In PART 1 we looked for the farthest place we could go on the surface of the earth. Now is time to explore beyond our home planet and even beyond the confined space of our solar system and our time:
A journey to the end of the Universe.
Now that we have somewhat satisfying answers for isolated places on the surface of the earth, let’s keep exploring for alternatives. If we are still looking for a place that provides more isolation and ensures we do not have contact with anyone anymore, we need to shift our eyesight up, toward the sky and the stars, and imagine all the possibilities to escape we could find in such a place. Let us get our science helmets on, and try to plot the ultimate escape strategy.
Our Universe is one of immense and inconceivable scale, punctuated by an abundance of cosmic landmarks like the 1 billion trillion (1,000,000,000,000,000,000,000) stars in the observable part of it; an absurd number that is beyond human comprehension. Yet, in such a vast and titanic place, there is an irony: how empty it is. Even with such abundance of cosmic landmarks, most of the universe is just a vacuum. To expose this, let us imagine we reduce every star in the observable universe to the size of a grain of sand, and hold one of those stars (the sun) at the palm of our hands, our nearest neighbors (Proxima Centauri) would be 6.9km (4.3miles) away from us. In fact, the typical separation between stars would be around 10km (6miles) in this model. And in in between, there is almost nothing. Nada.
The previous example, only considers how separated stars are from one another. Now consider stars tend to agglomerate within galaxies which are considered the most densely populated places on a universal scale. Therefore, things get even more impressive when we contemplate that our nearest galaxy is half a million times farther away than our nearest star (We would need to go to the moon and back 20 times to have a small glance of a representation of such a distance with the grain of sand scale – now compare that to a mere 6.9km or 4.3miles). And all that distance is mostly empty space.
In fact, it is expected that both the Milky Way galaxy (Our own) and the Andromeda galaxy (Our most important neighbored) will clash in about 4.5 billion years. That is an estimate of 400 billion stars (inside the Milky Way) and almost a trillion more (inside Andromeda) clashing. And yet, the result is almost no collisions between stars. That is how empty our universe is: even when two massive galaxies collide, their guts barely touch each other. Imagine an area the size of Europe (around 10 million squared Km) with 2 bees flying from the Atlantic Ocean on the East and 3 wasps flying in the opposite direction from the Asian continent – and expecting these to clash mid-air. Well, that gives us a good representation of the emptiness of galaxies.
Considering such distances, it could look like our universe forbids our desire to explore its depths. So for our intent of escaping it seems we are out of luck considering the limited and slow travel means we have at our disposal. Yet, there is a caveat and we are actually going to exploit.
Fortunately for us, within the laws of proven physics, there is a condition of space that might allow us to travel between distant galaxies, and beyond, within a human lifespan. Yet, it demands a sacrifice and a cost at such steep price that we would need to think quite hard about the overall endeavor before committing to it. A cost that emerges as a natural consequence of Einstein’s special theory of relativity.
And since we are committed to find the place where we could live a normal life with the most solitude; let’s pay that price and stop thinking about distant places in the middle of the ocean, and seek for a place so isolated that would become like an inaccessible island in the middle of space and time. Let us take then, a journey in a Constantly Accelerating Spacecraft (CAS).
Setting the rules
Now that we established our desire to go away and set our sight on the vast empty regions of the universe, and now that we have a medium to get there (Our CAS), let us explore real possibilities to reach such an objective. No exotic fictional alternatives are needed like warp-drives or wormholes, for this is a rigorous exploration of space and such exotic solutions are theoretically implausible to the best of our knowledge. We want to use proven physics within reach of our technological civilization, since at the end of the day, our desire is to really go to this ultimate place of awayness.
So we need to build a Constantly Accelerating Spacecraft.
It has to be a special ship that gives us the opportunity to thrive and live inside of its protecting shell. Let’s image a machine advance enough to provide us with artificial gravity and, has all the necessary materials to sustain our bodies and minds for a lifespan (50-80 years or so). Our ship would also be fitted with an almost a perfect shield (a couple km of state of the art material), for the high speed and acceleration would make any microscopic particle we encounter a deathly speck that carry the force of nuclear devices. Finally, then, we would have to find enough fuel to accelerate at 1G per second for at least 50 years.
Accelerating at 1G (1 gravity) per second means the velocity of our spacecraft accelerates 10 meters per second for each second it passes. Therefore, within the 1st second of our trip, our ship velocity would be 10m/s only to reach 20m/s the next second and 30m/s by the third second. After 10 seconds we would be traveling at 100m/s and would cover a distance of a bit more than half a Km (550m or 0.34miles) from our starting point. And just to get perspective on how much 10m/s is, it represents just 36km/h (22,5 miles per hour) so a speed most of us reach on vehicles constantly.
Not an impressive speed to start with, yet the important part is the impressive rate of acceleration (the relationship plotted below); a compound amount of acceleration interest that would ensure we could reach astonishing velocity within a relativistic small amount of time. Plus, this rate of acceleration would feel quite comfortable to us providing a surface we could stand on the back of the ship since it is equivalent to the 1G of force gravity have on all of us here on the surface: manufacturing a sensation of being in any place on earth gravity-wise. Life on board is relatively pleasant.
All these conditions are maybe less than a couple hundred years away from us technology-wise. Hence it is technically hard science fiction (meaning it is grounded in reality).
On our way…
We have a ship and everything is ready. The moment to depart this blue and green planet has arrive. The only home we have ever known. We look back, and for the last time we take the clouds, and the blue hue of the sky, we capture the trees in our memories. We shake the last hands and receive the last warming hugs. There is a mission to complete and we are eager to visit the loneliest place in the Universe.
We are on our way, accelerating at 10m/s. In is less than 2 and a half hours we pass near the moon – visualizing its silver surface through our portholes. After one and a half days we can see Mars, with its captivating red shade. The ship keeps accelerating, we feel a comfortable atmosphere inside and conduct a small celebratory dance for we are the humans that already traveled the farthest from earth. That place that contains everything that ever was for our species.
Just three weeks and our ship overtakes Voyager II (The farthest human object from Earth). We have left the solar system all together. We not only know this because of the distance, but also because the influence of the Sun diminished all around us (the instruments on board dictate not only less solar radiation but also less magnetic inference from our parent star). At this moment, our ship is traveling at 64 millions km/h (40 million m/h) or about 6% of speed of light: faster than any ship we would have ever built before. It is fast, but just a fraction of how fast we could be going given more time, and of course, a laughable speed compare to the speed of light. The speed of light will not be laughing in a few months though.
One year passed, we celebrate for the milestone while traveling ever faster toward Alpha Centauri (our nearest star system). Comfortably taking the void while a perpetual night sky is seen from our vantage point. Now it is impossible to have live conversation with Earth since it takes months for any kind of communication to arrive. Isolation is increasing while we elongate our umbilical cord with our mother planet to the max.
After 15 months we are one quarter (25%) of the distance to Alpha Centauri, but really one third of the way (33%) since we continue accelerating and every ticking second our propulsion system push us forward ever more rapidly, closing the distance faster than we have so far. We are already traveling at 87% of the speed of light and the ship systems tells us there is 1 light year of distance between us and Earth – we send back a laser bean denoting our crossing of this meaningful imaginary barrier. Special telescopes will look and see the laser beam in 1 year from now on earth.
From this point on Einstein Theory of Special Relativity it has ever greater effects on us considering one of the most revolutionary concepts that we learned in the 20th century is that time is not a universal measurement. It doesn’t matter how much our lives are governed by the same seconds, minutes, hours, and days, time will never be absolute. The rate at which it passes depends entirely on our speed and acceleration at any given moment. In summary, the rate at which time passes actually slows down the more we move. And because we are moving wildly fast in our constantly accelerating spaceship, time is passing half as fast for us and twice as fast on Earth: our original frame of reference.
It’s being 2 years and five of months in our travel. On Earth, it has being 5 years since we departed. Proxima Centauri (The closest of the 3 stars that conforms the Proxima Centauri system) can be sighted and a few days later we marvel at the sight of Centauri A and Centauri B – both Sun-like stars (Class G and K) that rotate each other. But our velocity is too great and the spectacle is but too short. Our velocity is 98% of the speed of light and increasing. We are getting closer to the total speed limit in our Universe (299,792 Km/s or 186,282 miles per second).
Intergalactic Space: within our Galaxy…
We are celebrating 4 years of our Journey, all systems and instruments are healthy. We are healthy. Our speedometer reads 99.95% of the speed of light and accelerating. Back on Earth, and according to Special Relativity, 31 years elapsed since our departure. Our friends are older and many things changed. Yet our spirit keep yearning to putting more distance from it. We are leaving the Local Bubble, a low-density region of the galactic interstellar medium that contains the Solar System among many other stars. Ironically, as soon as we leave the Bubble, our instruments start picking the existence of more material outside the ship for the Bubble contains around 0.05 atoms per cm3, or approximately one tenth of the average for the rest of the galaxy (0.5 atoms/cm3). Higher amount of hydrogen and helium density overall. We will be in this medium for a while.
Almost 8 year inside the ship and our motivation and unyielding spirit are galloping strong, almost as fast as our ship that already travels 99.99998% of the speed of light. We just leaved the Orion Arm, or the region of high concentration of gas and material that contains our planet. On Earth, by the way, a thousand and seven hundred and fifty one years passed since our departure. That is right 1,751 long years full of unimaginable changes. Our friends, family, country and maybe civilization are gone. Our mission might be just but a long forgotten note on history book, or maybe just a myth. Our next step, the edge of the galaxy that lays around 26,000 light years from our current position – a mere three years for us at this velocity.
We made it, we are officially the first human beings that leaved the Milky Way. We have travel more than 27,000 light years at a current speed of 99.99999994% of the speed of light. It only took us 10 years to be here, at least from our perspective. On earth things are a bit different since 26,991 years passed since our ship leaved its surface. A time scale so large that if we count it back from the 21st century we would not find humans in the Americas (for around 10,000 years) and the men from the Upper Paleolithic were still battling an ice age with sea levels 110 mt (360 ft) lower than in the year 2020. What changes has occurred on Earth since our departure? Are Humans still around after 26,000 years…? Probably yes. With that hope we send a high power communication beam back, it is just but a laser that still needs to travel back other 27,000 years from Earth perspective to reach a planet where no one is potentially listening. We still send the beam, even if it just means a small commemorative act.
We are now in the intergalactic medium (IGM); a place with a rarefied plasma that is organized in a cosmic filamentary structure. And when we say plasma, we mean a few atoms of hydrogen and Helium extremely separate among themselves. For all purposes, it is a place almost devoid of matter. Yet, our instruments still detect 1-10 particles per cubic meter, representing a dramatic drop when compared to the interstellar medium (inside the galaxy) of 1 million particles per cubic meter. This mean our shield receiving less impacts and suffering less damage and our ship finding less resistance.
Beyond our Galaxy…
15 years since our departure and the Andromeda Galaxy looks glorious with its spiral arms and bright shiny core; definitely bigger than the Milky Way to whom it is in trajectory of collision in 4.5 billion years from now – something we won’t be able to see.
At this point in our journey, we travel at 99.9999….9998% of the speed of light, where the number on nines in that expression would be bigger than the number of grains of sand on earth: for now on, we would refer to our speed as (X –> 1) which means it tends toward 100% of the speed of light (Limit of 1) and we can treat it as if it would be 100% since the number of decimal would not mess our calculations. We will never reach the speed of light, yet we are experiencing an ever smaller fraction to it.
On Earth, two million five hundred and thirty seven thousand years has elapse (2,537,000) and humanity as we know it, assuming we still have some descendant, does not longer exist. Our species has evolve into something different and homo-sapiens maybe went the cyborg route by introducing technological aspects to our bodies. Maybe our species exists within computers, or maybe, we in the ship are the last remnants of humanity. In any case, it is becoming meaningless to think of humanity at this point for even if we spend the next 45 years going back to Earth to close the gap (15 years for us to stop, turn around, and another 30 with half the time accelerating and the other half stopping]) almost 10 million years would have elapse since our departure by then. It would be basically a foreign world to us. For now and the future, our ship will be our only home. Our future is forward.
Gravity no more…
We only had to wait 3 years for the next milestone, in an undisclosed part of Space after 18 years and one month on our trip we detect the density of space outside of our ship to keep lowering to less than 0.5 particles per cubic meter. We are officially outside of the Virgo Cluster, the biggest region of space with gravitational bound objects. Just one representation of the biggest structure to have arisen thus far in the process of cosmic structure formation. It encompass a million galaxies destined to spend eternity together.
Yet, we are still within a mapped place in the Universe called the Laniakea Supercluster, which is no more than a group of clusters that do not have gravitationally bound and will separate after time. We are traveling at (X –> 1) yet the number of decimal places has expanded radically since our last check when passing near Andromeda three years back. On Earth, almost 65 million years (64,999,792) passed. Our departure is as distant to any life form still surviving there as the extinction of the dinosaurs is to us. If anyone remember us, we are but an aloof relic of a species that do not exist anymore and the current potential habitants of earth think of us as we think of rat-like mammals from our past.
Just a year and a couple of months after our departure from the Virgo Cluster is time for us to leave the Laniakea Supercluster. It’s being a little bit less than 15 months since that moment, now our trip sum up to an overall of 19 years since we took our foot off Earth. Yet, our distant planet of origin lays 250 million years ahead of our timeline. Our speed keeps increasing and getting closer and closer to the speed of light into an infinitely decreasing fraction of it.
We would need 3 more years of going through the motions to reach a new milestone. Actually, the most important and representative of all our trip, for at that point we won’t be a spaceship anymore. Yet for now, the ship is still stable while provides a cocoon of comfort we have learned to appreciate. It is our home and will continue being our place of living until it becomes our place of rest.
The Point of No Return….
Just a bit less than a quarter of a lifetime, 22 years of this fantastic journey. We are now wiser, have a better appreciation on the scale of things and how magnificent our universe is. Filled with beautiful orbs and flaming gas that composes a stunning and scattered art piece on a black background. Now, after twenty two years of traveling, with a speed that resembles the maximum limit in our universe, we are approaching to the Point of No Return. At this precise moment, we cross and invisible barrier that would separate us from our origins forever.
In this patch of space and time, when we are eight billion light years from earth (8,300,000,000) we lose the connection with our home plane, making it impossible for us to come back. Not matter the speed. The reason is equally simple and frightening. Since our departure, space itself has expanded (as it constantly does) – putting distance between everything that is not gravitationally bound. Imagine a deflated balloon where you draw a couple of points separated by a couple of centimeters (inches); now inflate the balloon. The points get separated. Well, it is the same effect that we see in the universe where new space is created all the time. Because of this expanding universe, now we are at a distance to Earth where the amount of space that separate us from our motherland is such, that it makes everything between us and our planet to expand faster than the speed of light. There is more new space between us and earth, and the expansion of such space grows faster than the speed of light.
We could never travel faster than the speed of light, just approximate it; this means we are now ripped eternally from that distant planet that once saw us depart. In scientific terms Earth is beyond our cosmic horizon and it becomes literally impossible to compare clocks with it (The last meaning full reading placed Earth at more than 8 billion years into the future – 8,000,000,000,000 -).
We celebrate on the cabin as we are not a spaceship anymore, at this node of space and time we become a timeship: traveling to the future at a pace that is frightfully fast and unable to reach anything that would still be visible from our portholes. Because of this, we can travel to the loneliest place in the Universe: to the end of time. Here we go…
So we keep going into our personal void. We continue travelling into the future, almost at the speed of light. Years pass while we stop remembering our childhood, while accepting the fact we are in the loneliest place anyone can travel to. After 50 years of our travel our instruments detect no particles outside of our spacecraft. At this point, it is impossible for us to compare our clock to anything else in the Universe. In fact, there is nothing that could affect us since space has expanded around us faster that we could move around it.
Now, after 50 years of traveling. We realize our ship is a monument to everything that it was. We are officially the loneliest people in the universe and the loneliest people that ever existed in all time. We not only has escape the Universe where earth sits at, but has traveled to a place that represents, in a sense, our own universe; for we are the only thing in our cosmic horizon. No one, nothing (Not even particles) can interact with us and we cannot interact with nothing. The size of the cosmos has expanded 10 ^ (10^65) times since you departed –a number so astronomically large that it cannot be written at all.
We live, by all practicalities, in our own cosmos. Welcome, to the end of time, the loneliest place in the universe.