The Edge of Impossible
The above statement might appear to be trivial at first, but the implications are quite intriguing if one thinks about it carefully. There are things that are impossible undisputedly and then there are things that seem to be impossible but are not actually. So, the question is where do we draw the line, what are the limits, the real impossibilities and what lies just short of these contrarieties?
FRINGES OF IMPOSSIBLE
There are things that are impossible like the entropy of an isolated system is irreversible and neither can it be effectively restrained to be constant. This renders a lot of highly desirable things impossible like the existence of indefinitely self-sustaining biological systems or in short immortality is unobtainable. Death is one of the things that fascinates curious minds across cultures and generations. There is a universal desire to control death- the ultimate end of consciousness. Fortunately, or unfortunately the laws of physics are absolute and not subvertible, but no one ever said that physical laws cannot be bent to extremes to achieve the desired outcome, at least sometimes we can do this if not always.
Now let us assume even if unending life was possible then what might be the aspirations of such an eternal being. Curiosity is an innate characteristic and a natural result of high intelligence, and the universe is super huge, so such a being might want to explore it but to what extent is the universe practically explorable? It turns out that complete exploration is simply not possible, not because of the size but because of the nature of the universe we live in, but still, what are the limits?
After we get bored of exploring a practically unending universe, we might turn our attention to entertainment and pleasures of living an eternal life. Now what might pique the interest of a being which has transcended all forms of material or biological existence.
Pursuit of absolute knowledge about everything seems like a promising candidate. So, what is the limit of what can be known, is there an upper bound to acquiring knowledge. Honestly no one can say as for now we are far too ignorant to know how much we don't know yet; but still a little discussion will harm no one so we will come back to this question later.
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For now let's explore the periphery of possibilities or as the title says " THE EDGE OF IMPOSSIBLE
The possibilities exceed what most might consider to be extremely satisfactory by inconceivable margins and that too is an understatement if you ask me. The limits are significantly farther than we could have imagined. Modern science has started to paint a spectacular picture of reality at every front, from mind-bending, common sense defying microscopic scales to majestically huge cosmic scales., but still, what is the extent of what is possible. Let's see
ACHIEVING IMMORTALITY
"Life is a brief intermission between birth and death, enjoy it"
This way we live on forever even after death. But today we are interested in the type of immortality most of us are familiar with definition wise -that is an unending life, a life without death or at least a life so long that death is irrelevant. We can start by understanding physical aspects of consciousness and let's just hope that consciousness is not result of emergent properties of brain, meaning brain is not something more than the sum of its parts, because that would make things much more complicated than they already are. I don't like the idea of emergence as I belong to physics background and I have a reductionist and physicalist approach toward understanding things, but I'm in no position to reject a beautiful as well as necessary idea like emergence in study of complex systems like consciousness, so we will discuss it if need be.
Origin of Consciousness
Evolutionary emergence of consciousness is one of the most puzzling phenomena in the study of Origin and development of life on Earth. Consciousness in itself is difficult as well as fascinating to understand.
How do we define consciousness? I can say that "Consciousness is one's awareness and knowledge of a set of information, either fundamental or abstract, that enables them to understand their environment and respond accordingly in ways that are appropriate for survival" but many might disagree with this definition. The Cambridge Dictionary defines consciousness as "the state of understanding and realizing something." The Oxford Living Dictionary defines consciousness as "The state of being aware of and responsive to one's surroundings.", "A person's awareness or perception of something."
Consciousness is something that all of us are familiar with, yet no-one exactly understands it. Despite millennia of analyses, definitions, explanations and debates by philosophers and scientists, consciousness remains puzzling and controversial, being "at once the most familiar and most mysterious aspect of our lives".
One thing about Consciousness that everyone can agree on is that is exists for sure. We can differentiate things that are conscious from things that are not.
Although understanding Consciousness might be difficult but it is quite self-explanatory how evolutionarily selective propagation of more and more conscious lifeforms is advantageous from a survival viewpoint. It is one of the characteristics that will evolve inevitably.
Earliest evidence of primordial lifeforms are microfossils that dates as far back as 4.28 billion years ago, not long after the formation of the Earth 4.54 billion years ago. These microfossils were found within hydrothermal-vent precipitates in rocks in Quebec (Canada). The level of consciousness these early microorganisms might have had is debatable, but it can be safely assumed that these organisms might have had some form of rudimentary consciousness and if not then such organisms with basic levels of consciousness might have evolved soon after the appearance of earliest lifeforms on Earth.
Higher levels of consciousness must have progressively evolved over long periods of time. It is possible that higher levels of consciousness might have convergently evolved through different evolutionary paths, but the earliest common ancestor must have had some kind of rudimentary consciousness. There should be a gradient of consciousness ranging from completely unconscious like that of cluster of organic molecules to highly intelligent beings like humans.
A living organism is a complex collection of non-living organic molecules. Earliest self-replicating molecules should have depended on random haphazard movement caused by external forces (flux of medium fluid in this case) to come in contact of other molecules for the purposes of replication or improvements of existing structures (evolution in its earliest form).
A look into motility of some primitive organisms can give some helpful insights on the origin of consciousness. Rupert Glasgow in his book Minimal Selfhood handles this treatise in a very empirical way. I referred to it for the research for this article. Give it a try if you want. Trichoplax Adhaerens is a marine invertebrate distributed in tropical waters worldwide. It is one of the simplest free-living sea-water animals. It is a heterotroph and moves haphazardly. Although one might consider it devoid of consciousness, it shows a kind of responsiveness by slowing down its movement when in regions of high concentration of food.
Now take a few steps ahead and we have light-sensitive organisms. In a wide variety of motile phytoplankton, including Chlamydomonas, Volvox, Euglena, and Kryptoperidinium, eyespots are light sensitive organelles residing within the cell. Eyespots are composed of photoreceptor proteins and typically red to orange carotenoid screening pigments. This association of photosensory pigment with screening pigment allows for detection of light directionality, needed for light-guided behaviors such as positive and negative phototaxis. Above examples give us an idea how higher levels of consciousness might have evolved in multicellular organisms through natural selection. Now let's see how multicellularity itself evolved and how complex brains emerged ultimately.
Emergence of Brain
Earliest multicellular organisms appeared around almost 600 million years ago while first unicellular organisms came into existence more than 4 billion years ago. So, it really took a very long time for life to evolve multicellularity from unicellularity, almost 3 billion years. The classic 1952 Miller-Urey Experiment and similar research demonstrated that most amino acids, the chemical constituents of the proteins used in all living organisms, can be synthesized from inorganic compounds under conditions intended to replicate those of the early Earth
It is known that complex organic molecules occur in the Solar System and in interstellar space, and these molecules may have provided starting material for the development of life on Earth. The evolution of multicellular life from simpler, unicellular microbes was a pivotal moment in the history of biology on Earth and has drastically reshaped the planet’s ecology. Very first organisms (unicellular) to show cooperative behavior might have formed groups or colonies with some form of task division that increased the survivability and growth of the group as a whole. Although this kind of organization is beneficial it is inefficient and flawed in many ways. In this kind of arrangement every individual cell is capable of performing all life processes itself and is independent and is not obliged to contribute to the interests of the group and yet reap benefits of the work done by other individual cells. We can call these freeloaders "cheater-cells" for convenience. The problem is that cheater-cells will grow faster and thrive as cheating is a more advantageous strategy in such arrangements, leading to eventual domination of population by cheater-cells with non-cooperative characteristics. This was the biggest hurdle in evolution of multicellular life and scientists still don't know the answer to the question how multicellularity evolved despite such compelling odds, but we should be glad it happened. Additionally, multicellularity appears to have evolved independently many times in the history of life despite the odds. To solve the mystery of how multicellular life persisted, scientists are suggesting what they call “ratcheting mechanisms.” Ratchets are devices that permit motion in just one direction. By analogy, ratcheting mechanisms are traits that provide benefits in a group context but are detrimental to loners, ultimately preventing a reversion to a single-celled state. One such mechanism is division of task among specialized cell and with this we enter the world of immense complexities.
Once we have specialized organs made of specialized cells that are really good at performing one or few tasks extremely efficiently but depend on the group for its survival. For example, cells in our lungs are extremely good at diffusing oxygen from the air but depends on blood cells for supply of glucose and proteins for sustenance. Same goes for other specialized organs.
Once we have a complex combination of specialized organs working together, a brain is necessary for effective coordination of different parts, but evolution doesn't work like that. Necessity has nothing to do with evolution. It depends on whether a characteristic gives inherent advantage over competition in a particular habitat with a given set of conditions and if being brainless is what achieves this so be it. And in most scenarios in history of life being brainless has proved to be more advantageous as there are significantly more species of organisms on Earth that are brainless than those with brain and central-nervous system. Evolution of brain is one of the most unlikely and least understood phenomena in the study of evolution. At first cells gave up their individuality then independence and now autonomy.
Highly advanced cerebral capabilities like that of humans comes at a severe price. Human brain constitutes about 3% of the total body mass but contributes to more than 20% of the total energy consumption of body on average. Sustaining such a power-hungry brain is not easy. Calorie requirements per unit body mass of humans is one of the highest in animal kingdom. We don't only need calorie dense food but also a broad variety of nutrients that are essential for optimal functioning of body and proper health. In today's post-industrial world achieving proper balanced diet is not considered a big deal thanks to highly organized social structures and a perfectly engineered artificial ecosystem that works with a considerable degree of efficiency.
Smallest individual units of brain are neurons. The number of neurons in the brain is about 10¹¹. For instance, Azevado et al physically counted them and found 0.6-1 * 10¹¹. Eric Chudler has collected estimates from a range of textbooks, which estimate 1-2 x 10¹⁰ of these (10%-30%) are in the cerebral cortex. The number of synapses in the brain is known much less precisely but is probably about 10¹⁴. For instance, Human-memory.net reports 10¹⁴-10¹⁵ (100 – 1000 trillion) synapses in the brain, with no citation or explanation. Wikipedia says the brain contains 100 billion neurons, with 7,000 synaptic connections each, for 7 x 10¹⁴ synapses in total. The number of synapses per neuron varies considerably. According to Wikipedia, the majority of neurons are cerebellum granule cells, which have only a handful of synapses, while the statistics above suggest that the average neuron has around 1,000 synapses. Purkinje cells have up to 200,000 synapses!
A single neuron sits in a petri dish, crackling in lonely contentment. From time to time, it spontaneously unleashes a wave of electric current that travels down its length. If you deliver pulses of electricity to one end of the cell, the neuron may respond with extra spikes of voltage. Bathe the neuron in various neurotransmitters, and you can alter the strength and timing of its electrical waves. On its own, in its dish, the neuron can’t do much. But join together 302 neurons, and they become a nervous system that can keep the worm Caenorhabditis elegans alive sensing the animal’s surroundings, making decisions and issuing commands to the worm’s body. Join together 100 billion neurons—with 100 trillion connections—and you have yourself a human brain, capable of much, much more.
An interesting fact about brain cells is that it’s even possible that your brain cells might have longer maximum lifespans than you do. In 2013, researchers transplanted neurons from old mice into the brains of longer-lived rats and found that the cells were still healthy after living for two whole mouse lifespans!
Current experiments suggest that lifespan of neurons is at least twice that of the organism itself or more than 200+ years in case of humans!! Still the biological breakdown is inevitable even though 200+ years look promising, but if we want to achieve immortality then we need to leave behind our biological selves.
Evolving Beyond Biology
If you count each interaction between synapses as 1 operation, then brain runs about 10¹⁷ operations per second. This adds up to a total of 3.1104×10²⁶ operations in a lifespan of 100 years. So, the question is that whether or not is it possible to generate the computing power necessary to digitally replicate the brain function of at least one lifespan for one human. This computational requirement will increase by many degrees of order when you consider the entire population.
Let us assume we need 100 petaflops (1pFLOP=10¹⁵operations) of processing power to simulate brain functions of one human just to be generous. Then we need a computer with a processing speed of 1.1×10²⁶ floating operations per second or 1100 billion petaflops to carry out neural operations necessary for simulating brain function of 11 billion humans which is going to be total population of the world at the end of this century.
FUGAKU is the most powerful supercomputer in world today with a processing speed of 412 petaflops which is nothing compared to 1100 billion petaflops of all the humans combined. One human brain output a processing speed of 100 petaflops so it can be said that for the first time in history man-made computers have surpassed a human brain, although not by much, in terms of raw processing power, which is impressive but still not that impressive when you take several facts under consideration. Although a human brain and the FUGAKU supercomputer are roughly comparable in computational power, they differ enormously in terms of their thermodynamic properties. The FUGAKU will occupy approximately 2,000 square meters of floor space (equivalent to four basketball courts), will consume about 29,899.23 kW of power, will require an intricate cooling system (hidden under the floor) to dissipate the resulting heat, and will be utterly non-portable. A human brain is about the size of your two fists, consumes about 15 watts (even when you are solving a hard physics problem), and is completely practical to carry around since it has a mass of about 1.5 kg. It is also worth pointing out that brains, unlike computers, self-assemble themselves and are also able to program themselves. FUGAKU might be able to simulate brain function of a few humans but to simulate entire population we would need 3 billion FUGAKU super-computers which is not practical in terms of power consumption. In terms of power consumption that would be equivalent to 90 thousand TW (90k terra watt or 9×10¹⁶ watt) or in terms of energy consumption that is 3 trillion TWh per year. For contrast total energy production of world in 2020 was just 25 thousand TWh which is almost 100 crore times less than the requirement of our hypothetical scenario.
We need a power source that can output this enormous 90 thousand Terra Watt(9×10¹⁶W). Luckily, we don't need to look very far or at least not far compared to the scale of our galaxy. Look up in the sky and we have a burning fireball of nuclear energy continuously spitting enormous amounts of radiation into the space, our Sun😎.
The power output or luminosity of the Sun is 3.8 x 10²⁶ W !!, this is the total amount of energy released from the Sun every second! which is far more than sufficient for our hypothetical requirements. The real problem is how to harness this enormous energy output of our lovely sun.
Earth's surface is too small to capture even a tiny fraction of this energy and also Earth is too far from the Sun and hence the intensity drops too low when sunlight reaches us. In order to efficiently harness sun's energy, we need to get closer. There are some theoretical megastructures than can get the job done. A Dyson Sphere is fictional megastructure built around a star composed of many individual solar satellites completely encompassing the star to harness more than 90 percent energy output of a star.
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Although building a stable Dyson sphere system is currently beyond humanity's engineering capacity, such megastructures are theoretically possible. The sheer volume of meterial that would be required for such a construction cannot be produced on earth. It will be possible to draw material from inner planets of solar system to build initial infrastructure then it would be possible to start mining the entire solar system to construct a full fledged Dyson Sphere. Power output of Dyson Sphere will be enough to power billions of supercomputers like FUGAKU. Actually a Dyson Sphere is simply a overkill for the task at hand as this would give virtually unlimited computing power to a newly born type-2 civilization, much more than what is required, so power source was never a problem but the engineering solutions necessary to harness this power is the real challenge.
Once the problem of computing is solved then the next step would be to create functioning digital copy of a brain or mind more precisely ,and this is the tricky part. The big question is "Copy what exactly?!"
As we have already discussed how difficult it is to pinpoint what exactly is consciousness . Let us assume brain is completely understandable within the bounds of physical laws of nature then if we successfully understand physics and chemistry at all scales including microscopic and Quantum scales, we will be able to completely explain and replicate structure and function of brain including consciousness. Now we need to convert this information into digital data to make a digital model of brain that will evolve in time based on the understanding of laws of physics and biochemistry in a computer simulation. If knowledge of natural laws turns out be accurate then the digital replica of brain must be identical to that of the biological counterpart in terms of structure and function. Such a copy should be able to simulate consciousness accurately.
All of this would only be possible if our assumption is correct that brain is completely physical and consciousness is a result of physical properties of brain that can be understood and explained by natural laws.
Digital Consciousness
Human consciousness is result of interaction of 100 billion neurons via 700 trillion synapses . There are also combined effects of many neurotransmitters and also the fact that brain is always coupled with a body. The body might have some bearing on our perception of universe. All these factors combined form an immensely complex system that is very difficult to understand completely and hence difficult to simulate artificially.
Theoretically it is possible to simulate any physical system provided that sufficient data is available to describe an initial state. To construct a digital model of human brain a lot of physical data has to be fed into computers just to begin the work. Obtaining this data with required level of detail is a really difficult challenge for today but this can be done and that too in a foreseeable future. A lot of work is already being done in this field. Now, even if a static model is built successfully, that takes all the necessary variables involved under consideration, generating a working digital simulation still comes with completely different set of problems. A complete understanding of physics and biochemistry will be required to understand working principles under which various components of brain and body interact to give rise to the convoluted consciousness humans experience. This is a very fundamental problem faced by scientists in all areas of technological development working on the cutting edge of scientific research. Sometimes a strong need is felt for a theory of everything. It might be possible to attain a complete understanding of universe as the scientific development so far looks very promising so let us be optimistic and assume that at some point a sufficiently advanced civilization that will descend from homo sapiens will achieve this milestone.
Complete understanding of physical laws is necessary to animate the digitally constructed static model to be able to evolve in time from one moment to another based on natural laws, identical to that of the mind of a real person. Then the digital simulation will be able to think and process sensory input like a real human.
If all these problems are solved successfully then let's hope that consciousness is not result of some unpredictable emergent properties of brain and body, meaning it depends completely on physical properties of brain and natural principles of interaction of subatomic particles.
To construct a static digital model of brain we need data extraction systems to to completely record and store, in a digital format, physical structure of brain down to atomic level. Currently we don't have any such technology that is even remotely capable of this but it is a matter of engineering so this can change very soon.
Digital minds will have functional immortality which can exist for as long as the civilization exists in time
LIMITS OF HUMANITY
There is a finite maximum speed limit of translation of matter or data that is the speed of light which is impressive at almost 3lakh km/s but it is still nothing compared to the scale of the Observable Universe which extends to a radius of about 46 billion(4.6×10¹⁰) lightyears in every direction radially assuming the rate of expansion to be constant but data suggests that this actually is not the case. In fact the Cosmic Inflation is accelerated and if our calculations of expansion rate are correct then the observable universe might be hundreds of times bigger.
Also pay attention to the word "OBSERVABLE" here which means the extent of universe as far as we can see. A team of scientists led by Mihran Vardanyan at the University of Oxford did a statistical analysis of all of the results. By using Bayesian model averaging, which focuses on how likely a model is to be correct given the data, rather than asking how well the model itself fits the data. They found that the universe is at least 250 times larger than the observable universe, or at least 7 trillion(7×10¹²) light-years across!!!.
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Cosmic Microwave Background Fluctuations
Even if the the currently accepted figure is correct which is 92 billion lightyears across diametrically in the sphere of observation and continuously expanding at a rate faster than the speed of light then we can safely say that the exploration of entire universe by any civilization, no matter how advanced, is impossible either physically or observationally. Every year many galaxies cross the point of no reach , more than 90% of all the galaxies are already so far that it is not possible to catch them even if light speed travel was possible. One may then ask how are we still able to see these galaxies?! . As we already know that the speed of light is finite hence it takes light billions of years to reach earth from far-off galaxies. The light of such galaxies that we see today started off billions of years ago when these galaxies were still within reach. Most of the universe that we see today are past images of it, the further we look into the space the further back in time we see. In a way universe is showing us things that are unreachable, even for light.
The most disturbing thing is that we don't even know how big the real universe might be because light from the galaxies beyond a certain distance will never reach earth .i.e. 46 billion lightyear.
So, how much of the universe can we explore?
First thing that is needed to be done in order to explore any significant portion of space is to develop space propulsion technology that can accelerate spacecrafts to speeds comparable to that of the speed of light.
Fastest man-made spacecraft ever is the Parker Solar Probe which set the record at 150km per second!! relative to the sun at the time of its closest approach to sun on 29th April 2021(last month), which is impressive but with this speed(150km/s) it would take almost 9,000 years! to reach Proxima Centauri B which is the nearest star to us at 4.24 lightyear.
Voyager-1, which has travelled furthest from Earth of any spacecraft, took nearly 35 years to leave the Solar System. Our current propulsion technology is primitive at best when it comes to interstellar travel. Any meaningful exploration of universe would require significantly higher speeds that are comparable to light speed or maybe even faster than light itself. For this significant advancements in space propulsion is required. There are some theoretical ideas that can achieve this which I might discuss some other day but today we'll assume that we will succeed in attaining relativistic speed travel in most plausible ways at some point in time through diligent efforts as we would have achieved digital immortality till then so we will have a lot of time to figure out such things.
So how fast can we go in the best case scenario? It turns out that it is theoretically possible to achieve atleast 95% speed of light, anything beyond that would come with tremendous increase in relativistic mass hence increase in required thrust to accelerate and decelerate the spacecraft. At 0.95c (95% speed of light) the mass would increase 1000% .i.e. 11 times of rest mass, which is huge but manageable.
Let's say we achieve this speed then how far will we be able to explore.
Let's say civilization lasts for 10 million years then in this time period we will be able to go as far as 9.5 million lightyears. We will be able to explore anything in the radius of 9.5 million lightyears. This does not mean we can thoroughly examine every planet and stars within this radius. How much of the universe is this sphere of 9.5 million lightyears. It turn out that this is 0.000005% of the observable universe!. Think about this extremely small number for a moment
This might sound heartbreaking that even in best of the best scenarios we will only be able to explore only 1 by 200 million volume of observable universe. Now that is a limit that brings us to realisation that how tiny and insignificant we are compared to the scale of the universe.
But there is nothing to get sad here. Our own galaxy has almost 400 billion stars 🤩 and we haven't yet figured out how to leave our own solar system.
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