In a previous post I described mathematicians’ ongoing search for key properties of prime numbers. That effort may seem to belong entirely within the realm of pure mathematics; but surprisingly, the importance of primes goes far beyond the abstruse obsessions of ivory-tower mathematicians. In fact, the use of prime numbers underlies some of the most dramatic events in the news these past weeks: the story behind Edward Snowden’s revelations that the National Security Agency (NSA) is snooping on the communications of both American citizens and European diplomats.
While the Europeans have protested about their internal communications being intercepted by the NSA—ironically—the tools that one can use for protection from spying by anyone are readily accessible online, in the professional literature, and in publicly-available manuals and textbooks. These methods all rely on clever uses of prime numbers.
The essentials of these techniques are far from new. The foundations of a program to create codes so powerful that they could not be broken even if an eavesdropper were to use the entire available worldwide computing power were laid more than 35 years ago. The year 1976 saw the development of the Diffie-Hellman key exchange method (named after Whitfield Diffie and Martin Hellman; the names Ralph Merkle, James Ellis, Clifford Cocks, and Malcolm Williamson are often also associated with it); and the following, 1977, witnessed the appearance of the RSA algorithm. Both methods have advanced over the past three and a half decades, but information about their extensions is also readily available to anyone.
How do these techniques work? I will explain both methods here—necessarily in a simplified way. (Those interested in learning more can read some of the articles in the links that appear throughout this post.)
Mathematically, the Greco-Roman-Etruscan number system is an endlessly repetitive number system that is inefficient and cumbersome. To write 3333, which we do by repeating the sign 3 four times, a Roman would have had to scribble down MMMCCCXXXIII—three times as many characters. And I challenge anyone to multiply this number by MMDCCCLXXIX—using only the Roman system (meaning without translating these numbers into what they would be in our base-10 number system and then back into Roman numerals). Surprisingly, this clunky old Roman number system, with its ancient Greek and Etruscan roots, remained in use in Europe until the thirteenth century!
Our base-10 system derives its power and efficiency from the fact that we use a zero. The zero here is not just a concept of nothingness (and something every schoolchild learns you are forbidden to divide by), but also a place holder. The zero is a sign we place in a location in a number when there is nothing there—to tell us, for example, that 40 means four tens and no units, or that 405 is four hundreds, no tens, and five units.
From the hidden life of microbial ecosystems, to cybercrime, to the long chain of consequences set into motion by not washing your hands after using the toilet, Thursday’s TED 2013 spotlight illuminated the unseen systems of our world that impact all of us, sometimes fatally.
“Diarrhea is a weapon of mass destruction,” declared Rose George on TED’s main stage Thursday afternoon.
George is on a crusade for better sanitation, which has brought her from India to Africa to the tony conference space at Long Beach, where she pointedly noted she’d washed her hands after a trip to the toilet. George told the audience that though diarrhea kills a child every 15 seconds and can be easily and cheaply prevented, it rarely receives the attention given to diseases such as malaria, which kills fewer people per year.
George’s book The Big Necessity wades deeply not only into the dangers of poor hygiene but the benefits of waste if managed correctly: “Waste is a resource that we’re wasting,” said George, who added fecal matter can be an “inexhaustible and infinite” energy source.
Spend a few minutes chatting with Taylor Wilson and three things will happen: You will feel old. You will feel dumb. You will feel like you’ve squandered your life.
Wilson, who first garnered fame as the kid who built a nuclear reactor in his Reno garage, told the crowd gathered to hear him Wednesday at TED2013 that he’s left his first love, fusion, for a fling.
“I’m really into fission now,” declared Wilson, still in his teens. “Is fission played out or is there something left to innovate there?”
Wilson’s fission flirtation has led him to develop a compact molten salt reactor that he says needs refueling only once every 30 years, and “loves to eat downblended uranium.” Because much of the reactor is buried and its uranium is not weapons-grade, Wilson added, it’s less vulnerable either to terrorist attack or misuse.
While his talk on Wednesday’s main stage in Long Beach was as polished as entrepreneurs three times his age, it was when I sat down with Wilson later in the day that I found myself thinking: I just hope he uses his powers for good.
A spark. A vision. A lightbulb over the head.
These are the ways we often define that moment of creative inspiration that puts us on a path of making something, whether it’s a knitted iPad case (see Etsy for more examples than you might expect) or something slightly loftier, such as a global education system.
Dr. Sugata Mitra, announced Tuesday as the winner of the 2013 TED Prize and the $1 million that comes with it, had that a-ha moment when he was watching children in a Delhi slum learn, and teach each other, how to use a computer he’d put in a kiosk on the street with no instructions. The Hole in the Wall experiment led Mitra to develop SOLE, Self-Organized Learning Environments, and, eventually, his current project, the School in the Cloud. Mitra believes children can learn even complicated ideas and find elegant solutions when they work collaboratively and organically, without rote exercises, unforgiving evaluation tests and guided adult instruction.
“The teacher sets the process in motion, then stands back and lets the learning happen,” said Mitra, addressing the Long Beach audience at TED2013 after his win was announced. “And then admires the answer.”
Asked to describe the five senses, most of us can rattle them off without hesitation: sight, sound, smell, taste and touch. But what do those words mean, and do they mean the same thing to every person?
Take sound, for example. Randall Poster, who has worked as a music supervisor on movies ranging from School of Rock and Velvet Goldmine to Moonrise Kingdom, believes the inherent audience experience of a score or soundtrack has changed.
While researching music for the HBO series Boardwalk Empire, Poster unearthed a treasure trove of “photoplay music,” sheet music written for the musicians performing live at local nickelodeons in the silent film era. The titles of photoplay compositions—“In a Merry Mood” and “Agitato Mysterioso,” for example—reveal the emotional response from the audience that the music would provoke. It’s a response, however, that makes assumptions about its audience’s culture.
“Music renders the collective psychology of the moment, of the human condition,” said Poster, speaking at a seminar Monday at the TED2013 conference in Long Beach, Calif. “But what sounded suspenseful in 1920 may not sound suspenseful today.”
Pete Etchells is a lecturer in biological psychology based in Bristol, UK. He writes about science in the news at Counterbalanced, but secretly wishes he were an astronaut. You can find him on Twitter at @drpeteetchells.
I’m never taking a photo of myself and sticking it up on Facebook ever again. How could anyone possibly contemplate it, when they’ve got to compete with self-portraits like this one? Thanks NASA.
Really, there’s so much awesomeness in this photo. It’s a picture of a robot, taken on another planet. A freaking robot! On another world! Evidently though, not everyone shares this sense of wonder. At around the same time that Curiosity was taking pictures of itself, Felix Baumgartner was being interviewed by the UK’s Telegraph, and had this to say:
“I think we should perhaps spend all the money going to Mars to learn about Earth. I mean, you cannot send people there because it is just too far away. That little knowledge we get from Mars I don’t think it does make sense.”
Disheartening words from someone who you would think would share so much in common with the Mars exploration mission, given his recent space jump. Baumgartner’s words completely miss the point, because Curiosity’s story isn’t just about what happens on Mars. It’s also about what happened on Earth before it left, and what is still happening now. It’s the story of extraordinary life-saving technologies, like heart pumps and advances in drug treatments, but it’s also the story of ordinary, everyday things like mattresses, hockey sticks and baseball bats. These are technologies that NASA and its offshoot companies never originally set out to develop; instead, they were born out of ingenious solutions to practical problems faced in the space program.
Mark Changizi is an evolutionary neurobiologist and director of human cognition at 2AI Labs. He is the author of The Brain from 25000 Feet, The Vision Revolution, and his newest book, Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man.
There are few things more romantic than being a discoverer, whether it be Captain James Cook’s Sandwich Isles or Alvin Roth’s and Lloyd Shapley’s recent-Nobel-winning work on stable allocations. And the excitement exists even among us regular-folk scientists—our discoveries may not be of the magnitude of Sir Alexander Fleming’s penicillin or Einstein’s special relativity, but we bask away unheeded. “Dear world, here is my beautiful solution to the puzzle.” Not only is the solution typically beautiful—that’s often what makes a good discovery “good”—but it is packaged into elegantly-written journal articles or glossy books. On the basis of the splendor of our discoveries, laymen might wonder whether our minds are beautiful as well.
Far be it from me to debunk the mythical, magician-like qualities sometimes attributed to us scientists, but the dirtiest little secret in science is that our science minds are just as dirty and unbeautiful as everyone else’s… and this has important implications, both for aspiring students and for how science is funded. I’ll get to these later.
Now, it’s not that the entire scientific process behind discovery is ugly. Much of it is elegant. Good experimental design, valid statistics, analyses of hypotheses—there are sound principles guiding us, the same ones we teach our students.
But where we see the everyday-ness of our science minds is in the discovery process itself, that is, in the efforts to find the new idea (hypothesis, theory, whatever) in the first place. Discoveries can be dressed up well, but the way we go about finding our ideas is almost always an embarrassing display of buffoonery.
Mark Changizi is an evolutionary neurobiologist and director of human cognition at 2AI Labs. He is the author of The Brain from 25000 Feet, The Vision Revolution, and his newest book, Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man.”
The silent purr of an electric car is a selling point over the vroom of a gasoline engine, but it comes with an undesirable side effect: An electric car can pounce on unsuspecting passerbys like a puma on prey. In fact, the NHTSA found that hybrid electric cars are disproportionately dangerous to pedestrians. To deal with this problem, it has been proposed that sound be added to hybrid and electric vehicles, whether it be bird-songs or recordings of someone making “vroom vroom” sounds.
In this light, I wondered whether it might be possible to add “smart sound” to these dangerously quiet cars destined to rule the road in the near future. The solution, I realized, might come from faster-than-light-speed objects on the moon. I’ll get to this crazy-sounding part in a bit.
The Melody of Movement
In setting out to solve this problem, I reasoned that when electric cars are moving very fast they make enough sound to be heard due to the rumblings of the car parts. It’s when they’re moving at lower speeds that they’re most perilous, because at these speeds they’re most silent. Therefore, if electric cars are to be fitted with some sound, it should be designed to work even at lower speeds—or, especially at lower speeds.
Next question was, What sort of sound do we want on slowish, stealthy electric cars? To answer this, it helps to grasp the sorts of cues your auditory system uses for detecting the movement of objects in your midst.
The most obvious auditory cue is that nearer objects are louder, and so when you hear a moving object rising in loudness, you know it’s getting closer.
But that’s not the most important auditory cue. To illustrate why, imagine walking along a curb with traffic approaching and passing you from behind. The important observation here is that when this happens you aren’t in the least worried. Even without seeing the car, you know it’s merely passing you despite the massive crescendo in its sound. Why?
The Doppler shift changes the observed pitch of the siren as the car moves.
You know the car isn’t going to hit you because of its pitch. Due to the Doppler shift, this car has a falling pitch, and this falling pitch contour tells your brain unambiguously that, although the car is going to get arm-reachably close, it is going to pass you rather than collide with you. If it were going to collide with you, its pitch would be high and constant—that’s the signature of a looming collision.
Neuroskeptic is a neuroscientist who takes a skeptical look at his own field and beyond at the Neuroskeptic blog.
Life is dominated by the Earth’s cycles. Day and night, spring and autumn, change the environment in so many ways that almost all organisms regulate their activity to keep up with time and the seasons. Animals sleep, and many hibernate, moult, and breed only at certain times of the year. Plants time the growth of seeds, leaves, fruit and shoots to make the most of the weather.
But what about humans? We sleep, and women menstruate, but do other biological cycles affect our behavior? The Internet has offered researchers a unique resource for answering this question.
For example, according to research published recently in the Archives of Sexual Behavior from American researchers Patrick and Charlotte Markey, Americans are most likely to search for sex online during the early summer and the winter.
The authors looked at the Google Trends for a selection of naughty words and phrases, and this revealed a pretty marked 6 month cycle for searches originating from the USA, with two yearly peaks in the search volumes. The words were related to three categories: pornography, sex services (e.g. massage parlors), and dating websites.
Google Trends searches for pornography-related words over time
This image shows the graph for pornography searches—the grey line—with an idealized six-month cycle also shown for comparison, the black line. The data show a strong twice-yearly peak. The picture was similar for two other categories of sexual words: prostitution and dating websites.