Space and Science

Could Earth be a ‘waterworld’? It may have started that way

Ashley Strickland
By Ashley Strickland, CNN
3 minute read
Updated 11:14 AM EST, Mon March 2, 2020
This artist's illustration shows a young Purussaurus attacking a ground sloth in Amazonia 13 million years ago.
This artist's illustration shows a young Purussaurus attacking a ground sloth in Amazonia 13 million years ago.
Jorge A. González
This bundle of bones is the torso of another marine reptile inside the stomach of a fossilized ichthyosaur from 240 million years ago.
This bundle of bones is the torso of another marine reptile inside the stomach of a fossilized ichthyosaur from 240 million years ago.
Jiang et al.
Researchers uncovered the fossilized fragments of 200,000-year-old grass bedding in South Africa's Border Cave.
Researchers uncovered the fossilized fragments of 200,000-year-old grass bedding in South Africa's Border Cave.
Lyn Wadley/Wits University
Meet Sasha, the preserved and reconstructed remains of a baby woolly rhinoceros named that was discovered in Siberia.
Meet Sasha, the preserved and reconstructed remains of a baby woolly rhinoceros named that was discovered in Siberia.
Albert Protopopov
Stone tools made from limestone have helped researchers to suggest that humans arrived in North America as early as 30,000 years ago.
Stone tools made from limestone have helped researchers to suggest that humans arrived in North America as early as 30,000 years ago.
Ciprian Ardelean
This image shows both sides of the 1.4 million-year-old bone handaxe made from the femur of a hippopotamus. It was most likely crafted by ancient human ancestors like Homo erectus.
This image shows both sides of the 1.4 million-year-old bone handaxe made from the femur of a hippopotamus. It was most likely crafted by ancient human ancestors like Homo erectus.
Berhane Asfaw
This illustration shows Kongonaphon kely, a newly described reptile that was an early ancestor of dinosaurs and pterosaurs. The fossil was found in Madagascar. It lived about 237 million years ago.
This illustration shows Kongonaphon kely, a newly described reptile that was an early ancestor of dinosaurs and pterosaurs. The fossil was found in Madagascar. It lived about 237 million years ago.
Courtesy Alex Boersma
The Okavango Delta in Botswana showcases a patchy landscape where the ability to plan results in a huge survival payoff.
The Okavango Delta in Botswana showcases a patchy landscape where the ability to plan results in a huge survival payoff.
Tim Copeland
This is a clutch of fossilized Protoceratops eggs and embryos, discovered in the Gobi Desert of Mongolia. They provide evidence that dinosaurs laid soft-shell eggs.
This is a clutch of fossilized Protoceratops eggs and embryos, discovered in the Gobi Desert of Mongolia. They provide evidence that dinosaurs laid soft-shell eggs.
M. Ellison/AMNH
These tools, made from the bones and teeth of monkeys and smaller mammals, were recovered from Fa-Hien Lena cave in Sri Lanka. The sharp tips served as arrow points.
These tools, made from the bones and teeth of monkeys and smaller mammals, were recovered from Fa-Hien Lena cave in Sri Lanka. The sharp tips served as arrow points.
M.C. Langley
This labeled map shows the complete ancient Roman city of Falerii Novi as it currently exists underground.
This labeled map shows the complete ancient Roman city of Falerii Novi as it currently exists underground.
L. Verdonck
Fragments of the Dead Sea Scrolls found in the 1950s are seen here.
Fragments of the Dead Sea Scrolls found in the 1950s are seen here.
Najib Albina/Courtesy Israel Antiquities Authority
This is one of the 408 human footprints preserved at the Engare Sero site in Tanzania. The fossilized footprints reveal a group of 17 people that traveled together, likely including 14 women, two men and one juvenile male.
This is one of the 408 human footprints preserved at the Engare Sero site in Tanzania. The fossilized footprints reveal a group of 17 people that traveled together, likely including 14 women, two men and one juvenile male.
William Harcourt-Smith
Blade-like stone tools and beads found in Bulgaria's Bacho Kiro cave provide the earliest evidence for modern humans in Europe 47,000 years ago.
Blade-like stone tools and beads found in Bulgaria's Bacho Kiro cave provide the earliest evidence for modern humans in Europe 47,000 years ago.
Tsenka Tsanova
This artist's illustration shows what an early, small ichthyosaur that lived 248 million years ago may have looked like. It resembled a cross between a tadpole and a seal, grew to be one foot long and had pebble-like teeth that it likely used to eat invertebrates like snails and bivalves.
This artist's illustration shows what an early, small ichthyosaur that lived 248 million years ago may have looked like. It resembled a cross between a tadpole and a seal, grew to be one foot long and had pebble-like teeth that it likely used to eat invertebrates like snails and bivalves.
Stefano Broccoli
This is an artist's illustration of Adalatherium hui, an early mammal that lived on Madagascar 66 million years ago.
This is an artist's illustration of Adalatherium hui, an early mammal that lived on Madagascar 66 million years ago.
Andrey Atuchin
This is an artist's illustration showing a cross-section of Earth's forming crust approximately 3 to 4 billion years ago.
This is an artist's illustration showing a cross-section of Earth's forming crust approximately 3 to 4 billion years ago.
Alec Brenner/Harvard University
Illuminated medieval manuscripts are full of intricate decorations, illustrations and colors, including "endangered colors" that can no longer be recreated today.
Illuminated medieval manuscripts are full of intricate decorations, illustrations and colors, including "endangered colors" that can no longer be recreated today.
Duarte Belo
These monkeys can be found in ancient Grecian frescoes. And the details are so accurate that researchers were able to identify them as vervet monkeys and baboons.
These monkeys can be found in ancient Grecian frescoes. And the details are so accurate that researchers were able to identify them as vervet monkeys and baboons.
Bernardo Urbani/Antiquity Journal
Archeologists have found the oldest string of yarn at a prehistoric site in southern France. This photograph, taken by digital microscopy, shows that of the cord fragment, which is approximately 6.2 mm long and 0.5 mm wide.
Archeologists have found the oldest string of yarn at a prehistoric site in southern France. This photograph, taken by digital microscopy, shows that of the cord fragment, which is approximately 6.2 mm long and 0.5 mm wide.
C2RMF
This illustration shows Elessaurus gondwanoccidens, a long-legged reptile that lived in South America during the Early Triassic Period. It's a cousin to other mysterious early reptiles that arose after the Permian mass extinction event 250 million years ago.
This illustration shows Elessaurus gondwanoccidens, a long-legged reptile that lived in South America during the Early Triassic Period. It's a cousin to other mysterious early reptiles that arose after the Permian mass extinction event 250 million years ago.
Márcio L. Castro
The skeletal remains of Homo antecessor are on display in this image. A recent study suggests antecessor is a sister lineage to Homo erectus, a common ancestor of modern humans, Neanderthals and Denisovans.
The skeletal remains of Homo antecessor are on display in this image. A recent study suggests antecessor is a sister lineage to Homo erectus, a common ancestor of modern humans, Neanderthals and Denisovans.
Prof. José María Bermúdez de Castro
A nearly two-million-year-old Homo erectus skullcap was found in South Africa. This is the first fossil of erectus to be found in southern Africa, which places it in the area at the same time as other ancient human ancestors.
A nearly two-million-year-old Homo erectus skullcap was found in South Africa. This is the first fossil of erectus to be found in southern Africa, which places it in the area at the same time as other ancient human ancestors.
Therese van Wyk/University of Johannesburg
This painting shows what Antarctica may have looked like 90 million years ago. It had a temperate swampy rainforest.
This painting shows what Antarctica may have looked like 90 million years ago. It had a temperate swampy rainforest.
Alfred-Wegener-Institut/James McKay
This artist's illustration of Dineobellator notohesperus shows them in an open landscape, across what is now New Mexico, along with Ojoceratops and Alamosaurus in the background.
This artist's illustration of Dineobellator notohesperus shows them in an open landscape, across what is now New Mexico, along with Ojoceratops and Alamosaurus in the background.
Courtesy Sergey Krasovskiy
Ikaria wariootia was a worm-like creature that lived 555 million years ago. It represents the oldest ancestor on the family tree for most animals.
Ikaria wariootia was a worm-like creature that lived 555 million years ago. It represents the oldest ancestor on the family tree for most animals.
Sohail Wasif/University of California-Riverside
This is the 3.67-million-year-old 'Little Foot' skull. The view from the bottom (right) shows the original position of the first cervical vertebra, which tells us about her head movements and blood flow to the brain.
This is the 3.67-million-year-old 'Little Foot' skull. The view from the bottom (right) shows the original position of the first cervical vertebra, which tells us about her head movements and blood flow to the brain.
courtesy R.J. Clarke
This is an artist's illustration of the world's oldest modern bird, Asteriornis maastrichtensis, in its original environment. Parts of Belgium were covered by a shallow sea, and conditions were similar to modern tropical beaches like The Bahamas 66.7 million years ago.
This is an artist's illustration of the world's oldest modern bird, Asteriornis maastrichtensis, in its original environment. Parts of Belgium were covered by a shallow sea, and conditions were similar to modern tropical beaches like The Bahamas 66.7 million years ago.
Phillip Krzeminski
This donkey skull was recovered in a Tang Dynasty noblewoman's tomb. The researchers determined that she played donkey polo and was buried with her donkeys so that she may continue her favorite sport in the afterlife.
This donkey skull was recovered in a Tang Dynasty noblewoman's tomb. The researchers determined that she played donkey polo and was buried with her donkeys so that she may continue her favorite sport in the afterlife.
T. Wang, Junkai Yang and Songmei Hu
Hundreds of mammoth bones found at a site in Russia were once used by hunter-gatherers to build a massive structure 25,000 years ago.
Hundreds of mammoth bones found at a site in Russia were once used by hunter-gatherers to build a massive structure 25,000 years ago.
Alex Pryor
A fossil of an ancient rudist clam called Torreites sanchezi revealed that Earth's days lasted 23.5 hours 70 million years ago.
A fossil of an ancient rudist clam called Torreites sanchezi revealed that Earth's days lasted 23.5 hours 70 million years ago.
Wilson44691/Wikipedia
This is an artist's impression of dinosaurs on prehistoric mudflat in Scotland, based on varied dinosaur footprints recovered on the Isle of Skye.
This is an artist's impression of dinosaurs on prehistoric mudflat in Scotland, based on varied dinosaur footprints recovered on the Isle of Skye.
Jon Hoad
A new study suggests that ostrich eggshell beads have been used to cement relationships in Africa for more than 30,000 years.
A new study suggests that ostrich eggshell beads have been used to cement relationships in Africa for more than 30,000 years.
John Klausmeyer/Yuchao Zhao/Brian Stewart
This rock lined the seafloor roughly 3.2 billion years ago, providing evidence that Earth may have been a 'waterworld' in its ancient past.
This rock lined the seafloor roughly 3.2 billion years ago, providing evidence that Earth may have been a 'waterworld' in its ancient past.
Benjamin Johnson
These stone tools were found at the Dhaba site in India, showing that Homo sapiens survived a massive volcanic eruption 74,000 years ago.
These stone tools were found at the Dhaba site in India, showing that Homo sapiens survived a massive volcanic eruption 74,000 years ago.
Chris Clarkson
The remains of 48 people who were buried in a 14th century Black Death mass grave were found in England's Lincolnshire countryside.
The remains of 48 people who were buried in a 14th century Black Death mass grave were found in England's Lincolnshire countryside.
Antiquity Publications Ltd
The articulated remains of a Neanderthal have been found in Shanidar Cave, representing the first discovery of its kind in 20 years.
The articulated remains of a Neanderthal have been found in Shanidar Cave, representing the first discovery of its kind in 20 years.
Graeme Barker/Cambridge University
A rare disease that still affects humans today has been found in the fossilized vertabra of a duck-billed dinosaur that roamed the Earth at least 66 million years ago.
A rare disease that still affects humans today has been found in the fossilized vertabra of a duck-billed dinosaur that roamed the Earth at least 66 million years ago.
Assaf Ehrenreic
Venezuelan Palaeontologist Rodolfo Sánchez is shown next to a male carapace of the giant turtle Stupendemys geographicus, for scale.
Venezuelan Palaeontologist Rodolfo Sánchez is shown next to a male carapace of the giant turtle Stupendemys geographicus, for scale.
Edwin Cadena
This artist's illustration shows the newly discovered Tyrannosaurus rex relative, Thanatotheristes degrootorum.
This artist's illustration shows the newly discovered Tyrannosaurus rex relative, Thanatotheristes degrootorum.
Julius Csotonyi
The newly discovered species Allosaurus jimmadseni represents the earliest Allosaurus known. It was a fearsome predator that lived during the Late Jurassic Period millions of years before Tyrannosaurus rex.
The newly discovered species Allosaurus jimmadseni represents the earliest Allosaurus known. It was a fearsome predator that lived during the Late Jurassic Period millions of years before Tyrannosaurus rex.
Andrey Atuchin
Remains found in ancient Herculaneum boat houses revealed that people trying to flee the eruption of Mount Vesuvius slowly suffocated as volcanic clouds overtook the town.
Remains found in ancient Herculaneum boat houses revealed that people trying to flee the eruption of Mount Vesuvius slowly suffocated as volcanic clouds overtook the town.
Antiquity Publications Ltd
The Wulong bohaiensis fossil found in China's Jehol Province shows some early, intriguing aspects that relate to both birds and dinosaurs.
The Wulong bohaiensis fossil found in China's Jehol Province shows some early, intriguing aspects that relate to both birds and dinosaurs.
Ashley Poust
Shell tools were recovered from an Italian cave that show Neanderthals combed beaches and dove in the ocean to retrieve a specific type of clam shell to use as tools.
Shell tools were recovered from an Italian cave that show Neanderthals combed beaches and dove in the ocean to retrieve a specific type of clam shell to use as tools.
Villa et al., 2020
A closer look at the Heslington brain, which is considered to be Britain's oldest brain and belonged to a man who lived 2,600 years ago. Amazingly, the soft tissue was not artificially preserved.
A closer look at the Heslington brain, which is considered to be Britain's oldest brain and belonged to a man who lived 2,600 years ago. Amazingly, the soft tissue was not artificially preserved.
Courtesy Dr. Axel Petzold/University College London
Researchers from Russia's RAS Institute of Archeology excavated the burial sites of four women, who were buried with battle equipment in southwestern Russia and believed to be Amazon warrior women. The oldest woman found in the graves bore a unique, rare ceremonial headdress.
Researchers from Russia's RAS Institute of Archeology excavated the burial sites of four women, who were buried with battle equipment in southwestern Russia and believed to be Amazon warrior women. The oldest woman found in the graves bore a unique, rare ceremonial headdress.
Institute of Archaeology RAS
Teen Tyrannosaurus rex were fleet-footed with knife-like teeth, serving as mid-sized carnivores before they grew into giant bone-crushing adults.
Teen Tyrannosaurus rex were fleet-footed with knife-like teeth, serving as mid-sized carnivores before they grew into giant bone-crushing adults.
Julius T. Csotonyi
A Homo erectus skull cap discovered in Central Java, Indonesia reveals how long they lived and when the first human species to walk upright died out.
A Homo erectus skull cap discovered in Central Java, Indonesia reveals how long they lived and when the first human species to walk upright died out.
Rizal et al
This is an artistic reconstruction of Lola, a young girl who lived 5,700 years ago.
This is an artistic reconstruction of Lola, a young girl who lived 5,700 years ago.
Tom Björklund
Part of the scene depicted in the world's oldest cave art, which shows half-animal, half-human hybrids hunting pigs and buffalo.
Part of the scene depicted in the world's oldest cave art, which shows half-animal, half-human hybrids hunting pigs and buffalo.
Endra
An ancient Egyptian head cone was first found with the remains of a young woman buried in one of Amarna's graves.
An ancient Egyptian head cone was first found with the remains of a young woman buried in one of Amarna's graves.
courtesy Amarna Project
A lice-like insect was trapped in amber crawling and munching on a dinosaur feather.
A lice-like insect was trapped in amber crawling and munching on a dinosaur feather.
Taiping Ga
Newly discovered penguin species Kupoupou stilwelli lived after the dinosaurs went extinct and acts as a missing link between giant extinct penguins and the modern penguins in Antarctica today.
Newly discovered penguin species Kupoupou stilwelli lived after the dinosaurs went extinct and acts as a missing link between giant extinct penguins and the modern penguins in Antarctica today.
Jacob Blokland, Flinders University
This illustration compares the jaws and teeth of two predatory dinosaurs, Allosaurus (left) and Majungasaurus (right).
This illustration compares the jaws and teeth of two predatory dinosaurs, Allosaurus (left) and Majungasaurus (right).
Sae Bom Ra/Adelphi University
This is an artist's illustration of Najash rionegrina in the dunes of the Kokorkom desert that extended across Northern Patagonia during the Late Cretaceous period. The snake is coiled around with its hindlimbs on top of the remains of a jaw bone from a small charcharodontosaurid dinosaur.
This is an artist's illustration of Najash rionegrina in the dunes of the Kokorkom desert that extended across Northern Patagonia during the Late Cretaceous period. The snake is coiled around with its hindlimbs on top of the remains of a jaw bone from a small charcharodontosaurid dinosaur.
Courtesy Ral Orencio Gomez
University of South Carolina archaelogist Christopher Moore (second from right) and colleagues collect core samples from White Pond near Elgin, South Carolina, to look for evidence of an impact from an asteroid or comet that may have caused the extinction of large ice-age animals such as sabre-tooth cats and giant sloths and mastodons.
University of South Carolina archaelogist Christopher Moore (second from right) and colleagues collect core samples from White Pond near Elgin, South Carolina, to look for evidence of an impact from an asteroid or comet that may have caused the extinction of large ice-age animals such as sabre-tooth cats and giant sloths and mastodons.
University of South Carolina
Core samples from White Pond near Elgin, South Carolina, show evidence of platinum spikes and soot indicative of an impact from an asteroid or comet.
Core samples from White Pond near Elgin, South Carolina, show evidence of platinum spikes and soot indicative of an impact from an asteroid or comet.
University of South Carolina
The Sosnogorsk lagoon as it likely appeared 372 million years ago just before a deadly storm, according to an artist's rendering. The newly discovered tetrapod can be seen in the left side of the image below the surface.
The Sosnogorsk lagoon as it likely appeared 372 million years ago just before a deadly storm, according to an artist's rendering. The newly discovered tetrapod can be seen in the left side of the image below the surface.
Mikhail Shekhanov for the Ukhta Local Museum
Bronze goods recovered from a river in northern Germany indicate an ancient toolkit of a Bronze Age warrior.
Bronze goods recovered from a river in northern Germany indicate an ancient toolkit of a Bronze Age warrior.
Volker Minkus
Mold pigs are a newly discovered family, genus and species of microinvertebrates that lived 30 million years ago.
Mold pigs are a newly discovered family, genus and species of microinvertebrates that lived 30 million years ago.
Courtesy George Poinar Jr.
Ferrodraco lentoni was a pterosaur, or "flying lizard," that lived among dinosaurs 96 million years ago. The fossil was found in Australia.
Ferrodraco lentoni was a pterosaur, or "flying lizard," that lived among dinosaurs 96 million years ago. The fossil was found in Australia.
Scientific Reports
These Late Bronze Age feeding vessels were likely used for infants drinking animal milk.
These Late Bronze Age feeding vessels were likely used for infants drinking animal milk.
courtesy Katharina Rebay-Salisbury/Nature
This is the first depiction of what mysterious ancient humans called Denisovans, a sister group to Neanderthals, looked like. This image shows a young female Denisovan, reconstructed based on DNA methylation maps. The art was created by Maayan Harel.
This is the first depiction of what mysterious ancient humans called Denisovans, a sister group to Neanderthals, looked like. This image shows a young female Denisovan, reconstructed based on DNA methylation maps. The art was created by Maayan Harel.
courtesy Maayan Harel
Researchers found a fossil of one of the oldest bird species in New Zealand. While its descendants were giant seafaring birds, this smaller ancestor likely flew over shorter ranges.
Researchers found a fossil of one of the oldest bird species in New Zealand. While its descendants were giant seafaring birds, this smaller ancestor likely flew over shorter ranges.
Canterbury Museum
A painting shows the new species of giant salamander called Andrias sligoi, the largest amphibian in the world.
A painting shows the new species of giant salamander called Andrias sligoi, the largest amphibian in the world.
ZSL
After her discovery in 2013, Victoria's 66-million-year-old, fossilized skeleton was restored bone by bone. She's the second most complete T. rex fossil on record.
After her discovery in 2013, Victoria's 66-million-year-old, fossilized skeleton was restored bone by bone. She's the second most complete T. rex fossil on record.
Courtesy IMG
An artist's illustration shows how different an ancient "short-faced" kangaroo called Simosthenurus occidentalis looked, as opposed to modern kangaroos. Its skull more closely resembles a koala.
An artist's illustration shows how different an ancient "short-faced" kangaroo called Simosthenurus occidentalis looked, as opposed to modern kangaroos. Its skull more closely resembles a koala.
Nobu Tamura
An artist's illustration of Cryodrakon boreas, one of the largest flying animals that ever lived during the Cretaceous period. Although researchers don't know the color of Cryodrakon's plumage, the colors shown here honor Canada, where the fossil was found.
An artist's illustration of Cryodrakon boreas, one of the largest flying animals that ever lived during the Cretaceous period. Although researchers don't know the color of Cryodrakon's plumage, the colors shown here honor Canada, where the fossil was found.
David Maas
A graphic thermal image of a T. rex with its dorsotemporal fenestra glowing on the skull.
A graphic thermal image of a T. rex with its dorsotemporal fenestra glowing on the skull.
Brian Engh
A complete skull belong to an early human ancestor has been recovered in Ethiopia. A composite of the 3.8 million-year-old cranium of Australopithecus anamensis is seen here alongside a facial reconstruction.
A complete skull belong to an early human ancestor has been recovered in Ethiopia. A composite of the 3.8 million-year-old cranium of Australopithecus anamensis is seen here alongside a facial reconstruction.
Cleveland Museum of Natural History
The remains inside grave IIIN199, found under Prague Castle in 1928, belong to a man from the 10th century. His identity has been the subject of great debate for years.
The remains inside grave IIIN199, found under Prague Castle in 1928, belong to a man from the 10th century. His identity has been the subject of great debate for years.
Institute of Archaeology of the CAS/Prague Castle Excavations
Vertebrae fossils of a previously undiscovered type of stegosaurus were found in Morocco. Researchers say they represent the oldest stegosaurus found.
Vertebrae fossils of a previously undiscovered type of stegosaurus were found in Morocco. Researchers say they represent the oldest stegosaurus found.
courtesy Natural History Museum
The La Chapelle-aux-Saints Neanderthal skull shows signs of external auditory exostoses, known as "surfer's ear" growths, in the left canal.
The La Chapelle-aux-Saints Neanderthal skull shows signs of external auditory exostoses, known as "surfer's ear" growths, in the left canal.
Erik Trinkaus/Washington University
The Fincha Habera rock shelter in the Ethiopian Bale Mountains served as a residence for prehistoric hunter-gatherers.
The Fincha Habera rock shelter in the Ethiopian Bale Mountains served as a residence for prehistoric hunter-gatherers.
Götz Ossendorf
The world's largest parrot, Heracles inexpectatus, lived 19 million years ago in New Zealand. It was over 3 feet tall and weighed more than 15 pounds.
The world's largest parrot, Heracles inexpectatus, lived 19 million years ago in New Zealand. It was over 3 feet tall and weighed more than 15 pounds.
Dr Brian Choo/Flinders University
Saber-toothed cats, dire wolves and coyotes had different hunting patterns according to a new study of predator fossils found in the La Brea Tar Pits.
Saber-toothed cats, dire wolves and coyotes had different hunting patterns according to a new study of predator fossils found in the La Brea Tar Pits.
Mauricio Antón
Researchers found 83 tiny glassy spheres inside fossil clams from a Florida quarry. Testing suggests that they are evidence of one or more undocumented meteorite impacts in Florida's distant past.
Researchers found 83 tiny glassy spheres inside fossil clams from a Florida quarry. Testing suggests that they are evidence of one or more undocumented meteorite impacts in Florida's distant past.
Kristen Grace/Florida Museum
This primitive dinosaur had a wide W-shaped jaw and a solid bony crest resembling a humped nose.
This primitive dinosaur had a wide W-shaped jaw and a solid bony crest resembling a humped nose.
ICRA Art
An illustration of a Microraptor as it swallows a lizard whole during the Cretaceous period. The well-preserved fossils of the Microraptor and the lizard were both found, leading to the discovery that the lizard was a previously unknown species.
An illustration of a Microraptor as it swallows a lizard whole during the Cretaceous period. The well-preserved fossils of the Microraptor and the lizard were both found, leading to the discovery that the lizard was a previously unknown species.
DOYLE TRANKINA
The back of a skull found in a Grecian cave has been dated to 210,000 years ago. Known as Apidima 1, right, researchers were able to scan and re-create it (middle and left). The rounded shape of Apidima 1 is a unique feature of modern humans and contrasts sharply with Neanderthals and their ancestors.
The back of a skull found in a Grecian cave has been dated to 210,000 years ago. Known as Apidima 1, right, researchers were able to scan and re-create it (middle and left). The rounded shape of Apidima 1 is a unique feature of modern humans and contrasts sharply with Neanderthals and their ancestors.
Katerina Harvati, Eberhard Karls University of Tübingen
A 33,000-year-old human skull shows evidence of being struck with a club-like object. The right side of the man's head has a large depressed fracture.
A 33,000-year-old human skull shows evidence of being struck with a club-like object. The right side of the man's head has a large depressed fracture.
Bucharest University Laboratory of Paleontology
The recently discovered fossilized femur of an ancient giant bird revealed that it weighed nearly as much as an adult polar bear and could reach 11½ feet tall. It lived between 1.5 million and 2 million years ago.
The recently discovered fossilized femur of an ancient giant bird revealed that it weighed nearly as much as an adult polar bear and could reach 11½ feet tall. It lived between 1.5 million and 2 million years ago.
Andrey Atuchin
This jawbone belonged to a Neanderthal girl who lived 120,000 years ago. It was found in Scladina Cave in Belgium.
This jawbone belonged to a Neanderthal girl who lived 120,000 years ago. It was found in Scladina Cave in Belgium.
J. Eloy/AWEM/Archéologie andennaise
This is an artist's illustration of the newly discovered dinosaur species Fostoria dhimbangunmal.
This is an artist's illustration of the newly discovered dinosaur species Fostoria dhimbangunmal.
Illustration by James Kuether
Radiocarbon dating has revealed that this Iron Age wooden shield was made between 395 and 255 BC.
Radiocarbon dating has revealed that this Iron Age wooden shield was made between 395 and 255 BC.
University of Leicester
The incredibly well-preserved fossil of a 3 million-year-old extinct species of field mouse, found in Germany, which was less than 3 inches long, was found to have red pigment in its fur.
The incredibly well-preserved fossil of a 3 million-year-old extinct species of field mouse, found in Germany, which was less than 3 inches long, was found to have red pigment in its fur.
University of Gottingen
A mass grave dated to 5,000 years ago in Poland contains 15 people who were all from the same extended family.
A mass grave dated to 5,000 years ago in Poland contains 15 people who were all from the same extended family.
Morten Allentoft et. al
This is an artist's impression of the Ambopteryx longibrachium, one of only two dinosaurs known to have membranous wings. The dinosaur's fossilized remains were found in Liaoning, in northeast China, in 2017.
This is an artist's impression of the Ambopteryx longibrachium, one of only two dinosaurs known to have membranous wings. The dinosaur's fossilized remains were found in Liaoning, in northeast China, in 2017.
Min Wang/Chinese Academy of Sciences
Reconstruction of a small tyrannosauroid Suskityrannus hazelae from the Late Cretaceous.
Reconstruction of a small tyrannosauroid Suskityrannus hazelae from the Late Cretaceous.
Courtesy Andrey Atuchin
Researchers have been studying Archaeopteryx fossils for 150 years, but new X-ray data reveal that the bird-like dinosaur may have been an "active flyer."
Researchers have been studying Archaeopteryx fossils for 150 years, but new X-ray data reveal that the bird-like dinosaur may have been an "active flyer."
ESRF/Pascal Goetgheluck
A 160,000-year-old Denisovan jawbone found in a cave on the Tibetan Plateau is the first evidence of the presence of this ancient human group outside the Denisova Cave in Siberia.
A 160,000-year-old Denisovan jawbone found in a cave on the Tibetan Plateau is the first evidence of the presence of this ancient human group outside the Denisova Cave in Siberia.
Dongju Zhang/Lanzhou University
An artist's illustration of Simbakubwa kutokaafrika, a gigantic carnivore that lived 23 million years ago. It is known from fossils of most of its jaw, portions of its skull and parts of its skeleton. It was a hyaenodont, a now-extinct group of mammalian carnivores, that was larger than a modern-day polar bear.
An artist's illustration of Simbakubwa kutokaafrika, a gigantic carnivore that lived 23 million years ago. It is known from fossils of most of its jaw, portions of its skull and parts of its skeleton. It was a hyaenodont, a now-extinct group of mammalian carnivores, that was larger than a modern-day polar bear.
Paleoartist Mauricio Anton
The right upper teeth of the newly discovered species Homo luzonensis. The teeth are smaller and more simplified than those belonging to other Homo species.
The right upper teeth of the newly discovered species Homo luzonensis. The teeth are smaller and more simplified than those belonging to other Homo species.
Callao Cave Archaeology Project
The towering and battle-scarred "Scotty" is the world's largest Tyrannosaurus rex and the largest dinosaur skeleton ever found in Canada.
The towering and battle-scarred "Scotty" is the world's largest Tyrannosaurus rex and the largest dinosaur skeleton ever found in Canada.
Amanda Kelley
Researchers discovered unknown species at the Qingjiang fossil site on the bank of the Danshui River, near its junction with the Qingjiang River in Hubei Province, China.
Researchers discovered unknown species at the Qingjiang fossil site on the bank of the Danshui River, near its junction with the Qingjiang River in Hubei Province, China.
Dong King Fu/Northwest University Xi'an
During a study of the ancient Iberian population, the remains of a man and woman buried together at a Spanish Bronze Age site called Castillejo de Bonete showed that the woman was a local and the man's most recent ancestors had come from central Europe.
During a study of the ancient Iberian population, the remains of a man and woman buried together at a Spanish Bronze Age site called Castillejo de Bonete showed that the woman was a local and the man's most recent ancestors had come from central Europe.
Luis Benitez de Lugo Enrich/Jose Luis Fuentes Sanchez
Durrington Walls is a Late Neolithic henge site in Wiltshire. Pig bones recovered at the site revealed that people and livestock traveled hundreds of miles for feasting and celebration.
Durrington Walls is a Late Neolithic henge site in Wiltshire. Pig bones recovered at the site revealed that people and livestock traveled hundreds of miles for feasting and celebration.
Andrew Matthews/PA Wire/AP
An artist's impression of a Galleonosaurus dorisae herd on a riverbank in the Australian-Antarctic rift valley during the Early Cretaceous, 125 million years ago.
An artist's impression of a Galleonosaurus dorisae herd on a riverbank in the Australian-Antarctic rift valley during the Early Cretaceous, 125 million years ago.
Courtesy James Kuether
The remains of 137 children and 200 llamas were found in Peru in an area that was once part of the Chimú state culture, which was at the peak of power during the 15th century. The children and llamas might have been sacrificed due to flooding.
The remains of 137 children and 200 llamas were found in Peru in an area that was once part of the Chimú state culture, which was at the peak of power during the 15th century. The children and llamas might have been sacrificed due to flooding.
John Verano/Tulane University
The tooth of an extinct giant ground sloth that lived in Belize 27,000 years ago revealed that the area was arid, rather than the jungle that it is today.
The tooth of an extinct giant ground sloth that lived in Belize 27,000 years ago revealed that the area was arid, rather than the jungle that it is today.
Stan Ambrose/VOPA
An artist's illustration of what the small tyrannosaur Moros intrepidus would have looked like 96 million years ago. These small predators would eventually become Tyrannosaurus rex.
An artist's illustration of what the small tyrannosaur Moros intrepidus would have looked like 96 million years ago. These small predators would eventually become Tyrannosaurus rex.
Courtesy Jorge Gonzalez
Examples of tools manufactured from monkey bones and teeth recovered from the Late Pleistocene layers of Fa-Hien Lena Cave in Sri Lanka show that early humans used sophisticated techniques to hunt monkeys and squirrels.
Examples of tools manufactured from monkey bones and teeth recovered from the Late Pleistocene layers of Fa-Hien Lena Cave in Sri Lanka show that early humans used sophisticated techniques to hunt monkeys and squirrels.
Noel Amano/ Max Planck Institute for the Science of Human History
Footprints thought to belong to Neanderthals have been found in the Catalan Bay Sand Dune.
Footprints thought to belong to Neanderthals have been found in the Catalan Bay Sand Dune.
Courtesy Universdad de Sevilla
Two of the fossil specimens discovered in Korea had reflective eyes, a feature still apparent under light.
Two of the fossil specimens discovered in Korea had reflective eyes, a feature still apparent under light.
Paul Selden/University of Kansas
An artist's illustration of Mnyamawamtuka moyowamkia, a long-necked titanosaur from the middle Cretaceous period recently found in Tanzania. Its tail vertebra has a unique heart shape, which contributed to its name. In Swahili, the name translates to "animal of the Mtuka with a heart-shaped tail."
An artist's illustration of Mnyamawamtuka moyowamkia, a long-necked titanosaur from the middle Cretaceous period recently found in Tanzania. Its tail vertebra has a unique heart shape, which contributed to its name. In Swahili, the name translates to "animal of the Mtuka with a heart-shaped tail."
Mark Witton
The oldest evidence of mobility is 2.1 billion years old and was found in Gabon. The tubes, discovered in black shale, are filled with pyrite crystals generated by the transformation of biological tissue by bacteria, found in layers of clay minerals.
The oldest evidence of mobility is 2.1 billion years old and was found in Gabon. The tubes, discovered in black shale, are filled with pyrite crystals generated by the transformation of biological tissue by bacteria, found in layers of clay minerals.
El Albani & A. Mazurier/IC2MP/CNRS - Université de Poitiers
Researchers recently studied climate change in Greenland as it happened during the time of the Vikings. By using lake sediment cores, they discovered it was actually warmer than previously believed. They studied at several sites, including a 21st-century reproduction of Thjodhild's church on Erik the Red's estate, known as Brattahlíð, in present day Qassiarsuk, Greenland.
Researchers recently studied climate change in Greenland as it happened during the time of the Vikings. By using lake sediment cores, they discovered it was actually warmer than previously believed. They studied at several sites, including a 21st-century reproduction of Thjodhild's church on Erik the Red's estate, known as Brattahlíð, in present day Qassiarsuk, Greenland.
G. Everett Lasher/Northwestern University
This is an artist's illustration of Antarctica, 250 million years ago. The newly discovered fossil of a dinosaur relative, Antarctanax shackletoni, revealed that reptiles lived among the diverse wildlife in Antarctica after the mass extinction.
This is an artist's illustration of Antarctica, 250 million years ago. The newly discovered fossil of a dinosaur relative, Antarctanax shackletoni, revealed that reptiles lived among the diverse wildlife in Antarctica after the mass extinction.
Adrienne Stroup/Field Museum
Bone points and pierced teeth found in Denisova Cave were dated to the early Upper Paleolithic. A new study establishes the timeline of the cave, and it sheltered the first known humans as early as 300,000 years ago.
Bone points and pierced teeth found in Denisova Cave were dated to the early Upper Paleolithic. A new study establishes the timeline of the cave, and it sheltered the first known humans as early as 300,000 years ago.
Katerina Douka
This artist's illustration shows a marine reptile similar to a platypus hunting at dusk. This duckbilled animal was the first reptile to have unusually small eyes that most likely required it to use other senses, such as the tactile sense of its duckbill, to hunt for prey.
This artist's illustration shows a marine reptile similar to a platypus hunting at dusk. This duckbilled animal was the first reptile to have unusually small eyes that most likely required it to use other senses, such as the tactile sense of its duckbill, to hunt for prey.
Gianluca Danini
Although it's hard to spot, researchers found flecks of lapis lazuli pigment, called ultramarine, in the dental plaque on the lower jaw of a medieval woman.
Although it's hard to spot, researchers found flecks of lapis lazuli pigment, called ultramarine, in the dental plaque on the lower jaw of a medieval woman.
Christina Warinner/Max Planck Institute
A Neanderthal fossil, left, and a modern human skeleton. Neanderthals have commonly be considered to show high incidences of trauma compared with modern humans, but a new study reveals that head trauma was consistent for both.
A Neanderthal fossil, left, and a modern human skeleton. Neanderthals have commonly be considered to show high incidences of trauma compared with modern humans, but a new study reveals that head trauma was consistent for both.
Ian Tattersall
The world's oldest figurative artwork from Borneo has been dated to 40,000 years ago, when humans were living on what's now known as Earth's third-largest island.
The world's oldest figurative artwork from Borneo has been dated to 40,000 years ago, when humans were living on what's now known as Earth's third-largest island.
Luc-Henri Fage
A 250,000-year-old Neanderthal child's tooth contains an unprecedented record of the seasons of birth, nursing, illness and lead exposures over the first three years of its life.
A 250,000-year-old Neanderthal child's tooth contains an unprecedented record of the seasons of birth, nursing, illness and lead exposures over the first three years of its life.
Tanya Smith/Griffith University & Daniel Green/Harvard University
An artist's illustration shows giant nocturnal elephant birds foraging in the ancient forests of Madagascar at night. A new study suggests that the now-extinct birds were nocturnal and blind.
An artist's illustration shows giant nocturnal elephant birds foraging in the ancient forests of Madagascar at night. A new study suggests that the now-extinct birds were nocturnal and blind.
John Maisano for the University of Texas at Austin Jackson School of Geosciences
Kebara 2 is the most complete Neanderthal fossil recovered to date. It was uncovered in Israel's Kebara Cave, where other Neanderthal remains have been found.
Kebara 2 is the most complete Neanderthal fossil recovered to date. It was uncovered in Israel's Kebara Cave, where other Neanderthal remains have been found.
J. Trueba/Madrid Scientific Films
The world's oldest intact shipwreck was found by a research team in the Black Sea. It's a Greek trading vessel that was dated to 400 BC. The ship was surveyed and digitally mapped by two remote underwater vehicles.
The world's oldest intact shipwreck was found by a research team in the Black Sea. It's a Greek trading vessel that was dated to 400 BC. The ship was surveyed and digitally mapped by two remote underwater vehicles.
BLACK SEA MAP/EEF EXPEDITIONS
This fossil represents a new piranha-like fish from the Jurassic period with sharp, pointed teeth. It probably fed on the fins of other fishes.
This fossil represents a new piranha-like fish from the Jurassic period with sharp, pointed teeth. It probably fed on the fins of other fishes.
Courtesy M. Ebert and T. Nohl/Jura-Museum
The fossil skull of the young Diplodocus known as Andrew, held by<strong> </strong>Cary Woodruff, director of paleontology at the Great Plains Dinosaur Museum.
The fossil skull of the young Diplodocus known as Andrew, held by Cary Woodruff, director of paleontology at the Great Plains Dinosaur Museum.
John P. Wilson
Two small bones from the Ciemna Cave in Poland are the oldest human remains found in the country. The condition of the bones also suggests that the child was eaten by a large bird.
Two small bones from the Ciemna Cave in Poland are the oldest human remains found in the country. The condition of the bones also suggests that the child was eaten by a large bird.
Okla Michal/AP Images
This artist's illustration shows the newly discovered dinosaur species Ledumahadi mafube foraging in the Early Jurassic of South Africa. Heterodontosaurus,another South African dinosaur, can also be seen in the foreground.
This artist's illustration shows the newly discovered dinosaur species Ledumahadi mafube foraging in the Early Jurassic of South Africa. Heterodontosaurus,another South African dinosaur, can also be seen in the foreground.
Viktor Radermacher/University of the Witwatersrand
A 73,000-year-old red cross-hatch pattern was drawn on a flake of silicrete, which forms when sand and gravel cement together, and found in a cave in South Africa.
A 73,000-year-old red cross-hatch pattern was drawn on a flake of silicrete, which forms when sand and gravel cement together, and found in a cave in South Africa.
Craig Foster
A suite of Middle Neolithic pottery including typical Danilo ware, figulina and rhyta that was used to hold meat, milk, cheese and yogurt.
A suite of Middle Neolithic pottery including typical Danilo ware, figulina and rhyta that was used to hold meat, milk, cheese and yogurt.
Sibenik City Museum
These four dinosaurs showcase the evolution of alvarezsaurs. From left, Haplocheirus, Xiyunykus, Bannykus and Shuvuuia reveal the lengthening of the jaws, reduction of teeth and changes in the hand and arm.
These four dinosaurs showcase the evolution of alvarezsaurs. From left, Haplocheirus, Xiyunykus, Bannykus and Shuvuuia reveal the lengthening of the jaws, reduction of teeth and changes in the hand and arm.
Viktor Radermacher/University of the Witwatersrand
Eorhynchochelys sinensis is an early turtle that lived 228 million years ago. It had a toothless beak, but no shell.
Eorhynchochelys sinensis is an early turtle that lived 228 million years ago. It had a toothless beak, but no shell.
Yu Chen/IVPP
The leg bones of a 7-year-old, recovered from an ancient Roman cemetery, show bending and deformities associated with rickets.
The leg bones of a 7-year-old, recovered from an ancient Roman cemetery, show bending and deformities associated with rickets.
Historic England
The famed Easter Island statues, called moai, were originally full-body figures that have been partially covered over the passage of time. They represent important Rapa Nui ancestors and were carved after a population was established on the island 900 years ago.
The famed Easter Island statues, called moai, were originally full-body figures that have been partially covered over the passage of time. They represent important Rapa Nui ancestors and were carved after a population was established on the island 900 years ago.
Dale Simpson Jr/University of Queensland
Researchers stand at the excavation site of Aubrey Hole 7, where cremated human remains were recovered at Stonehenge to be studied. New research suggests that 40% of 25 individuals buried at Stonehenge weren't from there -- but they possibly transported stones from west Wales and helped build it.
Researchers stand at the excavation site of Aubrey Hole 7, where cremated human remains were recovered at Stonehenge to be studied. New research suggests that 40% of 25 individuals buried at Stonehenge weren't from there -- but they possibly transported stones from west Wales and helped build it.
Adam Stanford of Aerial-Cam Ltd.
The fossil of the newly discovered armored dinosaur Akainacephalus johnsoni was found in southern Utah.
The fossil of the newly discovered armored dinosaur Akainacephalus johnsoni was found in southern Utah.
Natural History Museum of Utah
The foot is one part of a partial skeleton of a 3.32 million-year-old skeleton of an Australopithecus afarensis child dubbed Selam.
The foot is one part of a partial skeleton of a 3.32 million-year-old skeleton of an Australopithecus afarensis child dubbed Selam.
Zeray Alemseged/University of Chicago
The asteroid impact that caused dinosaurs to go extinct also destroyed global forests, according to a new study. This illustration shows one of the few ground-dwelling birds that survived the toxic environment and mass extinction.
The asteroid impact that caused dinosaurs to go extinct also destroyed global forests, according to a new study. This illustration shows one of the few ground-dwelling birds that survived the toxic environment and mass extinction.
Philipp M. Krzeminski
The remains of a butchered rhinoceros are helping researchers to date when early humans reached the Philippines. They found a 75% complete skeleton of a rhinoceros that was clearly butchered, with 13 of its bones displaying cut marks and areas where bone was struck to release marrow, at the Kalinga archaeological site on the island of Luzon.
The remains of a butchered rhinoceros are helping researchers to date when early humans reached the Philippines. They found a 75% complete skeleton of a rhinoceros that was clearly butchered, with 13 of its bones displaying cut marks and areas where bone was struck to release marrow, at the Kalinga archaeological site on the island of Luzon.
Thomas Ingicco/Mission Marche aux Philippines
This is just one of 26 individuals found at the site of a fifth-century massacre on the Swedish island of Öland. This adolescent was found lying on his side, which suggests a slower death. Other skeletons found in the homes and streets of the ringfort at Sandby borg show signs of sudden death by blows to the head.
This is just one of 26 individuals found at the site of a fifth-century massacre on the Swedish island of Öland. This adolescent was found lying on his side, which suggests a slower death. Other skeletons found in the homes and streets of the ringfort at Sandby borg show signs of sudden death by blows to the head.
Kalmar County Museum
The skeleton of a young woman and her fetus were found in a brick coffin dated to medieval Italy. Her skull shows an example of neurosurgery, and her child was extruded after death in a rare "coffin birth."
The skeleton of a young woman and her fetus were found in a brick coffin dated to medieval Italy. Her skull shows an example of neurosurgery, and her child was extruded after death in a rare "coffin birth."
University of Ferrara
This portion of a whale skull was found at the Calaveras Dam construction site in California, along with at least 19 others. Some of the pieces measure 3 feet long.
This portion of a whale skull was found at the Calaveras Dam construction site in California, along with at least 19 others. Some of the pieces measure 3 feet long.
Sara Yogi/UC Berkeley
A Stone Age cow skull shows trepanation, a hole in the cranium that was created by humans as as surgical intervention or experiment.
A Stone Age cow skull shows trepanation, a hole in the cranium that was created by humans as as surgical intervention or experiment.
Fernando Ramirez Rozzi/Nature
On the left is a fossilized skull of our hominin ancestor Homo heidelbergensis, who lived 200,000 to 600,000 years ago. On the right is a modern human skull. Hominins had pronounced brow ridges, but modern humans evolved mobile eyebrows as their face shape became smaller.
On the left is a fossilized skull of our hominin ancestor Homo heidelbergensis, who lived 200,000 to 600,000 years ago. On the right is a modern human skull. Hominins had pronounced brow ridges, but modern humans evolved mobile eyebrows as their face shape became smaller.
Nature Ecology and Evolution
On the left is a 13,000-year-old footprint as found in the sediment on Calvert Island, off the Canadian Pacific coast. On the right is a digitally enhanced image, showing details of the footprint.
On the left is a 13,000-year-old footprint as found in the sediment on Calvert Island, off the Canadian Pacific coast. On the right is a digitally enhanced image, showing details of the footprint.
Duncan McLaren/University of Victoria
A central platform at Star Carr in North Yorkshire, England, was excavated by a research team studying past climate change events at the Middle Stone Age site. The Star Carr site is home to the oldest evidence of carpentry in Europe and of built structures in Britain.
A central platform at Star Carr in North Yorkshire, England, was excavated by a research team studying past climate change events at the Middle Stone Age site. The Star Carr site is home to the oldest evidence of carpentry in Europe and of built structures in Britain.
POSTGLACIAL project/University of York
This wall with paintings is in the La Pasiega Cave in Spain. The ladder shape of red horizontal and vertical lines is more than 64,000 years old and was made by Neanderthals.
This wall with paintings is in the La Pasiega Cave in Spain. The ladder shape of red horizontal and vertical lines is more than 64,000 years old and was made by Neanderthals.
P. Saura/Nature
These perforated shells were found in Spain's Cueva de los Aviones sea cave and date to between 115,000 and 120,000 years ago. Researchers believe these served as body ornamentation for Neanderthals.
These perforated shells were found in Spain's Cueva de los Aviones sea cave and date to between 115,000 and 120,000 years ago. Researchers believe these served as body ornamentation for Neanderthals.
João Zilhão/Nature
The earliest modern human fossil ever found outside of Africa has been recovered in Israel. This suggests that modern humans left Africa at least 50,000 years earlier than previously believed. The upper jawbone, including several teeth, was recovered in a prehistoric cave site.
The earliest modern human fossil ever found outside of Africa has been recovered in Israel. This suggests that modern humans left Africa at least 50,000 years earlier than previously believed. The upper jawbone, including several teeth, was recovered in a prehistoric cave site.
Rolf Quam/Binghamton University
This is an excavated structure at the northern edge of the Grand Plaza at Teposcolula-Yucundaa in Oaxaca, Mexico. Researchers investigated a "pestilence" cemetery associated with a devastating 1545-1550 epidemic. New analysis suggests that salmonella caused a typhoid fever epidemic.
This is an excavated structure at the northern edge of the Grand Plaza at Teposcolula-Yucundaa in Oaxaca, Mexico. Researchers investigated a "pestilence" cemetery associated with a devastating 1545-1550 epidemic. New analysis suggests that salmonella caused a typhoid fever epidemic.
Courtesy Christina Warinner/Teposcolula-Yucundaa Archaeological Project
Standing about 4 feet tall, early human ancestor Paranthropus boisei had a small brain and a wide, dish-like face. It is most well-known for having big teeth and hefty chewing muscles.
Standing about 4 feet tall, early human ancestor Paranthropus boisei had a small brain and a wide, dish-like face. It is most well-known for having big teeth and hefty chewing muscles.
Fred Lewsey/Cambridge Universy
A grand grave of a great Viking warrior excavated during the 1880s has been <a href="http://www.cnn.com/2017/09/14/health/female-viking-warrior-grave/index.html">found to be that of a woman</a>. She was also buried with a gaming board and pieces, hierarchically associated with officers to use for battle strategy and tactics. The drawing is a reconstruction of how the grave with the woman originally may have looked.
A grand grave of a great Viking warrior excavated during the 1880s has been found to be that of a woman. She was also buried with a gaming board and pieces, hierarchically associated with officers to use for battle strategy and tactics. The drawing is a reconstruction of how the grave with the woman originally may have looked.
Þórhallur Þráinsson/Neil Price/Uppsala University
An illustration shows the <a href="http://www.cnn.com/2017/08/24/world/dodo-extinct-new-insight/index.html">dodo</a> on Mauritius near the Mare aux Songes, where many dodo skeletons have been recovered.
An illustration shows the dodo on Mauritius near the Mare aux Songes, where many dodo skeletons have been recovered.
Julian Hume/UK National History Museum
A 5,000-year-old <a href="http://www.cnn.com/2017/07/19/world/ancient-dog-evolution-study/index.html">dog skull</a> found in Germany underwent whole genome sequencing. It was found to be very similar to the genome of modern dogs, suggesting that all modern dogs are direct ancestors of the domesticated dogs that lived in the world's earliest farming communities in Europe.
A 5,000-year-old dog skull found in Germany underwent whole genome sequencing. It was found to be very similar to the genome of modern dogs, suggesting that all modern dogs are direct ancestors of the domesticated dogs that lived in the world's earliest farming communities in Europe.
Amelie Scheu/Nature Research
Razanandrongobe sakalavae, or "<a href="http://www.cnn.com/2017/07/04/world/giant-crocodile-razana-study/index.html">Razana</a>," was one of the top predators of the Jurassic period in Madagascar 170 million years ago. Although it looks different from modern-day crocodiles and had teeth similar to a T. rex's, Razana was not a dinosaur but a crocodile relative with a deep skull.
Razanandrongobe sakalavae, or "Razana," was one of the top predators of the Jurassic period in Madagascar 170 million years ago. Although it looks different from modern-day crocodiles and had teeth similar to a T. rex's, Razana was not a dinosaur but a crocodile relative with a deep skull.
Fabio Manucci
An artist's reconstruction shows Macrauchenia patachonica, which roamed South America thousands of years ago. Combining a range of odd characteristics from llamas and camels to rhinos and antelopes, <a href="http://www.cnn.com/2017/06/27/world/extinct-animal-ungulate-macrauchenia-darwin-tree-of-life/index.html">Macrauchenia</a> defied clarification until now and has been added to the tree of life. It belongs to a sister group of Perissodactyla, which includes horses, rhinos and tapirs.
An artist's reconstruction shows Macrauchenia patachonica, which roamed South America thousands of years ago. Combining a range of odd characteristics from llamas and camels to rhinos and antelopes, Macrauchenia defied clarification until now and has been added to the tree of life. It belongs to a sister group of Perissodactyla, which includes horses, rhinos and tapirs.
Jorge Blanco/Nature Research
This prosthetic device was made for a priest's daughter who had to have her right big toe amputated 3,000 years ago. This <a href="http://www.cnn.com/2017/06/22/health/ancient-egypt-wooden-toe-prosthetic-trnd/index.html">surprisingly lifelike toe</a> was made to look natural by a skilled artisan who wanted to maintain the aesthetic as well as mobility during the Early Iron Age. It was designed to be worn with sandals, the footwear of choice at the time.
This prosthetic device was made for a priest's daughter who had to have her right big toe amputated 3,000 years ago. This surprisingly lifelike toe was made to look natural by a skilled artisan who wanted to maintain the aesthetic as well as mobility during the Early Iron Age. It was designed to be worn with sandals, the footwear of choice at the time.
University of Basel
The oldest fossil remains of Homo sapiens, dating back 300,000 years, <a href="http://www.cnn.com/2017/06/07/health/oldest-homo-sapiens-fossils-found/index.html">were found</a> at a site in Jebel Irhoud, Morocco. This is 100,000 years older than previously discovered fossils of Homo sapiens that have been securely dated. The fossils, including a partial skull and a lower jaw, belong to five different individuals including three young adults, an adolescent and a child estimated to be 8 years old.
The oldest fossil remains of Homo sapiens, dating back 300,000 years, were found at a site in Jebel Irhoud, Morocco. This is 100,000 years older than previously discovered fossils of Homo sapiens that have been securely dated. The fossils, including a partial skull and a lower jaw, belong to five different individuals including three young adults, an adolescent and a child estimated to be 8 years old.
Courtesy Jean-Jacques Hublin/MPI-EVA, Leipzig
Nodosaurs were herbivores who walked on four legs and were covered in tank-like armor and dotted with spikes for protection. But this recently unveiled 110 million-year-old fossil is the <a href="http://www.cnn.com/2017/05/14/americas/perfect-dinosaur-fossil-alberta-canada-museum-trnd/index.html">most well-preserved</a> of the armored dinosaurs ever unearthed.
Nodosaurs were herbivores who walked on four legs and were covered in tank-like armor and dotted with spikes for protection. But this recently unveiled 110 million-year-old fossil is the most well-preserved of the armored dinosaurs ever unearthed.
Sue Sabrowski/Royal Tyrrell Museum
<a href="http://www.cnn.com/2017/01/30/health/earliest-human-ancestor-deuterostome-saccorhytus-history-study/index.html" target="_blank">Microfossils found in China</a> have revealed what could be our earliest known ancestor on the tree of life. Saccorhytus was a tiny, bag-like sea creature that lived 540 million years ago.
Microfossils found in China have revealed what could be our earliest known ancestor on the tree of life. Saccorhytus was a tiny, bag-like sea creature that lived 540 million years ago.
Jian Han, Northwest University, China
In 2016, researchers <a href="http://www.cnn.com/2017/02/03/world/dinosaur-rib-195-million-year-old-collagen-history/index.html">discovered ancient collagen and protein remains</a> preserved in the ribs of a dinosaur that walked the Earth 195 million years ago.
In 2016, researchers discovered ancient collagen and protein remains preserved in the ribs of a dinosaur that walked the Earth 195 million years ago.
courtesy Robert Reisz
By studying the skeleton of this medieval pilgrim, researchers have been able to <a href="http://www.cnn.com/2017/01/26/health/leprosy-medieval-pilgrim-skeleton-study/index.html">genotype leprosy</a>. They also discovered that leprosy-causing bacteria have changed little over hundreds of years, possibly explaining the decline in the disease after it peaked in medieval Europe as humans developed resistance.
By studying the skeleton of this medieval pilgrim, researchers have been able to genotype leprosy. They also discovered that leprosy-causing bacteria have changed little over hundreds of years, possibly explaining the decline in the disease after it peaked in medieval Europe as humans developed resistance.
Courtesy Magdalen Hill Archaeological Research Project
The discovery of a species that lived 6.6 million years ago in southwestern China suggests that <a href="http://www.cnn.com/2017/01/24/asia/china-ancient-otter/index.html">ancient otters </a>had "wolf-like" proportions, and weighed roughly 100 Ibs. The creature -- whose skull was excavated in Yunnan province -- would have been twice the size of today's otters.
The discovery of a species that lived 6.6 million years ago in southwestern China suggests that ancient otters had "wolf-like" proportions, and weighed roughly 100 Ibs. The creature -- whose skull was excavated in Yunnan province -- would have been twice the size of today's otters.
Yunnan Institute of Cultural Relics and Archaeology
The <a href="http://www.cnn.com/2016/12/08/health/dinosaur-tail-trapped-in-amber-trnd/index.html">tail of a 99-million-year-old dinosaur</a> was found entombed in amber in 2016, an unprecedented discovery that has blown away scientists. The amber adds to fossil evidence that many dinosaurs sported feathers rather than scales.
The tail of a 99-million-year-old dinosaur was found entombed in amber in 2016, an unprecedented discovery that has blown away scientists. The amber adds to fossil evidence that many dinosaurs sported feathers rather than scales.
Royal Saskatchewan Museum (RSM/ R.C. McKellar)
For the first time, researchers discovered <a href="http://www.cnn.com/2016/12/05/health/malaria-evidence-roman-empire/index.html">genomic evidence of malaria in 2,000-year-old human remains</a> from the Roman Empire. The discovery was made in 2016.
For the first time, researchers discovered genomic evidence of malaria in 2,000-year-old human remains from the Roman Empire. The discovery was made in 2016.
Luca Bandioli/Pigorini Museum
Ancient finds
CNN  — 

Perhaps Kevin Costner’s famously bloated 1995 film “Waterworld” deserves more credit.

A new study suggests that our planet could have been entirely covered in water after all, about 3.2 billion years ago, researchers said.

In order to investigate ancient Earth, University of Colorado Boulder researcher Boswell Wing and study co-author Benjamin Johnson had to dig up the dirt evidence for ancient oceans.

And they found a chunk of it sitting in Northwestern Australia’s outback, at a site called Panorama.

Germany's Ries Crater (or Nördlinger Ries) is not easily discerned in space-based images. The crater's existence was probably just as subtle to the medieval Europeans who established a settlement inside it and unknowingly matched their 1-kilometer- (0.6-mile-) wide city to the likely diameter of the meteorite that formed the crater. Data acquired September 6, 2007
Germany's Ries Crater (or Nördlinger Ries) is not easily discerned in space-based images. The crater's existence was probably just as subtle to the medieval Europeans who established a settlement inside it and unknowingly matched their 1-kilometer- (0.6-mile-) wide city to the likely diameter of the meteorite that formed the crater. Data acquired September 6, 2007
NASA

Related article Could life have existed on a warm, wet Mars? Ancient Earth crater may explain how

“Today, there are these really scrubby and rolling hills that are cut through by dry river beds,” said Johnson, an assistant professor at Iowa State University in Ames. “It’s a crazy place.”

The geologic site is home to a piece of 3.2 billion-year-old ocean crust, conveniently turned on its side like a time capsule just waiting to reveal our planet’s secrets.

Benjamin Johnson inspects rock at Panorama. This was once an ancient hydrothermal vent.
Benjamin Johnson inspects rock at Panorama. This was once an ancient hydrothermal vent.
Jana Meixnerova

On one end, there’s the remnant of the crusty outer shell that once belonged to Earth. On the other, the base reveals where water came up through hydrothermal vents on the ocean floor.

“There are no samples of really ancient ocean water lying around, but we do have rocks that interacted with that seawater and remembered that interaction,” Johnson said.

The tubes are filled with pyrite crystals (generated by the transformation by bacteria of biological tissue) found in layers of clay minerals. Parallel horizontal layers are fossilized microbial mats. CREDIT: A. El Albani & A. Mazurier / IC2MP / CNRS - Université de Poitiers
The tubes are filled with pyrite crystals (generated by the transformation by bacteria of biological tissue) found in layers of clay minerals. Parallel horizontal layers are fossilized microbial mats. CREDIT: A. El Albani & A. Mazurier / IC2MP / CNRS - Université de Poitiers
El Albani & A. Mazurier/IC2MP/CNRS - Université de Poitiers

Related article Ancient mucus trail led to oldest evidence of mobility on Earth

By studying the rocks, they could analyze the water that passed through it. They gathered more than a hundred samples across the area. The study published Monday in the journal Nature Geoscience.

The key to their analysis was looking for isotopes, or evidence of oxygen that’s been trapped in the rock. They were looking for Oxygen-16, a lighter isotope, and Oxygen-18, which is heavier.

One was more prevalent than the other in ancient seawater, with the balance leaning toward the heavier Oxygen-18.

“Though these mass differences seem small, they are super sensitive,” Wing said, study co-author and an associate professor in the Department of Geological Sciences at the University of Colorado Boulder.

Today, the land masses across Earth soak up those heavier oxygen isotopes from water, preserved in wet soils rich in clay.

A vista of Panorama can be seen today, resembling nothing like the ancient ocean it once hosted.
A vista of Panorama can be seen today, resembling nothing like the ancient ocean it once hosted.
Benjamin Johnson

The researchers believe that the reason for the amount of Oxygen-18 they found in the Panorama samples is because there wasn’t any soil, or landmasses comprised of it, to absorb the isotopes.

But that doesn’t discount the fact that small islands may have existed.

“There’s nothing in what we’ve done that says you can’t have teeny, micro-continents sticking out of the oceans,” Wing said. “We just don’t think that there were global-scale formation of continental soils like we have today.”

An artist's impression of the massive bursts of ionizing radiation exploding from the center of the Milky Way and impacting the Magellanic Stream.
An artist's impression of the massive bursts of ionizing radiation exploding from the center of the Milky Way and impacting the Magellanic Stream.
James Josephides/ASTRO 3D

Related article The center of the Milky Way exploded when ancient human ancestors walked the Earth

If that’s the case, when did the continents form in this scenario? We know that plate tectonics pushing together are responsible for their formation.

Wing and Johnson are continuing their investigation, albeit among younger rock formations across the globe, to find evidence suggesting when the birth of the continents occurred.

This also impacts when and how life might have formed on early Earth. The debate over this pushed scientists to investigate the ‘waterworld’ theory in the first place.

“There was seemingly no way forward on that debate,” said Johnson. “We thought that trying something different might be a good idea.”

An image from "Waterworld" shows Kevin Costner as the Mariner, Jeanne Tripplehorn as Helen and Tina Majorino as Enola.
An image from "Waterworld" shows Kevin Costner as the Mariner, Jeanne Tripplehorn as Helen and Tina Majorino as Enola.
Universal/Getty Images/File

“The history of life on Earth tracks available niches,” said Wing, “If you’ve got a waterworld, a world covered by ocean, then dry niches are just not going to be available.”

At least single-celled life on early Earth wouldn’t have needed to barter dirt or scoot around on floating islands – so perhaps its best that “Waterworld” is in our past and not a dystopian future.