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As social animals, humans tend to form groups that can range in size from a few individual members to entire nation-states. Historically and through the present day, human groups frequently come into conflict. A noted feature of human intergroup…

Humans have used dried bovine dung (manure) as a fuel source since prehistoric times. In India, for example, many people burn cow or buffalo dung for cooking fuel. This bioresource provides a low-cost fuel as well as an efficient means of waste…

Wind-pollinated plants—including trees, grasses, and weeds—produce most of the pollen that affects seasonal allergy sufferers. Wind-pollinated plants produce great amounts of pollen grains that are very small in size. For example, one ragweed plant…

Neuroscientists have long sought to explain how the brain correctly recognizes a stimulus despite the stimulus appearing under different circumstances with widely variable external factors. For example, with regard to olfactory stimuli, humans can…

Renowned as adept fliers and as some of the first insects to have ever developed wings, with a fossil record going back more than 300 million years, dragonflies (class Odonata) have long interested scientists across interdisciplinary lines. A recent…

Researchers are learning more about how plants respond to "alarm signals" released by other plants that are under attack by herbivores. To warn conspecifics about predators, many animals issue alarms by vocalizing or emitting odors. In the case of…

Studies have shown that all classes of vertebrates—and even some invertebrate species—have the cognitive ability to discriminate among different quantities. For example, many kinds of studied animals can distinguish specific numbers of objects in…

Food packaging prevents contamination and extends the shelf-life of food products, making food safe and available to the public. Common food-packaging materials include metals, glass, paper, and plastics. Of these, metals, glass, and recyclable…

To bolster food security in a warming world, engineers are developing a coating that could better protect seeds, such as beans, from drought in semiarid regions. The coating mimics a mucilage-based hydrogel produced naturally by some seeds, such as…

Genealogists and anthropologists have long disputed the provenance of domestic dogs (Canis lupus familiaris). Although genetic analyses and fossil evidence indicate that the domestic dog descended from the gray wolf (Canis lupus), the exact location…

Food waste occurs at all levels of the supply chain and beyond, from farm to table, for reasons ranging from spoilage to over-buying. The U.S. Department of Agriculture’s (USDA) Economic Research Service defines food waste as “the edible amount of…

Approximately 75% of flowering plants—including about a third of agricultural food crops—depend on the distribution of pollen by an array of animals known collectively as pollinators. These animals include insects such as bees and wasps…

Pasta comes in various sizes and shapes, ranging from long and flat (such as linguine and spaghetti) to short types in the shape of shells (conchiglie), corkscrews (fusilli), and many others. Shaped pastas contain a larger volume of air, resulting…

Black holes pack an extraordinary amount of mass into a small spatial volume, resulting in gravitational fields so powerful that not even light can escape. These extreme objects occur as two distinct populations in the universe. The first, called…

In a potential watershed moment for physics, the first results from the Muon g-2 (pronounced gee minus two) experiment have strongly indicated that particles called muons deviate from precise predictions of their behavior in the standard model of…

The diverse totality of microorganisms regularly found on and in the human body is collectively referred to as the human microbiota or microbial flora, with the largest microbial community in the body residing in the large intestine, or colon.…

In the future, will global demand for coffee outstrip supply? The International Coffee Organization thinks so, based on droughts in Central America, crop-destroying freezing weather in Brazil, and global climate change. In general, coffee is a very…

A new mathematical approach called emulation dramatically decreases the amount of time necessary to solve equations describing key properties of atomic nuclei. The approach will help physicists run simulations far more quickly—and without the need…

According to the Intergovernmental Panel on Climate Change (IPCC), to avoid the major impacts of climate change, such as deadly heat and decreased crop yields, will require limiting global warming to a maximum increase of 1.5 to 2.0 degrees Celsius.…

Alpha particles, consisting of two protons and two neutrons but no electrons, are abundant in nature as radioactive decay products of heavy elements and familiar to us for the health risks they pose. Yet despite more than a century's-worth of…

Forest fires are becoming more problematic across the globe. For example, climate change has extended fire season in the United States by about 80 days since 1970 because of extreme weather events, such as prolonged drought, according to the U.S.…

For the first time, researchers have used the spin rates of black holes in the wide-ranging and ongoing search for dark matter. A recent study proposed that if a certain kind of dark matter particle, known as an ultralight boson, existed in a…

A new study has offered a possible explanation for a mysterious drop in brightness exhibited by the star Betelgeuse, an event known as the Great Dimming. Betelgeuse is an aged, red supergiant star located relatively close to Earth and readily…

Particle physicists have reported the likely first-ever sighting of a long-theorized subatomic process known as a triangle singularity. The process involves a pair of particles, called kaons, exchanging one of their two constituent particles before…

The discovery of gravitational waves in 2015 revolutionized astronomy by opening up an entirely new way of studying extreme cosmic phenomena. Now researchers have reported the first evidence for a previously theorized but never-before-seen kind of…

Astronomers have found oddly synchronized star formation rates in 36 dwarf galaxies scattered around the Milky Way Galaxy. These dwarf galaxies all showed declines in star formation rates starting around six billion years ago, and then showed…

After a 203-day journey covering 472 million kilometers (293 million miles), NASA's Perseverance rover successfully landed on Mars on February 18, 2021. Perseverance is the largest and most sophisticated machine to ever land on another world.…

Scrap tires are a common waste material, although markets do exist. According to the U.S. Tire Manufacturers Association, of the roughly 270 million scrap rubber tires generated each year in this country, about 100 million tires are used as fuel;…

In 2012, Voyager 1 became the first humanmade object to leave the solar system when the space probe traversed the heliopause—the boundary at which the outflow of plasma from the Sun, known as solar wind, gives way to the collective solar winds from…

Ample evidence—from lake-, river-, and delta-like geological features to aqueous mineralogy—supports the inference that Mars once had vast quantities of water pooling and flowing across its surface. A longstanding question has centered around what…

Wildfires are a natural phenomenon in many ecosystems, including forests along the U.S. Pacific West Coast, as natural fires serve to rejuvenate ecological communities. However, from mid-August through mid-September 2020, forests in California,…

Cosmochemists have discovered the oldest solid material known to exist on Earth. The material, stardust, consists of silicon carbide grains measuring around one micrometer in size. The grains date back approximately 7 billion years, or about 2.5…

In September 2020, researchers answered a longstanding question about why planetary nebulae display such a rich variety of shapes. Winds from aging stars produce planetary nebulae as the winds eject the stars' outer layers, shrouding the stars in…

Wildfires, also termed bushfires or forest fires, are currently devastating large swaths of land in Australia. Detrimental ecologic consequences of these uncontrolled combustions of forest fuels and vegetation are numerous. One of the most serious…

The American beech (Fagus grandifolia) is native to forest regions east of the Mississippi River and is a key tree species in the United States. In particular, it is very abundant from Ohio to the New England states. The tree is also found in the…

Many questions concerning the sustainable production of biofuels have emerged over recent years in terms of land and water use, pollution from fertilizer and pest-control chemicals, greenhouse-gas production, net energy production, and whether…

The nearest images of the Sun obtained to date have revealed a new phenomenon, dubbed campfires, which appear as small, bright flickers of light all over the Sun's surface. The Solar Orbiter, a European Space Agency spacecraft launched in February…

Astronomers have discovered the closest black hole on record, located 1,100 light-years away from our solar system. This black hole is part of the star system HR 6819, which consists of two bright, bluish stars. On a clear, dark night, these stars…

Obscured by a hazy atmosphere 100 times thicker than Earth's, Venus is a notoriously difficult world to study. Ground temperatures on Venus exceed 450°C (842°F)—enough to melt lead and to have quickly degraded the Soviet robotic landers last placed…

Scientists have suggested a possible connection between ancient Neandertals (Homo neanderthalensis) and the severity of disease in patients affected by COVID-19. In short, certain genes acquired from Neandertals during instances of interbreeding…

Observations from the Hubble Space Telescope have solved a significant cosmic mystery that will help scientists better understand dark matter, an enigmatic substance theorized to outnumber normal matter at least fivefold. In 2018, astronomers were…

Using an artificial intelligence technique known as deep learning and high-resolution remote sensing, scientists have counted and mapped the location of trees in 11,000 satellite images covering more than 1.3 million square kilometers (500,000…

Researchers searching for a hypothetical fourth type of neutrino have found no evidence for the particle, according to a new study. Very low-mass and highly abundant, neutrinos are elementary particles that barely interact with the rest of matter.…

Astronomers have observed a galaxy from when the universe was only 1.4 billion years old that is remarkably similar to our Milky Way. Although lacking spiral arms like our galaxy, this distant galaxy does display a rotating disc and a starry,…

The earliest representatives of modern humans—those belonging to Homo sapiens—evolved from more archaic humans approximately 150,000–300,000 years ago in eastern Africa. During succeeding years, the geographical range of anatomically modern humans…

The ExoMars orbiter has detected a green glow emanating from excited oxygen molecules in the dayside atmosphere of Mars. The observations, gathered over a six-month period last year, confirm a four-decades-old prediction and represent the first time…

Highly energetic light emitted by aged stars causes asteroids to keep spinning faster and faster to the point of disintegration, a new study finds. The findings help explain why white dwarf stars—remnants of Sunlike stars—often have metallic…

With a miniature version of the kind of television antennas that often adorned rooftops before the advent of satellite and cable TV, researchers have demonstrated the conversion of electrical signals into light beamed in a particular direction. This…

A new study has shown that dangerous hydrogen-burning flames can persist in unexpectedly narrow spaces and with very low fuel volumes. The findings highlight potential challenges involved in the safe storage and transport of hydrogen gas, which…

Famously durable, diamond is the hardest natural substance that occurs in any significant abundance on Earth. Yet according to a new study, on the nanoscale—a scale size of just billionths of a meter—diamond can, in fact, be bent and deformed. This…