Some 65 million years ago the greatest asteroid impact in a billion years may have sown life throughout the solar system, even as it ravaged life on Earth. Blasted debris escaped Earth’s gravitational force forming irregular orbits around the sun, eventually finding its way to the planets and moons of the solar system.
Mars was eventually dusted with the debris and according to a 2013 study in the journal Astrobiology, the 14-kilometer-wide object ejected tens of thousands of pounds of impact rubble that may have landed on Saturn’s moon, Titan and on Europa and Callisto, which orbit Jupiter – all satellites that scientists believe harbor promising habitats for life. Mathematical models indicate that at least some of this debris still carried living microbes.
The Death Star
“If on a certain evening about sixty-six million years ago, you were somewhere in North America and looked up at the sky, you would have soon made out what appeared to be a star,” writes Douglas Preston in The Day the Dinosaurs Died. “If you watched for an hour or two, the star would have seemed to grow in brightness, although it barely moved. That’s because it was not a star but an asteroid, and it was headed directly for Earth at about forty-five thousand miles an hour.”
Paved a Pathway for the Emergence of the Human Species
The air in front of the asteroid was compressed and violently heated as it entered the Earth’s atmosphere and blasted a hole generating a supersonic shock wave that rang around the planet., It began vaporizing on impact, mingling with vaporized Earth rock, and forming a fiery plume, which reached halfway to the moon before collapsing in a pillar of incandescent dust. The asteroid struck a shallow sea where the Yucatán peninsula is today. As it did, it ended the Cretaceous period at the dawn of the Paleogene epoch creating the pathway for the emergence of the human species.
Alien Object Towered a Mile above the Cruising Altitude of a 747
“The asteroid itself was so large that, even at the moment of impact, the top of it might have still towered more than a mile above the cruising altitude of a 747,” writes Peter Brannen in Ends of the World. “In its nearly instantaneous descent, it compressed the air below it so violently that it briefly became several times hotter than the surface of the sun,” hitting Earth with enough force it could lift a mountain back into space at escape velocity.
Q Machine Paints a Terrifying Picture
A few years ago, reports Preston, scientists at Los Alamos National Laboratory used what was then one of the world’s most powerful computers, the so-called Q Machine, to model the effects of the impact, creating a slow-motion, second-by-second false-color video of the event:
“Within two minutes of slamming into Earth, the asteroid, which was at least six miles wide, had gouged a crater about eighteen miles deep and lofted twenty-five trillion metric tons of debris into the atmosphere. Picture the splash of a pebble falling into pond water, but on a planetary scale. When Earth’s crust rebounded, a peak higher than Mt. Everest briefly rose up. The energy released was more than that of a billion Hiroshima bombs, but the blast looked nothing like a nuclear explosion, with its signature mushroom cloud. Instead, the initial blowout formed a “rooster tail,” a gigantic jet of molten material, which exited the atmosphere, some of it fanning out over North America. Much of the material was several times hotter than the surface of the sun, and it set fire to everything within a thousand miles. In addition, an inverted cone of liquefied, superheated rock rose, spread outward as countless red-hot blobs of glass, called tektites, and blanketed the Western Hemisphere.”
The Three-Meter Problem
Scientists still debate many of the details of the asteroid impact, which are derived from computer models, and from field studies of the debris layer, knowledge of extinction rates, fossils and microfossils, and many other clues, writes Preston. “The over-all view is consistently grim. The dust and soot from the impact and the conflagrations prevented all sunlight from reaching the planet’s surface for months. Photosynthesis all but stopped, killing most of the plant life, extinguishing the phytoplankton in the oceans, and causing the amount of oxygen in the atmosphere to plummet. After the fires died down, Earth plunged into a period of cold, perhaps even a deep freeze. Earth’s two essential food chains, in the sea and on land, collapsed. About seventy-five per cent of all species went extinct. More than 99.9999 percent of all living organisms on Earth died, and the carbon cycle came to a halt.”
Earth Itself became Toxic
Earth itself became toxic from the impact, vaporizing layers of limestone, releasing powerful greenhouse gases into the atmosphere: a trillion tons of carbon dioxide, ten billion tons of methane, and a billion tons of carbon monoxide. The impact also vaporized anhydrite rock, billowing ten trillion tons of sulfur compounds aloft. combining with water to form sulfuric acid, which then fell as an acid rain.
One of the enduring mysteries of paleontology is the so-called “three-meter problem” –in a century and a half of assiduous searching, almost no dinosaur remains have been found in the layers three meters, or about nine feet, below the KT boundary that marks the dividing line between the Cretaceous period and the Tertiary or Paleogene period. Consequently, reports Preston, numerous paleontologists have argued that the dinosaurs were on the way to extinction long before the asteroid struck, owing perhaps to the volcanic eruptions and climate change. Other scientists have countered that the three-meter problem merely reflects how hard it is to find fossils. Sooner or later, they’ve contended, a scientist will discover dinosaurs much closer to the moment of destruction.
Buried in the KT boundary are the answers to our questions about one of the most significant events in the history of life on the planet. If one looks at the Earth as a kind of living organism, as many biologists do, writes Preston,you could say that it was shot by a bullet and almost died. Deciphering what happened on the day of destruction is crucial not only to solving the three-meter problem but also to explaining our own genesis as a species.
The Day the Earth Rained Glass
Enter one Robert DePalma: In March 2019, The Daily Galaxy posted “The Day the Earth Rained Glass” –Prelude to Extinction that described the horror of the impact. The beginning of the end started with violent shaking that raised giant waves in the waters of an inland sea in what is now North Dakota. Then, tiny glass beads began to fall like birdshot from the heavens. The rain of glass was so heavy it may have set fire to much of the vegetation on land. In the water, fish struggled to breathe as the beads clogged their gills, says paleontologist Robert DePalma about the killing field laid down soon after the asteroid impact that eventually led to the extinction of all ground-dwelling dinosaurs, the so-called K-T boundary, that exterminated 75 percent of life.
“This is the first mass death assemblage of large organisms anyone has found associated with the K-T boundary,” said DePalma, curator of paleontology at the Palm Beach Museum of Natural History. “At no other K-T boundary section on Earth can you find such a collection consisting of a large number of species representing different ages of organisms and different stages of life, all of which died at the same time, on the same day.”
Hell Creek geological Formation
DePalma’s discovery was in the Hell Creek geological formation, which outcrops in parts of North Dakota, South Dakota, Montana, and Wyoming–some of the most storied dinosaur beds in the world. At the time of the impact, the Hell Creek landscape consisted of steamy, subtropical lowlands and floodplains along the shores of an inland sea. The land teemed with life and the conditions were excellent for fossilization, with seasonal floods and meandering rivers that rapidly buried dead animals and plants.
DePalma christened the site Tanis, after the ancient city in Egypt, which was featured in the 1981 film “Raiders of the Lost Ark” as the resting place of the Ark of the Covenant. In the real Tanis, archeologists found an inscription in three writing systems, which, like the Rosetta stone, was crucial in translating ancient Egyptian.
A cosmic impact powerful enough to wipe out all life on Earth’s surface would loft large amounts of rock into orbit around the sun. And most of these bits and pieces would end up falling back onto our bruised and battered planet, potentially bringing life back with them, said Steinn Sigurðsson, a professor in the Department of Astronomy and Astrophysics at Penn State University. “This is peculiarly reassuring,” Sigurðsson said last month at the Breakthrough Discuss conference at the University of California, Berkeley.
“If you have a sterilizing impact — if you have a beyond dinosaur killer, something that’s going to flash fry the entire planet — there is a significant probability that some biota is ejected and returns to the planet, hopefully gently, fast enough to reseed the planet,” he added. The existence of such “space refugees” is supported by computer simulations that Sigurðsson and colleagues recently performed to track the trajectories of rock blasted off Earth and the other rocky planets into orbit around the sun.
“We can trace our origins back to that event”
For the first hundred million years of their existence, before the asteroid struck, mammals scurried beneath the feet of the dinosaurs, “But when the dinosaurs were gone it freed them,” DePalma said. In the next epoch, mammals underwent an explosion of adaptive radiation observes Preston, evolving into a dazzling variety of forms, from tiny bats to gigantic titanotheres, from horses to whales, from fearsome creodonts to large-brained primates with hands that could grasp and minds that could see through time.
“We can trace our origins back to that event,” DePalma said. “To actually be there at this site, to see it, to be connected to that day, is a special thing. This is the last day of the Cretaceous. When you go one layer up—the very next day—that’s the Paleocene, that’s the age of mammals, that’s our age.
Image credit: ESO
Editor, Jackie Faherty, astrophysicist, Senior Scientist with AMNH. Jackie was formerly a NASA Hubble Fellow at the Carnegie Institution for Science. Aside from a love of scientific research, she is a passionate educator and can often be found giving public lectures in the Hayden Planetarium. Her research team has won multiple grants from NASA, NSF, and the Heising Simons foundation to support projects focused on characterising planet-like objects. She has also co-founded the popular citizen science project entitled Backyard Worlds: Planet 9 which invites the general public to help scan the solar neighbourhood for previously missed cold worlds. A Google Scholar, Faherty has over 100 peer reviewed articles in astrophysical journals and has been an invited speaker at universities and conferences across the globe. Jackie received the 2020 Vera Rubin Early Career Prize from the American Astronomical Society, an award that recognises scientists who have made an impact in the field of dynamical astronomy and the 2021 Robert H Goddard Award for science accomplishments.