If We Assume

CUBEHELIX, or How I Learned to Love Black/White Printers

2013-05-22T01:59:00.004-07:00

Anyone who's chatted with me about figure design (at least in Astronomy) in the last two years has probably heard my rantings and ravings about some strange color pallet called cubehelix (not to be confused with timecube). I flat out love this color scheme, and I think it could work for you! Here's why:

1. It Works Better for YOU

The most notable feature about CUBEHELIX (or "cubehelix" if you prefer) is that it prints equally well in color and black & white! This is a great time saver when making figures for publications where color is only available online (if like in Astronomy you still use journals with print copies). CUBHELIX accomplishes this by cycling through the RGB cube, while constantly increasing the saturation (black to white). I like this figure, which explains how CUBEHLIX works and its name:

From Dave Green

To demonstrate the printability, I have made color palettes in both color and black & white for CUBEHELIX and the default for most plotting packages: rainbow:

Now that's some sweet desaturation!

CUBEHELIX is also more information-dense as a result. When we use colors for contour/density maps, we're trying to convey a third dimension of data in "flatland" (2D space). With rainbow, you rely on color alone. With CUBEHELIX we do this with both color and saturation... and as we'll see later, you can even effectively do this for multiple datasets at once!

2. It's Better for Everyone Else Too!

Since CUBEHELIX desaturates "correctly", people with black & white printers are going to love you. They can print your amazing contour maps out and actually understand them! This goes double for showing figures on projectors. If the red channel goes out, or yellows are weak, your plots are going to be bulletproof. As I've said over and over: if I'm thinking about weird colors in your data visualization, I'm not thinking about the insightful or groundbreaking results you're trying to show.

Perhaps even more importantly, CUBEHELIX is pretty friendly for your colorblind readership! Here's an example of my default CUBEHELIX color scheme, followed by simulations for how it is seen by people with three types of colorblindness:

These colorblindness simulations were done via this very nice tool.

CUBEHELIX generally does very well for all these forms of colorblindness, thanks to the constant change in saturation. Approximately 8-10% of men have some form for color perception deficiency, and if you make density maps with normal saturated rainbows you're kicking this audience (possibly students, colleagues, future employers) in the knees. Shouldn't our default color schemes be the easiest for everyone to see?

Fun aside: test how well you can differentiate colors! (I scored a 15...)

3. It's Super Versatile

CUBEHELIX, as defined by Dave Green (2011), has several useful "knobs" you can adjust. This includes: how many times through the rainbow to go, from what color to start, which direction to go (roygbiv vs vibgyor), how fast to go from black to white, and how saturated to make the colors.

A few simple examples to demonstrate the versatility! Here I've included 4 tests:

my default scheme going "backwards" through the rainbow wheel once (rotation = -1, vibgyor),
once through the wheel the proper direction,
zero color movement (just black to white) starting at blue,
and 5 times through the rainbow... because why not?!

This makes a nearly limitless family of color palettes available. If you have multiple datasets to plot together you could use rotation=0 and simply change the starting color. Making heatmap schemes in any hue is effortless. If your figures include both contours and lines/points, you could use the pastel-like CUBEHELIX for the contours and highly saturated/deep colors for the points to make the contrast really pop.

4. You probably already have it

Rejoice! CUBEHELIX is already included in the current version of matplotlib! If you Astronomers use IDL for plotting, I have created an easy to use version. Bonus: David Fanning now includes my CUBEHELIX code in his widely used software library!

A few other versions exist as well, check out Dave Green's website for details. If your language environment of choice is not included, and you can create custom color pallets using RGB vectors (or possibly even with hex codes) it is almost trivial to code up the original color scheme as I did in IDL (use the original paper). I'd love to see it added to Tableau...

Finally, here are some fun examples of figures I've created (from this blog) using various CUBEHELIX settings... happy graphing!

Binary Clock from James Davenport (or see it on Visually)

Keck: A 10-m Paintbrush

2013-05-07T23:04:00.000-07:00

My friend Sebastian shared this awesome image with me today, and was kind enough to let me post it here:

"Focusing Keck" by Sebastian Pineda (Caltech)

This is a screenshot taken from one of the guider cameras on Keck, one of the largest optical telescopes in the world. Each hexagonal cluster of points is actually a single star being focused by each of the mirror segments! The dots are small since each segment is essentially in focus, and Keck has tremendously good "seeing"

Normally each segment of the primary mirror would focus to the exact same location. However the mirrors are slightly (and intentionally) misaligned, allowing the operators to see the focus for each of the 36 primary mirror segments. For comparison, here's one of the Keck primary mirrors in its full glory:

(Copyright W. M. Keck Observatory)

Of course Keck routinely produces stunning images of the cosmos (check some out here!) but I thought this simple black/white image above was amazing. In one image it captures the simplicity and beauty of observational astronomy, while reminding us of the engineering marvel that allowed its creation. It reminds me of the million little things that must go right each night to make astronomy happen.

Science in action! Clear skies, Sebastian!

The Cost of Astrophysics

2013-04-23T01:43:00.002-07:00

One of my favorite posts so far on If We Assume was "The Pace of NSF Funded Research", in which I showed that NSF-funded astronomy grants produce papers for up to 15 years! I made that figure while on an airplane with my friend Eric (who does cool stuff like this!) so that's fun too.

The data for that project came from the brilliant people at Harvard's CFA Library, who gathered every Astro paper published since 1995 that referenced a NSF AST grant. When they updated this database to include the budget amount for each grant, and were kind enough to notify me, I knew it was time to do a follow-up post!

The question that immediately jumped to my mind:

How much does a typical Astronomy paper cost taxpayers?

Caveat Lector
I want to acknowledge this kind of analysis could be seen as inflammatory, insulting, or misleading. Please consider it in the lighthearted spirit it was intended.

1. A Typical AST Grant Costs $249k

Here I'm just showing a simple histogram (with log $ bins). Almost all grants are a few hundred-thousand dollars. The typical (median) is $249k, which for reference would pay for about 4 years of support for a graduate student at the UW, including overhead, tuition, salary, publication/page charges, 2 new computers, 4 domestic conferences, and a couple international conference trips.

2. Typical Grant size has started to drop recently

The orange line traces the median grant size each year. Our new tradition in America is to evidently not pass federal budgets. I'm not going to claim this is the cause of the drop in median grant allocation, but it's interesting that the last time a budget seems to have been passed in this country is 2009... My belief is that the NSF has tried to keep scientists from leaving the field, so giving out smaller grants means more people can still pay their rent.

3. A typical paper costs about $20k

According to some very simple (read: bad) math, take the # of papers produced divided by the budget of the grant and you get some kind of "cost per paper". This assumes that papers are the only real product of research, which is not entirely true. Conspicuously, this is about on par with a year's stipend for a graduate student (not including overhead and tuition, which about doubles that cost). I don't know if people will think this is too high or low (what is the going market price for a paper?) but the more I consider it the better a deal it seems!

Here is an obtuse way of looking at this. Orange lines track the cost per paper versus grant size for fixed numbers of papers. Kind of silly

4. Paper costs are remarkably stable since 1995

There is a slight steady increase, but generally this is quite flat. The steep rise in the past 5 years is due to grants not yet reaching their full measure (see first post about grant productivity)

5. Small grants are more "efficient"

Maybe this goes without saying, and maybe this is the stupidest result of this entire analysis, but the best "bang for your buck" is in small grants... especially if they're reasonably productive! Naturally this kind of metric rewards people who cite every grant they've ever worked on in every paper, but is that a bad thing?

Below I show the "papers per dollar", literally inverting the metric from before (# of papers produced / grant amount). Once again we assume that papers are all that matters. In red I've highlighted the "most efficient grant", that which produced the most numbers of papers for the least number of dollars. (note this may be supplanted as newer grants continue to rack up papers)

By the power vested in me by the internet, I pronounce Detailed Modeling of Radiation Transport in Supernovae (1998) the most efficient AST grant since 1995, with 56 papers citing the grant and a meager $50267 awarded. Congratulations to Dr Peter Hauschildt.

6. Bigger $ grants don't necessarily yield more citations

If the number of papers is related to the "productivity" of a grant, the number of citations probes the "impact" of a grant. Interestingly, there does not appear to be much correlation between expensive grants and more "impactful" science. Take from that what you will.

I am also pleased to announce the winners for highest "impact per dollar" (literally # of citations for the grant / cost of grant). Below in blue I have marked the winner, Submillimeter Studies of the Cosmological Star Formation and AGN Histories (2000) with 3157 citations and only $37159! Well done, Dr Lennox Cowie. A slim $11.77 per citation! Notable runner up in this category is again Detailed Modeling of Radiation Transport in Supernovae (1998) in red, with 3571 citations.

Lastly: Citations versus Papers

I also realized that this database provided an interesting testbed to consider how papers gather citations. Generally this is a topic of great debate and interest, especially for young researchers. Below I've plotted the # of total citations a grant receives versus the total # of papers it produced. Of course this should show some correlation.

Also shown for reference is the "1:1 line" representing 1 citation for every paper (a baseline for impact?), the "20:1 line" indicating 20 citations for every paper (reasonably good I'd say!), and something I've dubbed the "Line of Self-Citation". This curious line was calculated like so: if every subsequent paper you publish contains a citation for every previous paper you've published. I guess this would be better called the "Line of Cumulative Self-Citation".

Obviously citation behavior never literally follows this Line of Self-Citation; imagine how horribly boring a paper with 100 different self-citations would be. Also - I'm not sure if this database has intentionally removed self-citations (sometimes done). What I find curious is that this Line of Self-Citation does a reasonable job of at least going through the data.

Finally: I'm not sure what to really make of this last figure, but I don't think I've ever seen anything quite like it. Have you? I'd love to hear your thoughts/feedback!

The Reddit Effect - II

2013-04-10T18:55:00.002-07:00

Today I'll share a couple observations about web traffic. Take from it what you will.

Below are two charts/tables, directly taken from my "dashboard". The first lists my Top 10 Articles, ranked by total numbers of pageviews. This shows a smooth exponential-ish distribution, not too heavy on any single article.

(apropos: I really like the built-in stats tools with Blogger!)

The second chart lists the Top 10 Traffic Sources for this site. The traffic from Reddit is more than double that of all other sources combined! WOW!

This isn't to say that Reddit is the best place to advertise your work. It can go largely unnoticed if you don't participate in the Reddit community, and getting traction within any social news aggregator is often a subtle game. However, your potential exposure can be much higher than places like Facebook.

These stats also don't account for external exposure. For example, I'd wager more than 865 people read Huffington Post's coverage of my Starbucks post.

My intuition is that I need to diversify my readership sources some, that Reddit doesn't necessarily create a stable base (for a host of reasons). But I'm making this whole blog thing up as I'm going, just trying to do my best, so who's to say what's "best"?

April Fools - UFOs and the Humorous New Frontiers of Science

2013-04-01T00:01:00.000-07:00

"And now for something completely different..."

Today I have posted my first April Fools arXiv paper: Detection Rates of Unidentified Moving Objects in Next Generation Time Domain Surveys. It semi-seriously explores the possibility for LSST to place real limits on the visitation rate of UFOs to our world. This is an idea I'd been kicking around for a few years - it's silly, but not altogether absurd. I'd love to know what you think!

Like many astronomers, I read the astronomy section of the arXiv (astro-ph) daily over coffee. It is a repository where researchers post manuscripts for rapid (and free) dissemination and archival.

Link of interest: When to post to arXiv? (via AstroBetter)

I became aware of April Fools paper on the arXiv a few years ago, which range from silly inside-jokes between friends to the more subtle. My favorite is when you only realize the paper is a joke after you've started reading it! These are in short supply, but every year one or two come along.

More seriously, I love that the arXiv provides a reasonably legitimate forum to publish things that are more complex than a blog post, but perhaps less rigorous than a paper. Especially given how expensive it is to publish (page charges are routinely more than $125/page for authors), the arXiv gives scientists a valuable alternative.

There is value in the absurd.

Especially in astronomy, we must entertain the totally bizarre and fringe (at least to a point). In this age where astrophysics is becoming truly hard, less funded, and driven by massive collaborations, I have heard it said that astronomers risk becoming less creative. If you only do science that's a "sure thing", if you're not willing to speculate a little, if you haven't the guts to try something new or engage in a bit of academic creativity, then our majestic enterprise will surely fail.

So perhaps April Fools can also be a day where we shamelessly trot out some fun ideas, some semi serious or even speculative notions. We could create a Journal of Speculative Astrophysics specifically for ideas whose time may not have come just yet, one edition per annum (Fritz Zwicky could be the editor in perpetuity).

Or maybe I'll be unemployed on Tuesday! Either way, I want to believe...

A short list of other past April Fools papers...

If you know of any other real gems, drop them in the comments below or shoot me a line!!

The Greasiest Spoon in Town

2013-03-25T09:00:00.001-07:00

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Last month KIRO 7 reported on the "10 Dirtiest Restaurants" in Seattle (link to story now dead). Several establishments near UW were featured, and in the past month its been fascinating to watch how they (and the student patrons) reacted.

One UW-area Thai place on said list was quite upset, as they apparently have the same name as another Thai restaurant, and felt it was a case of mistaken identity. They posted a sign decrying the bad press, which didn't last long. My by-eye gauging is that their business maybe took a couple day dip, but has remained strong. Also - the place is by no means "clean".
Just down the 'Ave is a teriyaki restaurant, which absolutely deserves to be on this filthy list. I've had some frightful meals here over the past decade...

This got me thinking about restaurant inspections and food safety across the city, and I went in search of the data that could answer the question: where are the best & worst places to eat in Seattle, according to food inspectors? Mixing in some GIS shapefiles of Seattle neighborhoods, here's what I came up with:

The data contained about 192k inspections, spanning 2002 - 2009. More recent data was also available, but to get the general map this was all I needed.

There's lots of other fun things one can do with such a large database, including looking at when the food inspectors are most likely to visit a given location, and even when most restaurant inspections occur:

This map, and the initial KIRO report, are examples of the every-day insights you can gather from public data that society is collecting every day. Personal food/restaurant reviews are another great source of insight. Combining these, it could be very interesting if (e.g.) Yelp included the most recent food inspection reports for restaurants. Wouldn't you want to know? Fun stuff.

FYI: King County's Public Health reporting system can be found here.

Planck vs WMAP: CMB OMG

2013-03-21T08:42:00.001-07:00

There has been a lot of press and interest today for the first results from the Planck mission. The headlines read "Planck reveals an almost perfect Universe", which I'm sure will finally win the telescope some loving approval from it's high-expectations namesake...

This space telescope is busy measuring the Cosmic Microwave Background radiation, the fleeting thermal glow from the early universe. You can observe a piece of the CMB too - if you have an old TV, just turn it to static. Actually only a few % of that static noise is due to the CMB, but it's fun nonetheless!

When I was an undergrad I thought the CMB map produced by WMAP (the previous big name in this game) was incredible. Here's an animated gif I whipped up this morning comparing the Planck to WMAP results...

Two things stand out to me:

Planck has remarkably better spatial resolution
Planck chose a very different color scheme (smells like Python)

Planck was smart to ditch the gaudy rainbow color scheme. However, neither map does terribly well for colorblind people. Here I've run both the WMAP and Planck CMB maps through the handy online Vischeck tool...

Both these figures also desaturate very poorly to black/white, though the WMAP does a bit better. This is nitpicky, of course, but if you're going to have your results plastered across the world, choose a good color scheme. This is all in loving jest. Congrats to the Planck team on their great work!

Of course, no report of CMB results are complete without this seminal figure...

My Ignite Seattle 19 Talk

2013-03-18T11:24:00.001-07:00

Last month I gave a short talk at a super fun event: Ignite Seattle. If you don't know, Ignite is an awesome ongoing series where people give (hopefully) interesting talks. Each presentation is only 5 minutes and the slides auto-change every 15 seconds. This makes it especially fun and challenging for the presenters!

The wonderful Ignite organizer, Monica Guzman, also interviewed me for the Seattle Times Blog, which also led to a fun radio interview last week! I had a total blast with the Ignite talk. The crowd was about 730 people, and tons of positive energy! I'd love to do another Ignite, maybe next time on astronomy stuff.

I also learned a lot by prepping for this talk. I probably practiced 25 times over a couple days, which I think helped immensely. Everyone should be required to give talks like this where you have no control and no ability to go over time (*ahem* AAS)

Visualizing Devastation

2013-03-15T08:24:00.001-07:00

This week marked the second anniversary of a terrible natural disaster, the 2011 Tohoku earthquake in Japan. We watched the destruction unfold on television, hoping the friends we had in Japan were safe. It was absolutely heartbreaking and stunning to watch.

This earthquake was the 5th most powerful ever recorded (smaller than the 2004 Indian Ocean quake and the 1964 Alaska quake), and had massive after-shocks for months. Here is a very well done visualization that shows all the seismic activity around Japan in 2011

[direct link to video]

I watched this probably 4 times. It's brilliant and sobering. At first the subtle noises associated with each 'quake seem silly and unremarkable. When March 11 hits everything changes, and you're drawn in by sound, the sight, the movement...

The yellow line is the cumulative number of earthquakes per day. Before the big event the line is straight, a roughly constant background of small quakes that are always present in the ring of fire. By the end of the video, this line still hasn't gone back down to the normal flat line, indicating the rate of earthquakes per day is still much higher than before.

All I can say is wow. A beautiful visualization of a terrible disaster.

Rowing Across an Ocean of Contours

2013-03-12T06:30:00.000-07:00

Today I'm very happy to feature a guest post from my friend Angie Pendergrass, a PhD student in the Atmospheric Sciences department here at UW. She's got the mother of all side-projects: using her data analysis and climate modeling skills to help predict ocean currents for a group of ~~crazy~~ brave rowers...

Imagine you're rowing a boat across the ocean. You can't row very fast, just 3 knots if you try your hardest (that's a little slower than walking speed.) You have 4000 nautical miles nautical miles of sea to cover. Scattered across the ocean surface, you know there are some favorable currents and some eddies, spinning whirlpools of water about 50 nautical miles across, with current up to at least one knot. They can help you if you can ride them favorably, or they can suck -- a lot -- if they're against you. You really need to know what these eddies are doing!

Luckily you have a team of weather forecasters and a navigator ashore helping you out. There are actually some guys doing this row, called OAR Northwest. They set out from Dakar, Senegal in late January for Miami, Florida, and now they're halfway across the middle of the Atlantic; check them out at oarnorthwest.com. Your guest-author is their lead weather forecaster.

So now you should be super excited to hear that the National Center for Environmental Prediction (part of NOAA) runs a model of the ocean that diagnoses the ocean surface currents. Great, this is perfect! Let's take a look!

Well, I want to zoom in. I use some matplotlib tools (a python toolbox) - quiver to plot arrows, and contourf to plot filled contours. As it happens, if you just plot the current as a vector with quiver allowing the arrow size to get bigger for faster currents, the plot is nearly unreadable. Using color contours to show current speed and arrows to show direction is nice, I think.

You hopefully see the stars. One of them shows where the rowers are. How am I figuring this out? The boat sends back a data stream of its location and I find the most recent point. It's also really important for forecasting to get an idea of where they will be, for example, tomorrow. I find their location 24 hours ago and plot that. Then I extrapolate that line to project where the boat is headed.

I repeat that for forecast snapshots at every 6 hours out to 72. Then we (my forecast team) look at these plots and send forecasts every day or two, and send a summary to the rowers. Is there an eddy ahead? Will it help or hurt you? Should you go for it or avoid it? It would be kind of miserable for them to row against an eddy, and they may not even be able to make progress. On the other hand, it'd be a shame to miss a nice boost.

Check out this video of the rowers, the chief scientist, and my plots on Canadian TV!

Here's a harder question: are these current forecasts any good? This model was set up focusing mostly on more well-traveled coastal areas. It is probably untested for our purpose. No boats, even sailboats, go at speeds this slow. These currents are unlikely to make much of a difference to most mariners. Of course, oceanographers care, and they set out drifting buoys to measure currents by floating in it that should pick this up. However, this model is initialized from satellites, which should see eddies but won't pick up smaller-scale phenomena that the rowers notice.

So, next time you're setting out to row across the ocean, you'll know to make your surface current maps at a nice scale. And then row, row, row, regardless of what the forecasters tell you.

Stat Trek II - The Wrath of Cant

2013-02-28T08:23:00.002-08:00

Recently the State of the Union speeches were (once again) scrutinized due to their low "reading levels". In an awesome looking figure, The Guardian succinctly demonstrated that the grade levels of these annual addresses were steadily declining over the past century. In simpler terms: the speeches appeared to be getting "dumber". This may be historically due in part to changing American dialects, as well as an evolving style of public speaking. Perhaps "reading level" tests don't always map well to spoken word, and they certainly don't capture the rhythmic or rhetorical value of oration.

cant (noun) | kant | - from Latin cantō: Jargon of a particular class or subgroup.

Last year I looked at the "readability score" for the Star Trek movie franchise. This basically entailed finding the closed-caption transcripts for all 11 films and sending them through an online Flesch-Kincaid Readability calculator. Such calculators use simple formulas based on the # of syllables per word and # of words per sentence to assign an approximate US grade level to the text. Basically, long sentences with big words equates to higher grade levels.

For part 2 in this series, I have examined the reading level for every episode of the Star Trek television franchise! Check it out...

Flesch-Kincaid reading level score for: TOS (yellow), TAS (orange), TNG (blue), DS9 (red), and VOY (green).
Higher grade levels imply more difficulty in readability.

I scripted the grade level calculations using the Natural Language Toolkit (nltk) in Python. This made cleaning the text and breaking up the words and sentences trivial, and I was able to run it on all the closed caption transcripts (over 600 of them!) in a matter of minutes. The grade levels are systematically higher than those found for the Star Trek films, but this may well be due to different programs calculating the readability that could count (e.g.) syllables differently.

The data themselves are cool to look at, and three trends in readability stood out to me:
1) TNG rises over its run
2) DS9 and VOY decrease over their runs
3) DS9 had the lowest scores of any series

To understand why these trends occur it's important to consider exactly how this score is computed, as well as the impact of scoring television with such indexes. The Flesch-Kincaid grade level index is defined as (from wikipedia):

There are only two components to the score: average length of sentences and average length of words. Since this is television virtually all of the words are dialog-based, which typically uses shorter sentences. Secondly, people also don't frequently use 6-syllable words in casual conversation... except in Star Trek!

You see, Star Trek has long been in the business of making science and math cool and accessible. In science we tend to use big words to describe things, often by combining obscure or foreign sounding words. That's just part of the scientific jargon. (Fun fact: the very first class I took in college was titled "Bio-scientific Etymology"). Star Trek naturally imitates this, and characters regularly engage in "technobabble", verbal texture meant to be both descriptive and dense. This adds to the whole futuristic je ne sais quoi, helping to remind the viewer that these people are indeed spacefaring badasses.

So my hypothesis is then: in the case of Star Trek, and maybe sci-fi as a whole, the so-called reading grade level score is driven by the amount of technobabble in a script. In this scenario, we could explain the three observed trends by the nature of the stories being told. For example, consider just Deep Space Nine's slow reading level decay:

Around Season 3 (~1995) the "Dominion War" story line became a (the?) central part of the DS9 plot. As the "War" raged on, the need for tech-heavy scripts with fancy science-talk declined. We instead had loads of (albeit enjoyable) episodes dealing with religion and faith, with war and death, with conflict and humanity. This makes total sense for the Old-West style story being told about a frontier space station/town, which was extremely character driven.

By contrast, The Next Generation and Voyager were both traveling ship-based shows. The action came from the Crew's ability to outwit and out-think new obstacles every week. This in turn often required complex schemes of re-wiring/hacking their ship, and pushing the laws of physics to their apparent limits.

For the curious: the highest grade level episode was "Inter Arma Enim Silent Leges", a timely latin phrase from Cicero, usually rendered in English as "In times of war, the law falls silent". The lowest grade level episode was "It's Only a Paper Moon", probably because of all the singing...

Lastly, given the scrutiny that POTUS has received for his "low-grade speech(es)", I wondered how the people actually felt about the wide range of reading levels in Star Trek. I matched fan ratings (1=worst, 10=best) of DS9 episodes to the readability scores shown above:

The take away result: people don't seem to care much. In other words, higher readability scores don't necessarily translate to more enjoyability. This finally brings me to the title for this article: The Wrath of Cant. Jargon will elevate your reading score, but you still have to tell a good story!

How long do Popes usually serve?

2013-02-12T01:38:00.000-08:00

Yesterday Pope Benedict XVI announced his imminent resignation from the Papacy, to the surprise of millions (if not Billions) of people. His reign as leader of the Catholic church feels very short for two reasons:

1) he is the first Pope for several hundred years to resign
2) his predecessor was the second longest serving Pope in history

For those of us young enough to not remember a time before Pope John Paul II, the 8-year reign of Benedict XVI feels particularly brief. I then wondered: how many years on average does a Pope reign?

The average duration turns out to be... 7.3 years (median of 6 years). Additionally, there's no strong increase in length of reign over time. In other words: despite lifespans increasing, Popes still tend to have a short tenure. It appears Benedict XVI really isn't too far off the average!

I then thought to compare these numbers with another distinguished group of (historically) men: Justices of the Supreme Court of the United States. Fun fact: there have been a total of (including those currently serving/reigning) 113 Supreme Court Judges, 264 Popes. These justices have an average service on the bench of 16.4 years (median 16 years)!

To compare these two populations of people, I have reverse-sorted their durations of service in to cumulative distributions. The way to read this diagram is: 60% of Popes reign 10 or more years, and less than 20% of Popes serve 20 years or more. By contrast, 65% of Justices serve 20 years or more.

Cumulative distribution for the years of service of Popes and US Supreme Court Justices.

Update:
Some people were curious about the raw distributions of Popes vs Justices...

When to find an apartment

2013-02-01T08:59:00.001-08:00

Last September my friend Sarah asked me: "When is the best day to find an apartment in Seattle?"

My buddy John suggested it would be around the 10th of the month, since Seattle's Landlord-Tenant laws dictate that 20 days notice is typically required to terminate rentals. This seemed like a reasonable guess to me, though I imaged there could be an increase towards the end of the month, and possibly a sharp drop at the 1st of each month.

I couldn't find any studies on the topic via Google (please point me to them if you find any!) so it was time to generate some data. I recorded the number of apartment listings for "Capitol Hill" four times a day (7AM, 1PM, 7PM, 1AM) over four months.

Here is the obligatory figure:

Results

No "best" day to find rentals in Capitol Hill every month was found. This is due to longer timescale variations in the number of listings.
Holidays (particularly Thanksgiving and New Years) marked low points in rentals. Nobody wants to move over a holiday weekend...
There was a bump around the 10th each month, except October. The bump is what John predicted.
I posit that the lack of an October 10th bump (in fact it showed a dip!) may be due to academic schedules. Lots of UW students live on Capitol Hill, and UW starts school the last week in September. Much of the rental market is probably tied up then.
The number of Ads varies according to time of day. More rentals are listed at 7PM, fewest at 7AM.
I'm left with lots of questions about the long-term trend in rentals, which anecdotally from this figure I'd say is increasing (Probably the brilliant folks at Seattle Bubble can say more about this. Check their great blog out if you find this kind of stuff interesting, I've been a long time reader)
I also could have (read: didn't) recorded the average price for rentals. That would have been super neat... Someone should do that... oh well!

So Sarah, to finally answer your question, the best time to look for an apartment is in the evening on the 10th of the month, particularly December 10th-12th, but definitely not October 10th.

The Minivan That Could

2013-01-22T06:00:00.000-08:00

Today I'm thrilled to feature another guest post from a friend of mine! Meredith Rawls and I met years ago in San Diego while both getting our masters in astronomy. I remember she drove this great old van around, and swore up and down it was the most reliable car she'd ever known. When she told me recently they had been keeping data on every tank of gas purchased since '96, I was thrilled! Take it away, Meredith!

Way back in 1996, my parents decided to buy a minivan. I was in middle school, so I don’t remember much about the decision-making process, but it had something to do with taking more family camping vacations and wanting a new vehicle that was versatile and reliable. Apparently they did their research, because today I am still the happy driver of a 1996 Toyota Previa with 200,000 miles and counting.

Meredith and her husband with their Toyota Previa at White Sands.
Photo by David Morrison

You’ve probably seen these funny, almost retro egg-shaped minivans now and again. They were only sold in the US between 1990 and 1997, and had a unique mid-engine design. Today, Previas are well regarded as over-engineered proverbial tanks: with regular maintenance and a bit of luck, many survive well into their 300,000s.

Once my family decided on the van, my mom called nearly every Toyota dealer in the state. When they asked her what color she wanted, she replied “anything but plaid!” My dad purchased a little spiral notebook that would live in the glovebox. On the drive home in our new Previa, I remember stopping for gas. Dad broke out that little pink notebook for the very first time and began recording data.

Of course, once you begin taking data every single time you buy a tank of gas, you can’t just stop. He really enjoyed calculating the mileage every now and then, and insisted that my mother also painstakingly record data every time she bought gas. When I got my driver’s license many years later, my handwriting joined theirs in the pink notebook. Eventually the Previa came with me to college in California, and has been with me ever since. Now in New Mexico, my husband drives the van most often and has carried on our slightly-silly tradition of recording miles driven, gallons of gas purchased, and money paid.

One day in 2012, on a long and boring drive to Albuquerque, I decided it was time to do something about all this data. So, I typed it all up (while grumbling about Mom’s handwriting, Dad’s imaginary 25-gallon tanks of gas, my husband’s disregard for lined paper, and my own dyslexia). It actually took that trip to Albuquerque and another to Tucson to enter all 200,000 miles worth of data, and I have a new respect for people who do data entry on a regular basis!

Without further ado: the results!

The Previa's MPG performance has been remarkably stable over time. Large annual dips between 1998 and 2003 correspond with family road trips where we were pulling our pop-up camper. Spikes between 2005 and 2009 are when we road tripped without the camper. There are clearly many, many variables at play here! I was pleased to learn that my van’s average lifetime mileage is 20.42 MPG with a standard deviation of 2.19, while the median is 20.51. (So I’m not lying when I say my van gets better than 20 MPG! Ha!)
[note: the Previa's EPA fuel economy rating is 17 MPG!]

Some key moments in the Previa's MPG history

June 1996, purchased in Spokane WA

August 1998, road trip with pop-up camper to southwestern US

December 2000, rear-ended by a bread truck

July 2002, road trip with pop-up camper to northern CA

May 2005, road trip to southern CA

June 2007, moved to Claremont CA

May 2008, moved to Richland WA

August 2008, moved to San Diego CA

August 2010, moved to Las Cruces NM

May-August 2011, traveled while van stayed parked at home

It is fascinating to see how the price of gas has changed over time. I suspect this is largely influenced by geography, as gas is taxed differently in different states. However, a dramatic drop in price was seen in late 2008/early 2009 while the van was in San Diego. This was a country-wide gas price drop.

There is a clear seasonal trend with mileage, as with all vehicles: they run more efficiently in warmer months and less so in colder ones. There is also a lot of scatter. Some of this may come from errors in data entry (either recording or transcribing), or from not filling the gas tank to the exact same level each time (my dad tends to top off the tank when he fills it, while I prefer let it be done when the pump clicks off). The larger scatter during summer months is mostly due to the aforementioned road trips!

Some of the other variables that contribute to scatter include: highway vs. city driving, running the A/C, individual driving styles (e.g. see Berry 2010), quality/octane of gas in different geographical regions (we always purchase the cheapest regular gasoline), tire pressure, other maintenance-related factors, whether we were towing a pop-up camper (and thus using the “overdrive” setting), how much weight is being carried, humidity and weather… what factors can you think of that affect mileage?

Meredith Rawls is a PdD student in Astronomy at New Mexico State University

Evolution of Cars

Quantified Self

Never take SR 520

Happy MLK Day

2013-01-21T11:23:00.002-08:00

Today is notable for (at least) two reasons:
1) it marks the public Inauguration of President Obama's 2nd term
2) it is Martin Luther King day for America

As someone employed in higher education, and a strong believer in education as the best remedy for our society, I have high hopes that the next four years will see increased attention and passion for education equality.

In that spirit, here's a map derived from a previous article I wrote:

Food for thought: Why are rural colleges/universities more likely to have fewer black students per capita than their state as compared to urban schools?

Good luck, Mr President. I don't envy your job.

1 Year of Blogging

2013-01-19T18:24:00.001-08:00

Today I felt rather proud: my blog turned one year old! The first post was mostly a placeholder, something to get the ball rolling. In it I posed the question: how long does the typical blog last? I still think this would be an interesting problem to gather data on... anyone have a good source of data?

So far If We Assume is a roaring success in my eyes. I've managed to publish about 4 posts per month on average, I've had some notable pickups/press, met some fascinating people, and I feel my blog traffic has been quite good!

A year of traffic on ifweassume.com

The blog itself has changed, grown, and shifted focus. I think it's fascinating to look back at my earlier posts, seeing what worked, what didn't. I definitely wonder: what will my blog look like in a year? What will I be writing about? I'd like to do some more astronomy related posts, and I thoroughly enjoy having guest posts on my blog.

Thanks to so many people for all the awesome conversations, ideas, support, and opportunities! I know Year 2 will be even more exciting!!!

Mapping Constellations

2013-01-16T18:18:00.000-08:00

Astronomers use coordinate systems in the sky to keep track of where celestial objects are; the most common is the Equatorial system. When I teach this, I try to get students to imagine a world globe extended out to the stars. On this globe the constellations look like political boundaries...

Today this got me thinking: what if we laid the 88 constellation boundaries on top of a world map? This is what you get:

It's a cute idea, a bit confusing. Labels are placed at the "center of mass" for each region. Constellations are larger in the north, which I believe is due to historical European bias in defining these regions.

Then I took it a step further and asked: what if we used the constellation boundaries to draw the political lines for our planet?

If the world's political boundaries were drawn using constellations.

FULL RESOLUTION MAP HERE

Some Highlights

There are obvious problems with some of these lines. Antarctica doesn't need so many countries. Africa, Asia, and Europe now have too few. Some of the suggested boundaries/borders are amusing, some bear striking resemblance to historical or cultural lines. Here are three highlights....

Australia, largely unchanged from the 1840's, and strikingly similar to present day! I thought this was funny.

Europe looks a bit over simplified. The British Islands are still divided. The Roman/Catholic nations largely banded together in Europe, and perhaps the Huns stuck around?

North America has a few extra countries now, but overall the results are very interesting! If these constellation were guides that we could move slightly we could get Seattle, Portland and maybe the Bay Area into one incredibly chill state. This would likely be called Cascadia, or maybe Jefferson. Probably Vancouver and Victoria would want in on that. The east coast British colonies are well contained.

[ related external link: The USA redrawn as 50 states with equal populations ]

Canada is largely intact, except the eastern corner near Quebec. I think it's safe to assume this combined Quebec - New Brunswick - Nova Scotia country would speak French! Alaska's main populated areas get their own "New Greenland", or something. I suppose ExxonMobil would own the northern chunk of Alaska... we'll call that "Petrolia".

Accidental Art

2013-01-09T18:31:00.002-08:00

Sometimes the best things in life are free. Sometimes they are pure accidents. In the case of the image below, it's a bit of both!

My good friend, and fellow graduate student, Nick was using a piece of code I had told him about. Alas, I did not tell him about all the settings the code required, and it spit out nonsense. (Sorry Nick!)

But what lovely nonsense it is....

Oops - this was supposed to look more like this, not that

We quickly figured out the error, thankfully, and now his code is off and running. So often little typos can cause your computer to do strange and awesome things. We thought this "error" was beautiful, and worth sharing. Now the repaired code creates a map of the Milky Way in the mid-infrared, which is also beautiful in a different way... and that's how science is done!

What's Trending in Astronomy - #AAS221

2013-01-08T10:56:00.005-08:00

It's that time of year again, when the US astronomers dust off their poster tubes, put batteries in their laser pointers, find their one button up shirt and head to the Winter meeting of the American Astronomical Society (AAS).

Currently it's in Long Beach, CA. While I'm not attending this year, I have been following a lot of the action on Twitter! If you're curious what these mad scientists are discussing, but don't time to read lots of current papers, I turned the entire 297 page abstract book in to a word cloud of the 250 most used terms...

Full resolution version of the word cloud is here!

While this may not resemble what is trending in the media about astronomy, it's neat to see what scientists are discussing amongst themselves. Also, a point of personal pride, stars>galaxies, at least in this diagram.

p.s. I am of course kidding about the one button up shirt remark. Scientists are actually dynamic and attractive folks!

Quantifying Happiness?

2013-01-06T22:04:00.003-08:00

Over the holidays I spent a weekend vacationing in San Francisco with my lovely wife. We had a great time eating and drinking our way around the City by the Bay. I brought back a wonderful souvenir: a tin of excellent coffee beans from one of the many cafes I wandered in to that weekend.

I truly enjoyed the coffee, the simple presentation of the beans in the tin, and the memories of the great breakfast we had at their cafe. (Food/drink is always my favorite souvenir). I enjoyed it so much, I made this silly "graph" charting my happiness as I opened and sampled the coffee a few days before Xmas.

This raised a question in my mind that I invite you, dear reader, to comment on!

Can we really quantify happiness?

In other words, could we actually measure the enjoyment of something as simple as a cup of coffee in real time?

I know research has been done on quantifying pain, and the state of happiness does release lots of unique chemicals into the brain. But happiness is a complex and often subtle emotion. In what way does elation differ from stoic satisfaction?

Of course, I'm not the only one considering such questions. Given how important happiness (and its many variants) is to quality of life, health, stress, and consumerism, I'd imagine it's an important area of research.

It is also a topic of frequent pseudo-charts, like mine above. Here are a few from PhD comics to amuse: Work output vs time, Vacation vs stress, Motivation level vs time. My first officemate in gradschool also once drew "Happiness vs Time in Gradschool". It was an illuminating, albeit somewhat depressing, visualization.

I invite your thoughts, links to relevant literature, or links to other good pseudo-charts on the subject in the comments below!

Visualizing the Evolution of Cars

2013-01-04T23:56:00.007-08:00

From user 27147 on Flickr, Creative Commons licensed, some rights reserved.

I've always been a big fan of cars. Like with sports, cars are a subject for which people love to quantify things. Horsepower, curb weight, engine displacement, top speed, miles per gallon... all of these attributes are carefully measured, graded, evaluated, and play a factor in the car market. In high school I knew every stat for my '87 D50...

When I looked at cars over the last couple decades, the change in one particular attribute stood out to me: cars are getting big! (both heavier and larger) I'm not the only one noticing this, of course, and cars used to be very large. So I asked myself: How have car sizes, and efficiencies, changed with time?

I started by looking at data for one of my all time favorite brands: BMW

Getting Bigger

Here is the curb weight for the BMW 3-series, M3, and 5-series over their entire history. Also shown: the average passenger car from the National Highway Traffic Safety Administration (NHTSA) since the 1950's.

A few things stand out to me: The 3-series seems to follow the typical car trend for most of its life. Also, check out that huge drop in curb weight in the 1970's, due largely to the oil crisis.

Sure enough, the 3-series (and every other car) has been packing on the pounds over the last 20 years. Here's the same kind of diagram for the Honda Accord, also showing the evolution in horsepower:

Source article

Here are both BHP and curb weight since the 1950's. While both curves bottom out at around 1980, the horsepower starts to drop off as early as 1970, while the curb weight takes another 6 or 7 years to drop. The impression this gives me: people were willing to sacrifice power before they gave up luxury,

Getting Stronger

Looking at the horsepower evolution more over time, here I compare the BMW 3-series horsepower to that of the normal car sold in America (again from NHTSA). In this figure I also have the BPA data for median passenger car, which yields a larger estimate for the typical horsepower since ~1999.

For the beginning of its life, the 3-series was a typical sized car with a powerful engine. Mixed with the luxurious interior, this truly was the "Ultimate Driving Machine". Sometime around 1999, however, the BMW became downright average according to this figure. I've heard similar sentiments from people, underwhelmed by the sportiness of the late 90's / early 00's 3-series. After 2010 BMW got back on the "horse", so to speak, and the latest incarnation of 3-series vehicles are absolute beasts!

Getting Better

While cars (and Americans) have been getting bigger for the last 20 years, cars have at least become more efficient... the jury's still out about people. Here is a figure showing the slight increase in fuel economy, despite the increase in curb weight, from 1980 to 2006.

Source article

This got me excited about the actual improvement in cars, beyond the addition of bluetooth syncing and spinners. So using the large database on cars from fueleconomy.gov, I investigated the improvements of cars since the 80's.

Here is a grid of the fuel efficiency for 33,058 cars since the mid 1980's till today. The improvement in MPG has been marginal.

Here now is the correlation between MPG and engine displacement for the same 33k cars. As you expect, the cars with tiny engines get great milage, and the monsters with 6L engines get terrible MPG. The orange line is a power law fit.

Finally, I decided to break this down by year, fitting power laws for cars from each year's data. This produced an awesome result: Cars really are getting more efficient! Despite getting heavier and more feature rich, as well as steadily increasing horsepower, passenger vehicles are getting more efficient!

There's a wealth of information kept about these 33k cars, including the evolution of your favorite brand or model! I'd love to see more analysis of this data. I also have become fascinated with the notion of a principle component analysis (or the like) of the body styles of cars over time, hopefully to quantify the evolution of styles! If anyone has a huge database of clean car photos, I think this would be a super cool project...

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Data Sources

http://en.wikipedia.org/wiki/BMW_3_Series

http://en.wikipedia.org/wiki/BMW_M3

http://en.wikipedia.org/wiki/BMW_M5

http://www.nhtsa.gov/fuel-economy

http://www.nhtsa.gov/cars/rules/CAFE/HistoricalCarFleet.htm

http://www.nhtsa.gov/cars/rules/CAFE/NewPassengerCarFleet.htm

http://www.fueleconomy.gov/feg/ws/index.shtml

http://www.epa.gov/otaq/tcldata.htm

Some similar analysis

http://www.wired.com/wiredscience/2012/08/fuel-economy-vs-mass/

Talk With Your Hands

2012-12-31T09:26:00.001-08:00

In the last few years TED conferences have come to represent the top rung for "intellectual rock stars." What began as a small annual talk series in the early 1990's, has ballooned into an international sensation since they began providing videos online in 2006. It's a remarkable powerhouse that has made data experts like Hans Rosling a household name. TED now comes with legions of fans, people willing to pay several thousand dollars for the privilege of sitting in the audience, a fellowship program (a shining example), and even a "play along in your hometown" version called TEDx.

TED is not without critics, as with all successful endeavors. The founder of TED is no longer involved, and is trying to "reinvent conferences again". Here's an interesting review of the growing "intellectual populism" that TED is contributing to; not necessarily a bad thing, but it's interesting.

One thing that I have taken away from watching a fair number of TED talks since 2006, as well as watching the late Steve Jobs speak, is the value in being a seriously good public speaker. There's a lot involved in making a great talk, from slide design and composition (a recent post I wrote on the importance of contrast in slides for Visually), to speaking tone, pace, inflection, and body language.

Recently I noticed something about the thumbnails shown for TED videos: the frame chosen from the talk seemed to usually feature people gesturing with both hands.

Gesturing with your hands is very normal when you talk, especially when you're giving a lecture or speech. Funny or unusual hand motions when talking can become iconic (I've always loved Dana Carvey's George Bush Sr. impression for this). Good hand motions can even help you convey your authority or confidence when talking, which is absolutely an asset.

I wondered, looking at a few dozen of these thumbnails, how many hands do people typically gesture with in TED talk thumbnails?

So, consumate scientist that I am, I gathered some data!

I pulled up the thumbnail previews for all 1,409 TED videos. For each thumbnail I recorded a 0, 1, or 2, indicating how many hands I thought the person shown was gesturing with. Some frames did not have a person, which was given a 0.

The cataloging was highly subjective (obviously), as well as biased. For example, in some talks people have laser pointers, in others they hold a microphone. In a few they stand behind lecterns, and recently they wear a headset mic leaving both hands free. One could improve the subjectivity by having many people repeat the exercise of choosing [0,1,2] for each frame (Mechanical Turk, anyone?)

Once I had all 1,409 videos pulled up, I could also trivially grab some other statistics. For instance: the median TED talk video is 15:38 long

Also interesting, though not surprising as the TED franchise grows: the rate of TED videos is increasing, with 6.04 being published every week in 2012 on average.

As my initial observation suggested: the most common posture is using both hands to gesture, though it's not an overwhelming majority of frames.

Finally, and most perplexing to me: in 2012 the rate of people using both hands to gesture (again, in the TED video thumbnails) is increasing!

So the message: if you want to be a TED-quality speaker, talk with your hands, both of them even!

A template TED video thumbnail: use both hands when you talk!

That's it for If We Assume, 2012. It's been a wild ride so far, and a total blast. 2013 here I come!

Plots that Changed the World - III

2012-12-28T06:30:00.000-08:00

Today I'm very happy to publish the next installment of my continuing series of posts on visualizations that changed the world. (Part I, Part II) The title is, of course, a double entendre as I'm both reviewing the plots (graphs/maps/diagrams) that are themselves historic or represent key points in history, as well as the "plots" of the story behind them.

Magellan - Traveling the World

As a child, you should come across some variant of this map once or twice. If your childhood was anything like mine, it was sandwiched between boring spelling lessons and unimaginative math quizzes. But, dear reader, ponder for a moment the absolute magnanimity of what these people accomplished. They sailed around the %&@$ planet!!!

The voyage of Ferdinand Magellan, from Wikipedia

To me one of the most interesting lasting bit of history is that the expedition unwittingly discovered the need for the International Date Line. After the numerous deaths (insert more crazy shit here) these guys kept an accurate ships log for over 1000 days. Sometimes I can't even remember what day of the week it is. When they arrived back home, the surviving sailors realized their log was off the local calendar by 1 day. Consider the death, drama, plight, and sheer insanity of the voyage... and they were concerned about 1 day in 1000! Evidently this was an exciting discovery at the time; I find it entrancing to this day.

Oh, and those "Magellanic Clouds" (the Milky Way's satellite galaxies, LMC and SMC), yeah, they discovered those too NBD.

The course they took is roughly the same as the one taken today by sailors, with one small difference. While this map may be simple, there is SO much history that still impacts us today drawn on it. The spread of exploration, so fundamental to human passion, often walks hand in hand with death and disease. Which brings me to my next figure...

The Plague - Infecting the World

Ahhhh yes... the Bubonic Plague. The Great Pestilence. The Black Death.

Spread of the Black Death plague over time

I couldn't think of a more polite way to start a description for one of the most horrible pandemics in recorded history. The above map shows, somewhat confusingly, the spread of the disease as it entered Europe from central Asia. The color scheme is appropriately macabre, but overall this is a terrible graphic. The colors imply to me differing intensities or mortality rates, but the legend indicates they represent time. The arrows convey all the real information here... but now we can do better!

Thanks to the miracle of animated gifs, we can unambiguously describe the progression of The Plague! With the addition of Asia to the map, you really get a sense for how truly widespread this pandemic was. It was not simply European or English history as I was taught in school (though it did wipe out 50% of the English population!) but in fact ravaged large portions of Asia, Africa, and Europe.

Landmarks of Science

I. da Vinci's Anatomy

I have been moved by the work of Leonardo da Vinci since I was a child. My mother took me to see a traveling exhibit of his drawings and designs in Canada. I still remember the exhibit and the wonder I felt from it almost 20 years later (see, exposing your kids to science/history work!)

I couldn't believe --and still can't-- that one man was a cutting edge mechanical engineer, master painter/artist, and student of human anatomy. Genius unparalleled; inquisitiveness unending.

Study of the human arm, c. 1510

It almost seems insulting or trivial to choose this particular image as a visualization that changed the world. In honesty I simply chose one from the Wikipedia page. Almost any of his work would be fitting for this, nearly all of it was revolutionary. Some of it took decades after his death to even be published, though it didn't help that he wrote backwards!

II. Periodic Table

Today the periodic table looks like a silly diagram to many people, hanging like retro wall art in science classrooms. Its easy to forget that this so-called "table" is actually a sophisticated and information dense (if a bit obtuse) masterpiece. I don't know why they're always so hideously colored, though... that's on you to find out.

The modern periodic table of elements

Here's a short article on the history of the periodic table, spanning about 100 years of advances in the fundamental understanding of chemistry. The "table" went thru several iterations before arriving at the "castle-like" layout we know and love, due to the evolving understanding of atoms. Science has the nasty habit of carrying around bits and pieces of old theories or naming conventions. Even when they have been found to be unphysical or plain wrong, parts linger in our scientific vernacular like inactive DNA... Chemistry (like astronomy) is riddled with silly old conventions.

Interestingly, other versions of the periodic table still do exist, but largely today are just visual games. Here's a cool one:

I love this quote I found about the Periodic Table:

"For the first time I saw a medley of haphazard facts fall into line and order." C.P. Snow

III. Darwin's Tree

I came across this understated visualization when reading about Charles Darwin. Evidently, this is the only visualization in his famous book, On the Origin of Species! Given that we're still "arguing" about the merit of teaching this in schools (almost 100 years after the issue famously played out in the courts) this diagram certainly must qualify as one that has changed the world!

From On the Origin of Species.

The figure is also interesting in that it is one of the first tree diagrams. Darwin's early sketch on the subject also pointed towards versions of network diagrams that have become popular today.

An early Darwin "tree"

This whole field of study has given way to a slew of other famous visualizations, such as...

From Thomas Henry Huxley's Evidence as to Man's Place in Nature

(which looks great on T-shirts), and this....

The Pedigree of Man by Ernst Haeckel

and this...

Great minds once again think alike, it seems. I've started to find more people doing posts (or have in the past) like this series. Here's a few that caught my eye...

Diagrams that Changed the World (BBC)
Top 5 Data Visualizations of All Time (Tableau)
100 Diagrams that Changed the World (Scott Christianson via Amazon)
12 Great Visualizations that Made History (Drew Skau via Visually)
Best Data Visualizations Ever Created (from Quora)

[ Related Posts ]

Plots that Changed the World - I

Plots that Changed the World - II

The Chart that Wasn't There

2012-12-27T06:47:00.000-08:00

Hop on over to the Visually blog today to see my guest post:

The Chart that Wasn't There: Avoiding Disappearing Plots in Presentations

You can see my Visually page here, where I post versions of some of the figures that have been featured here on If We Assume.

Thanks to Drew Skau and the great folks at Visually for inviting me to write a piece!

Kepler Binary Clock

2012-12-17T06:19:00.000-08:00

Here's a fun animation I created, artistically visualizing over 1,300 eclipsing binary stars from Kepler.

Binary Clock from James Davenport (or see it on Visually)

Each "hand" represents a binary pair, and each concentric ring groups the binaries by their orbital period. In the center are hundreds of binary systems with orbits shorter than a day (the shortest is just 6 hours!) At the speed of the video, these orbits are a blur. The outer-most hand tracks a binary star system with an orbital period of about 120 days. This is considered quite a long period binary, even though it's 3 times shorter than an Earth year!

Here are some extra details:

Period data from v1.96 of the Kepler Binary Catalog.
Animation is 1500 postscript frames,
converted to png with ImageMagick,
animation made with ffmpeg.
Music: As Colorful As Ever by Broke For Free