-5 minutes to Kepler teleconference!

Watch here.

Woohoo! 715 new planets in one go were announced during the teleconference.

A few screen captures:

photo 2 photo 1

knownexoplanets (1)

Arc posted two new papers (Lissauer et al., 2014 & Rowe et al., 2014) and a media kit.


Look at that histogram go!

Figure 3 of Rowe et al., 2014
Figure 3 of Rowe et al., 2014

This figure from Rowe et al., 2014 shows the incident flux (normalized to the incident flux on Earth) versus the radius of the planet (in Earth radii). There’s something interesting to be said about it, but it will deserve a blog post on its own…

Setting up a nice AucTeX environment on Mac OS X

Most people I know use TeXShop on Mac OS X. While it’s a pretty good TeX editor, I think Emacs is overall vastly superior. Of course, I’m rather biased since I already use Emacs for everything else… Perhaps this post will be useful to other Emacs-addicted astronomers.

In my setup, I use the AUCTeX package coupled with the Skim PDF viewer (if you’re not using Skim, download it, it’s brilliant!). One of the advantages of this combination is that Emacs and Skim can be kept in sync, like in the screenshot below.

Skim + Emacs/AUCTeX nirvana. Note that the current highlighted line in Skim corresponds to the cursor position in Emacs.
Skim + Emacs/AUCTeX nirvana. Note that the current highlighted line in Skim corresponds to the cursor position in Emacs.

I found it a bit difficult to set up the AUCTeX package with sensible defaults, so I’ll reproduce here my configuration in hopes that it will be useful to someone else.

The salient lines are the ones configuring latexmk and Skim. You should have latexmk installed if you are using the TeX Live distribution; Skim can be downloaded for free here. You can stick this script in your Emacs initialization file (see my dotemacs repository if you’d like to see my other Emacs configs). I shamelessly copied those lines from this Stack Overflow answer.

Two LaTeX gems: ShareLaTeX and latexdiff

Here are two really cool LaTeX tools every astronomer should enjoy.

ShareLaTeX is an online LaTeX writing tool. It’s great for collaboratively writing LaTeX documents of any size, and a life-saver when you don’t have access to your own laptop with a TeX installation on it — just grab a web browser, navigate to ShareLaTeX and write away, then grab the PDF product. (You can also chat with collaborators, browse revisions, and a bunch of other useful niceties.)

A sample ShareLaTeX project.
A sample ShareLaTeX project.

The folks behind ShareLaTeX generously announced today that they made their product open-source. Here is the GitHub page with their source code. It appears to be extremely easy to run your own local installation, if you so desire.

While working on a grant application (in the old, inefficient fashion: on a Dropbox shared folder) I wished there was some way to send “diffs” of my changes to the PDF to my collaborators, in order to save them the time to hunt for the changed word or sentence. Emery Berger’s blog directed me to the latexdiff tool, which I had somehow never heard about! It’s quite easy to install (if you use MacPorts, it’s a simple sudo port install latexdiff), and the resulting PDF diffs are nice and clear.

A sample latexdiff output.
A sample latexdiff output.


AstroTRENDS: No so weaselly after all


Substitute damn every time you’re inclined to write very; your editor will delete it and the writing will be just as it should be. — Mark Twain

Damn right!

In my last post, I showed a plot of the number of abstract that contained weasel words, as tracked by AstroTRENDS:

chart-2I interpreted this trend as a steady change in the style and “audacity” of astronomy papers, and I believed that a possible cause was hedging. (See Writing without conviction? Hedging in science research articles.) Note that I was not making a statement about the quality of the research, but merely about an interesting trend I had not seen mentioned elsewhere.

Perhaps I should have used more weasel words in my post! I acted upon Ben Weiner’s suggestion: use a set of non-weasel words as a control to verify whether the trend was due to an increase in verbosity instead. I track this set of keywords (a mix of adverbs and adjectives that I deemed to be neutral):

Fast OR Slow OR Large OR Small OR Before OR After OR High OR Low OR Many OR Few OR More OR Less OR Inside OR Outside OR Recently OR Just

This is available as “Non-weasel keywords” in the AstroTRENDS drop downs.

And here’s the plot!

The two appear to be tracking each other pretty well. It seems to me to be a strong indication of the correctness of Ben’s guess that verbosity is the main driver here. However, simple keyword search may still not be telling the whole story (e.g. because certain keywords “saturate” as the abstracts get longer, appearing more than once), so a better approach could be to study a small sample of abstracts through the years.


Weasels (green) vs. non-weasels (yellow)
Weasels (green) vs. non-weasels (yellow)

Turns out that there’s a comprehensive ADS API, described on GitHub here, so with a bit of rejiggering I will be able to let AstroTRENDS do free-form queries (via Michael Kurtz.), and do a bit of abstract munging myself.

AstroTRENDS: Weasel words

Credit: Cliff

I added a bunch of new keywords to AstroTRENDS, mostly suggested by friends and people in the community who had read my Facebook post.

A thought I had yesterday is the following: has the astronomical literature become more speculative, and perhaps less committed to audacious claims, in recent times? It is difficult to test this hypothesis  by merely querying ADS for abstract keywords. It would certainly be better served by a natural-language processing analysis of the full text, although this is just my uninformed speculation.

A much simpler way is to search for the so-called “weasel words” (such a funny way of describing them from a non-native speaker POV!). Matthew Might (a CS professor from the University of Utah) has a really interesting article about the different abuses of language that are common among technical writers, and he created some automated tools for detecting them. It’s a great read. (There’s even an emacs minor mode called writegood based on his recommendations, which I will be testing for sure). Although I don’t necessarily agree with a strict adherence to all of his points, there are certainly some great pieces of advice there.

Taking his post as a reference, I added a new “weasel words” pseudo-keyword to AstroTRENDS. The “weasel words” keyword shows the result of an ADS query of refereed abstracts containing the following boolean expression:

Could OR Possibly OR Might OR Maybe OR Perhaps OR Quite OR Fairly OR Various OR Very OR Several OR Exceedingly OR Vastly OR Interestingly OR Surprisingly OR Remarkably OR Clearly OR Significantly OR Substantially OR Relatively OR Completely OR Extremely

We can easily disagree on whether using these words in an abstract constitutes “weaseling”, or has any sort of nefarious purpose (I certainly pepper my writing with more than my fair share of those). It is still an interesting exercise to verify whether usage of those words has increased over time. The following plot shows the fraction of articles containing those words (i.e. number of articles containing the words normalized by the total article count) each year.



Keeping all the caveats above in mind, there is a definite upward, pretty linear-by-eye trend going on. I’m not sure whether it has to do with simple evolution of language and style, less boastful writing, an accident of fate/bug on my part, or some other factor.

This is of course a super-shallow analysis that would require far more insight than what I offered in this post, but it’s still intriguing. I tried to altavista whether this is well-known, but have come empty handed so far. Any ideas?

You can play with the interactive plot itself by clicking this link.

UPDATE: Ben Weiner made a really good point on the Facebook astronomer group.   He suggests that an additional, alternative explanation could simply be that abstracts have become, on average, more verbose with time, which would explain the higher frequency of fluffy adjectives and adverbs. This could be checked with a control set of non-weasel words… which I will definitely try.

How did this post do with writegood-mode? Pretty nicely… but I got a grade of “11” on Hemingway, with about 9 out 24 sentences being hard to read.  Oh well.
Weasel image credit: Cliff

The beauty of grainy photographic plates

I’m working on a small bit for a project, involving cross-fades between old-timey photographic plates of spiral galaxies, and their modern high-resolution counterparts.

Although the level of detail in this image of M33 is astounding, there is a certain beauty to the photographic plate (mouse over the image to fade into the black-and-white plate).


I had to resize and rotate both images to make them more or less coincide for a pleasant cross-fade — until I got frustrated at trying to make every pixel match…

The photographic plate holds a certain romantic value. In my early childhood I owned a lot of old astronomy books (and pilfered quite a lot from my relatives). The black-and-white reproductions on those pages had an indefinable fluid, mysterious quality to them.  If I squinted hard enough, perhaps I could catch some hitherto unknown detail or physical phenomenon? My mindset was definitely more serious and reverential to the gorgeousness of the universe back then, and it’s sometimes sad to think I lost some of that  childhood determination in discovering the mysteries of the universe, which felt so close for the picking:

Vedi, in questi silenzi in cui le cose
s’abbandonano e sembrano vicine
a tradire il loro ultimo segreto,
talora ci si aspetta
di scoprire uno sbaglio di Natura,
il punto morto del mondo, l’anello che non tiene,
il filo da disbrogliare che finalmente ci metta
nel mezzo di una verità.
Lo sguardo fruga d’intorno,
la mente indaga accorda disunisce
nel profumo che dilaga
quando il giorno più languisce.
Sono i silenzi in cui si vede
in ogni ombra umana che si allontana
qualche disturbata Divinità.

One of my favorite poems is apropos. [I limoni, by Eugenio Montale; translation].

The blurriness and undeterminedness of the early observations of galaxies gave rise to the split between the idea of nebulas within the Galaxy versus “island universes”. (Read more about it here and here.)

Image credits: The black-and-white photograph is from this page; the color photograph is from APOD (Adam BlockMt. Lemmon SkyCenterU. Arizona).

Link: The Sound Of Mandelbrot Set

The Ripples blog  published a very nice post about “sonifying” the Mandelbrot set. The resulting sound files (linked in the post) are quite interesting, especially the “SlowDivergence” soundbite. The post also tipped me off about  playitbyr, an R package that converts a data.frame (a table of values) into an auditory graph. The soundbites demoed on the webpage are really cool — you should check them out!

The sonification window of Systemic v1.
The sonification window of Systemic v1.

The “classic” version of Systemic (v1, Java) has a feature for sonifying the orbital dynamics of exoplanets, originally written by Aaron Wolf (now a Turner Postdoctoral Fellow at the University of Michigan).

Non-interacting planets only generate pure sine-wave tones — not very interesting. It gets much more exciting once you introduce planetary interactions. Resonant and unstable systems, in particular, generate much more delicate or dramatic samples. Oklo.org has a few posts about the sonification feature, with downloadable soundbites.

I have not been a very good steward of this feature — it didn’t make it into Systemic2 (or the web app) since I didn’t want to work on migrating the Java code.  The existence of playitbyr, though, means I do not have to reinvent the wheel, definitely reigniting my interest in implementing this feature!

[Via R-bloggers.]

AstroTRENDS: A new tool to track astronomy topics in the literature

A screenshot of AstroTRENDS, showing three random keywords: Dark Energy, Spitzer, and White Dwarf.
A screenshot of AstroTRENDS, showing three random keywords: Dark Energy, Spitzer, and White Dwarf. White Dwarfs are the “old reliable” of the group.

Inspired by this post by my good friend Augusto Carballido, I created a new web app called AstroTRENDS. It’s like Google Trends, for astronomy!

AstroTRENDS shows how popular specific astronomic topics are in the literature throughout the years. For instance, you could track the popularity of Dark Energy vs. Dark Matter; or the rise of exoplanetary-themed papers since the discovery of the first exoplanets in 1992. As an example, check out this post I wrote about whether the astronomical community has settled on the “extrasolar planet” or “exoplanet” monicker.

You can normalize keywords with respect to one another, or the total article count, to track relative trends in popularity (say, the growth of “Transits” papers compared to “Radial Velocity” papers). Finally, you can click on a specific point to see all the papers containing the keyword from that year (maybe that spike in a keyword is connected to a discovery, a new theory or the launch of a satellite?).

How does it work? I crawled ADS for a small number of keywords that I thought were interesting (but you can ask me for more!), and counted how many refereed articles were published containing that keyword in the abstract for each year between 1970 and 2013. Keywords containing multiple words are contained within quotes, to specify that all words must be in the abstract.

Play and have fun with it, and if you find an interesting trend, you can share it with others by copying and pasting the address from the “Share” box. (Feel free to send it to me, too!)

Open AstroTRENDS

Link: Zooniverse Disk Detective

Disk Detective is the newest Zooniverse citizen science project.  Volunteers delve into more than 500,000 objects seen at different wavelengths, and help pick out potential circumstellar disks.

An animated gif I made scrolling through different wavelengths on Disk Detective.
An animated gif I made scrolling through different wavelengths on Disk Detective.

The idea is super cool, the bit of classifying I did was fun, and the website looks great. Outstanding job!

Erika Nesvold has a nice writeup of the project on Astrobites.