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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…

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…

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…

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…

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…

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…

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.…

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…

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…

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…

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…

Using old data from the NASA spacecraft MESSENGER, researchers have demonstrated how to measure the average lifetime of a neutron from space. This finding is important because, despite decades of efforts, physicists still cannot definitively say how…

With the launch of the next-generation James Webb Space Telescope in October 2021, astronomers will finally be able to perceive distant galaxies that host quasars—the most luminous objects in the universe. Quasars shine forth with the equivalent…

In a surprising find, researchers have detected phosphine (PH3) in the atmosphere of Venus. This poisonous, colorless, flammable gas is nonetheless considered a strong sign of life, or "biosignature." Biosignatures are gases or combinations of gases…

In December 2019, a new solar cycle started. Solar cycles are the roughly 11-year periods—documented going back nearly 270 years—over which the Sun’s magnetic activity peaks and troughs. This activity is marked by the formation of sunspots on 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…

The supermassive black hole at the center of the Milky Way serves as a unique laboratory for testing predictions of general relativity. In a new study, researchers report that a long-studied star—called S2 or sometimes S-02—moves in a rosette-shaped…

After a 40-year search, astronomers have identified the first star shown to pulsate on only one side. Many kinds of stars, called variables, undergo natural pulsations, or periodic changes in brightness that are visible across the whole star. The…

Molten iron rains from the evening skies of an exoplanet designated WASP-76b, according to a new study. WASP-76b is a gas giant—a large planet with a vast gaseous envelope, like Jupiter—located about 390 light-years from Earth. Astronomers used an…

Stellar explosions known as supernovae may be behind several anomalous rises in radiocarbon captured in tree rings over the past 40,000 years, according to a recent study that adds mounting evidence to the hypothesis that supernovae can impact…

On July 20, 1969, the bulkily space-suited figure of astronaut Neil Armstrong descended the ladder of Apollo 11’s lunar lander, planted his boot in the Moon's gray dust, and declared: "That's one small step for a man, one giant leap for mankind."…

Researchers recently discovered a black hole with a mass estimated at 3.3 times the mass of the Sun, which is significantly less than the lowest-mass black holes previously detected with approximately 5 times the Sun's mass. The new finding opens…

After a decades-long search, astronomers have detected the signature of a molecule predicted as the first type to have ever formed in the universe. Called helium hydride and symbolized HeH+, this positively charged ion consists of a helium atom that…

At the Woranso-Mille paleontological site in northern Ethiopia, researchers have discovered a 3.8 million-year-old cranium (skull) belonging to a primitive hominin known as Australopithecus anamensis. Initially unearthed in 2016, but not reported…

Researchers recently announced the discovery of the farthest object ever identified within our solar system. Designated 2018 VG18 and nicknamed Farout, the object is located about 120 astronomical units (AU) from the Sun, or 120 times the average…

In a breakthrough for astronomy and physics, the Event Horizon Telescope (EHT) has obtained a direct image of a black hole. The first black hole captured in this manner is a supermassive one at the heart of a nearby galaxy, Messier 87. Further study…

Researchers have reached a key new milestone in the continuing search for worlds like Earth that could support life elsewhere in the universe. For the first time, water vapor has been detected in the atmosphere of an exoplanet that resides within…

Researchers Chi Ma of Caltech and Alan Rubin of the University of California at Los Angeles reported in the journal American Mineralogist (September 2019) the discovery in a meteorite of the first natural occurrence of the iron-carbide mineral…

Researchers have recorded the most massive neutron star on record, weighing as much as 2.17 Suns but packed into a city-sized sphere just 30 kilometers (19 miles) across. This astonishingly dense object is seemingly at the limits of the maximum mass…

New research from the U.S. National Aeronautics and Space Administration (NASA) predicts that the next decade will be a favorable period for human exploration due to lower risks of inclement "space weather"—a term that refers to radiation conditions…

Astronomers have arrived at a new, precise measurement of the mass of the Milky Way. Historical estimates have varied widely, from 500 billion times the mass of the Sun—a quantity known as a solar mass—to as high as three trillion solar masses. The…

Among the most remarkable geophysical features in the solar system are four fissures—nicknamed tiger stripes—that streak across Saturn's moon Enceladus. Liquid water from this moon's interior erupts from these 130-kilometer- (80-mile-) long clefts…

The bacteria that live in the gut (gastrointestinal tract) constitute a large part of an individual's microbiome (also known as microbiota). In general, gut bacteria, also referred to as the microbial flora of the gut, are harbored by normal,…

Psychedelic drugs, also termed hallucinogenic or psychotomimetic drugs, induce transient states of altered perception resembling or mimicking the symptoms of psychosis and are characterized by profound alterations in mood. Because psychedelic drugs…

After exploring Mars for almost 15 years, the Opportunity rover has roved its last. In February 2019, NASA announced the end of any further attempts to communicate with the machine, which has been unresponsive since stricken by a planet-wide dust…

New research involving the analysis of spectra obtained from the Hubble Space Telescope has revealed that the vast, yellow patches on the surface of Jupiter's moon Europa are made of table salt, NaCl. The results, which overturn a prevailing view of…

A star encircling the supermassive black hole at the core of the Milky Way Galaxy has offered a new, precise test of general relativity. Put forth by German-born U.S. theoretical physicist Albert Einstein in 1915, the theory of general relativity…