About 66 million years ago, an asteroid larger than Mount Everest struck Earth off the coast of the Yucatán Peninsula and wiped out at least 75% of all species, including nearly all dinosaurs.

The resulting climate change, not the asteroid impact itself, killed most dinosaurs

Although the Chicxulub impact caused widespread destruction through earthquakes and tsunamis, the subsequent nuclear winter, acid rain, and eventual greenhouse warming drove mass extinction. Roughly 70% of species, including all non-avian dinosaurs, went extinct.

Dinosaurs would likely still roam Earth if the Chicxulub asteroid had hit elsewhere

Some scientists argue that the asteroid's impact would have been less severe if it had struck the ocean instead of shallow seas. In this scenario, small dinosaurs might have become urban survivors, living in cities alongside humans, much like pigeons or rats do today.

A modern-day version of the dinosaur-killing asteroid would kill billions of people

Such an asteroid would level Central America, trigger tsunamis, spark global fires, and plunge the planet into an artificial winter lasting over a decade. Bunkers would be insufficient for survival without years of provisions.

Research suggests a 95-kilometer-wide (59-mile-wide) asteroid impact could boil the Earth's oceans

Even a 1-kilometer-wide (0.62-mile-wide) asteroid can trigger earthquakes and tsunamis on impact with oceans. The overwhelming majority of asteroids that reach Earth are much smaller and burn up in the atmosphere before reaching the ground.

There have been five mass extinction events in Earth’s history

Each extinction event has resulted in the loss of at least 70% of Earth’s species at the time of the event, often due to significant changes in global temperatures. The most recent event occurred 66 million years ago and wiped out all non-avian dinosaurs.

Studies show the asteroid that killed the dinosaurs was from the outer asteroid belt

Isotopic evidence confirms the rock was a carbon-rich asteroid, likely born beyond Jupiter and later knocked into Earth's path after billions of years of orbital drift and gravitational nudges. Its path spanned over 4 billion years and ended in the extinction of 75% of life, including all nonavian dinosaurs.

The Age of Dinosaurs ended in fiery disaster

How did dinosaurs become extinct? Explore the Cretaceous extinction event and the role of the Chicxulub impact in the death of dinosaurs (except birds).

Dinosaurs emerged 245 million years ago when Earth’s continents were still conjoined

Once the supercontinent split apart, dinosaurs evolved into thousands of species as they adapted to their changing environments. All non-avian dinosaurs went extinct about 66 million years ago following an asteroid impact, while avian dinosaurs evolved into today’s birds.

Variations in beak shape helped birds survive the dinosaur extinction event

The asteroid that struck Earth 66 million years ago killed some avian dinosaurs. The smaller species endured by reproducing more quickly and adapting to the environment. Their different beaks allowed them to eat more varied foods for survival.

Discovering how the dinosaurs went extinct may have helped avert nuclear war

This NPR Throughline episode explains how the 1980 discovery that an asteroid-driven dust cloud killed the dinosaurs inspired Cold War scientists' fears of "nuclear winter"—a sunlight-blocking aftermath of nuclear war that may have discouraged leaders from launching one.

Jupiter may have affected the trajectory of the asteroid that wiped out the dinosaurs

Despite its reputation as Earth’s cosmic shield, Jupiter’s gravity pulls more asteroids into Earth-crossing orbits. Simulations show that Earth experiences over three times more asteroid impacts because of Jupiter’s influence than if Jupiter didn’t exist.

There are lots of weird ideas about dinosaur extinction, like hungry, hungry caterpillars

One of the great historical puzzles is this: why did the dinosaurs go extinct? Whether an asteroid, poison plants, volcanos and climate change, or something else, it's still a mystery. Scientists have been debating this question for almost a hundred years. One insect scholar suggests that caterpillars are the culprits.

Humans were forced to adapt to survive a supervolcano eruption 74,000 years ago

The Toba supereruption ejected 2800 cubic kilometers of ash, resulting in global cooling from blocked sunlight and acid rain. Archaeological sites show that humans developed bow-and-arrow technology to survive in arid conditions by fishing in seasonal waterholes.

What did Earth look like when dinosaurs roamed?

The face of the Earth isn’t remotely the same as when the dinosaurs ruled the roost. The passing of millions of years, plate tectonics, and a spotty track record with asteroid collisions have changed the planet’s surface. Use this interactive globe to see what the Earth looked like millions of years ago.

Earth is constantly bombarded by material from space

Most of this matter is composed of small particles, with any smaller than 33 feet in diameter burning up in the atmosphere. Larger asteroids can reach the ground, and those larger than several thousand feet cause global damage, including earthquakes and tsunamis.

Craters found on the moon and the calculated dates of these impacts, based on rocks returned by the Apollo missions, suggest that Earth was pummeled by asteroids for millions of years—a period known as the Late Heavy Bombardment.

Watch visualization of different-sized asteroid impacts

The animations range from a 4-meter-wide asteroid that would burn up in the atmosphere with the impact of 0.6 Hiroshima nuclear bombs to a 940-kilometer asteroid the size of the dwarf planet Ceres, which would produce a mass extinction event.

Mammals gradually expanded in size and diversity after the dinosaur extinction

After an asteroid impact caused a mass extinction event 66 million years ago, small mammals were among the few surviving species. With fewer predators, mammals steadily grew larger as new habitats emerged.

If the Earth stopped spinning, 85% of the world's population would experience supersonic winds

The planet's equator moves about 470 meters per second—over 1,000 miles per hour—and air there would continue moving at this speed for several minutes if the ground stopped rotating. These conditions would cause tsunamis, global storms, and fling debris fast enough to destroy nearly all human-made structures.

What would happen if a massive asteroid struck Earth?

While NASA states that no known asteroid currently threatens Earth, past impacts demonstrate that the risk is real. The agency has tested deflection technology to alter an asteroid's path, as this visualization imagines a worst-case collision scenario.

Dinosaurs’ feathers and greater metabolism helped them survive polar conditions

Studies of dinosaur footprints alongside ice-deposited rock fragments indicate that early dinosaurs adapted to cold weather before the volcanic winters of the Triassic-Jurassic extinction event. These geological events helped dinosaurs to flourish by wiping out their amphibious competitors.

If the sun disappeared, we would not know about it for 8 minutes and 20 seconds, at which point the Earth would suddenly move in a straight line on its way out of the solar system.

Underwater volcanoes significantly contributes to marine extinctions during the Triassic period

An analysis of ocean basins in the Tibetan Plateau helped identify three major periods of volcanism—250-248, 233-231, and 210-208 million years ago—which released significant amounts of greenhouse gases, altering ocean chemistry. The low-oxygen conditions may help explain half of Earth's Triassic extinctions.

Why Earth would become a more deadly environment without the ozone layer

The ozone layer blocks almost all of the sun's harmful, including dangerous UVC rays that can damage cells by breaking chemical bonds. Without it, rates of skin cancer, crop failures, oceanic die-offs, and widespread ecosystem collapse would increase significantly, making Earth largely uninhabitable.

Rapid environmental changes are exacerbating natural extinction processes

Human activities behind climate change, habitat destruction, pollution, and overhunting have resulted in extinction rates up to 1,000 times greater than normal, triggering massive biodiversity loss. This has led scientists to refer to the current geological age as the Anthropocene era, in which humans are the dominant force shaping nature.

How the loss of Earth's atmosphere would cause oceans to boil at freezing temperatures

Many phenomena requiring air pressure, from the flight of birds and aircraft to the act of breathing, would no longer be possible. Because sound travels through vibrating air molecules, the loss of the planet's atmosphere would also create a silent environment. Even during daytime hours, the sky would resemble a clear night sky.

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.

Supervolcanoes can eject enough material to fill one-fourth of the Grand Canyon

Although extremely rare, their released material can trigger winters by blocking the sun and cooling the Earth’s surface for years. The Toba supereruption 74,000 years ago disrupted food chains and reduced the human population to a few thousand.

Estimates say 2.5 billion total T. rexes lived on Earth

Roughly 68 million years ago, the Tyrannosaurus rex was king of the North American ecosystem. Researchers used the dinosaur's size, metabolic rate, age of sexual maturity, and other factors to determine 20,000 individuals likely were alive at any given time, more than 120,000 20-year generations. This piece breaks down how they arrived at those numbers.

View the 10 biggest volcanic eruptions in recorded history

The Mount Tambora eruption in 1815 was the deadliest and released so much sun-blocking ash and gas that 1816 became known as “the year without summer.” The resulting global food shortages are estimated to have killed over 71,000 people.

What did the world of the dinosaurs look like?

Mesozoic means "middle life" and this is the time of the dinosaurs. This era includes the Triassic, Jurassic, and Cretaceous Periods, names that may be familiar to you. It ended with a massive meteorite impact that caused a mass extinction, wiping out the dinosaurs.

Could the world's largest solar storm happen again?

In 1859, the world witnessed the most intense solar storm in recorded history. The electromagnetic deluge of dust and gas lit up the night sky and sparked fires, disrupting Earth's magnetic field and putting on a show for the millions. If a storm with a similar intensity today occurred, scientists believe it would be catastrophic for our communications systems. Learn what would happen if the Carrington Event happened again here.

Supermountains the size of the continental US may have sparked complex life on Earth

Geological records show that the Nuna and the Transgondwanan Supermountains existed around the same time as two major jumps in species complexity on the planet: the rise of large organisms and the Cambrian explosion, respectively. Researchers believe that the erosion of these mountains deposited major nutrients into the oceans and boosted oxygen levels, both of which supported more complex species.

In 1962, the US detonated a nuclear weapon in space, which produced an electromagnetic pulse that disabled three low Earth orbit satellites and damaged electrical equipment in Hawaii.

Ten impact craters you can visit

See photos of ten wild Earth impact craters across the world, the result of impacts occurring between thousands and millions of years ago.

Why Earth will be made uninhabitable by the sun far sooner than when the sun dies

The star has enough fuel to continue fusing hydrogen into helium for another 5 billion years, but the gradual increase in core temperature from these reactions will brighten the sun by 10% every billion years. Some models predict that the increased radiation will be enough to vaporize all of Earth's surface water about 1 billion years from now, long before the sun becomes a red giant and disintegrates the planet.

The global impacts of the 1877 'super' El Niño and what could result from similar future events

The 1877 El Niño event lasted approximately 18 months, raised temperatures in the Niño 3.4 region of the equatorial Pacific Ocean by 2.7 degrees Celsius (4.86 degrees Fahrenheit) above average, and contributed to a global famine that killed more than 50 million people. Such events are expected to exacerbate drought-related risks to global food security, driving up food prices worldwide. (Some readers may experience a paywall.)

Ballistic experiments show that tardigrades are unlikely to be an alien species

Those fired from guns at speeds as high as 825 meters per second (1,845 mph) could be resuscitated after impact. Shock pressure from greater speeds tore apart the samples, suggesting they could not survive asteroid impacts if brought to Earth from outer space.

Explore an interactive timeline of Earth's 4.5-billion-year history to visualize shifting landmasses and oceans, view the locations of significant asteroid impacts, and learn about major geological and biological events.