The conditions needed for cloud iridescence, or rainbow clouds

Tiny water droplets can blur a rainbow's colors into a foggy white

When sunlight enters water droplets, it can reflect from the inside and spread out into different colors, producing a series of colorful arcs—supernumerary bows—which we refer to as rainbows. For droplets a few hundredths of a millimeter in size, these arcs overlap onto each other, producing fogbows of white light.

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.

View the ten basic cloud types, categorized by height and composition

Among the features of these types, cirrus clouds can display various colors at sunrise and sunset, while altocumulus clouds can produce a corona phenomenon around the sun or moon. Nimbostratus clouds are thick enough to block out the sun entirely.

Colorful thunderstorm phenomena can be viewed from the International Space Station

Transient luminous events are lightning-related phenomena that occur in the atmosphere above storm clouds. These events often look like columns of red light resulting from electrical discharge, but may also appear as purple tendrils or long blue jets.

Cloud formation requires water vapor and condensation nuclei to build from

The nuclei—particles like dust, salt, and smoke—act like jumpstarts that water molecules can start to accumulate onto to form clouds. Condensation nuclei are about 1/100th the size of cloud droplets, which are mostly water.

View the rainbow effect on the waters at First Landing State Park

The phenomenon results from light interacting with a thin film of natural oils on the surface of swamps and marshes at the site, not unlike the coloration seen in soap bubbles. The oils originate from decaying vegetation or from anaerobic bacteria reducing iron in soil. (Some readers may experience a paywall.)

Lightning results from the rapid flow of charges through the atmosphere

Lightning in storm clouds forms from the collisions between graupel—small hail particles—and smaller ice particles, which transfer electrons. Layers of opposing charges form as these differently sized particles rise and fall. When air can no longer insulate these layers, electricity discharges, equalizing these regions.

Atmospheric composition and temperature impact the color of lightning

Just as fire ranges from red to blue with increasing temperature, lightning's blueish-white comes from the superheating of air. The emission of light from the predominantly nitrogen- and oxygen-rich atmosphere produces a purple tint, with additional color caused by light scattering from humidity, hail, dust, and ash.

Rayleigh scattering of light gives the atmosphere its blue skies and red sunsets

Light is deflected from its original path by atmospheric particles, where bluer light is scattered more than other colors. When the sun is at its highest point in the sky, it travels through the thinnest part of the atmosphere, scattering some blue light across the sky. A greater atmospheric path length at sunset scatters more colors, leaving only red, yellow, and orange.

Atmospheric processes amplify the strength of storms by coalescing clouds

Research has shown that turbulent mixing of air at the edges of clouds and other small-scale thermal activity beneath them help clouds group together, intensifying short bursts of rainfall, especially in tropical regions. Simulations reveal this produces more powerful storms than predicted by older models, though they may occur less frequently.

Clouds' subtle climate effects require significant computational power to simulate

Responsible for reflecting sunlight and preventing thermal energy from entering the Earth system while also trapping energy and keeping it in the system, clouds are understood to substantially influence climate predictions. Because even supercomputers struggle to accurately model their dynamic behavior, researchers have used AI to indirectly incorporate clouds into climate models.

A guide to building your own cloud chamber to observe cosmic rays

Using felt, alcohol, dry ice, and a clear container—such as a fish tank—you can create a region of supersaturated air that will cling to passing particles, forming trails of cloud-like droplets. Muons will create straight paths, alpha particles will leave thicker ones, and electrons or positrons will zigzag.

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.

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.

Snowflakes form when water vapor turns directly into ice

Every water molecule has a slightly bent shape due to electron repulsion and regularly forms bonds with hydrogen molecules. When they freeze, they form a six-sided (or hexagonal) lattice, resulting in the six-sided symmetry of snowflakes. As the snowflake falls, more water molecules freeze onto its six sides, forming the unique, beautiful geometric designs.

Rivers in the sky

A short introduction to atmospheric rivers, including a handy illustration on the science behind them, the phenomena that help transport water vapor from the tropics across the globe.

Airborne microplastics may influence cloud formation and climate

Microplastics are increasingly found in the atmosphere and may affect the climate by reflecting or absorbing sunlight based on their pigmentation. Like mineral dust, they may become cloud seeders and alter regional precipitation patterns as they become more abundant.

Explaining the Leidenfrost effect, where water can hover and move against gravity

Water droplets can glide across surfaces whose temperatures are well above water's boiling point. This heat instantly vaporizes the bottom of the droplet, creating a layer of steam that the rest of the droplet rides and bounces upon. This can be seen when sprinkling water on skillets to determine if the surface is hot enough to cook on.

Cloud 9 is a dark-matter-dominated failed galaxy

Identified in 2023, the starless, gas-rich object is the first of its kind seen by astronomers and provides a window into the early stages of galactic formation without observations relying on visible matter as a proxy. The existence of such REHLICs, or Reionization-Limited-H I Clouds, was predicted by cold dark matter cosmological models.

'Try to be a rainbow in someone's cloud.'

- Maya Angelou

Lichtenberg figures capture lightning-like patterns within insulators

When high-energy electrons from particle accelerators are fired into materials like acrylic, they form a charged plane before discharging into scarred patterns within the material. By evenly charging a cylindrical bottle through rotation during the irradiation process, a 3D figure of lightning in a bottle can be created.

Niagara Falls generates its own microclimate

Constant mist from the Falls produces localized weather effects, including rare ice formations that can rise over 100 feet high in winter.

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.

Photographer catches stunning shot of an aurora over an Icelandic waterfall

Photographer Cari Letelier captured a stunning shot of the aurora borealis over the Godafoss waterfall in Iceland, a composite image pulled from nearly three dozen exposures. The aurora phenomenon is typically visible in Earth's northern latitudes...

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.

Chemtrails are formed from condensing water vapor and soot from jet fuel

Conspiracy theories about the phenomenon—also known as contrails—began circulating in the 1990s, but have gained significant traction on social media platforms. Chemtrails are more common in high-humidity conditions, where they persist and form cirrus clouds.

Watch lightning strike a building at 40,000 frames per second

When the built-up layer of negative charge at the bottom of clouds is sufficiently high, a network of charge filaments will emerge. If one of the filaments meets a rising strand of positively charged particles, a highly conductive path forms, and charges across all filaments move to the path, generating lightning

Fulgurites are glass sculptures made by lightning vaporizing sand

Sometimes referred to as fossilized lightning, these tube-like structures are formed when high-temperature electrical currents fuse mineral grains into crystals, which can feature branching patterns resembling filaments of current. Their name derives from "fulgur," the Latin word for lightning.

Watch underwater photosynthesis make water look like champagne

In shallow waters where sunlight can reach, photosynthetic reactions absorb water and dissolved carbon dioxide, producing bubbles of oxygen at the surface of plants. As these bubbles rise to the water's surface, a fizzy appearance is created.

Layers of minerals revealed by erosion give Vinicunca its distinct colorations

Located in Peru's Andean mountains, Rainbow Mountain is known for its vibrant colors, which result from layers of minerals such as clay, sandstone, argillite, and limonite exposed over millions of years by rain, snowfall, and strong winds.

What is freezing fog?

Freezing fog is a weather condition in which fog containing supercooled water freezes on contact with objects, forming a layer of ice and possibly dangerous driving conditions. Get the breakdown with this explainer.

Double rainbow appears in New York City on 9/11 anniversary

On the evening of the 9/11 anniversary in 2023, a double rainbow appeared after a thunderstorm across Manhattan, providing inspiration 22 years after the terrorist attacks there. Peruse several amateur images taken of the phenomenon which were shared on social media, including shots from up high in condos overlooking Central Park and from across the Hudson River in New Jersey.

The extremophilic origins of watermelon snow and its impact on glacial melting

Also known as "blood snow," the red coloration is produced by snow algae that thrive in extremely cold conditions and take the shape of red spherical cysts in winter. To protect themselves from more intense summer solar radiation, these psychrophiles accumulate red, orange, and yellow pigments, intensifying their coloration and causing glaciers to reflect less sunlight than if they were white.

Meteorologists believe they know the weather that inspired the terror behind Munch's painting 'The Scream'

Helene Muri, a meteorologist at the University of Oslo, believes the clouds causing the man such terror are nacreous. "We do know that there were mother-of-pearl clouds in the Oslo area in the late 19th century," she said, though she was careful to note that it was still a hypothesis.

Tropical cyclones consist of three main parts: the eye, the eyewall, and rainbands

The eye is a calm, clear central area surrounded by an eyewall of intense thunderstorms. Rainbands are spiral bands of clouds and thunderstorms extending from the eyewall.

Cerulean eruptions result from sulfur being heated by molten rock

During eruptions, warm-colored lava at temperatures between 700 and 1,200 degrees Celsius (1,300 and 2,200 degrees Fahrenheit) burns minerals as they escape from underground reservoirs. In some volcanoes, such as Indonesia's Kawah Ijen and Ethiopia's Danakil Depression, abundant sulfur compounds that burn with blue flames appear to change the color of the melted rock.

How chefs suspend liquid in edible pearls resembling caviar to introduce a new texture to fluids

Through spherification, drops of a solution of sodium alginate and a flavored liquid are placed in a calcium lactate solution, which forms a chemical skin around them. This is because calcium replaces the sodium in the alginate chains, forming a gel around each drop's liquid interior.

Crackling, popping, and rustling sounds have been reported during auroras

At the altitudes where auroras take place—between 100 and 300 kilometers (62 to 186 miles)—air is not dense enough to efficiently vibrate and carry sound waves to the ground. However, one theory suggests that the geomagnetic energy behind auroras can trigger electrical discharges near the surface, which may be the cause of reported sounds.

Where does your glass come from?

Glass is created from silica sand, soda ash, and limestone. The more transparent you want your glass to be, the higher the purity you need from your silica—a rarity. Colorless, low-iron glass featured in skyscraper windows and Apple's cube-shaped showrooms has increased demand for such pure silica.

Rain-catching tubes provide new hydropower source for tropical regions

An experiment in Singapore showed that charge separation could be established by rainwater flowing through narrow tubes. The separation, which creates a voltage, could be scaled up in regions of high rainfall to provide a clean energy source.

During World War II, turbulence was used to make ice cream

Before a mission, bomber crews packed buckets of ice cream mix into the rear gunner's compartment. Once airborne, freezing air solidified it, and turbulence churned it smooth, so that pilots had a fresh ice cream after landing.

Planeterrellas create artificial auroras that mimic the atmospheric displays of light by setting up an electric field between two metal balls in a jar filled with a small amount of air.

Auroral myths include Valkyries, firefoxes, and torchlight from giants fishing at night

In Norse mythology, the light displays were considered reflections from the Valkyries' armor as the female warriors brought the souls of heroes to Valhalla. In Finland, firefoxes were thought to move so fast that they created sparks in the sky as their tails brushed against mountains.

A diamond's color comes from impurities, defects, and unique formation processes

While most diamonds are transparent and sparkly, the presence of nitrogen and boron during formation can make them yellow, orange, or blue. Radiation can produce green diamonds, and structural deformities can introduce red hues.

See February 2026's best science images, including raining iguanas.

Light has been modeled as a wave and a stream of particles throughout history

Isaac Newton first identified white light as composed of a spectrum of colors, which he believed consisted of particles of different hues. Various light phenomena, including refraction, led Christiaan Huygens to develop an alternative wave model. Quantum mechanics validated both models through the concept of wave-particle duality.

Scientific applications of bubbles include logic gates, laser production, and medical imaging

Microbubbles of nonreactive gas can be administered to improve the reflection of sound waves and the resulting imaging during an ultrasound. Bouncing light waves within a bubble can stimulate emission of light from a trapped chemical, just as occurs within a laser, and bubbles can act as valves that control the flow and reaction rates in microfluidic systems.

Scientists use ground-based radar data to detect turbulence within clouds

NCAR developed the NEXRAD Turbulence Detection Algorithm and the Graphical Turbulence Guidance system to provide forecasts up to 18 hours ahead using ground-based Doppler radar data. Software systems also utilize an automated observation and reporting package—the EDR system—found on Delta, United, and Southwest Airlines aircraft.

Tetrachromacy allows humans to observe 10 times the normal amount of colors

Resulting from a mutation on the X chromosome, the rare genetic condition causes individuals to possess an additional type of photoreceptor cell, typically sensitive to the orange range, located between the standard red and green cones. This enables the perception of approximately 100 million colors.

Though less common, tornadoes can form without the presence of thunderstorms

Supercell tornadoes involve rising warm air—updrafts—from the strongest type of thunderstorm—supercells—to help turn horizontally rotating tunnels of air into vertical columns. In non-supercell tornadoes, which are generally weaker as a result of forming within less energetic systems, vertical rotation is present from the start near ground level.