Neutron star collisions may be the universe's gold factories

How neutron stars serve as laboratories for testing Einstein's theory of gravity

Data from a 16-year study of an orbiting pair of spinning neutron stars showed that measurements of gravitational wave energy and the bending of light around the system were consistent with predictions made by general relativity to an accuracy of at least 99.99% across seven tests. (Some readers may experience a paywall.)

In 1974, a pair of neutron stars provided the first evidence of gravitational waves

Observations of a pulsar—a rapidly rotating neutron star that emits light—revealed it to be part of a system of two stars that orbited one another in a shrinking orbit, indicating gradual energy loss. Calculations showed that the changing orbit was consistent with gravitational waves predicted to carry energy away from such a system.

How gold, platinum, and many rare earth elements form during neutron star mergers

While massive stars naturally fuse elements as heavy as iron, an analysis of gravitational waves from the collision of two neutron stars revealed that more massive elements are created in this environment via rapid neutron capture—the r-process. This phenomenon sees existing iron nuclei absorb plentiful free neutrons, many of which decay into protons, creating new elements.

Watch an artist's impression of two neutron stars merging in a kilonova explosion

Such an event produces enough light to briefly outshine an entire galaxy and to produce characteristic gravitational wave and gamma-ray signals. On August 17, 2017, these signals were captured by the LIGO–Virgo and Fermi/INTEGRAL observatories, respectively, from a kilonova about 130 million light-years away.

Neutron stars, the remains of some massive stars after they explode in a supernova, are the densest directly observable objects in the universe.

Neutron stars, the remains of some massive stars after they explode in a supernova, are the densest directly observable objects in the universe.

Fritz Zwicky predicted the existence of dark matter and neutron stars

The former resulted from analyzing the motion of galaxies in the Coma Cluster, a subset of the approximately 30,000 galaxies he cataloged during his life. When hypothesizing an origin for observed high-energy particles called cosmic rays, Zwicky and colleague Walter Baade thought they could come from exploding stars, or supernovae—a term he coined—which would leave behind a collapsed star made entirely of neutrons.

The hypothetical matter that neutron stars' cores may contain, including strange quarks

Models of the extreme pressures and energies in neutron stars suggest conditions resembling those believed to have existed within a fraction of a second after the Big Bang. In these environments, the quarks that make up protons and neutrons in trios may instead form pairs that combine to form one quantum object. (Some readers may experience a paywall.)

Why starquakes may explain various phenomena associated with neutron stars

Fast radio bursts—repeated millisecond-long pulses of enormous energy from neutron stars—are emitted with a timing that resembles the earthquakes and aftershocks seen on Earth when geological activity releases energy from within the planet. Although pulsars should gradually spin more slowly as they lose energy from emitting jets of radiation, sudden increases may result from interior matter moving during starquakes.

Hawking suggested studying black holes could reveal truths about the universe's start

After predicting black holes could evaporate and before undergoing a tracheotomy, Stephen Hawking conducted interviews in his voice, explaining phenomena like black holes and the Big Bang. In this clip, he explains how curiosity drives humans to become “masters of the universe.”

LIGO confirmed Stephen Hawking's theorem about black hole surface areas

Black holes are known to grow with increased mass but lose energy during mergers through the emission of gravitational waves. Amid these competing factors, the black hole area theorem—confirmed in 2021 using LIGO data—states that a merged black hole's size cannot be smaller than the combined surface area of its progenitors.

Try to catch the 'sound' of black holes in gravitational wave detector data

In "Black Hole Hunter," users try to listen for gravitational wave signals from black holes in four sample data files that include substantial background noise. With each level, learn more about black holes while being faced with ever-quieter signals.

Type Ia supernovae are 'standard candles' used to accurately measure cosmic distances

These explosions are caused by white dwarfs—remnants of low-mass stars—that reignite and explode, with every explosion brightening and dimming in the same way. By comparing them, astronomers have mapped the locations of galaxies alongside velocity data to determine the universe's expansion rate across time and the existence of dark energy.

Scientists turn alchemists, transforming transform lead into gold

Fulfilling alchemists' dreams, scientists at the Large Hadron Collider (LHC) transmute lead into gold. While the 86 billion gold nuclei produced were short-lived, the experiment sheds light on how electromagnetic fields can play a critical role in nuclear transmutation.

One study suggests that dark matter may have originated from a dark Big Bang

A student-faculty team at Colgate University modeled the event as occurring months after the conventional Big Bang and determined the potential gravitational wave signal that would have been left behind. Future gravitational wave detectors are expected to be sensitive enough to observe this signal, if it exists.

The graviton may be the last missing piece of the Standard Model

While the electromagnetic, strong nuclear, and weak nuclear forces can be explained through interactions with particles, gravity is instead best modeled through spacetime curvature. Discovering a quantum particle of gravity would unite the two pillars of modern physics—quantum mechanics and general relativity—toward developing a theory of everything.

LIGO can detect changes in spacetime one ten-thousandth the width of a proton

Gravity is the weakest of the fundamental forces in nature, meaning the length of objects only changes by minuscule amounts as gravitational waves ripple through space from distant, albeit massive, cosmic events. LIGO's sensitivity can measure an object shifting its position by one seven-hundred-trillionth of the width of a human hair.

Explaining 'impossible' black holes

When stars collapse, the black holes they form can have the mass of either 50 suns or over 120—but current models claim strongly that no black hole should have a mass that falls in between that range. But in 2019, gravitational wave observatories detected two within it: one at 66 solar masses, the other at 85. The discovery disrupted established science and left researchers questioning the Standard Model of physics.

Ernest Rutherford's gold foil and nitrogen experiments revealed nuclear structure

Observing high-angle deflections when alpha particles were fired at gold foil led to an atomic model with a dense, positively charged nucleus. Firing those particles at nitrogen resulted in the emission of hydrogen nuclei—protons—leading to the discovery of the subatomic particle.

Collisions between cosmic rays and atmospheric particles dwarf particle accelerators

According to Einstein's model of gravity, confining immense energy into a sufficiently small region would warp space-time enough to create a black hole. If accelerators actually did create black holes, then trillions more would be produced daily in the atmosphere, where collisions are millions of times more energetic.

The 2017 Nobel Prize in physics was awarded to LIGO's founders

Rainer Weiss, Kip Thorne, and Barry Barish won the award for their contributions to the detector a year after the discovery of gravitational waves was announced. Acknowledging the Nobel statutes limited the prize to no more than three people, Thorne stated, "our marvelous discovery is the work of more than a thousand."

Fermilab's ICARUS experiment is searching for hypothetical sterile neutrinos

Neutrinos are a group of three chargeless, lightweight particles that can transform into one another via a quantum mechanical phenomenon called neutrino oscillations. The rate of these oscillations can be determined by measuring the amount of each type at different distances, where data inconsistencies would suggest the existence of new physics.

Physicists detect the sound of heat in superfluids, theorized since 1938

Referred to as "second sound," the flow of heat in a superfluid resembles a sound wave bouncing back and forth. The heat-mapping techniques used to make the detection may improve the study of neutron stars and superconductors.

Quantum mechanics-based technology may explain the Fermi paradox

It describes the discrepancy between the high likelihood of life beyond Earth given the vastness of the universe and the lack of evidence for such life, since extraterrestrial civilizations have not communicated with us. However, quantum communication—a more information-dense and effective method than classical means—requires massive receivers and very narrow signals, which would easily miss Earth, making a lack of signals expected.

The heat death of the universe will mark the perceptive end of time

Under this scenario, all matter and energy will be scattered as far out as possible, with no stars left to produce measurable light between objects. With no way of observing changes or increasing the disorder of the universe further, events could not be distinguished from one another, and time would lose meaning.

The first image of a black hole was captured by creating an Earth-sized virtual observatory from a network of eight radio telescopes.

NASA designed the Golden Record using hydrogen to ensure it's universally readable

The Golden Record holds what is essentially a human "time capsule," featuring music, nature sounds, and greetings from around the world. NASA used the radiation period of hydrogen's simplest transition as a baseline to convey timing and structure. The first coded image is included on the cover as a test so aliens can check if they decoded it correctly.

According to the physics of black holes, our 4D reality may be a hologram—a projection of information coded on a 2D surface on the edge of the universe.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

How fusion—which releases energy when two lighter atoms combine to form a heavier atom—differs from fission

After NASA's Voyager 1 captured Earth as a single pixel as it left the solar system in 1990, astronomer Carl Sagan used the image to reflect on humanity's fragility and the responsibility to protect 'the only world we've ever known.'

Stars appear to twinkle because turbulence in the motion of molecules in Earth's atmosphere causes light to bend and wiggle rapidly on its way to the surface—a phenomenon called scintillation.

Track the location of the Voyager probes, currently between 13 and 15 billion miles away from Earth.

In 1984, Operation Smash Hit intentionally crashed a 239-ton train into a nuclear waste canister at 100 miles per hour to prove the canister's safety, which remained completely intact and lost just 0.29 of its 100 pounds of pressure.

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

Astronauts have repaired genetic damage in space using CRISPR—a molecular tool that can make precise changes to DNA and is used in single-celled organisms to attack invasive viruses.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

One disco producer saw 'Star Wars' four times on its opening weekend and was so inspired that he recorded the album 'Star Wars and Other Intergalactic Funk,' which produced a chart-topping single.

Waves off the coast of Nazaré, Portugal, can reach over 100 feet and are caused by the area's deep underwater canyon geography

Explore chaos in this simulation of two double pendulums, where small differences in the release angles produce wildly different outcomes.

Watch how deep-sea mining equipment collects and processes polymetallic nodules—metal-rich, potato-shaped rocks—from the ocean floor and creates environmentally damaging plumes of sediments.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

Clever Hans was a 1900s horse that was believed to be able to solve math equations, tell time, and read and comprehend German, until a psychology student discovered how he got his answers.

Netflix profits when you're not watching, and its movies are designed that way—read a detail-rich critical essay exposing lesser-known Netflix takes

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

Double world record holder Hunter Ewen helped conquer his fear of balloons, called globophobia, by training to win Guinness World Record titles for balloon inflation.

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.

Hotels in Cannes, the glamorous city on the French Riviera, hire hawks to ward off seagulls during the city's famous film festival.

Warren Buffett's former professor Benjamin Graham is known as the 'father of value investing,' a strategy in which investors seek to buy stocks trading below their intrinsic worth.

The US dollar is the most widely circulated currency in the world, and is involved in nearly 90% of global transactions