Mikhail Popov alerted me to a neat hidden feature of Google spreadsheets: automatic word association. If you highlight two or more related words in a column and then hold down option (or control, on Windows) while dragging down from the corner square, it will fill the remaining cells with words from the same category as the source words you selected. For example, I just tried it with "R" and "SAS" and (mostly) got a list of other computational software:
OK, it gets a but funky towards the end there. It does better generating a list of predictive models given "decision trees" and "linear regression" as root words:
That's pretty amazing. Buzzfeed has a list of other word-association-generated lists, including wine varietals and Star Wars characters. What lists can you generate?
That's all for this week. Have a great weekend, and we'll be back on Monday.
I can barely get my Ar.Drone to land on the box it came on (I am not a good drone pilot), but these quadrocopters from can frickin' juggle (with thanks to Donnie Berkholz):
One small concession to my pride is that they're not being manually operated: check out this post from ETH Zurich's Flying Machine Arena to see the physics and math and vision processing behind the automation that makes it work. How long before there's an all-robot acrobatics show from Cirque su Soleil? I'd totally go see that.
That's all from me this week. Have a good weekend!
While astronomers were waiting for one asteroid to fly by, something much more exciting happened: a different, much smaller rock plunged through the atmosphere over Russia to become a spectacular meteor. Many Russians have dashboard cameras running at all times, so the event was caught hundreds of times on video. Here's one of my favourites: wait a few seconds to see the meteor suddenly appear in the sky and create an impressive train as it streaks by:
Talking Points Memo has a great roundup of other videos, including several of curious Russians filming the train in a serene blue sky, only to be jolted by the sound of the sonic boom created by the supersonic object. (Many people were injured by shattered glass from the boom, not as had been reported, by falling rock.) Phil Plait has some great reporting on the event, including this photo (by Itar-Tass Photos/Newscom) of where the meteorite apparently plunged through the ice of a frozen lake:
While astronomers knew about the flyby of 2012 DA14 ahead of time, this Russian meteor was not being tracked and came as a complete surprise. Just imagine if something like this had happened in a big city like New York! The damage and danger from thousands of skyscraper windows exploding from the sonic boom would catastrophic enough, not to mention the explosion that could occur if a small object like this actually hit a building. That's why it's critical to fund NASA's asteroid-tracking program, not just so we'll know if a dinosaur-killer is on the way, but so we can be forewarned of smaller, but still dangerous, objects like this one in Russia.
Something to think about over the weekend! Have a good one.
If you listen carefully (and read the subtitles), this computer-controlled piano speaks English words in the voice of a child (via ScienceTip):
It's an interesting work of art and a cool (although not exactly innovative) engineering project, but what's surprising to me is not that reproducing a voice with piano keys is possible, but that it does it so poorly that captions are required. Naively, I would have thought that decomposing any waveform into 88 frequencies (or maybe 52 - it looks like only the white keys are used) would reproduce the original sound with decent fidelity, but it seems that's not the case.
Compare this to the way that we represent colours on a computer screen: just 3 frequencies (R, G, and B) are sufficient to represent any real-world colour which is, in fact, a continuous spectrum of frequencies — just like sounds. I know our eyes have just three different types of colour receptors and I'm sure that has something to do with it. Still, colours seem more complex to sounds to me, so this kinda blows my mind.
I used to think I was pretty good at geography. So I thought this Mercator Puzzle, where you just have to move 15 country outlines (out of place, but not rotated) to the actual country locations on the map would be pretty easy. It's not. (Via FlowingData.)
The problem is that this map (like most maps) uses the Mercator Projection to represent a 3-D surface on a 2-D plane. This translation from globe to page distorts country outlines, especially near the equator. That's why most people think Australia is smaller in landmass than the USA, when in fact it's about the same size as the lower 48. (Australia's the easy one to spot in this puzzle -- drag it over the USA to check and see.) When I was at school in Australia we'd often see equal-area Peters Projection maps on the wall (sometimes even with South at the top), but that projection isn't without its own issues.
This version of R.E.M.'s 1991 hit Losing my Religion has been digitally reworked so that the music and lyrics are in a major scale instead of the usual minor scale:
It's amazing how a melancholy ballad is transformed into a hopeful ditty just by shifting the notes a little bit. You can find more songs rescaled like this from Major Scaled's Vimeo page. Something to brighten up your days this weekend -- enjoy! (via Andrew Sullivan)
This video tour of the International Space Station from NASA commander Sunny Williams (via Andrew Sullivan) is just amazing:
I loved, loved watching this -- it made me feel like I was six again, when I wanted to be an astronaut. I hope NASA does more videos like this to inspire more boys and girls to be scientists and aspire one day to float as effortly in Space. Do check it out this weekend if you don't have time right now, seriously it's worth it.
The bit of the video where Commander Williams is in the cupola and watching the surface of Earth glide below made me wonder: just how much of the Earth can you actually see from the ISS? Google searching didn't reveal the answer, but it's just a simple bit of trigonometry, right? (Cue me spending far too long scratching diagrams and equations on paper...) We just need to find the height of the viewable spherical cap, which if my math is right is just h*r/(h+r), where h is the orbit height and r is the diameter of the Earth. (Don't you just love it when all the terms in a complex formula cancel out, and you're left with something simple?) I wrote an R function to calculate the proportion of the surface that would be visible:
visible.surface <-function(r=6378,h=370){# r - radius of planet (default: radius of earth in km)# h - height of satellite (default: mean orbit alt of ISS)## find "x", depth of sperical cap
x <- h*r/(h+r)## ratio of spherical cap, ## 2*pi*r*x, https://en.wikipedia.org/wiki/Spherical_cap## to surface area of sphere## 4*pi*r^2## returned as a percentage
x /(2*r)*100}
The Earth has a radius of 6478 kilometers, and the ISS is in a low-Earth orbit that averages about 370km above the surface. Plugging those numbers in, we surprisingly find that only 3% of the Earth's surface is visible from the ISS at any one time!
> visible.surface(6378,370)[1]2.741553
Running some other calculations,
From the top of the world's tallest building, the 830m Burj Khalifa, you can see 0.0065% of the Earth's surface (about 33,000 square kilometers)
Astronauts on the Space Shuttle (orbiting at 390km) could see at most 2.9% of the surface at a time
GPS satellites (orbiting at 20,200km) have a view of 38% of the earth's surface
The famous "Blue Marble" photograph shows only 43.8% of the Earth's surface
An astronaut on the moon can see only 49.2% of the Earth's surface (and conversely, we on Earth see 49.8% of the Moon's surface)
So it turns out you have to get a long, long way away from Earth until you can get close to seeing a complete hemisphere!
Melbourne's transit operator Metro Trains wanted to create a campaign to get out train safety messages to people who normally wouldn't pay attention to them. They succeeded: this adorably dark PSA (with a song in the style of — but not, as I thought, by — the awesome Of Monsters and Men) was a viral hit, generating more than 35 million views and a worldwide top-10 song on iTunes:
Those Australians certainly have a knack for catchy PSAs. And yet, despite it going viral I nonetheless managed to miss it until it was named Andrew Sullivan's Mental Health Break of the Year.
I wondered at the time how you could make such a video, and the creators have now revealed their secret. It turns out the process is pretty simple:
On a map, draw a circle centered on the target landmark
Using Google Street View, find locations along the circle where the landmark is visible. You'll need around 20 locations, fairly equally spaced around the circle
At each location, take a couple of photos spaced a few feet apart. Each photo should align the landmark with a reference mark in the viewfinder. Using two photos allows the foreground to move in parallax, giving a sense of motion.
Stitch the photos together using PhotoShop. Align the landmark position so that it rotates in place, and add movement blur to the foreground to give a sense of motion.
The whole process is explained in the video below, and demonstrated with Toronto's CN Tower.
Ever wondered what fire is made of? It can be considered to be a plasma: neither solid, liquid nor gas, but a rather a collection of energetic, ionized particles. Stripped of their electrons, these ionized particles give fire some interesting electrical properties:
Enjoy your weekend, and if you're spending it sitting by an open fire, you may be looking at it in a new way.
