The origins of our fascination with time travel

The earliest mention of time travel

Time travel has fascinated humans for centuries. It appears in myths, literature, and science fiction. One of the earliest examples comes from the 400 BCE Hindu epic Mahabharata, describing time dilation long before Einstein’s Theory of Relativity. By the 19th century, stories introduced machines enabling time travel—setting the stage for modern sci-fi.

Five potential ways to achieve time travel

While the author discounts the possibility of traveling to the past, it lays out five hypothetical modes of catapulting into the future: speed, gravity, suspended animation, wormholes, and light. Each has some scientific basis, but none are realistic for humans. Read the article to learn where they offer promise and where they fall short.

A scientific analysis of famous time travel stories

This 8-minute video explores how time travel influences the narrative arc of several movies, books and video games, from Harry Potter to A Christmas Carol. (Warning: it contains spoilers!) J.K. Rowling and Charles Dickens set myriad parameters as they’re worldbuilding to avoid paradoxes and create quasi-logical timelines. By drawing diagrams as he’s speaking, the video breaks down how time works in some of popular culture’s most beloved fictional universes.

Tips for writing time travel stories

Are you thinking of writing a story that involves time travel? You might want to read this guide first. It offers questions to consider, mistakes to avoid and strategies to employ to ensure you avoid paradoxes, plot holes and implausibilities.

The grandfather paradox of time travel

If you went back in time and killed your grandfather when he was a child, what would happen to you? One of your parents would never be born, so you wouldn’t be born either. But, if you’re never born, how could you kill your grandfather in the first place? This so-called grandfather paradox is something physicists, philosophers and sci-fi writers constantly ponder. Read the piece to learn how they’ve been trying to reconcile it.

A detailed interactive timeline of technology since 1500

Tech devices are heirs to a complex history of both technological invention and social history. What if you could visualize how radio, TVs, and other devices are connected to the past and each other? Trace the elaborate genealogies of your phone and computer with this interactive timeline showing tech inventions since 1500.

Philosophers have debated the nature of time since at least the 6th century B.C.E.

Greek philosopher Parmenides of Elea was skeptical of time and reasoned that if it were real, then the present would emerge from nothing because the future did not yet exist. Just as the color red is our perception of a specific wavelength of light, others have suggested time is a psychological projection based on how we interpret the world.

The history of ghosts, explained

The afterlife has perplexed humans across different periods, cultures, and belief systems. The desire to understand what comes next is often explored through the telling of ghost stories. Learn more about the spooky phenomena here.

Experimenting with space-time

Einstein's theory of general relativity—that mass literally bends space and time—can be difficult for the human brain to imagine. This interactive resource lets you create celestial objects, imagine their effect on space-time, and see how they interact with each other (best viewed on desktop).

Space travel sparked inventions we now use every day

Technologies developed for space exploration produced lasting spinoff innovations—from camera phones to memory foam—displaying how the space race reshaped everyday life here on Earth

Many believe modern fan fiction began with 'Star Trek'

While people have always reinterpreted preexisting stories, fanfiction is often noted for its communal, interactive element, which many believe started with the TV show "Star Trek." Fans were so passionate about the show that they began creating stories set in the show's universe and sharing them with fellow superfans through conventions and self-published fanzines, like 1968's "Spockanalia."

A timeline of human fossil discoveries

A key part of writing a coherent story about our origins is finding and identifying the remains of our ancestors and understanding their significance. Scientists will not always agree on identifications and opinions will change as new find are made and new ways of studying them are developed.

Imagine thousands of alternate histories of the world

AlternateHistory.com has hosted fan-written "what if" timelines, discussions, and speculative fiction since 2000, making it the largest online gathering of alternate history enthusiasts, with over 10,000 active members and a wiki cataloging hundreds of user-created scenarios. Two highlights to pique your interest: what if the Vikings had settled North America? What would have had to happen for the storyline of George Orwell's "1984" to come true?

Why don't humans hibernate?

Hibernation is a superpower in the animal world that allows certain species to time travel from difficult times to abundance. This essay in Aeon explains this helpful natural process and why humanity's technological advancements may have hindered our ability to participate in the practice. Learn about the rising interest in human hibernation as a result of modern adversity, and if it could potentially become a reality.

Why atoms are used to keep track of time and define the meaning of a second

Small variations in the production of human-made devices, such as mechanical watches and pendulums, make them unreliable for the ultraprecise timekeeping required by modern technology, including financial transaction timestamping and GPS. Because atoms obey fundamental laws of nature and never wear out, their light emissions when energized provide a consistent timekeeping signal.

How one silent movie came to define science fiction

Fritz Lang's 1927 epic "Metropolis" set the template for much of the science fiction that followed, establishing themes that would come to define the genre through films like "Star Wars" and novels like "Brave New World." This short documentary from DW digs into the history of the film and its long-lasting impact.

Explore a NASA timeline of the entire Voyager mission

This infographic leads users through the entire Voyager mission timeline, starting at its conception and moving through launch, to each destination, and finally, the Voyagers' crossing into interstellar space.

A brief history of artificial intelligence

The concept of artificial intelligence and what it may mean for humanity has evolved as computer technologies have grown increasingly powerful through the decades. Beginning with the first (massive) computers in the 1940s, scientists have sought to make the machines as intelligent as humans. But it wasn't until computing power made exponential gains have computers begun to imitate human behavior.

What exactly is déjà vu?

While people have wondered about déjà vu for a long time, only recently have scientists started experimentally investigating what might trigger it. Read this deep dive into the latest science.

The history of coffee

From its likely origins in what is now Ethiopia to today's worldwide consumption, this video uses a map to show how coffee conquered the world. Follow along and see how pilgrimages and centuries of trade influenced the spread of the beverage we all know so well.

'The urge to explore has propelled evolution since the first water creatures reconnoitered the land. Like all living systems, cultures cannot remain static; they evolve or decline. They explore or expire.'

- Astronaut Buzz Aldrin (1930-present)

The history of chemistry, from alchemists to probing atoms before World War I

Those involved in the predecessor of the modern scientific discipline engaged in experimentation to develop recipes that would transform ordinary matter into gold and to create medicines, cosmetics, dyes, and alloys. Over the course of centuries, scientists identified unique elements, organized them based on their properties in the periodic table, and eventually developed the technology to discover the internal structure of atoms.

Abandoned malls prompt 'liminal' vibes of being stuck in time

A Toronto-area tour of empty malls brings participants face-to-face with the past. Part nostalgia, part archaeology, this meditation on the "liminal" spaces of a bygone era provokes eerie reflections on our relationship to time and place.

The quest to find natural ways to extend lifespan

Tales of searching for the Fountain of Youth persist. Our modern-day version is marked by promises of pharmaceutical miracles and a proliferation of viral "biohacking" routines. One doctor’s quest to unlock the keys to longevity stimulated much of this renewed fervor, though his ideas are often taken out of context.

Learn more about the history of fireworks, which dates back to an accidental invention during an alchemist's quest for information about immortality.

Why do some people always get lost?

Using GPS, anthropological data, and VR, scientists have learned that one's sense of direction is largely influenced by upbringing. A person's wayfinding ability can be measured by how accurately they point toward an out-of-sight location, a challenge further complicated by imagining they're somewhere else and pointing toward a third location. Anxiety, safety concerns, and dislike of wandering can negatively impact one's sense of direction, which can improve with practice.

The first horror movie is believed to be George Méliès' 1986 short 'The Haunted Castle,' which pioneered the use of special effects

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

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

Before humans, the Soviet Union and the United States sent animals—including apes, dogs, and cats—to space during the Space Race.

Researchers believe the brain consolidates memories, processes emotions, and plans for the future during dream states

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

The concept of phantom limbs, the perception that amputated limbs are still present, dates back to a French military surgeon in the 16th century.

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.

Hear about the 250-year history of the United States Postal Service, complete with some of its strangest deliveries, important innovations, and the figures that made it an American institution.

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.

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

While the first exchange-traded fund (a 'basket' of different assets that can be bought and sold on a stock exchange) in the US only launched in 1993, the global ETF market has grown to more than $10T in the short time since.

English mathematician Ada Lovelace wrote the first computer algorithm a century before computers existed and hypothesized that computing devices would one day be able to compose music—foreseeing the generative AI systems of today.

Explore a list of the 100 best novels of all time, compiled by some of the world's best living writers, including Salman Rushdie, Stephen King, and Jennifer Egan.

The Mona Lisa's celebrity status and repeated restorations have obscured what made the painting so revolutionary for its time

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

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

20,000 letters to the advice columnist 'Dear Abby' provide insight into prevailing sex, religion, and LGBTQ fears, anxieties, and concerns from the 1950s onward.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'

Hear 50 years of iconic hip-hop samples, the genre's foundational looped tracks

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

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.