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Every month, SCIENTIFIC AMERICAN—the longest-running magazine in the U.S. and an authoritative voice in science, technology and innovation—provides insight into scientific topics that affect our daily lives and capture our imagination, establishing the vital bridge between science and public policy. Key information from this month’s issue: • TECHNOLOGY In cities across the U.S., police are using technology to predict where and when crimes are about to happen. One example is Memphis’s predictive policing system, Blue CRUSH, that has lowered violent and major property crimes by 26 percent and murders by 40 percent, since its launch in 2006....

Electric motors are, without a doubt, a mature technology—more than a century separates Nikola Tesla’s invention of the induction motor and the launch of the Tesla electric car. Even so, there’s still room to make them more energy efficient, to cut their cost of production, boost their resilience, reduce the amount of waste heat they generate and trim their weight. That’s crucial. Not only do electric motors consume half the world’s electricity in powering much of modern life—from fans, compressors, pumps and appliances to the engines of cars and trucks—but better efficiency would also open up exciting new possibilities, such as electrically powered commercial flight....

Sadness. Disappointment. Frustration. Anger. These are some of the reactions from LGBTQ+ astronomers over the latest revelations regarding NASA’s decision not to rename the James Webb Space Telescope (JWST), given that the agency long had evidence suggesting its Apollo-era administrator James Webb was involved in the persecution of gay and lesbian federal employees during the 1950s and 1960s. The new information came to light late last month when nearly 400 pages of e-mails were posted online by the journal Nature, which obtained the exchanges under a Freedom of Information Act (FOIA) request....

Although mutations, the driver of evolution, occur at random, a study of the bacterium Escherichia coli reveals that nature often finds the same solution to the same problem again and again. Over time, random mutations enable organisms to adapt and diversify, often when geographically separated groups of the same species grow better suited to their local environment and less like members of the other group. But that’s not the only way that genetic diversity can arise....

Endless Light In “All the Light There Ever Was,” Alberto Domínguez, Joel R. Primack and Trudy E. Bell discuss measurement of the extragalactic background light, which is made up of all the accumulated light from galaxies throughout the universe’s history. How can that background radiation still be sloshing around? If light travels in a straight line, except for gravitational lensing, why didn’t it become lost long ago? DAVID MARANZ via e-mail In answering the question “Why is the night sky dark?...

Where do our emotions come from? Scientists addressing this long-standing philosophical question recently got some answers by using—bear with us—videos of people licking vomit off their fingers and other revolting scenarios. Human emotions are associated with measurable changes in heart rate, gut motility and sweat gland secre­tions, but some experts have argued that these bodily responses are simply a general stress reaction and therefore cannot account for different types of emotions....

Key concepts Physics Gravity Forces Angle of repose Introduction Have you ever seen video footage of an avalanche or landslide rolling down a hill? Why is it that at one moment everything seems fine then suddenly the mountain begins to slump? This movement has something to do with how the snow or soil is piled up on the mountain. Granular materials such as snow or soil generally pile up relatively well....

When record rains mingled with spring snowmelt in the lower Mississippi River Basin in April 2011, liquid disaster flowed southward and forced some hard choices: The U.S. Army Corps of Engineers blasted a hole in a levee in the river system to save the city of Cairo, Ill., from inundation—at the expense of more than 100,000 acres of farmland. Mandatory evacuations were ordered in Memphis, where floodwaters lapped at historic Beale Street....

Relativity lies at the heart of the most fundamental theories of physics. Formulated by Albert Einstein in 1905, relativity is built on the key idea that physical laws take the same form for any inertial observer–that is, for an observer oriented in any direction and moving at any constant speed. The theory predicts an assortment of well-known effects: among them, constancy of the speed of light for all observers, slowing of moving clocks, length contraction of moving objects, and equivalence of mass and energy (E = mc2)....

Critics have derided the 140-character messages posted daily on Twitter as trivialities. Yet to researchers, the popular social media site presents a rich trove of data. Barbara Poblete and her colleagues at Yahoo Research in Santiago analyzed tweets in the wake of February’s Chilean earthquake to learn how rumors propagate online. They found that people used Twitter to sort truth from falsehoods. Poblete’s group saw that 62 percent of tweets with earthquake-linked keywords from users in the Santiago time zone questioned or denied rumors that later turned out to be false....

After I hit middle age, I noticed that printed words on a page didn’t look as crisp as they used to. Like many people, I’ve been wearing reading glasses ever since. But one day recently I squeezed a few drops of a new prescription drug into my eyes instead. A few minutes later, the text in front of me was clearer and more sharply focused. But I also noticed the shared kitchen in my office suite was strangely dim, even with the lights on....

So what is a quantum eraser actually erasing? This question is addressed in some detail in two articles from 1999 and 2004 that one of us (Kwiat) coauthored. The conclusion of those investigations was that the phenomenon that everyone calls quantum erasure would perhaps more accurately be described as quantum editing. The point is that the final analyzing element filters all of the events into two groups and one can choose to do that filtering in different ways....

Scientific American presents Everyday Einstein by Quick & Dirty Tips. Scientific American and Quick & Dirty Tips are both Macmillan companies. Last week, I went on a three-mile bike ride with my kids. We were on our way home when the skies started to look dark. We weren’t worried however, because it was only 3pm and the weatherman said it wouldn’t start raining until after 7pm and even then we could expect just some light showers....

Warm, dry winds sweeping across Antarctica can temporarily cause extraordinary melting events. Known as “foehn” winds — from a German word often translated as “hair dryer” — they pack a major punch, even during the frigid fall and winter months. It’s a natural phenomenon, periodically occurring in various regions of the ice sheet. But some researchers say continued climate change could alter some of the atmospheric circulation patterns driving the winds, potentially causing them to occur more frequently in the future....

And then there were five. Five privately funded teams have secured verified launch contracts to blast their robotic spacecraft toward the moon, keeping them eligible for the $30 million Google Lunar X Prize (GLXP), contest organizers announced today (Jan. 24). The remaining teams are Florida-based Moon Express, Israel’s SpaceIL, India’s Team Indus, Hakuto of Japan and the international outfit Synergy Moon. Eleven other teams had been in the running, but they failed to lock up a verified launch deal by the deadline of Dec....

Call it getting in your own way, call it self-defeating behavior, call it accidentally-on-purpose shooting yourself in the foot. Whatever you call it, if you have a goal, you can make sure it doesn’t happen with self-sabotage. Self-sabotage is any action that gets in the way of achieving your goals. On a diet? Kids’ pizza crusts have no calories if they’re inhaled standing over the sink, you know? Want to rock your work assignments and get that promotion?...

A new plant is rising from the fields around Emmetsburg, Iowa—one that will ferment into ethanol the cobs, stems and husks of corn from nearly 50,000 hectares of farmland. Such cellulosic ethanol offers a way to get the energy and environmental security benefits of biofuels without disrupting the food supply when the edible corn itself is used. “The facility will be operational in 2014,” says Jeff Lautt, chief executive of Poet, LLC, one of the largest brewers of ethanol in the U....

A study published last week in the journal Stroke found that drinking even one can of diet soda a day triples your risk of dementia. Not surprisingly, this caused quite an uproar. Sharyn posted her concerns on the Nutrition Diva facebook page: “I’m disturbed by a report I heard yesterday about a possible link between artificial sweeteners and dementia. I’m reluctant to stop using artificial sweeteners on the basis of a single study....

KUTA, Albania—Taulant Hazizaj, a cage fighter turned environmentalist, stands on a browning hillside overlooking his extensive olive grove and the sweeping braids of the Vjosa River, watching as two workers scrape a small circle around the base of each tree, readying them for a new drip-irrigation system. Soon, though, too much water might be his problem because the Albanian government looks to implement a plan to build an enormous dam just downstream....

Hurricane Alex rumbled through the Gulf of Mexico recently, disrupting efforts to capture or clean up the oil gushing from BP’s Macondo well and giving a preview of what a powerful tropical cyclone might do at the ongoing environmental disaster. With everyone from the U.S. National Oceanic and Atmospheric Administration (NOAA) to Columbia University scientists predicting that this year’s hurricane season will be more active than normal, Alex is likely to foreshadow disruptions to come....