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Homo sapiens sapiens has spread across the globe and increased vastly in numbers over the past 50,000 years or so—from an estimated five million in 9000 B.C. to roughly 6.5 billion today. More people means more opportunity for mutations to creep into the basic human genome and new research confirms that in the past 10,000 years a host of changes to everything from digestion to bones has been taking place. “We found very many human genes undergoing selection,” says anthropologist Gregory Cochran of the University of Utah, a member of the team that analyzed the 3....

The universe is getting bigger every second. Galaxies are flying apart from one another, clusters of galaxies are zooming away from other clusters, and the empty space between everything is growing wider and wider. This much was known since the 1920s, when observations by Edwin Hubble and others revealed that the cosmos is expanding. But more recently, astronomers found that the process is speeding up—the pace of the expansion of the universe is rising, so that galaxies are receding from one another faster now than they were a moment ago....

Tracking endangered orangutans was no easy feat a scant three years ago. It required counting treetop nests in places like the Leuser Ecosystem on Indonesia’s Sumatra Island to gauge the health of a population that was under fire from poachers and palm oil barrens. Aerial surveillance using remote sensing satellites was often too expensive for local conservation groups and, even when affordable, the views were routinely obscured by cloud cover. “I was thinking it would be a lot easier if we had a camera somewhere up in the sky that would take pictures of the canopy of the forest and allow us to determine where orangutans are and how many there are,” says Serge Wich, a primate biologist at Liverpool John Moores University and an expert on orangutans....

For billions of years, the history of life has been written with just four letters — A, T, C and G, the labels given to the DNA subunits contained in all organisms. That alphabet has just grown longer, researchers announce, with the creation of a living cell that has two ‘foreign’ DNA building blocks in its genome. Hailed as a breakthrough by other scientists, the work is a step towards the synthesis of cells able to churn out drugs and other useful molecules....

GRENOBLE, FRANCE; AND PARIS—James Clark arrived at the foot of the French Alps in the midst of a historic heat wave. It was a fitting welcome, given his work. The Duke University professor is one of 43 scientists who are relocating their climate research to France as part of the “Make Our Planet Great Again” initiative, or MOPGA. Launched by France in response to America’s withdrawal from the Paris climate agreement, MOPGA aims to draw top scientists from around the world to conduct climate-related research in French and German labs....

While the COVID-19 pandemic continues to rage around the world, another disease could be on its way out. Only 14 cases of infection with Guinea worm—a parasite that causes painful skin lesions—were reported in humans in 2021. This is the lowest tally ever for an infection that, as recently as the 1980s, was found in more than 20 countries and infected 3.5 million people a year (see ‘On the way out’)—however, a remaining reservoir for the parasite in animals means eradication could be a while off, if indeed it is possible, say some scientists....

Key concepts Mathematics Patterns Interference Optical illusion Introduction Have you ever wondered why our eyes are drawn to patterns? We see patterns in art and music, and also in our daily lives. Patterns can provide a sense of order and can make a hectic-looking world a little more manageable. They are the basis of many assumptions and predictions. We assume we will have lunch at noon if that is what we always do....

It began last October, with a simple mosquito bite on the Caribbean island of Saint Martin. With that itch-inducing nip from an infected mosquito, a disease known for causing patients to stoop over in pain made its first locally acquired appearance in the Western Hemisphere. By mid-December, two dozen cases of the viral disease had been confirmed. More than 1,000 cases have since scattered across the Caribbean isles, inching ever closer to the U....

For a second time, NASA has decided not to rename its flagship James Webb Space Telescope (JWST). The decision follows a historical investigation into the telescope’s namesake, a former NASA administrator who held high-ranking government positions at a time when the United States systematically fired LGBT+ employees for their sexual orientation. Many LGBT+ astronomers and other scientists have spoken out against having Webb’s name on the telescope, saying the association perpetuates a dark and hateful period in American history....

This week Arkansas became the first state to ban physicians from giving hormones or puberty-delaying drugs to transgender people under age 18. Doctors who do so could be stripped of their licenses and sued. The law is called the Save Adolescents from Experimentation (SAFE) Act. It became official on Tuesday afternoon, when the state’s Republican-controlled legislature voted to override Governor Asa Hutchinson’s attempted veto. Nineteen other states have introduced similar legislation, and some of the bills outline strict penalties....

On July 17, a high-ranking official at the U.S. National Institutes of Health (NIH) pulled the plug on a hotly anticipated clinical trial for a government-funded vaccine to combat human immunodeficiency virus (HIV), the bug that causes full-blown AIDS. The announcement by Anthony Fauci, director of the NIH’s National Institute of Allergy and Infectious Diseases (NIAID), was the latest in a series of setbacks in the search for a vaccine the world has been anxiously awaiting for more than two decades....

Lay down some hot black stuff, and you’ve got a road, right? Not quite. Much more is hidden underneath. Terminology explains a lot about road construction. Scottish engineer John McAdam is generally credited with designing in the early 19th century the first modern roads made by compressing thick deposits of crushed, angular stones. Builders later poured hot tar to bind the top layer, producing a “tarmacadam” pathway, or tarmac. Although this term lingers, the method has not been used for decades (not even at airports)....

The protein family notorious for causing neurogenerative diseases such as Creutzfeldt-Jakob—not to mention mad cow—appears to play an important role in healthy cells.* “Do you think God created prions just to kill?” muses Eric R. Kandel of Columbia University. “These things have evolved initially to have a physiological function.” Kandel’s work on memory helped to reveal that animals make and use prions in their nervous systems as part of an essential function: stabilizing the synapses involved with forming long-term memories....

“The heat has been and continues to be a factor in drought expansion,” Brad Rippey, a meteorologist with the U.S. Department of Agriculture and this week’s Drought Monitor author, told Climate Central. New information coming in about reservoir levels, stream flows and groundwater pumping prompted Rippey to increase the amount of California covered by exceptional drought to 58 percent from 34 percent (all of the state is in some level of drought)....

Sen. Marco Rubio disputed the idea that he’s a climate skeptic in the second GOP debate, asserting instead that he opposes policies to reduce emissions if they burden the U.S. economy while failing to affect global temperatures. “America is not a planet,” said Florida’s Rubio. The interaction occurred 149 minutes into the three-hour program, drawing in several candidates who repudiated the idea of enacting an “insurance policy” to guard against the risk of sea-level rise and other impacts of planetary warming....

It can fairly be said that modern psychiatric diagnosis was “born” in a 1970 paper on schizophrenia. The authors, Washington University psychiatry professors Eli Robins and Samuel B. Guze, rejected the murky psychoanalytic diagnostic formulations of their time. Instead, they embraced a medical model inspired by the careful 19th-century observational work of Emil Kraepelin, long overlooked during the mid-20th-century dominance of Freudian theory. Mental disorders were now to be seen as distinct categories, much as different bacterial and viral infections produce characteristic diseases that can be seen as distinct “natural kinds....

The following essay is reprinted with permission from The Conversation, an online publication covering the latest research. Do you find yourself worried by the implications of Humans, Channel 4’s new drama about the exploits of near-human intelligent robots? Have you ever fretted over the apocalyptic warnings of Stephen Hawking and Elon Musk about the threat of superintelligent artificial intelligence? Have your children ever lay wide-eyed thinking aboutrobot drone armies, such as those in Marvel’s film Avengers: Age of Ultron?...

“The advocate of industry and enterprise, and journal of mechanical and other improvements”: that mission visually underscored the logo of our very first issue, dated Thursday, August 28, 1845. In the latest installment of Scientific American’s delivery on that promise, we bring you this month’s cover story, “Top 10 Emerging Technologies of 2018,” a collaboration between Scientific American and the World Economic Forum’s Expert Network. What’s an “emerging” technology? It must be a potentially disruptive solution that is poised to change the world....

In the world of electronics, the term “aspect ratio” refers to the shape of your screen. Today’s high-definition television picture has a 16:9 aspect ratio—a rectangle with those proportions. The older, standard TV picture had a 4:3 aspect ratio—not quite square but squarish. Films, IMAX movies and photographs all have aspect-ratio standards of their own. This cacophony of conflicting shapes can lead to some ugly results. Remember watching widescreen movies on standard TVs?...

Mitochondria, the organelles known to every junior high school student as “the powerhouses of the cell,” go back some two billion years. Although these energy producers were identified in the 1800s, how they became fixtures in cells is still under debate. Mitochondria’s ancestor was a free-living bacterium that another single-celled organism ingested. Most biologists think that the bacterium benefited the host: in one hypothesis, these premitochondria supplied hydrogen to make energy....