Great circles provide the shortest path between two points on a sphere

Explore a visualization of curved spacetime under general relativity

While depictions involving bends in elastic fabrics are common to illustrate gravity, they are circular representations that rely on gravity in the real world to depict gravity in the model. The river model instead shows how bends in spacetime convert speed through time into speed through space, producing acceleration.

Explore Lewis and Clark’s 8,000-mile journey in Google Earth

Follow the Corps of Discovery’s full route from St. Louis to the Pacific and back on Google Earth. Explore key camps, Native encounters, and natural landmarks through satellite imagery and on-the-ground photos.

GPS satellites are programmed to account for their faster passage of time in space

The Global Positioning System relies on signals from satellites to calculate locations on Earth by measuring time and distance. However, their orbits, being farther from Earth's center, cause them to experience less gravitational time dilation. These systems would be off by 11 kilometers per day without relativistic corrections.

This flat map is still wrong, but it's the least wrong of all flat maps

While flat maps can never be as perfectly scaled as a globe, they're far more practical than carrying around a sphere. Researchers set out to minimize six major errors of flat maps, including boundary cuts and skewed proportions, by simply squashing...

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.

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.

Earth's circumference was estimated over 2,000 years ago using geometry and shadows

By measuring the angle of the shadow cast in Syene when no shadow was cast in Alexandria, Eratosthenes used the distance between the two cities and trigonometry to estimate the Earth's circumference to within a few percentage points of the actual value.

How scientists study Earth's geocorona, the farthest portion of the planet's exosphere

Seen via ultraviolet radiation scattered by neutral hydrogen in the region, observations by the ESA/NASA Solar and Heliospheric Observatory indicate that the geocorona extends roughly 50 times Earth's diameter above its surface. At this distance, the geocorona extends beyond the Moon's orbit.

The origin of shortest-path algorithms and how they became optimized for navigation apps

In 1956, Dutch programmer Edsger Dijkstra spent about 20 minutes developing an algorithm to demonstrate how computers could quickly determine the shortest route between Rotterdam and Groningen. Since then, modified versions of Dijkstra's formulation comprise the processing backbone of systems such as Google Maps and Apple Maps.

Why parts of the Earth are colder when the planet is closer to the Sun

The Earth orbits the Sun in an elliptical shape, and winter in the Northern Hemisphere occurs when the Earth reaches the point in its orbit closest to the Sun, known as perihelion. The lower temperatures result from the hemisphere tilting away from the Sun.

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.

Why roller coaster loops are never circular

The beloved looped roller coaster rides used to be shapes as perfect circles and constructed with wood, resulting in wobbly machinery that gave people whiplash. After the invention of steel and further scientific understanding, Six Flags debuted The Great American Revolution—a modern, oval loop with steel that offered a safer and smoother experience.

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.

The informal boundary between the Earth and outer space lies within the atmosphere

Located approximately 100 kilometers (62.1 miles) above Earth's surface, the Kármán line serves as the approximate location where air density is too low to support aerodynamic lift to keep an aircraft airborne. Beyond this height, thrust is needed to propel objects through the air.

Taxicab geometry defines displacement as the sum of vertical and horizontal distances

In this mathematical system, pi is valued at four, and circles aren't round—they appear as diamonds with corners instead. The system simplifies pixel distances in digital imaging and helps engineers with robot navigation and chip design.

While geography pertains to Earth's surface features, areography pertains to Mars

Unlike Earth, Mars lacks geological activity and oceans, though geological evidence suggests they both existed in the past. Its northern regions have far fewer craters than the southern ones, indicating that the rock in the north formed more recently.

The deepest human-made hole on Earth is in Russia’s Arctic North

Driven by Cold War competition, the Kola Superdeep borehole was a project in the 1970s to uncover the composition of the Earth by boring underground. The mission managed to go 7.6 miles into Earth’s crust, the deepest human-made hole on Earth.

A strike-slip fault and glaciers created Scotland's unusually straight Great Glen

In satellite images, Scotland's highlands present an unusually straight line in the landscape to viewers. This line occurs along a fault where two plates move against each other horizontally. Amid recent ice ages, receding glaciers deepened this fault.

The 'sense' of direction comes from two strategies involving unique brain regions

Egocentric navigation utilizes the caudate nucleus and posterior parietal cortex, relying on a person's position in space to determine their direction of movement. Spatial navigation uses landscape features for orientation and is driven by the hippocampus.

The event horizon is an inescapable sphere around a black hole singularity

The horizon is often surrounded by an accretion disc of superheated material that orbits the black hole while emitting radiation. Light emitted behind a black hole can be bent around it to create the appearance of a ring of material known as a photon sphere.

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.

Hurricanes, which rely on air consistently spinning in the same direction, cannot cross the equator because air curves in opposite directions north and south of it.

Movement of molten metal around its solid inner core creates Earth's magnetic field

According to the geodynamo process, the rotation of the planet and the looping, convective flow of electrically conductive iron and nickel produce dynamic electric currents, which generate a self-sustaining magnetic field. This is unlike natural, stationary magnets, which possess a static field created when the metal cooled and its atoms aligned with Earth's magnetic field.

Explore the night's sky from anywhere

Stellarium Web is a planetarium running in your web browser. It shows a realistic star map, just like what you see with the naked eye, binoculars or a telescope. Using its interface, you can click on object's visible at your location on the Earth...

On one sailor's race to sail around the world solo

People wanting to sail around the world in modern times can sign up for the Golden Globe Race, a decades-old, organized sprint to circumnavigate the world by ship. This long-form article follows one woman's journey as she attempted to complete the...

The Koch snowflake has an infinite perimeter enclosing a finite area

Counterintuitively, although it would be impossible to build a fence along the edges of the shape because it would require an infinite amount of materials, this perimeter can be contained in a larger shape with a finite perimeter and limited area. This is equivalent to enclosing an infinitely long spiral that never reaches the center within a circle.

Six Degrees of Wikipedia, where any two articles connect in six clicks or fewer

Enter any two topics (or use suggestions) and find the shortest path of links between them. The game playfully illustrates the vast interconnections of human knowledge.

Visualize the path of every solar eclipse from 1900 to 2099 and see what each looks like when observed from different locations on Earth.

The 'overview effect' heightens one's sense of unity and connectedness

Coined by space philosopher Frank White in 1987, the term refers to the paradigm-shifting experience a person undergoes upon viewing Earth from space. Commercial spaceflights aim to bring this perspective to a broader audience, inspiring changes in behavior and worldview among participants.

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.

Explore our favorite visualization of the immense scale of space, from an astronaut to the size of the observable universe

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.

Stanford built a Google Maps for the Roman Empire, revealing how much it cost to travel in the ancient world

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

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.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

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

SpongeBob exemplifies Aristotle's philosophy for living well because he understands that happiness doesn't come from external factors like money, recognition, or power.

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

Crows are believed to have intelligence on par with a seven-year-old child and demonstrate complex behaviors, from problem-solving with tools to recognizing human faces.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

The American Society of Civil Engineers' infrastructure report card gave the US a C in 2025, its highest grade since the project launched in 1998.

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.

Planarian flatworms are small, aquatic worms with exceptional regenerative capabilities. When cut, the worms can regenerate multiple bodies in a matter of weeks.

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

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

'Grand Canyon of the Yellowstone,' a work by American painter Thomas Moran, inspired Congress to establish Yellowstone National Park.

Legendary architect Frank Lloyd Wright designed the SC Johnson headquarters in Wisconsin, aiming to make a cathedral-like workplace

Venture capital is a form of funding provided to early-stage companies with high growth potential, typically in exchange for an equity (or ownership) stake