In 2016, researchers studied a remote section of the Atlantic Ocean between Africa and South America, an area where they saw no planes or ships for days. The location was significant because it sits above the Mid-Atlantic Ridge, where two tectonic plates meet beneath the ocean. The team deployed instruments to detect waves and seismic activity, returning a year later to collect data.
The instruments revealed that hot liquid rock is constantly rising from deep below, pushing the tectonic plates apart. As a result, the Atlantic Ocean is expanding roughly two inches per year, slowly pushing Europe and Africa away from the Americas. The Pacific Ocean, meanwhile, is shrinking by about a fifth of a square mile per year. Some scientists project that the Pacific could eventually disappear entirely over millions of years.
Tectonic plates move at varying speeds, some comparable to the rate of human hair and fingernail growth. Over hundreds of millions of years, these movements could lead to the formation of a new supercontinent. Researchers have outlined several possible scenarios.
In one scenario, the Americas collide with Antarctica before moving toward Africa, which would have already merged with Europe and Asia. In another, the Atlantic stops widening and instead begins closing, creating a landmass surrounded by the Pacific. A third scenario envisions both the Atlantic and Pacific shrinking into small bodies of water while a new ocean forms elsewhere. A fourth predicts Africa, Australia, and most other continents drifting north, leaving Antarctica isolated.
The Earth has experienced similar continental shifts before. Around 300 million years ago, the planet had a single supercontinent called Pangaea, surrounded by one ocean. Over time, it broke apart into the continents known today. Geological evidence supports this history, including matching plant and animal fossils found on continents now separated by large oceans, and the way the coastlines of Africa and South America align like puzzle pieces.
Scientists have also studied the boundaries between oceans, noting that the Atlantic and Pacific do not mix easily at their meeting point. This is due to differences in density, salt content, and temperature, as well as ocean currents that move in different directions. The distinct boundary is visible in satellite images as a clear line between waters of different colors.
The Gulf of Mexico behaves less like a typical gulf and more like an independent ocean system. It is semi-closed, unusually deep in places, and positioned in the tropics where it absorbs large amounts of solar heat. This heat can intensify hurricanes passing through the region, as seen with storms like Katrina and Harvey. The basin also feeds the Gulf Stream, which carries warm water toward Western Europe, moderating climates there. The region supports significant economic activity, including offshore oil production and reef tourism, though it also carries environmental risks. In 2010, the Deepwater Horizon disaster released an estimated 4.9 million barrels of oil over three months, the largest accidental marine spill in history.
The history of asteroid impacts also offers context for understanding Earth’s vulnerability. Sixty-six million years ago, a large asteroid struck near what is now Mexico, an event widely associated with the extinction of the dinosaurs. In 2022, researchers identified a second impact crater off the coast of West Africa, called the Nadir crater, about five and a half miles wide. Using high-resolution 3D seismic imaging, scientists confirmed that an asteroid between 1,500 and 1,640 feet wide created it. The impact triggered a tsunami and left a damage zone extending thousands of miles. Some experts have speculated that this asteroid may have been a fragment of the same object that created the Chicxulub crater, though this remains a theory.
In 1908, an object estimated at 150 to 300 feet in diameter exploded in the atmosphere over Siberia, leveling 80 million trees across roughly 830 square miles. The Tunguska event left no impact crater because the object burst several miles above the ground. In 2013, a smaller asteroid about 60 feet in diameter exploded over Chelyabinsk, Russia. The shock wave damaged around 7,200 buildings, but there were no direct fatalities.
NASA continues to track near-Earth objects. One asteroid, Bennu, is considered potentially hazardous, with a small chance of impacting Earth in the late 22nd century. The probability is currently estimated at 1 in 2,700.
Volcanic islands also present risks. A mega-tsunami that struck Africa thousands of years ago moved boulders weighing hundreds of tons, leading scientists to estimate waves as tall as 800 feet. The likely cause was a flank collapse on the volcanic island of Fogo, where a chunk of the volcano fell into the ocean. Fogo remains active and last erupted in 2014. Scientists note that smaller volcanic islands can also experience collapses, which can generate tsunamis. The 1958 Lituya Bay event in Alaska, triggered by an earthquake and landslide, produced a wave over 1,700 feet tall, though only five people died. Researchers continue to monitor volcanic islands for signs of instability, including those in Hawaii, the Canary Islands, and the Caribbean.
Sea level is not uniform across the globe. At the Panama Canal, the Pacific Ocean sits about eight inches higher than the Atlantic, due to factors including water temperature, salinity, winds, and variations in Earth’s gravity. The planet’s gravity field is uneven because the crust and mantle vary in density. In the Indian Ocean, a region called the Indian Ocean Geoid Low has sea level sitting more than 328 feet lower than the surrounding area. Researchers now believe this depression was caused by hot magma plumes rising from the mantle, potentially linked to the breakup of an ancient ocean around 140 million years ago. Computer simulations suggest that sinking tectonic plates disturbed material deep below, setting off the plumes. The feature could persist for millions of years or eventually smooth out as mantle material shifts.
The 2004 Indian Ocean tsunami remains one of the deadliest natural disasters in modern history. An undersea earthquake of magnitude 9.3 struck off the coast of Sumatra, triggering waves that killed around 230,000 people across multiple countries. The city of Banda Aceh lost more than 60,000 residents within half an hour of the quake. Thailand, India, and Sri Lanka also suffered heavy losses. The earthquake, which lasted about ten minutes, moved sections of the seafloor upward by 130 feet, displacing massive amounts of water. A warning system has since been established in the Indian Ocean, using undersea pressure sensors and satellite communication. However, a real-life test in 2012 revealed weaknesses, as many residents in Banda Aceh ignored evacuation towers and instead fled by car, causing traffic jams. Public education efforts continue, with officials emphasizing warning signs such as strong ground shaking, rapid water recession, and unusual ocean sounds.
In 2014, a NASA satellite captured an image of a nearly perfect circular cloud formation about 280 miles wide in the Pacific Ocean. Scientists attributed the ring to a closed-cell convection pattern, where warm air rises and cooler air sinks, creating a circular structure. The image also showed a phenomenon called sunglint, where sunlight reflects off the ocean surface and creates shiny or dark patches in satellite images. These effects, while visually striking, can interfere with scientific observations of ocean color and phytoplankton blooms.
Some unusual sky phenomena have straightforward explanations. Spiral shapes sometimes seen at night are often leftover fuel from SpaceX Falcon 9 rockets that freezes and reflects sunlight high in the atmosphere. Lenticular clouds, which form near mountains under specific air-flow conditions, can resemble flying saucers but are a normal weather phenomenon. Falling space debris can create bright fireballs, and plane contrails, especially at sunset, can sometimes look like smoke from a crash.
The Cascadia Subduction Zone, stretching from Vancouver Island to Northern California, poses a significant earthquake and tsunami risk. In 1700, a magnitude 9 earthquake in this zone triggered a tsunami that reached Japan. Researchers confirmed the connection through geological records and Japanese historical documents. Scientists estimate that earthquakes this strong occur every 200 to 1,000 years, meaning the region is due for another. A future event could affect around 15 million people, with estimates of 13,800 deaths and 107,000 injuries. Roads, bridges, and airports would likely be severely damaged, and phone and power outages could last for months. Eastern Washington, shielded by the Cascade Mountains, may fare better and could serve as a staging area for recovery.
In the deep ocean, scientists have found that some jellyfish species are confined to the Arctic due to invisible barriers. A subspecies with a small knob on top of its body is found worldwide, while a knobless version remains trapped in the Arctic. Researchers used 120 years of photographs and DNA testing to investigate the difference. They suspect the North Atlantic drift acts as a biological boundary, though the exact reason remains unclear. The finding resembles the Wallace Line, a famous invisible border in Indonesia described by Alfred Russel Wallace in the 19th century. The line separates Asian and Australian wildlife, even where islands are only a short distance apart. Deep underwater trenches that never dried out have kept the two ecosystems separate for millions of years.
Research on ocean waves has shown that they can grow larger than previously believed. A recent study found that three-dimensional waves, formed when waves from different directions meet, can become twice as steep as two-dimensional waves before breaking. In tests using a tank with 168 mechanical paddles, researchers observed that these waves can continue growing without producing a whitecap. This suggests that ships, oil rigs, and offshore wind farms may need to be designed to withstand larger waves than current standards assume. Rogue waves, once dismissed as sailor stories, were officially confirmed in 1995 when an 84-foot wave struck a Norwegian gas platform. Since then, researchers have documented hundreds of such events, though they remain difficult to predict. A recent computer system using buoy data has shown it can predict about three out of four rogue waves five minutes in advance.
The simultaneous eruption of all volcanoes on Earth would have severe consequences, including global ash coverage, blocked sunlight, and acid rain. However, geologists note that such an event is highly unlikely because most volcanoes have separate magma sources and are not connected. Although some volcanoes share magma systems locally, there is no unified mechanism that could trigger a global eruption. Most volcanoes are active individually, with only about 10 to 20 erupting on any given day.
Antarctica contains more than 130 volcanoes beneath its western ice sheet, making it the largest volcanic region on Earth. Most of these were discovered in 2017. Only two are confirmed active: Deception Island and Mount Erebus, which has been continuously erupting since at least 1972. Supervolcanoes, such as Yellowstone, possess vast magma chambers and have the potential for extremely large eruptions, though current monitoring shows no signs of imminent activity.
European coastlines also face tsunami risk. The Mediterranean has experienced at least 290 tsunamis since 1600 BCE, though only about 10 percent of the world’s tsunamis occur in this region. In 1755, an earthquake near Lisbon triggered a tsunami that destroyed much of the Portuguese capital. UNESCO has established tsunami warning centers covering the Mediterranean and the Northeast Atlantic, and communities in Spain, France, and other countries have installed evacuation signs and procedures. Officials estimate that a tsunami of at least three feet could hit these coastlines within the next 30 years. Wetenschappelijk meteo-tsunamis, triggered by weather conditions, also pose a risk, particularly during summer.
In November 2020, a wave measuring about four stories tall was recorded off the coast of Vancouver Island, Canada. Marine Labs, the company operating the buoy that recorded it, verified the data and sent it to a rogue wave scientist at the University of Vancouver. The wave, officially recognized in February 2022, was three times the height of surrounding waves and became the most extreme rogue wave ever recorded. It caused no damage because it occurred far offshore. Rogue waves can also form in lakes, where a phenomenon known as the “three sisters” involves a series of large waves that can overwhelm ships. Some researchers believe rogue waves may have contributed to the disappearance of vessels in the Bermuda Triangle, where storms from multiple directions converge. Sneaker waves, which are similar to rogue waves but occur near shore, can sweep people off beaches and jetties without warning.
Scientists have also discovered a large freshwater reservoir beneath the ocean floor off the coast of Massachusetts. During Expedition 501, researchers drilled about 1,300 feet below the seafloor and found a layer of sediment soaked with fresh water beneath a seal of clay and silt. The reservoir may extend from offshore New Jersey to Maine and holds enough water to supply a city the size of New York for 800 years. Researchers believe the water may have come from glaciers melting during the last ice age, though they are still analyzing samples to confirm its origin. Fresh water is becoming an increasingly important resource, as the United Nations reports growing water shortages worldwide. Researchers plan further expeditions to identify similar reservoirs near Indonesia, Australia, and South Africa.
The largest earthquake ever recorded occurred in Chile in 1960, with a magnitude of 9.5. It lasted about ten minutes and triggered tsunamis across the Pacific, affecting Hawaii, Japan, and the Philippines. The quake shifted Earth’s axis and made days shorter by 1.26 microseconds. If an earthquake twice that size struck without warning, the resulting tsunamis could affect coastlines in China, Korea, Vietnam, and Australia, with waves potentially reaching 160 feet. Scientists emphasize the importance of recognizing natural warning signs, such as receding water, and moving to higher ground quickly.
