The day the dinosaur era ended: This is how the disaster spread minute by minute

First came a blinding flash, a shock wave, and a massive tsunami; then dust, soot, and aerosols covered the sky, halting photosynthesis and toppling food chains. Two researchers recreate what the hours, years, and tens of millions of years after the Chicxulub impact looked like

"In a flash, she was burned, and her world was changed forever," write researchers Monica Grady and Michael J. Benton.

Thus ends the last day of an imaginary female Tyrannosaurus rex, walking through the conifers of late Cretaceous North America. She sniffs a Triceratops carcass, spots an Ankylosaurus near a lake, and finally raises her head toward a point of light that is getting brighter in the sky.

Grady, professor of planetary and space sciences at the Open University in the UK, and Benton, professor of vertebrate paleontology at the University of Bristol, used this literary image as an opening for a scientific reconstruction of one of the fateful days in the history of life.Their article in The Conversation They describe what could be seen, heard, and even smelled during the impact and in the hours, weeks, and years that followed. The following news story is an original journalistic adaptation of their article, supplemented by studies published in recent years.

The day before impact: A star that doesn't move

A day before the disaster, the world was operating almost as normal. The climate was warm, sea levels were much higher than they are today, and large parts of eastern Mexico and the southern United States were covered in shallow water.

The asteroid, estimated to be 10 to 15 kilometers in diameter, would have been visible for days as a star-like point of light. As it traveled almost directly toward Earth, its motion across the sky would have been minimal. Only in the final hours would it have become bright enough to be visible in daylight.

There was no warning system, no safe place to evacuate to, and the creatures living at the time had no way of understanding that the brightening spot was a celestial body approaching at a speed of tens of kilometers per second.

Moment of impact: Crater within seconds

About 66 million years ago, the asteroid struck what is now the northern Yucatan Peninsula in Mexico. At the time, the area was covered by a shallow sea with a seabed rich in limestone, carbonates, and sulfur-containing minerals.

The impact created the Chicxulub crater, about 200 kilometers in diameter. The asteroid's kinetic energy was converted into heat, shock waves, and seismic vibrations within seconds. Seawater, the asteroid itself, and vast amounts of rock were melted, crushed, or vaporized. ([Nature][1])

First, a temporary cavity was created, much deeper and wider than the asteroid. The crater floor rose back up, like a water surface after a rock fall, creating a high central peak. But the rock was unable to support the structure: the peak collapsed outward, creating a ring of buried mountains, which were explored tens of millions of years later by drilling.

Imaging studies suggest that the asteroid struck at a steep angle, probably about 45 to 60 degrees. Such an angle would have been particularly effective in blowing material from the ground into the atmosphere and spreading dust and gases from both climates around the world. ([Nature][2])

The first few minutes: flash, blast wave, and supersonic winds

A creature nearby would first see a light much brighter than sunlight. It might have heard faint crackles as the radiation rapidly heated the ground and air above it. The supersonic boom would come later, because light travels faster than sound.

Near the crater, it was impossible to survive the heat and the blast wave. At greater distances, earthquakes, strong winds, and pressure waves spread. Rocks that were dislodged from the ground were blown hundreds and even thousands of kilometers away.

However, the precise reconstruction of the immediate devastation is largely based on computer models. There is no way to know what the temperature was at any given point or how quickly the winds died down. The extent of the fires sparked by the thermal radiation and the hot material that returned to the atmosphere is also still a matter of scientific debate. ([Nature][3])

The tsunami crosses the oceans

Because the asteroid hit the sea, the impact dislodged huge amounts of water and seabed. Waves hundreds of meters high or more were generated near the crater, washing the shores of the Gulf of Mexico.

A global simulation published in 2022 showed that the tsunami spread from the Gulf into the Atlantic Ocean, and then into the Pacific and Indian Oceans. Researchers compared its initial energy to thousands or even tens of thousands of large modern tsunami events. Evidence of erosion and seafloor disturbance was found at sites thousands of kilometers from the impact site.

The waves weakened as they moved farther away, but even on distant shores they could inundate large areas, uprooting vegetation and altering habitats. However, the tsunami alone was not the main cause of the global extinction. The really big threat was already building up high in the atmosphere.

The first hour: The sky begins to burn and darken.

Material ejected from the crater penetrated the upper atmosphere and even briefly escaped into space. Droplets of molten rock and mineral grains cooled into tiny spheres and returned to the Earth's surface.

Their re-entry heated the atmosphere. In some areas, vegetation caught fire, and soot from the fires mixed with the rock dust and compounds ejected from the crater. Within hours, the belt of material surrounding the Earth began to block an increasing portion of sunlight.

In places far from the impact, including parts of Asia, Europe and New Zealand, nothing may have been felt for the first hour except a change in the color of the sky. The creatures living there survived the blast – but faced a slower, more prolonged disaster.

The first days: from the heat to the cold

The dust, soot, and sulfur spray reduced the amount of sunlight reaching the surface. Temperatures began to drop, and plants and phytoplankton had difficulty photosynthesising.

For years, researchers believed that sulfur compounds were the main cause of the “impact winter.” The asteroid struck sulfur-rich rocks, and heating the rocks released gases that could turn into reflective aerosols. These gases also contributed to acid rain and the rapid acidification of the ocean surface.

A study published in 2025 confirmed that a huge amount of sulfur was emitted, but estimated it at an average of 67 billion tons—about a fifth of some earlier estimates. This suggests that sulfur's share in creating the global winter was probably smaller than previously thought, and that dust and soot played a more central role.

Weeks and years of darkness

A study published in Nature Geoscience in 2023 examined the size of dust grains in the Cretaceous-Paleogene boundary layer. The researchers found a large amount of fine silicate dust, whose grains were small enough to remain in the atmosphere for years.

According to the simulations, some of the dust could have remained in the air for up to 15 years. The average global temperature could have dropped by as much as 15 degrees Celsius, and the amount of light available for photosynthesis would have dropped to a level that would have prevented almost any primary production for nearly two years.

Not every region was equally dark or cold, and not all the results occurred at exactly the same time. The numbers vary between models depending on assumptions about the amount of dust, grain size, soot, and sulfur. But the overall picture is clear: food systems on land and at sea lost the foundation on which they relied.

Why did the large animals disappear?

The dinosaurs that lived far from Mexico were not necessarily killed on the day of impact. Many of them survived the first few hours and even days, but encountered a world where plants died, prey disappeared, and temperatures plummeted.

Large animals needed large amounts of food and could not hide in burrows or survive for long on small food supplies. Non-avian dinosaurs, pterosaurs, ammonites, and large marine reptiles disappeared completely.

In contrast, some groups of small creatures had advantages: the ability to burrow, live in water, feed on seeds and decaying organic matter, or slow down their metabolism. This is how lineages of small mammals, birds, crocodiles, turtles, lizards, snakes, and amphibians survived.

In total, an estimated 75% of the species that lived on Earth became extinct. None of the surviving groups emerged from the disaster unscathed; the difference was that a few populations managed to hold out until light and vegetation returned. ([Nature][1])

Ten years after the impact: a world without large dinosaurs

As the dust and soot settled and the light returned, food systems were rebuilt. Ferns and fast-growing plants were the first to spread across the damaged areas, followed by new forests.

But the ecosystems were no longer the same. The large animals that had dominated the land for more than 150 million years had disappeared, and small surviving species were able to expand into the vacated niches.

Mammals did not emerge from the impact – they had coexisted with the dinosaurs for millions of years – but the disappearance of their competitors and large predators opened up new possibilities for them. Over the next millions of years, they evolved into large and diverse groups, including primates.

Life has returned to the center of the crater as well.

Surprisingly, the impact area itself did not remain a permanent wasteland. A study published in 2025 found that a hydrothermal system formed in the hot rocks of the crater pumped minerals and nutrients into the water above it.

According to the researchers, this system contributed to the development of marine life at the site over hundreds of thousands of years. The place that was the epicenter of the disaster gradually became a nutrient-rich environment – ​​an extreme example of the ability of life to exploit even the consequences of a devastating event. [UT Institute for Geophysics]

66 million years later

The Chicxulub crater is now mostly buried under younger rocks and the waters of the Gulf of Mexico. It does not look like a regular crater from the ground, but its outline can be identified by gravity, magnetic, and radar measurements. A series of sinkholes on the Yucatan Peninsula indirectly mark part of its rim.

It was not until 1980 that Luis Alvarez, his son Walter, and their colleagues suggested that an unusual iridium layer found in rocks around the world indicated an asteroid impact. In 1991, the Chicxulub crater was identified as a site of suitable age and size. Since then, evidence has accumulated from rocks, fossils, drilling, and climate simulations.

Grady and Benton's reconstruction is not an exact snapshot of the day of the impact. Some of the details are based on models that researchers continue to refine, and the debate over the relative weight of dust, soot, and sulfur is still ongoing. But the conclusion is not very controversial: the collision quickly changed the climate, halted food production, and led to mass extinctions.

The asteroid not only ended the era of the great dinosaurs. It opened a new evolutionary path, which eventually led to the appearance of humans – creatures capable, 66 million years after the event, of reading the remains of the disaster from a thin layer of rock.

For the original publication: Opening the original publication

More on the subject on the science website

• What killed the dinosaurs?
• The asteroid that wiped out the dinosaurs was a carbonaceous asteroid
• The asteroid that killed the dinosaurs hit at the worst angle
• The birds survived the extinction of their dinosaur relatives thanks to the ability to eat seeds
• Dinosaurs thrived before the asteroid impact wiped them out
• The consensus around the assertion that an asteroid killed the dinosaurs is getting stronger
• The recovery was faster than expected.