range from 1-3 points. Exceptional posts will receive 5 points. Here are some examples:

1-pointer (short, sweet, shows that I've been thinking about astronomy while eating my Froot Loops)
2-pointer (this might be a 3-pointer)
2-pointer (more if accompanied by writing. Don't get me wrong, though, I love this!)
3-pointer (this student is thinking about the day-to-day aspects of an astronomy career)
3-pointer (whoa, this student has been checking out astro-ph abstracts!)
5-pointer (straight out of Sky and Telescope! :)
5-pointer (AstroBites for the win!)

Points will be a bit subjective, but the Central Limit will likely prevail and wash out injustices whenever they may occur.

The power of dumb questions

Fun fact: back in the summer of 1999 I, Prof. Johnson, was a SURF student working in the LIGO group for Prof. Libbrecht and Dr. Phil Willems. It's crazy to me that these great scientists are now my peers! But it's proof positive that SURFers go on to do great things.

One of my most vivid memories from that summer took place in the basement of Robinson Hall. I went to visit a fellow SURF student on whom I had a crush. In her office was a poster of M33, not unlike the one pictured here. After staring at it for half a minute, I asked her A Stupid Question: "Um, what are all these really big, bright stars outside of the galaxy? Fortunately, my fellow SURF student didn't roll her eyes, or laugh, or sigh.

Instead, she jumped up from her chair and seized the opportunity to teach a fellow student about something she was passionate about. She told me that the big stars were actually normal-sized, but that they were closer and in our own Galaxy. In the picture, we were looking past stars in the Solar Neighborhood, out through our galaxy, and into a very distant galaxy composed of stars so far away and so numerous that they blurred into structure of what we call M33.

At first I was embarrassed that I had overlooked such an obvious explanation. But then, suddenly, right before my eyes the image of M33 took on a three-dimensional shape that I had never seen before in an astronomical image. For the first time, I sensed the structure of the Milky Way. I felt how enormous it is. I realized how gigantic M33 really is. HFS, I can see!

This event illustrates the power of "stupid" questions. Stupid, obvious questions are my favorite variety. Science works when people challenge the obvious, revisit "old" knowledge that everyone "knows," and ask dumb questions. Please keep this story in mind during the semester and let it guide how you approach Ay20.

Let me start off asking a dumb question about the image of M33. Take a look at some of those foreground stars. Those stars are points of light, with no discernable dimension. The only reason they have any shape is due to the limitations inherent in the optics we use to view them. They are point sources. And yet, any astronomer will tell you that we know a great deal about those tiny points of light. We can measure their temperatures, radii, masses, magnetic fields, chemical compositions and search for planets around them. We know a bit about how they form, why they shine, how long they'll live, what their internal structures look like.

The dumb question that forms the basis of Ay20 this term is: Seriously? Are you seriously telling me we can know all of this from a point of light in the night sky?

Do you buy it? You shouldn't at this point. But by December I think you will, and I hope you'll remain as amazed as I am about it!

Monday, September 26, 2011

Times for Problem Solving Sessions

I'll be in Cahill 219 two evenings a week to host problem solving sessions so you can work together on the lab and problems leftover from class. Participation highly encouraged. One session will be Thursday 8-10 pm. The other session will be either Monday or Tuesday evening.

Please comment on this message to let me know whether Monday or Tuesday evening is better, and what time window is the best.


Ay20 class times

Hi Ay20!

Jackie here, your faithful TA. Our first Ay20 class meeting is 3-4 pm today in room 219 in Cahill. Since class participation will be very important in the structure of the class, it's crucial that everyone attend class.

This morning at the organizational meeting, we scheduled class for Mondays 3-4 pm, Wednesdays 9-10 am, Fridays 9-10 am.

Class updates will be posted to this blog. You should save the link to this blog and add it to your RSS feed. If you have Gmail, you can do this by going to the top of the screen in Gmail and clicking on "Reader", which takes you to Google Reader. Then click on the "Add a Subscription" button in the top left of the screen, and type in "".

Can't wait to meet you all!

PS - If due to some scheduling mishap you can't make it to class today, please email me ( and Prof. Johnson ( to let us know asap.

Sunday, September 25, 2011

Welcome to the Ay20 Blog

Welcome to the Ay20 course blog. Please add this to your favorite RSS reader so you can stay up to date on the latest class announcements, problem set hints, in-depth articles about topics we will only have a little time to cover, student contributions and much, much more. If you don't have a favorite RSS feeder, open up a Google account and use Google Reader.

All Ay20 students should also create their own blogs. Just go to, login with your Google account, set your URL to, and give yourself a clever title. You should then invite your friends and family to follow your blog. Outstanding posts will be reposted to this site, and possibly reposted again to the main Cahill Astronomy blog (coming in November 2011). Write in your own voice, but use proper grammar and spelling. You can be humorous; indeed, humor is encouraged. But all posts should reflect what you are learning in this class and others here at Caltech. Be creative by including your own photography, music, comic strips, drawings and poetry. Keep your posts concise and focused, and update often (at least twice a week).

While your grade depends on the quality of your posts, since your blog is open to the world I hope you put a lot of work into your writing simply because so many people will likely read it. If you'd like to get a sense for what goes into a good science blog, check out some of my favorites:

Cosmic Variance
An Illumination
Hogg's Research
Female Science Professor
Bad Astronomy
Saturday Morning Breakfast Cereal