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In my previous post I set up the problem of gun statistics and planet statistics (where I mean math-problem, rather than trouble-problem). There's a question of the number of guns per capita, versus the fraction of the population with a gun (fraction of citizenry that are gun-owners). Also in there is the number of guns per gun-owner.
Similarly, there's the question of the number of planets per star throughout the galaxy, the fraction of stars with a planetary system, and the number of planets per system.
To illustrate this mathematically (and this involves nothing but multiplication and division, so stay with me!), let's set up two scenarios. Both scenarios have five stars and five planets:
Now let's introduce some mathematical terms. The first is the total number of stars in our sample, $N_\star$. Next is the number of planets, $n_p$. In both of the cases in the figure above, $n_p = 5$ and $N_\star = 5$. The…
What if Jupiter were at 1 AU and we were its moon? This is what it'd look like:
The NASA Kepler mission might help us find a situation like this. David Kipping at the Harvard Center for Astrophysics is on the case.
Ta-Nehisi Coates recently asked his readership to "talk to him like he's stupid" about gun ownership rates in the US and in other countries. I really like it when he makes these requests. It's how I often feel about stories in the news, which make me feel like I'm walking in on the middle of a grown-up conversation. I need someone to talk to me like I'm stupid about Benghazi or the fiscal cliff. Fortunately, Slate and Salon are good sources for this sort of information, as is Andrew Sullivan.
Anyway, regarding gun ownership rates, the discussion that Ta-Nehisi sparked got a bit muddled over the question of guns per capita (number of guns per person) versus the number of guns per gun-owner. This is an important distinction. There are two ways to get 1 gun per person in a hypothetical town of 100 people. One way is to give a gun to every person in town. The other is to have one person in town with 100 guns.
Of course this whole discussion goes back to the most…
Via Facebook, this picture from earlier this year of me, and my sisters (from left to right, youngest to most experienced) Erin, Rachel and Christina. I'm often amazed that I came from the same beautiful gene pool. Fun facts: They are all artists and singers. I'm a scientist who can't carry a tune. We also all live along the same 20-mile stretch of the 210 freeway north of LA. We all have two kids each: 6 boys and 2 girls, and all 8 kids were born within a 10-year interval. Finally, our kids have skin tones that span Kenya to Sweden. Fun with genetics!
Sisters: Sorry we missed each other at Thanksgiving while I was out of town. I'm looking forward to seeing all of you at our Christmas celebration!
I'm hanging out with Prof. Nate McCrady right now in Prof. Jason Wright's kitchen. Given that I once sat in Frank Shu's stellar astrophysics class with both of them, it's a lot of fun to append "Prof" to each of their names!
Anyway, this post is about how Nate blew my mind. He's a professor at U. Montana and he just informed me of the following facts:
There is one area code in Montana. There are only 1,000,000 people in the whole state.The biggest city is Billings, pop. 105,000 (Pasadena has 138,000)There are only fourteen high schools with 1000+ students...in all of Montana
In high school I played football and ran track. After high school, I've tried running, biking, ultimate frisbee and a few other sports. But if you read my blog often, you know that my passion these days is basketball.
I find it challenging and exciting in much the same way that I enjoy science. There's just so many combinations of events and so much improvisation. Plus, it's something I can play alone (shooting around), with one other person, 2-on-2 or full-court 5-on-5, giving me plenty of opportunities to practice and participate. This is in contrast to, say, football, which I'll likely never be able to play again with a full team. And as a sport to watch live or on TV, it's fun and fast-paced without all the head trauma of my old sport.
A lot about why I love basketball is summarized in this outstanding sports article (h/t Bri) about the "Kobe Assist." The main point is that Basketball cannot be thought of and analyzed in the same way as baseball. Whil…
Here's a great blog post about one postdoc's first-year experience: As of October, I have now spent one year as an astronomy postdoctoral researcher straight out of graduate school. It has been a great year, though with plenty of ups and downs. I figure I should write down my thoughts about this experience. I have both good things and bad things to say, but I try to be honest, fair, and positive throughout. This may be of interest to curious grad students, or anyone really, especially if they have wondered about pursuing a postdoc or are just interested in astronomy in Chile. One thing to keep in mind is that this is an individual, personal experience and your own story or circumstances may be quite different. It's obviously difficult to approach this critically and unbiasedly, but here goes nothing...
In my last post I said that the spectra I was showing were not real, but instead models. However, it turns out those spectra I showed, the so-called Pickles library spectra, are actual stellar spectra! My bad. I was correct that there isn't a single instrument that provides that wide wavelength coverage. But that Pickles guy was pretty clever: "Each library spectrum was formed by combining data from several sources overlapping in wavelength coverage."
Like most former and current grad students, I'm a huge fan of PhD comics. I'm also a fan of the artist behind PhD Comics, Jorge Cham, in particular his online shows on scientific topics such as dark matter, the Higgs boson and Open Access publishing. When I first watched Dark Matters, my immediate thought was "Wow, this is an amazing teaching tool. I wonder if Jorge would like to do one on exoplanets."
So, even though I had never met him, I nervously typed out an email, proof-read it, reread it, and finally hit send. Lo and behold, I managed to set up a lunch meeting with Jorge and we talked about academia, comics, teaching, and my research. He agreed that it would be fun to do a video on Exoplanets and we scheduled a date to record the audio last Summer. I also applied for and received funding from the Caltech Innovation in Education fund to contract Jorge's expertise for the whole endeavor.
Jorge and I decided to do things a bit differently than his past animat…
To continue my exploration of gender parity in astronomy, I have called on my friend and fellow astronomer Annika Peter to guest blog for me.Annika and I have had several illuminating discussions over coffee about academia in general and women in science in particular. Here's the first in a series of posts from Annika.
My name is Annika Peter. I am a dark-matter and gravitational-dynamics junkie, currently finishing up a postdoctoral position at UC Irvine, and moving to a faculty position in the Departments of Physics and Astronomy at The Ohio State University. My husband is also an astrophysicist, currently a professor of astrophysics at Caltech. He is taking a professorship at OSU, too, so we have successfully found an excellent solution to our two-body problem! My two favorite aspects of my job are thinking deeply about and trying to solve some of the major mysteries of the universe, and working with undergraduate and graduate students. I am also a practical problem solver…