A blow–by–blow account has revealed what it would have been like to experience the impact of the dinosaur–killing asteroid.
Around 66 million years ago, a six–mile (10km)–wide space rock called Chicxulub smashed into Mexico.
The impact famously wiped out the dinosaurs, caused worldwide devastation and changed the course of history.
The collision released a huge dust and soot cloud that partially blocked out the sun and caused temperatures to plummet – and in the years that followed, it wiped out more than 50 per cent of all animal and plant species on Earth.
But the destructive event also paved the way for mammals to thrive – and for humans to evolve.
Now, the University of Bristol's Professor Michael Benton and The Open University's Professor Monica Grady have detailed the sights, sounds and smells of the famous impact.
'The event triggered instant changes to our planet and its atmosphere and led to the extinction of the dinosaurs and about half Earth's other species,' they wrote on The Conversation.
'But what would it have been like to experience such a gargantuan impact? Would you have died or survived? As experts on meteoritics and palaeontology, respectively, we've created a detailed timeline, based on decades of research, to take you right there.'
T–minus one day
The experts said that it would have been 'pleasantly warm', about 26°C (79°F), and wet at 'ground zero' at the time.
The asteroid, which has been visible in the sky at night for about a week, can now be seen in the daytime. It looks like a star or planet getting gradually brighter.
T=0 (impact)
A bright light is followed by a sonic boom as the asteroid hits the Yucatán Peninsula in southeast Mexico.
Anything near the impact site would have been incinerated instantly, the experts said.
'The asteroid is so huge that it almost certainly hits the ground before any living creature near the impact zone has time to run for cover,' they wrote.
Even if you were up to 1,242 miles (2,000km) from the epicentre, you'd have been killed quickly by thermal radiation and supersonic winds.
The impact famously wiped out the dinosaurs, who were the apex predators at the time, and caused worldwide devastation (file photo)
The Chicxulub asteroid slammed into a shallow sea in what is now the Gulf of Mexico around 66 million years ago
T–plus 5 minutes
Winds 'ease' to those of a category 5 hurricane, flattening everything within 1,500km (932 miles) of the impact.
Atmospheric temperatures in the region rise to 226.85°C (440°F) and the air fills with superheated steam.
'Next come the tidal waves, triggered by the vast quantities of displaced rock and water,' the experts said. 'These 100–metre mega tsunamis first strike the shores of what is now the Gulf of Mexico.'
Anyone up to 1,864 miles (3,000km) away who survived the first few seconds would likely die from overheating, earthquakes, hurricanes, fires, tsunami–driven floods or being hit by impact melt.
T–plus one hour
'Shockwaves on land and sea are only minor inconveniences compared with the fire that is still radiating down from the sky,' they wrote.
A belt of dust has circled the globe. The skies begin to darken in places as far away as New Zealand and Denmark.
This artist's reconstruction depicts North Dakota in the first months following the impact of an asteroid off Mexico's coast 66 million years ago, showing a dark, dusty and cold world in which the last non–avian dinosaurs were on the edge of extinction
Where did the asteroid come from?
We now know the origin of the asteroid that wiped out the dinosaurs.
By analysing the chemical signatures of rocks from the end of the Cretaceous Period, scientists have found that it came from beyond Jupiter.
Comparisons between the chemical record left behind by the strike 66 million years ago and known meteorite samples suggest that the Cretaceous asteroid was a carbonaceous chondrite.
This type of asteroid is one of the oldest known, having formed billions of years ago in the early solar system.
As these chondrites can only come from asteroids found beyond Jupiter, it suggests that the dinosaur–killing asteroid must have had its origins there too.
Source: Natural History Museum
T–plus one day
Huge tsunamis move east across the Atlantic and west across the Pacific, still reaching 50m (164ft) high.
The burning sky triggers wildfires across the globe. In what is modern Europe and Asia, the skies continue to fill up with dust and soot. Temperatures start to drop as sunlight is blocked.
'Trees and plants in general, including phytoplankton, close down as if for winter, unable to photosynthesise,' the experts explained. 'Any animals that rely on warm conditions ultimately hunker down and die.'
T–plus one week
It's getting darker and darker, with a global drop in surface temperatures of at least 5°C (9°F).
'This means that most of the dinosaurs and other large flying and swimming reptiles probably die from freezing within the course of this first week,' they said. 'Cooling temperatures and cloud cover also lead to rain. But not just any rain. Storms of acid rain fall across the Earth.'
Plants and animals on land and in shallow seas succumb to this corrosive rain while rotting vegetation, choking smoke and sulphur aerosols combine to make the planet stink.
Today, the event is marked by a thin layer of sediment called the K–Pg boundary, which can be found throughout the world in marine and terrestrial rocks, dated to 66 million years ago (pictured here in Zumaia, Spain)
T–plus one year
The atmosphere is still filled with dust and the sun hasn't shone for a year. Average temperatures are now 15°C (27°F) lower than before the impact.
The rotted skeletons of dinosaurs and marine reptiles are scattered everywhere. Small animals like mammals the size of rats and insects nest in crevices. More than 50 per cent of plants have died out.
T–plus 10 years
Earth is still in the grip of a fierce winter. Inland lakes and rivers around the world are iced over.
'Clearly, there were no humans about at this time – there weren't even any larger mammals,' the experts said.
'But given the only species that survived were those that could burrow or live below water, it is unlikely that you could have survived this long.'
However, life slowly begins to rebuild far away from the impact site as turtles, smaller crocodiles, lizards, snakes, some ground–dwelling birds and small mammals repopulate.
T–plus 66 million years
It is estimated that half the species of plants and animals alive at the end of the Cretaceous disappeared.
But the extinction of the dinosaurs led to the successful spread and evolution of mammals.
'It is salutary to think that without the asteroid collision, primates might never have reached the level we are at today,' the experts concluded.
'But it is equally salutary to consider that modern humans are causing some of the same changes to the atmosphere that ultimately killed our reptilian forebears and may one day also lead to our own demise.'
HOW THE DINOSAURS BECAME EXTINCT AROUND 66MILLION YEARS AGO
Dinosaurs ruled the Earth around 66million years ago, but suddenly disappeared in what is known as the Cretaceous-Tertiary extinction.
It was believed for many years that the changing climate destroyed the food chain of the huge reptiles.
However, in the 1980s paleontologists discovered a layer of iridium - an element that is rare on Earth but found in vast quantities in space.
When this was dated, it coincided precisely with when the dinosaurs disappeared from the fossil record.
A decade later, scientists uncovered the massive Chicxulub Crater at the tip of Mexico’s Yucatán Peninsula, which dates to the period in question.
Scientific consensus now says that these two factors are linked and they were both probably caused by an enormous asteroid crashing to Earth.
With the projected size and impact velocity, the collision would have caused an enormous shock wave and is likely to have triggered seismic activity.
The fallout would have created plumes of ash thought to have covered the whole planet, making it impossible for dinosaurs to survive.
Other animals and plant species had a shorter time-span between generations which allowed them to survive.
There are several other theories as to what caused the demise of the dinos.
One early theory was that small mammals ate dinosaur eggs and another proposes that toxic angiosperms (flowering plants) killed them off.