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.'

Voyager 1 captured Earth as a 'Pale Blue Dot' from 6 billion kilometers away

On Feb. 14, 1990, NASA's Voyager 1 space probe took the farthest photo of Earth ever captured. Earth appears so small in the image that it takes up less than a single pixel out of 640,000 in the photo's frame.

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

Explore the scale of the universe in this interactive adventure

The sheer enormity of the universe escapes our ability to conceive of its scale, despite the best efforts of human imagination. This interactive provides an intuitive sense of how small we are, from a single astronaut to the Milky Way and beyond.

New ways of seeing the cosmos have redrawn the map of human identity

From Galileo’s crude spyglass to the James Webb Space Telescope, each technological leap has expanded our observational reach and redefined philosophical and moral conceptions of our place in the universe. Identifying signs of life through the study of exoplanet atmospheres would represent the next great revolution.

'On the return trip home, gazing through 240,000 miles of space toward the stars and the planet from which I had come, I suddenly experienced the universe as intelligent, loving, harmonious..'

-Apollo 14 astronaut Edgar Mitchell, in "The Way of the Explorer"

'The more clearly we can focus our attention on the wonders and realities of the universe about us, the less taste we shall have for destruction.'

- Marine biologist and environmentalist Rachel Carson (1907-1964)

The world, one year after humanity goes extinct

The Earth is so shaped by human action, it's hard to imagine what it would look like without us. This brief, digestible explainer for kids highlights what a humanless world would look like one year after the extinction event.

Stephen Hawking on the need to explore space

Should we be content with being cosmic couch potatoes? In this interview, the late Professor Stephen Hawking lays out the case for continued and increased human space exploration, despite its cost and challenges.

See how distant aliens could preemptively strike humanity

Could aliens destroy us from light-years away? The team at Kurzgesagt imagines the impact of a highly sophisticated alien civilization setting out to crush humanity and considers the real-world logistics for warfare conducted across the Universe.

'There are no passengers on Spaceship Earth. We are all crew.'

- Philosopher Marshall McLuhan (1911-1980)

Carl Sagan, the host of 'Cosmos,' gave Bill Nye advice on his future show

Originally wanting to lean into his engineering background to explain the workings of objects such as bicycles and bridges, Nye ran his idea past his former professor at a college reunion. Sagan told him that children resonated with pure science, not technology, altering the show's future topics.

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.

Building the solar system to scale in the Nevada desert

On a dry lakebed in Nevada, a group of friends build the first scale model of the solar system with complete planetary orbits: a true illustration of our planet's humble position in space.

The Planetary Society provides an active role in advancing space exploration

Founded in 1980 by Carl Sagan, Louis Friedman, and Bruce Murray in response to public interest in space not adequately reflected in government investment, it is now the world’s largest nonprofit space organization, with more than 2 million members.

'The arts and sciences are avatars of human creativity. It's our attempt to influence things, the universe internal to ourselves and external to us.'

- Mae Jemison (1956-present), the first Black woman in space

Visualizing Earth's space garbage

An unsavory byproduct of humanity's brilliant exploration of space, the Moon, and more, is the rapid production of space debris floating around in orbit. Its estimated over 25,000 objects are in orbit, a number that grows everyday as satellites are decommissioned, rockets enter orbit, and more. Now, you can visualize what this debris looks like from a zoomed-out perspective with this brief video.

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.

Imagining a fourth dimension

Famous astronomer Carl Sagan attempts to describe what it's like to think about the fourth dimension using the famous Flatland example from author Edwin Abbott in this classic video.

Watch the full broadcast of humanity's first walk on the moon

On the night of July 20, 1969, Neil Armstrong stepped down the lunar module's ladder onto the moon's surface. The broadcast was watched by an estimated 650 million people—about a fifth of the then global population.

How the ancients calculated Earth's size correctly

Watch this seven-minute video to hear Carl Sagan explain how ancient Greek polymath Eratosthenes correctly calculated the size of the Earth in the third century BCE. At some point, Eratosthenes noticed a discrepancy in the length of shadows cast in different cities during the summer solstice. This observation grew into a simple experiment that enabled Eratosthenes, the head librarian at the Library of Alexandria, to calculate the Earth's size precisely.

Humans have existed for just 0.004% of Earth’s history

Born from the remains of the molecular cloud that birthed the sun, Earth experienced planetary-scale collisions, asteroid impacts, and lava seas. Life became possible after the planet cooled and formed a thin crust, atmosphere, and oceans.

An imperfection 1/50th the width of a human hair blurred Hubble's initial images

Not all parts of the space telescope's primary mirror focused incoming light to the same location, an effect known as spherical aberration. Because Hubble was designed to reside in low Earth orbit and be serviced by astronauts, service missions were deployed in the years after its launch to conduct repairs.

Unpacking the famous argument in the 'Are We Living in a Computer Simulation?' paper

In 2003, philosopher Nick Bostrom published a paper in a journal arguing the technological possibility that humanity is living in a simulation. The argument, while popularly mocked (or cheered), is presented seriously in the paper. This podcast episode explores the contours of the arguments in an accessible way.

Imagining the farms of the future

About 10,000 years ago, humans began to farm. This agricultural revolution was a turning point in our history and enabled the existence of civilization. Today, nearly 40 percent of our planet is farmland. Spread all over the world, these lands are the pieces to a global puzzle we’re all facing: in the future, how can we feed every member of a growing population a healthy diet? Brent Loken investigates in this seven-minute video.

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.

Defending Earth against asteroids

This three-minute video overview explains NASA's ambitious test to slightly alter the course of an asteroid by slamming a fast-moving space probe into its surface. Scientists hope to one day, if needed, use the technique to protect Earth from an asteroid impact.

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

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

Explore the known asteroids, comets, and spacecraft involved in asteroid studies within our solar system with 'Eyes on Asteroids,' a 3D visualization from NASA.

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.

See the most iconic photos from four decades of LIFE magazine

Apollo astronauts left items in the moon's 'toss zone,' including golf balls, family photos, and bags of human waste, to make room for lunar rocks.

Existentialist writer Jean-Paul Sartre coined the famous phrase 'Hell is—other people' in his play 'No Exit'

Learn how your body is, scientifically, like a firework with its own slow, controlled burn.

SpaceX's S-1 or 'prospectus' revealed many previously unknown details about the company, including its unprofitability despite doing $18.7B in revenue in 2025, exactly how many voting shares Elon Musk will have in the company (roughly 85%), and more.

The tragic Pulitzer Prize-winning image 'The Vulture and the Little Girl' (1993) generated controversy, raised concerns about ethics in photography, and eventually led to the photographer's death.

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.

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

The name 'Silicon Valley' arose from the founding of Shockley Semiconductor Laboratory in Fairchild Semiconductor in 1956-57, founded near Stanford University in Palo Alto

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.

Apeirophobia is an overwhelming fear of living forever, perhaps stemming from the brain's inability to conceptualize an infinite life.

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.

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.

Dorothy's famous entrance into Oz in 'The Wizard of Oz' relied on analog tricks, including a body double and sepia-toned paint, as much as it did on technology

The original copy of the Declaration of Independence is not a pristine document, and even features a smudged anonymous handprint in the bottom left corner.

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

The animatronic shark from Steven Spielberg's 'Jaws,' the first modern blockbuster, was a complex underwater apparatus called 'Bruce.'

Exploring the Larry Bird punch that almost changed March Madness

In preparation for this weekend's Eurovision finale, which is something like the World Cup of pop music, here's a young Céline Dion performing (for Switzerland?) at the 1988 competition.

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.