The comet 3I/ATLAS will make its closest approach to Earth on December 19, thousands of years after it started entering the solar system’s outer boundary called the Oort Cloud. Fast forward to 2025, Earth has changed dramatically due to changing climate, evolving humans and the rise of society. Now that 3I/ATLAS is flying past our planet, humans have invented agriculture, walked on the Moon, split the atom, discovered antibiotics, built the pyramids, sent spacecraft out of the solar system and achieved countless other milestones.
With this interstellar visitor approaching, here’s what Earth looked like 8,000 years ago.
Comet 3I/ATLAS’s journey through Oort Cloud
Before we dive into the condition of the Earth, you should know how comet 3I/ATLAS made it to the inner solar system. According to Harvard Physicist Avi Loeb, it began travelling through the Oort Cloud 8,000 years ago.
The Oort Cloud, named after Dutch astronomer Jan Oort, is the most distant region in our solar system comprising of hundreds of billions of icy objects. NASA says it’s called a ‘cloud’ and not a ‘belt’ because the objects do not necessarily travel in the same direction in a shared orbital plane around the Sun. The Oort Cloud is the origin point of many long-period comets when something disturbs the orbit of one of the icy bodies.
What was Earth like 8,000 years ago?
When 3I/ATLAS began entering the Oort Cloud, homo sapiens were the only human species left on Earth which was in the Holocene epoch. According to University of California’s Museum of Paleontology, the Holocene is the era comprising the last 11,700 years of Earth’s history and it marked the end of the last major ice age (Pleistocene).
Since it was a relatively warmer period, ice sheets were melting and oceans were rising, reshaping the coastal regions. While Sahara was transitioning from lush green to an arid region, forests were expanding in other parts of the world and humans were settling in permanent villages.
According to National Geographic, agriculture took root around 12,000 years ago enabling humans to pivot from a hunter-gatherer lifestyle. Author Yuval Nova Harari writes in his book Sapiens that farming began in south-eastern Turkey, western Iran and the Levant (region comprising Israel, Jordan, Syria, Lebanon, Palestine). By this time, humans were already making use of animals like dogs, goats, sheep, pigs and cattle that were domesticated hundreds of years before farming was widespread.
Despite all this progress, large civilisations like Egyptian, Mesopotamian, Indus Valley and Chinese had not emerged yet. In the Indian subcontinent, sparse settlement had sprouted after 7000 BC, with Mehrgarh in Balochistan, Pakistan, being the most prominent example. These settlements later evolved into the Indus Valley civilisation which existed between 3300-1300 BC, per Archaeological Survey of India.
Many agrarian societies also started emerging around 8000 years ago in China. Although, the Chinese land was inhabited as early as 780,000 years ago by Homo Erectus Pekinesis (Peking Man) along the Yellow River, followed by tribes like Hua and Xia – ancestors of ethnic majority Han Chinese – thousands of years later, writes Linda Jaivin in her book The Shortest History Of China.
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After a certain point, humans reigned supreme, outclassing eight other species – Homo habilis, Homo rudolfensis, Homo erectus, Homo antecessor, Homo heidelbergensis, Homo floresiensis (‘the hobbit’), Homo neanderthalensis (Neanderthals) and Homo naledi. There were also the Denisovans, our mysterious cousins who are said to have lived with Homo sapiens and interbred.
Archaeologists and geneticists have also found clear evidence of interbreeding between Homo sapiens and other species which improved the former’s chances of survival. According to a 2020 study published in Cell, people with African ancestry have close to 0.5 percent Neanderthal DNA in their genome whereas European and Asian genomes have 1.7 percent and 1.8 percent, respectively. Most of the mainland Wolly mammoths were already wiped out but a few survived on Wrangel Island in the Arctic until 4,000 years ago, per National History Museum. Giant sloths are also reported to have existed in the Caribbean and South America until 6,000 years ago along with the flightless bird Moa in New Zealand, which went extinct as recently as in the 13th century.
As 3I/ATLAS finally arrives near Earth this month, we have long moved on from stone tools to exploring space. It is now travelling on its hyperbolic outbound trajectory at a higher speed thanks to a slingshot from the Sun. The comet will leave the inner solar system within a few years but it will still take thousands of years to cross the Oort Cloud and reach interstellar space. By the time that happens, Earth may be unrecognisable and humans may colonise other planets, or perhaps not survive at all.
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