The question of “where is the end of Earth” is an enduring geographical inquiry. For millennia, people have sought to define the boundary between the known world and the unknown. This search has evolved from mythological edges imagined by early civilizations to the precise boundaries defined by modern science. The answer depends entirely on how the concept of an “end” is defined: as a perceived geographical boundary, a point of extreme remoteness, or a physical limit in the atmosphere.
Ancient Beliefs About Earth’s Edge
Early civilizations often conceptualized the limits of the world through mythology, typically assuming a flat, finite plane. The ancient Greeks, for example, believed the inhabited lands were encircled by a vast, fresh-water stream called Oceanus. This river was personified as the Titan Oceanus, separating the known world from the mysterious edge of the cosmos.
Beyond Oceanus lay a shadowy realm where the dome of the sky met the flat Earth. This mythical boundary was considered a place of danger and the ultimate limit. The fear associated with sailing too far, past the Pillars of Hercules, was rooted in the idea that sailors might literally fall off the edge or enter a chaotic void.
The geographical knowledge of the time was confined by this ring of water, which served as a natural and supernatural barrier. These early models reflected a limited scope of travel and a deep apprehension of the unknown that lay beyond familiar shores.
The Scientific Proof of a Spherical World
The idea of a geographical “end” was definitively rendered obsolete by empirical observations proving Earth is a roughly spherical object, or a geoid. Ancient thinkers provided observable proofs that the planet had no physical edges long before modern satellite imagery.
The Greek philosopher Aristotle, in the 4th century B.C., cited the way ships disappeared over the horizon. As a vessel sailed away, its hull would vanish before its mast and sails, which is consistent only with the curvature of the ocean’s surface.
Another compelling piece of evidence came from observing lunar eclipses. The shadow cast by the Earth onto the Moon’s surface is consistently curved and circular. Only a spherical object will project a circular shadow regardless of its rotational orientation, providing clear astronomical proof of the planet’s shape.
Around 240 B.C., Eratosthenes of Cyrene performed a famous experiment to approximate the Earth’s circumference with impressive accuracy. By measuring the angle of the sun’s shadow in two different Egyptian cities, Syene and Alexandria, he used geometry to calculate the planet’s overall size. These early scientific demonstrations established that the Earth is a continuous, self-contained sphere, eliminating the possibility of a final, precipitous edge.
Geographical Locations Referred to as the End
Despite the scientific consensus, the phrase “the end of the Earth” persists in modern language, referring to places of extreme remoteness, isolation, or dramatic geography. These locations represent the farthest reaches of human settlement or the final frontier before a vast, inhospitable expanse.
One of the most famous examples is Ushuaia, Argentina, which proudly calls itself the “City at the End of the World” (Fin del Mundo). Situated on the Beagle Channel, Ushuaia is widely considered the southernmost city in the world. Its remote location makes it the primary gateway for expeditions to Antarctica, embodying the idea of a last civilized stop before an immense, desolate wilderness.
Nearby, Cape Horn, the southernmost headland of the Tierra del Fuego archipelago, serves as a dramatic, unpopulated example. Historically, rounding this point was the most treacherous navigational challenge for sailing ships traveling between the Atlantic and Pacific Oceans. The isolation and tumultuous confluence of waters cemented its reputation as an ultimate geographical limit.
Other remote locations, such as the Tristan da Cunha archipelago in the South Atlantic, also share this figurative title due to their extreme isolation. The main island is one of the most geographically isolated inhabited places on Earth. These places represent the psychological and physical boundaries of human reach, symbolizing the limits of terrestrial exploration and settlement.
Defining Earth’s Outer Limit in Space
If the “end of the Earth” is defined vertically, as the boundary where the planet’s atmosphere and gravitational influence give way to outer space, the answer becomes a question of technical definition. The most commonly accepted boundary is the Kármán line, a conventional demarcation established at 100 kilometers (62.1 miles) above mean sea level. This altitude was calculated by Theodore von Kármán as the point where the air becomes too thin for conventional aerodynamic flight to be sustained, requiring a spacecraft to rely on orbital mechanics instead.
This boundary, however, is not a sharp, physical line, and various organizations utilize different altitudes for practical purposes. For instance, the United States Air Force and NASA have historically considered 80 kilometers (50 miles) as the altitude at which space officially begins. Beyond this lower boundary, the atmosphere continues to thin through layers like the thermosphere before reaching the outermost layer, the exosphere.
The exosphere, a tenuous shell of hydrogen and helium, can extend thousands of miles, with some estimates placing its outer limit at up to 6,200 miles (9,978 kilometers). Even further out, the Earth’s magnetic field, or magnetosphere, forms a protective bubble that interacts with the solar wind. The outer boundary of this magnetic influence, the magnetopause, represents the true extent of Earth’s geophysical domain, marking the final, complex limit where the planet’s immediate environment ends and the interplanetary medium begins.