Ring galaxies, the rarest kind in the universe

View a gallery of Einstein rings

As light from a distant galaxy spreads in all directions, rays that pass around a massive object, such as another galaxy, may be bent around it. If the massive object is positioned between the distant galaxy and our telescopes, we may observe this deflected light forming a ring around it.

Most of the observable universe's volume consists of voids and supervoids—enormous regions of space with little to no galaxies, stars, or light.

Most of the observable universe's volume consists of voids and supervoids—enormous regions of space with little to no galaxies, stars, or light.

Black holes 101

At the center of our galaxy, a supermassive black hole churns. Learn about the types of black holes, how they form, and how scientists discovered these invisible, yet extraordinary objects in our universe. This three-minute video from National Geographic tutors the viewer on the basics regarding the universe's most mysterious residents.

Are there any planets in the universe that aren’t round?

We think of all planets as spheres, but do they have to be spheres? To be classified as a planet, an object has to be sufficiently massive to reach a spherical shape through gravity. However, this doesn't mean they're perfectly round; for example, Earth has a slight equatorial bulge caused by centrifugal force from its rotation. Other observed planets feature tear-shaped formations while theorists posit donut-shaped planets. Read more here.

Dark matter's invisible pull shapes galaxies and our understanding of the cosmos

Though it makes up about 25% of the universe, dark matter can't be seen directly; its existence is inferred through its gravitational effects, like the unexpectedly fast rotation of galaxies. The concept began in 1933 but gained wide acceptance after Vera Rubin's galaxy rotation studies in the 1970s.

How many galaxies are there? (Hint: a lot)

The universe is considered by some to be infinite, while others find comfort in the fact that it may have an end. Click for more.

The sun is not as exceptional as once believed, but it remains rarer than most stars

Once believed to be the center of the universe, the sun is a G-class star, the same category to which about 6% of the Milky Way's stars belong. However, the sun is younger than 85%, more massive than 95%, and more metal-rich than about 93% of all stars. Unlike the sun, half of all stars also exist in multi-star systems.

Differential rotation and density waves create the arms of spiral galaxies

Stars and gas near the galaxy's center complete an orbit in less time than objects farther out. Pressure waves cause material to bunch, lagging behind stars and gas that orbit closer to the center and forming the arms.

A map of the Milky Way

Curious about the layout of the cosmos? This resource presents a detailed map of our galaxy, the Milky Way. Learn the basic structure and identify prominent global clusters, nebulae, main arms, spurs, and constellations. With numerous different maps and mediums, get oriented with the universe’s configuration and where exactly we fit into it.

What is the rarest color in nature?

Plants, animals, or minerals found in nature bear almost every color imaginable. There are two factors that influence what hues you see in the wild: physics and evolution. So, which colors are you least likely to see in the natural world? Victoria Hwang explores one of nature’s rarest spectacles.

The rare exoplanets orbiting distant pulsars

Pulsars are ridiculously volatile, massive, and super-dense. These objects are spread out around the universe, and their spinning magnetic fields blast out radioactive pulses. Rarely, some have planets orbiting them. There's not much hope for life there—pulsars emit regular deadly radiation—but they're still fascinating from a scientific perspective. This article further explores these amazing exoplanets.

The most bizarre numbers in the universe

Even for math-y types, some numbers are incomprehensible. This article dives into several kinds of numbers more complicated than even irrational numbers with endless decimals like "pi" or Euler's number: Noncomputable numbers. Read the bizarre...

Webb discovers galaxy that formed 280 million years after the Big Bang

The James Webb Space Telescope has discovered a galaxy that formed just 280 million years after the Big Bang. It is another in a series of increasingly ancient galaxies that, according to current formation models, should not have been able to form so quickly after the birth of the universe.

Animation of a Gamma-ray burst, the brightest explosion in the universe

Gamma-ray bursts are some of the most luminous explosions in the universe, the result of a star collapsing on itself and emitting massive jets of particles. See a brief animation of the phenomenon here.

View a gallery of various auroral shapes

Auroras can be generally classified as discrete (well-defined shapes) or diffuse (hazy shapes), with light taking various forms, including curtains, arcs, pillars, and rays. Some auroras can also pulsate, particularly after intense periods of auroral activity are winding down.

What is a singularity?

It's hard to imagine a singularity, which are described as an infinitely tiny point, created by gravity, until it has zero volume. The definition feels impossible, though perhaps not at the center of a black hole or at the beginning of the universe. Even then, singularities may be something else entirely. Singularities are a mathematical quandary that challenge us to better understand physics and the universe.

Visualizing the history of Saturn and its rings

Every 13 to 16 years, Saturn's rings become far less visible because its plane becomes exactly even with Earth's. This visual-rich essay explores the history of humanity's perception of Saturn, from Galileo's first sighting (and dubbing the rings "ears") to the idea that the rings won't last more than a few hundred millions years more. Explore this fascinating planet here.

There may be 74,963 kinds of ice, resulting from water molecules rearranging themselves

The theoretical limit greatly expands the known types of ice, with type Iₕ being the most common on Earth and forming hexagonal crystals. The extreme environments of planets like Uranus and Neptune can create a variety of ice with unique structures and properties, as these conditions can reshape these crystals into new geometries.

The rarest blood type in the world

Rh-null, also known as “golden blood,” is a blood type so rare, fewer than 50 people are known to have it. It lacks all 61 Rh antigens, making it a universal donor for rare Rh cases, but a nightmare in emergencies, since only Rh-null can be given back.

The universe may have been reborn from a state of emptiness

Some physicists propose the universe might be the latest in an eternal cycle of universes, each emerging from the empty remains of the one before. This model is inspired partly by Norse and Egyptian myth, suggesting the universe is a cosmic ouroboros—a self-consuming serpent representing an eternal return.

Astronomers use a set of scaffolding methods to measure distances across the universe

Different methods are used depending on how far away an object is—from radar for nearby planets, to parallax for stars, to redshift and supernovae for distant galaxies. These tools allow scientists to chart the universe across unimaginable scales using astronomical units (AU), light-years, and parsecs.

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

What is galactic archaeology?

In the same way that archaeologists excavate and analyze artifacts of human civilization, galactic archaeologists observe the light in the universe to glean lessons on its age, evolution, and more. Learn about this niche area of study with this 10-minute podcast.

All rainbows are 'raincircles' caused by water droplets separating white sunlight into a spectrum of colors, but Earth's surface blocks the bottom half of the circle from our line of sight.

A 'unicorn' is a private company with a $1B-plus valuation

Just like a horse with a spiraling horn on its head, private companies with a more than $1B valuation are rare creatures. But unlike the mythical creature, this type of “unicorn” is occasionally spotted in the wild. Unicorn companies include SpaceX, OpenAI, Skims, and more.

The science of symmetry | The Royal Society

Nature is full of symmetries, from spiral galaxies to florets of broccoli. So why do complex creatures break the pattern?This short video discusses why symmetry came to dominate life on Earth, and how many complex life forms, such as humans, transitioned from radial to lateral symmetry.

All rainbows are 'raincircles' caused by water droplets separating white sunlight into a spectrum of colors, but Earth's surface blocks the bottom half of the circle from our line of sight.

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

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.'

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.

See the 25 of the best photos of auroras from around the world.

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Corals are themselves not coral reefs—the term refers to the tiny marine invertebrates that build the rigid reef.

Shooting stars, or meteors, are fragments of asteroids and comets that burn up as they enter Earth's atmosphere, creating streaks in the sky called meteor showers.

See how each of the more than two million known species relates to each other—and to common ancestors—in this zoomable tree of life.

The United States is one of only around two dozen countries with a fully federal system of government, in which power is divided between national and state governments.

Three Ebola species are responsible for most large outbreaks of the disease, yet the only approved Ebola vaccine is known to work against just one of them.

Fear or disgust related to clusters of holes and cracks, called trypophobia, may stem from evolutionary processes to help us avoid pathogens.

Explore fun facts from the USPS, including unique post office buildings, a stamp that traveled past Pluto, and more.

When caught in the mouths of cardinal fish, seed shrimp release glowing, bioluminescent chemicals, which alert predators of the cardinal fish, prompting the shrimp's ejection.

Browse a detailed visual analysis of over 200,000 similes—comparisons that often use 'like' or 'as'—from popular fiction to see how frequently writers the same idiomatic expressions.

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'

Iran's Revolutionary Guard Corps is independent of Iran's regular army and is one of the most powerful and influential military-political organizations in the Middle East.

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.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.

Learn how to read a prospectus, the juicy document that any company must file with the SEC before going public.

Children are now three times more likely to say they want to be a YouTuber when they grow up than an astronaut, with some even attending 'YouTube camps' that teach kids how to create content for the platform.

The Brothers Grimm were lawyers before they were storytellers, but became interested in fairy tales as they began investigating how rules and customs had been passed down through cultures.