The Earth is the Only Home we have in the Universe: The Impenetrable Interstellar Moat

There is presently a widespread belief, which is encouraged by the plethora of science fiction novels, comic books, and especially Hollywood movies based on this belief, that human beings will one day colonize other planets, whether in our own solar system or in other solar systems or galaxies located elsewhere in the Universe. I declare that this belief is wholly, entirely, completely, and utterly false. Although it is possible, especially with the development of computer graphics programs that can mimic reality on a screen, to depict lifelike scenarios of human beings visiting and inhabiting other planets in films, the reality is very different and much more difficult to accomplish.

The French futurist and science fiction writer Jules Verne is famous today for having predicted, when he wrote his fictional works in the nineteenth century, a number of humanity’s technological inventions and accomplishments in the twentieth century. These include submarines for deep-sea exploration, flying machines, space travel, including going to the Moon, and Arctic and Antarctic expeditions. However, notwithstanding his remarkable prescience, there is one adventure that he wrote about which human beings will never accomplish: journeying to the centre of the Earth.

Because of the inaccuracy and incompleteness in his day of the knowledge of the composition of the Earth’s interior, in particular its core, Verne did not understand the insuperable difficulties that lie in the path of anyone who were to attempt to achieve this objective. He mistakenly believed, as geologists of his time probably believed, that the geological formations that exist a short distance below the Earth’s surface – rocks, caves, and subterranean rivers – continue all the way down, in a repetitive pattern, to the Earth’s centre. But this is not at all true, as modern scientific research and exploration have shown. People did not understand then that the composition of the Earth’s core and interior are very different from the features that we find on or just below the Earth’s surface.

Apart from the extremely high pressures that exist the further down one ventures – pressures which greatly increase the danger that the tunnel one has bored will collapse and crush whatever happens to be in its temporarily excavated space – there is a correspondingly great increase in temperature as one approaches the Earth’s core. It is now believed that the core is composed of a solid iron-nickel inner core which is surrounded by an outer core that consists mostly of molten iron, along with some other elements. While the melting point of iron is 1,538°C, the temperature of the Earth’s core is estimated to be about 5,600°C – a temperature that is much higher than the melting point of any known metal at normal atmospheric pressure. The only way a metal can remain solid at such a high temperature is if it is subjected to extremely high pressures – pressures that would instantaneously obliterate the human body’s delicate defences, or anything that we humans could ever build to protect ourselves from such high pressures. But even if we could construct a vessel that would remain solid at such high temperatures, any organism that was inside it would quickly be carbonized, just like an overdone baked potato or roasted pig, long before it reached the Earth’s centre.

Another source of the mistaken belief that we will one day colonize other planets comes from the examples of past explorers who discovered new lands. But the model of humans colonizing other continents in the past is highly misleading. Although the extension from the historical terrestrial to the futuristic extraterrestrial situation is easily made in one’s imagination, the ease of this cerebral transition masks the insuperable difficulties that exist in reality.

When the discoverers and colonists – adventurous men like Christopher Columbus, Amerigo Vespucci, Ferdinand Magellan, Vasco da Gama, James Cook, and their intrepid crews – set out on the wide oceans to explore the unknown parts, at least to Europeans, of the world, it is true that they were venturing into the unknown. However, they were not venturing into a completely alien and hostile environment that was not capable of supporting life. Although the places they visited, which, in many cases, have been named after them to pay them homage, at least by the descendants of the Europeans who were oblivious to the fact that these lands were already inhabited by human beings and therefore cannot be said to have been “discovered” by these explorers, were different from the places they had started from, they were nonetheless entirely capable of supporting human life. There was air that could be breathed, fresh water than could be drunk, a variety of different foods that could be eaten, and materials with which shelters, clothes, vessels, tools, ships, and other human necessities and conveniences could be fashioned.

But none of these elements that are essential to human life exist on the other planets in our solar system. We know that in the case of the closest celestial bodies to the Earth, our planet’s Moon and the planets Mars and Venus, although they are solid, unlike the larger gaseous planets Jupiter, Saturn, and Neptune, they are completely barren places that, in addition to the lack of water, either do not have an atmosphere or, if they do, are far too hot to support life as we know it. Although Venus has an atmosphere, it is uninhabitable because it is too close to the Sun and therefore too hot, with an average temperature that is estimated to be around 460°C. In terms of temperature, Mars is less inhospitable, but, as recent explorations of its surface have shown, it lacks the three vital elements that are needed to sustain human life – oxygen, easily accessible water in liquid form, and an environment that is suitable for growing food.

What this means is that these three and all other necessary elements must be transported to any planet that we attempt to colonize and inhabit. Although this is possible for short periods of time, as was demonstrated by the manned voyage to the Moon, this becomes insuperably difficult for longer periods. In addition, even if we were to construct a fleet of spaceships that could regularly make the trip from the Earth to another planet, the large amounts of fuel required to launch these ships, not just from the Earth’s surface, which is feasible, but from the surface of the other planet, which probably would not have a readily extractable source of the fuels that are needed to propel these and other vehicles, is another great obstacle to accomplishing this goal.[1]

Space stations are close enough to the Earth that they can be regularly supplied with everything that their tiny number of inhabitants need, and therefore they do not have to be self-sufficient. But even the closest planet is too far away to be supplied on a regular basis from the Earth, meaning that any colonists must be completely self-sufficient in food, water, and, most importantly, oxygen. The belief that human beings will one day colonize other planets is comparable to the alchemists’ mistaken belief that it is possible to transform base metals into gold,[2] for the project of colonizing other planets will require that we somehow find a way to create, extract, or transform the three vital elements of human life – oxygen, water, and food – from other substances which, at the present time, we are not at all capable of doing.

Another common theme of works of science fiction, whether they are literary or cinematographic, is that our planet will one day be, if it has not already been, visited by extraterrestrial alien creatures. However, contrary to what many over-credulous people believe, I declare that the chances of this happening, or that it has already happened, are pretty much zero. Those who believe this kind of science-fiction nonsense are committing the conception fallacy: because they can easily conceive or imagine alien creatures visiting the Earth, they believe this is probable or at least possible.

There is a symmetry in this case which many people seem not to realize: assuming they exist somewhere in the Universe, it is as difficult for any intelligent extraterrestrial creatures to reach the Earth as it is for us intelligent, creative, and resourceful human beings to reach an inhabited planet that is located elsewhere in the Universe. Whether it was intended or not, the enormously vast regions of outer space serve as a sort of interstellar moat – a vast, frigid, and barren expanse – that effectively makes the goal of travelling from one inhabited or inhabitable planet in our galaxy or the Universe to another planet insuperably difficult.

Despite the many discoveries that have been made by astronomers and physicists about the characteristics of this interstellar moat, such as the average temperature (just a few degrees above absolute zero), its vastness (measuring light-years between one star to another), its very low density (less dense than the best vacuum that humans can create on the Earth), and the absence of the things that we humans require to survive (no oxygen, food, or fuel, and very little water), there are nevertheless many people who credulously believe that our species will one day inhabit another planet besides the Earth, a planet that is located far, far away in another solar system or galaxy. Our inability to conceive these facts in their stark and inhospitable reality – the extremely low temperature and density, the vast distances, and the physical barrenness – make many people conceive of interstellar space travel as merely a longer and more difficult version of terrestrial travel. After all, haven’t we extraordinarily clever humans been able to send a human to the Moon, as well as send space probes into the outer reaches of our solar system? Then surely, we should also eventually be able to send human beings to other inhabitable planets in the Universe! It is only a question of time, according to many overoptimistic people.

The next time you read or hear someone making an outlandish claim such as “When human beings colonize the Moon, or Mars, or some other planet in the Universe,” remember or point out the simple fact that we clever human beings will never be able to travel the 6,370 km to the centre of the Earth.[3] Either we can accept our terrestrial limitations, and terrestrial existence as the only planetary or lunar existence we will ever know, except for brief and very costly ventures into the neighbourhood of our planet, or we can continue to waste time, effort, and our planet’s limited resources in pursuing the unachievable fantasy that our species will one day inhabit other planets.

If there is indeed a God – a Creator who made the Earth, the Sun, and the rest of the Universe, along with all the wondrous creatures that inhabit the Earth – then that God surely exhibited wisdom by confining us and our ever-increasing numbers to this planet, so that our selfish and destructive tendencies would not infect and mar, like a deadly, deforming, destructive, debilitating, and decimating virus, the pristine beauty that perhaps exists on another planet which is capable of supporting life somewhere else in the Universe.

There are limits to human ingenuity. There are problems that we humans will never be able to solve. There are dreams that we will never accomplish. Journeying to the centre of the Earth is one of these impossibilities. So too is colonizing and inhabiting another planet that is located somewhere else in the Universe. For better or for worse, the Earth is the only place in the vast Universe where human beings will be able to live, multiply, and thrive. And it therefore follows from this fact, if we truly are the rational creatures that Aristotle proclaimed us to be, that we, as a species, must cease acting like a bunch of selfish and vainglorious fools, by glorifying our many different non-living creations and behaving as if we are the only species that matters, and change, before it is too late, the destructive and rapacious manner in which we are presently living – a manner that, if it is continued unabated, will lead to our demise and eventual extinction, all because we were much too clever for our own good.

[1] Since these fuels, primarily oil and coal, are the result of dead life forms that have been transformed in the absence of oxygen and under high pressure over long periods of time, it cannot be expected that they will be found on planets where there never has been any life.

[2] Most people are not aware that Isaac Newton was a devoted lifelong alchemist. Apart from his scientific writings, he wrote many works on alchemy, which shows that even a brilliant man who made many important contributions to the advancement of human knowledge was nevertheless capable of believing things that are false.

[3] Not only will we never reach the Earth’s centre, we will never be able to get to the midpoint from the Earth’s surface to its centre, which is only slightly more than 3000 kilometres away. In fact, it is impossible for us to venture 1000, or even 500, kilometres below the Earth’s surface towards its centre. Although we are quite adept at travelling sideways along the Earth’s surface, and in recent times we have shown that we are even capable of travelling upwards away from the Earth, we are not capable of travelling any great distance downwards towards the Earth’s centre.