Did Humans Come From Outer Space?

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Did Humans Come From Outer Space?</h4>

All of us play our own small part in the wider human story. The history of our species has long captured the imaginations of scientists, researchers, writers, and more. So much so that some suggest that the truth of our kind is far stranger than it’s typically given credit for.

This video is divided into three sections. In the first, we take an in-depth look at the already incredible story of human evolution on Earth, up until this point. In the second, we consider it alongside the history of our neighboring planet, as well, Mars. And, finally, we spread our gaze even further to discuss theories that life may have actually spawned in the distant reaches of the Milky Way galaxy.

This is Unveiled, and today we’re answering the extraordinary question; did humans come from outer space?

It's hard to think of human beings as primitive creatures when so many traits separate us from the rest of the animal kingdom. We’re the only species to maintain a completely upright posture, for example, even amongst other primates. We boast a unique dexterity with our hands, and increased brain volume and intelligence, too. It all allows us to distinguish ourselves via the use of speech, the development of tools, the use of fire, and so on… to grow to where we are today; large, mass civilizations spanning every corner of the globe. However, humankind hasn’t always been quite so unique and complex. In fact, in a time not that long ago, relative to the age of the universe, our human ancestors had more in common with the modern squirrel than with modern people. So how did a small rodent-like tree climber evolve into the dominating species of today?

The story of human evolution begins with the extinction of the dinosaurs. When an asteroid struck land sixty-six million years ago (as per the most commonly held theory) it may have rained death down upon the reptiles… but it also allowed a new class of animals to rise out of their shadowed holes. With most of the world’s biggest creatures gone - and around 75% of Earth's total flora and fauna at the time, by most counts - whole ecosystems collapsed, and the food chain was thrown into turmoil. But the catastrophe left massive empty niches and key environmental roles just waiting to be filled.

And so, it was the mammals that rose to become the dominating class. And, because there were so many positions to fill, a rich and diverse evolutionary boom occurred across a relatively short period of time. Within the next ten million years, it’s thought that between three and five thousand species of mammals emerged on planet Earth, including the earliest classes of whales, bats, rodents and, crucially for the human story, monkey-like primates… our earliest ancestors.

These prehistoric primates then went through many changes very quickly… with the first significant development happening around sixty million years ago, when the evolutionary line divided into strepsirrhines (also called the wet-nosed primates) and haplorrhines (the dry-nosed primates). This was a key moment in the slow progression toward Homo sapiens, as while the strepsirrhines remained primarily nocturnal and reliant on their sense of smell, the diurnal haplorrhines developed larger brains and were therefore able to rely on their vision; thereby already showing two more human-like attributes.

From there, the haplorrhines continued to diverge for millions of years, with several of our primate cousins branching off the family tree. However, it wasn't until about twenty million years ago that another major development took place; the arrival of the first ape, known as Proconsul. While still quite monkey-like in behavior, the earliest apes began taking on physical attributes that were, again, increasingly human to today’s eyes. Importantly, they were significantly larger than their ancestors, weighing up to 110 pounds, while they notably lacked a tail. Still millions of years ago, and the apes continued their variation, branching into the Great and Lesser Apes and gradually giving birth to some of our other evolutionary cousins such as gibbons, orangutans, and gorillas - all of which had developed before the earliest humans came to be. As for our closest cousins, the chimpanzees and bonobos, they arrived much later… around seven million years ago, only. 

But what of the human ancestral branch itself? One of the first big steps in our transcendence from ape to human came with the evolution of the Ardipithecus, the first genuinely bipedal genus. Despite remaining a primarily tree-climbing species - with opposable big toes, small cutting teeth, and a brain size very similar to an ape - the Ardipithecus developed the breakthrough ability to walk on two legs. From here it took massive strides through the evolutionary timetable, and within about two million years - that’s now around four million years ago - the first Australopithecus evolved.

Australopithecus retained apelike features (including long arms and short legs) but they were becoming significantly more human still, largely thanks to one change… the opposable big toes present in earlier species had now moved to face forward on their feet. This meant they became more adjusted to walking reliably, which freed their hands for the earliest known use of stone tools. 

The Australopithecus thrived until around two million years ago, when evolution evolved along two more distinct directions. While one group is said to have developed stronger jaws to better help them to eat the nuts and vegetation specifically available at that time… another evolved with weaker jaws but with larger brains. While both branches survived for a significant period, those with the larger brain proved to be more adaptable in the long run… and they ultimately gave rise to the genus Homo, taken from the Latin for man, and here is where human history is said to truly begin.

The first member of the Homo genus was Homo habilis. Colloquially known as "Handy Man”, the progression of habilis is most notable for its ever-widening use of tools which, again, led to many major evolutionary advancements happening quickly. In fact, within just 500,000 years - so, we’re now about 1.9 million years ago - Homo habilis had given rise to another new classification, Homo erectus, to make possibly the most crucial evolutionary leap toward modern man.

Homo erectus was the first to closely resemble the proportions of a current human body. They had relatively elongated legs and shorter arms compared to the size of their torso, which was the result of their being fully adapted to living on the ground (rather than in trees). Homo erectus had a slightly larger brain size, too, although it was still only about 60% the size of a modern human’s… and they were the first to use fire as a tool. This, along with their bipedalism, enabled them to migrate outside of Africa, to become the first group to be widespread across Europe, Asia, and Africa. Finally, according to fossil evidence, Homo erectus not only gathered in social groups, but they actually cared for their old and weak - something that was virtually unheard of until this point. It’s believed that they had empathy and were emotionally developed as well as physically, something which allowed them to survive and even eventually thrive alongside modern humans… before going extinct just 110,000 years ago.

Over this period between 1.9 million years ago and 100,000 years ago, and as a result of Homo erectus' migratory patterns, new members of the Homo genus began springing up all across the world map. As each new species evolved to adapt to different environments, these various human groups began to diverge and cross over at various historical points, causing an intricate web of evolutionary lines. This has made it difficult to precisely know from which line after Homo erectus we (modern humans) find our origins. We may have evolved directly from Homo erectus or from one of the several species that branched off before or after it. Nevertheless, we do know that we were neither the first nor the last species to evolve along our branch… it’s just that we’re the ones that remain today.

First appearing around 300,000 years ago, Homo sapiens are (and were) distinguishable from other Homo groups most significantly by their having much larger brains, an adapted skull shape to house those larger brains, and a lighter skeletal frame. As a result, ancient Homo sapiens go down as being an exceptionally innovative group, developing advanced tools like fishhooks for hunting, bows, arrows and spears (also for hunting), sewing needles (for clothing), and various building materials and methods (for shelter). This ensured that sapiens would outlast all other Homo types… with the last Neanderthal, for example, dying out about 40,000 years ago.

But, while that’s the human story so far, evolution is far from being done. And as much as we tend to assume that we’re the ultimate, end-of-the-line model, it will actually continue to alter us well into the future. In the past 100,000 years, for example, the average height of Homo sapiens is thought to have shrunk slightly… although we do appear to have grown slightly taller in just the past couple of centuries. Meanwhile, although brains had been getting progressively larger throughout evolution up until this point, ours have actually decreased in size over the past 30,000 years or so... with it commonly said that a modern human has lost about a tennis ball’s worth of brain size compared to earlier sapiens. 

Luckily for us, we remain a reasonably intelligent species… but who’s to say what could happen in the future.

The prospect of life existing elsewhere in the solar system or wider universe has been at the center of debate for decades. Given the millions of stars and worlds “out there”, is Earth really the only one actually hosting anything? And even if it was found that life doesn’t exist on other planets right now, could it have existed somewhere else in the past? Somewhere relatively close to home? 

Did humans live on Mars before Earth? 

Though it’s widely believed that Mars in its current state couldn’t support complex life, there are various theories to suggest that ancient Mars may have been a much more hospitable, habitable environment - perhaps at one point even more so than Earth was. It’s thought that, more than three billion years ago, the “Red Planet” was actually similar to what Earth is now in terms of climate and conditions, with vast lakes and warmer weather patterns. In terms of whether it ever hosted life, NASA’s Curiosity Rover has provided plenty of apparent evidence that it may have - or at least that it was a possibility. 

Curiosity was launched in November 2011 and landed in August 2012 with the primary goal of exploring the Gale Crater - an area that’s now believed to have once been a sprawling body of water. The rover’s mission objectives were (and still are) very far-reaching, but much of what it does, collects, studies and records is done so that NASA scientists can try to determine whether Mars could ever have hosted life. 

First off, while navigating the Gale Crater, Curiosity discovered a host of specific molecules and carbon chains which, according to NASA, could have contributed to the formation of early life. Since then, during Curiosity’s further exploration of the Martian landscape, it has found evidence of sulfur, nitrogen, hydrogen, oxygen and carbon; elements that are also essential to life. We are, after all, carbon-based beings. The puzzle is by no means complete, and at the moment there’s no solid, irrefutable answer on whether life does, has or has never existed on Mars… But it does seem as though early Mars at least contained all of the fundamental pieces necessary for it to happen. 

John Grotzinger, the chief scientist behind the Curiosity Rover, has every confidence that Mars was once a habitable planet - even claiming that the water that once filled the Gale Crater would’ve been safe to drink! It’s an exciting thought, but it also ignites another question: If life was initially on Mars instead of Earth, then how did it eventually get here? Well - assuming for a second that life at some point did, in fact, exist on Mars - the prospect of the two planets somehow exchanging organisms might not be all that far-fetched, given their close proximity. At the closest point in their orbits, Earth and Mars are approximately 34 million miles apart. It is a massive distance, but not exactly insurmountable in the grand scheme of space. 

And here we get to the panspermia theory, which suggests that forms of life exist throughout the universe and travel through space mostly on meteorites. The chances of microbes actually surviving such high-speed, interplanetary, trans-star-system journeys are definitely low, but studies have shown that it is possible. And we do already know that various meteors from other celestial bodies have made their way to Earth. And that Mars has been pummeled with space debris in its past, as well. So, if there’s even a grain of truth in the panspermia theory, then it may well have played out on our planet and the “Red Planet” - and, across billions of years, such events may theoretically have passed vital material from Mars to Earth. 

Much more recently, scientists like Steven Benner, of the Westheimer Institute of Science and Technology, have added more fuel to the theory - arguing that, thanks to its store of the element boron, early-Mars may have actually been a better place than early-Earth for the creation of RNA or ribonucleic acid - an essential building block for life. So, perhaps life really did develop on Mars first before traveling to Earth… Or, at the very least, an adequate store of Boron made it to Earth via meteorites, to kickstart evolution here. 

It ties closely with the “Phosphate Problem”, which science has long been trying to figure out. The problem posits that early-Earth couldn’t sustain the vital phosphates needed to create life… But early-Mars could well have done. In 2013, shortly after Benner revealed his ideas on why Mars may have been a better breeding ground for basic life, the university of Nevada’s Christopher Adcock led a study which found that it was much more likely that phosphates on Mars would’ve developed in water; compared to phosphates on Earth which weren’t as compliant with water. So, seeing as we believe life started in water, Mars is arguably a more likely early home. 

As interesting and possible as it may seem, though, the idea that life existed on Mars is still just a theory. And the jump from the Red Planet perhaps hosting early microbial life to it being the long-lost-home for an ancient line of actual human beings that we no longer know about is a massive one. Depending on who you ask, some form of life may have existed (or may still exist) on Mars… But walking, talking, advanced, intelligent and recognizable humans? Not likely. 

For those trying to pinpoint the origin of life, though, Mars offers an alternative to our own planet - with some claiming that Earth increasingly seems a more unlikely source. But there are still plenty of questions hanging over Mars in general - not least, “what exactly happened to its atmosphere?” While there’s still no proof that life has ever existed or excelled there, the general consensus is that it’s at least possible.

The universe is 13.8 billion years old. Modern humans have walked Earth for only the last 300,000 years of that. So, what could’ve happened in the long stretch of time between the Big Bang and the emergence of homo sapiens on this planet? There’s a lot that we know, and a lot that we don’t… but some theories bridge the gap in more unusual ways than others.

A headline-making study in June 2020 claimed that there could be dozens of alien civilizations living in our galaxy, the Milky Way. Thirty-six was the most often-cited figure, although the upper estimate went past two hundred. That’s two hundred individual alien societies reportedly living on our doorstep, in cosmological terms.

Now, let’s be clear, there is so far zero actual proof that there are any alien civilizations out there. The general scientific consensus is that there must be, but we’ve so far found nothing by way of hard, irrefutable evidence. The Fermi Paradox continues to plague our search for extraterrestrial life! The 2020 study, though, was inspired by various projections and predictions, including the Drake Equation. Its claim of thirty-six neighboring alien groups has since been debated and disputed. But, say there are other bands of living beings… and say they really are not so far away from us… then what are they doing there?

Some theories, most notably the Zoo Hypothesis, argue that nearby, superior alien groups are busy watching and possibly experimenting on us. Others, like the Dark Forest Theory, suggest that any alien society trying to survive will wisely remain as quiet and undetectable as they possibly can. There are, though, some more unconventional theories to suggest that if there are aliens out there… they might not be all that different from us, at all. 

One study, published in December 2020 by researchers at CalTech, aimed to map the potential for life in the Milky Way more precisely than ever before. Paying close attention to the probability that life will - and does - eventually self-annihilate (as well as the likelihood of the emergence of life - of abiogenesis - in the first place) it delivered some interesting results. It found that life was most likely in the Milky Way around 8 billion years after it formed, and around 13,000 lightyears from the galactic center. Considering that we appeared more than 13.5 billion years after galaxy formation, and that we’re now 25,000 lightyears from the galactic center… this would suggest that humans are doing quite well for themselves. According to the study, we’re here far too late, in completely the wrong place, and are therefore way past the peak of life in this galaxy… and yet we’re surviving. Well done us.

But what do these conclusions infer about the rest of life in the Milky Way? One takeaway is that, if the study rings true, there should be a band of space almost halfway between us and the heart of the galaxy - 13,000 lightyears from the center - wherein life is much more likely to exist than anywhere else. But another is that most life in this galaxy should’ve emerged more than 5.5 billion years before we did. And, if that’s true, then what happened to it?

The short answer is… it killed itself off. The CalTech study highlights the key role self-annihilation likely plays in how far any civilization can reasonably spread. Away from the study, the general idea is that all life dies before it gets big enough to be noticed. The slightly frightening assumption, then, is that the same thing will happen to human beings. That we’ll only ever get so far before we destroy ourselves from within. 

But, still, if even just one such civilization did manage to survive, then they would certainly be considered ancient to our lowly minds. Recorded human history barely goes back five-and-a-half thousand years, but we’re now imagining life that’s five-and-a-half billion years old. 

Not that such a hypothetical life form should ever automatically be billed as ancient human, even if we could prove that it exists. The chances of anything else separately evolving to be even slightly recognisably similar to us are… extremely low. The aliens we see in movies and read about in books are all too often humanoid in nature, with eyes and hands and heads and some kind of audial language. But, in reality, they’d probably look nothing like us. And, according to some theories, might not even be carbon-based.

The picture gets a little stranger, though, when ideas on panspermia get thrown into the mix. Subscribers to various ancient alien theories argue that biological material could’ve been distributed all across the universe in the time since its inception. That we think that we’re rare on Earth, but that actually we’re just one of countless locations that life has reached. And this is what panspermia amounts to: the spreading of life throughout the cosmos, usually via space dust, asteroids and colliding planets.

Directed panspermia, though, brings a degree of agency to the table. The idea now being that life is deliberately spread to other worlds by advanced, traveling alien species. Again, there’s little by way of credible, mainstream science to suggest that this is what actually happened here on Earth. But, with such a long time-gap to fill between the start of this planet and the start of humankind on this planet… fringe theories abound that ancient humans either seeded here, or arrived and settled here, millions (or billions) of years ago. 

In this version of life, the universe and everything, it’s as though we’re a colony established in the distant past by an older, more advanced version of ourselves. Through the lens of the CalTech study, we might imagine that those older, superior humans had emerged long ago, out of the optimum region for life in the Milky Way… 13,000 lightyears away from the galactic center (and 12,000 lightyears away from us). They then brought their human civilization here, before carrying on their merry way into the rest of the galaxy.

But one final consideration for today’s question is; what if we aren’t the product of panspermia, but we’re actually the ones facilitating it? Another popular fringe theory is that life did originate on Earth, but the history of human evolution isn’t what we generally think of it as. Instead of the earliest hominins emerging around nine million years ago (and modern humans about 300,000 years ago), some claim that there were humans before this… and that they became advanced enough to leave Earth forever.

Importantly, there is, again, precious little scientific or historical evidence that this really is the case. It’s an idea, an unsubstantiated theory, but one that has captured the imagination of many a science fiction writer before now. Again, it allows us to imagine that the Milky Way is actually full of life, perhaps boasting far more than just the thirty-six civilizations suggested by the June 2020 study. Only, in this version of events, many of those could be our ancestors. It’s just that they started on Earth and then set off to the stars, just as we’re trying to do today.

The biggest argument against this line of thinking, however, is that it assumes that Earth is basically the center of everything. That’s despite the overwhelming statistical likelihood that it isn’t. If either panspermia theory is true - that we were spread by others, or that we started on Earth and are now spreading elsewhere - it’s much more likely the first one. To bring in the CalTech study one final time, even had humans somehow instantly appeared on this planet at the moment that Earth was born - an obvious impossibility - then they’d still be only 4.5 billion years old, which would still place us as arriving later than the optimum time for life in the Milky Way, 8 billion years after it formed.

The idea becomes marginally more palatable if we imagine that humans didn’t start on Earth… but were seeded here instead… by other humans. Then, theoretically, we’d have so much more time to play with across the history of the universe. Our story could be pushed further back, to a time before Earth, and a time within CalTech’s optimum parameters. And it can be pushed further forward, because we’re no longer confined to just one world. Earth becomes just one of many that we might have visited in the past (or in the future). And, suddenly, the rest of the Milky Way is our playground.

But, ultimately, all of those stipulations require us to make some gigantic leaps in our understanding of why we’re here, what it takes for us to survive, and how significant we really are in the universe. More and more scientists are growing to accept that alien life must exist somewhere in space. But human life? Perhaps we’ll only believe that when we see it!

So, what do you think? How does the story of human evolution make you feel? Could there really be ancient ties between us and Mars? And how likely do you believe it to be that, ultimately, we could simply be the far-flung produce of our wider, galaxy home?

For now, wondering where we came from is a fundamental, universal question. The answer might always be shrouded in a certain level of mystery. But that’s how humans may, potentially, have come from outer space.