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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…

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…

On January 15, 2022, in the South Pacific Kingdom of Tonga, the Hunga Tonga–Hunga Haʻapai submarine volcano violently exploded, sending ash 58 kilometers (36 miles) high into the mesosphere and triggering a tsunami with waves towering 15 m (49 ft)…

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…

The Antarctic ice sheet is the largest remnant of previous ice-age glaciations. Glaciers flow out from this ice sheet and feed into floating ice shelves along one-third of the Antarctic coastline. One of the largest ice shelves is the Filchner-Ronne…

In recent years, researchers have made considerable progress toward producing renewable energy in the form of hydrogen fuel through the electrolysis of water. In the most basic electrolytic cell, an electric current drives a chemical reaction at two…

The Hudson River estuary in the United States experiences a tide from New York Harbor (river kilometer 0/river mile 0) to Troy, New York (river kilometer 244/river mile 152). In the lower 60 kilometers (37 miles) of the Hudson River, the water is…

Atmospheric ozone plays a critical role in the biosphere by absorbing harmful ultraviolet radiation in the stratosphere—the layer of the atmosphere about 10 to 50 km (6 to 30 mi) above Earth’s surface. Since the adoption of the Montreal Protocol in…

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.…

Driven by global warming, sea level is rising. The extent of sea-level rise depends on how fast glaciers and ice sheets melt. According to the U.S. Interagency Sea Level Rise Taskforce, by the year 2100, global sea level will likely increase by at…

The Paris Agreement is a treaty signed by 196 member nations of the United Nations Framework Convention on Climate Change (UNFCCC) in an effort to reduce greenhouse-gas (GHG) emissions, primarily of carbon dioxide and methane, thereby limiting the…

Peatlands, also known as bogs and fens, are a type of wetland in which, over the course of hundreds to thousands of years, vegetation—mosses, sedges, trees, and other plants—have accumulated as partially decomposed organic matter. Peat itself covers…

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.…

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;…

Researchers at Northwestern University, Evanston, Illinois, USA, have developed a virus catcher of sorts—that is, a sticky and absorbent surface coating that traps droplets and aerosols (microdroplets) that land on the coating. Most often, fine…

An investigation of 890-million-year-old limestone rocks excavated from the mountains of Canada's Northwest Territories has revealed possible evidence of the oldest animal life on Earth. Prior to this study, the oldest undisputed fossils of animal…

Scientists predict that Earth’s climate will continue changing, depending in large part on the additional amount of greenhouse gases that humans emit into the atmosphere, leading to negative consequences for life on Earth. To avoid the most harmful…

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…

Researchers at Purdue University in Indiana, United States, have developed the whitest white paint on record, based on its ultrahigh reflection rating. By incorporating a pigment called barium sulfate (BaSO4) at the highest concentration possible,…

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…

Microplastics are raining down on national parks and other protected areas in the western United States at the rate of about 132 pieces of microplastic per square meter every day, according to a report in the journal Science (June 2020).…

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…

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…

The novel coronavirus SARS-CoV-2 that emerged in central China in late 2019 and subsequently spread across the world in 2020 led to the COVID-19 pandemic. The emergence of a previously unknown pathogen—such as the novel coronavirus—that could affect…

The world’s oceans and coasts provide a natural sink for excess carbon in the atmosphere. Scientists refer to carbon that is captured and stored this way as blue carbon. Well-known blue-carbon examples include mangroves and salt marshes—wetland…

If you think converting seawater to fuels that can power ships is a fantasy, think again. Researchers at the U.S. Naval Research Laboratory in Washington, D.C., have, in fact, accomplished this feat. In addition, the U.S. Navy has received a patent…

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…

During the past decade, the automotive industry has converted more than 50 percent of its internal combustion engines from a traditional technology called port fuel injection (PFI) to a new technology called gasoline direct injection (GDI). The…

Fingerprint identification is a widely used forensic method for linking an individual to a crime scene. Investigators at a crime scene can find invisible (latent) fingerprints, which consist of natural skin oils, by "dusting" surfaces with carbon…

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…

Heroin (C21H23NO5) is a white, crystalline powder synthesized from morphine, a natural alkaloid extracted from the seedpod of the Asian opium poppy plant, Papaver somniferum. It is a powerful opioid drug prepared by the addition of two acetyl groups…

A class of chemicals known as per- and polyfluoroalkyl compounds (PFAS) are particularly worrisome in the environment because they do not biodegrade. For this reason, scientists often refer to PFAS as “forever chemicals.” PFAS’s staying power…

Naturally ventilating a house, such as by opening doors and windows, has long been considered an effective strategy for exhausting indoor air pollutants. However, according to researchers reporting in the journal Science Advances (February 2020),…

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…

Ground-level, or tropospheric ozone (O3), is a strong oxidizing agent that reacts with living tissue. Consequently, tropospheric ozone is considered an air pollutant and a respiratory irritant at low concentrations. At higher concentrations,…

A rare and very large area of severely depleted ozone (03) opened up in the stratosphere above the Arctic Circle in March 2020. Scientists attribute this ozone hole to the persistence of a very strong polar vortex (a jet stream that circles the…

Over the course of history, smallpox has been among the most feared diseases of humankind. Caused by the variola virus (a DNA-containing member of the Poxviridae family) and spread by transfer through respiratory droplets during face-to-face…

Concrete is the most widely used construction material worldwide because of its versatility, strength, and durability. Applications range from roadways and dams to furniture and tiles. With proper manufacturing, reinforcement, and engineering…

Researchers from Drexel University in Pennsylvania, USA, have synthesized conductive and layered 2D materials known as MXenes (pronounced maxenes) using a water-free process. In doing so, scientists have opened up potential uses of MXenes as…

Many trees in forests worldwide rely on natural fires to create growing conditions necessary to perpetuate the ecosystem, or to stimulate germination. However, for more than 100 years, humans have been suppressing frequent natural low-intensity…

Persistent changes in the Earth's climate that have been occurring primarily as a result of human-caused greenhouse-gas emissions since the mid-twentieth century have led to significant increases in infectious diseases in wildlife, both in terms of…

The United Nations has proclaimed 2019 the International Year of the Periodic Table of Chemical Elements (IYPT2019). The same year also marks the 150th anniversary of the publication of Russian chemist Dmitri Mendeleev’s periodic table, containing…

Sea-level rise is caused by adding mass (water) and heat to the ocean. The Antarctic ice sheet represents a potentially large source of water. Knowing the speed and direction (velocity) at which the Antarctic ice sheet is flowing to the ocean is…

Plastic is a ubiquitous and life-saving product, but it is also rapidly becoming a significant environmental problem. Globally, less than 10 percent of plastics are recycled, about 12 percent are incinerated, and the vast majority are disposed of in…