Dylan Stoll | Copy Editor
Featured Image: Are we alone in the universe? | Courtesy of Pixabay
Imagine for an instance, you’re sitting out on your back porch, basking in the sun, smiling as the familiar sounds of a gentle summer day lull you to sleep. Suddenly, the ground begins to shake, and thunder erupts from the heavens. A massive object envelops your field of vision. At first, you assume it’s an asteroid of some sort, but its appearance is too uniform, and its surface gleams a metallic green.
There’s something unnatural about its approach, it appears to be slowing down. The front end of the gargantuan object lifts as it comes closer to the Earth. The object balances itself, remaining perfectly still as it blots out the sun completely. They’ve finally arrived.
Who or what, you might ask? Aliens.
Now, let’s ground ourselves for a moment. In all likelihood, this will not be our first encounter with an alien lifeform. Most scientists studying the possibility of life on other planets believe the first alien lifeforms we discover will probably be similar to extremophilic bacteria. Such organisms thrive in the harshest conditions known to Earth-dwelling creatures, making them well-suited for the extreme conditions found in space.
That being said, the search for intelligent extraterrestrials is not a venture to be taken lightly. Just last year, the U.S. government proposed a bill that would allocate $10 million towards NASA and their search for “technosignatures” in space.
These technosignatures include a Fast Radio Bursts (FRB), which are “transient radio pulses of length ranging from a fraction of a millisecond to a few milliseconds, caused by some high-energy astrophysical process not yet identified.” Recently, the Canadian Hydrogen Intensity Mapping Experiment discovered 13 FRBs, one of which is the second ever repeating FRB.
Many in the scientific community believe FRBs are the result of super-cataclysmic events such as the collapse of supramissive rotating neutron stars; binary neutron star mergings; the evaporation of primordial black holes; or more recently theorized, the buildup and collapse of a matter “crust” on certain types of neutron stars called “strange stars.” While all are plausible explanations, they still do not account for the fact that two of the detected signatures were, as the researchers said, “repeating FRBs.”
If these signatures were repeating, then that would mean their source of origin—the aforementioned stellar explosions—would be repeating as well, which makes no sense. So what is causing these peculiar, incredibly high-energy signatures?
Some believe that they are not the result of any natural, stellar event, but rather the mark of an intelligent, highly advanced alien species. There is the possibility that this particular species may have built a colossal radio transmitter to look for intelligent life such as ourselves, a beacon of sorts.
Another, more plausible alien theory, is that the FRBs are being used as a ‘wind’ of sorts, pushing the “light sails” of an alien spaceship. These extraterrestrial explorers would rely on a method of travel not unlike the vessels that brought Columbus to the Americas. A ship capable of this would also be capable of carrying approximately one million tonnes (to put that into perspective, the International Space Station weighs about 420 tonnes).
Interestingly enough, FRBs are not the only stellar event that have researchers scratching their heads. The star KIC 8462852, also known as “Tabby’s Star,” is known to dip in brightness—sometimes by one per cent, other times by as much as 20 per cent—and then returns to its former brightness, only to dip again thereafter. The reason this is so strange is because most stars do not oscillate their brightness in such a way. The repeating nature of the oscillations has led some to theorize that an orbiting alien megastructure may be to blame, as such a device would block light emanating from the star as it passes our field of view.
The idea of the megastructure was first postulated by Olaf Stapledon in 1937, through his science fiction novel ‘Starmaker’ in which he said: “Every solar system surrounded by a gauze of light traps, which focused the escaping solar energy for intelligent use.” The “light traps” he refers to are what are known as Dyson spheres, named after Freeman Dyson when he popularized the concept 23 years later in his paper “Search for Artificial Stellar Sources of Infrared Radiation.” A true Dyson sphere, in theory, would cover a star completely in a massive, structural sphere, which would act as a solar panel, capturing all light energy emitted. It would be the pinnacle form of energy acquisition, but would ultimately require resources we could barely imagine.
Though the Dyson sphere is more of a thought experiment than anything else, it still holds some ground in the scientific community. Researchers from the Search for Extraterrestrial Intelligence are on the lookout for excess infrared radiation, which would be indicative of the hypothetical Dyson sphere, as it has an estimated temperature ranging anywhere from 50 to 1,000 K.
But what if, despite all our best hopes, there is nobody out there? What if Earth and its inhabitants are the sole, flickering candle, the player who “struts and frets his hour upon the stage and is heard no more?”
This is the problem that the Fermi Paradox addresses. The Fermi Paradox, a brainchild of physicist Enrico Fermi, is rooted in the observation that any advanced civilization, given enough time, would be fully capable of colonizing the entirety of the Milky Way galaxy.
The universe is 13.8 billion years old. Look at how far humanity has reached within 200,000 years. We’ve gone from starting simple fires and fighting over resources, to artificial intelligence and launching people into space. Technological progression occurs at an exponential rate. If there were a civilization in existence for much longer than 200,000 years, it is only logical that such a civilization would be wholly capable of accomplishing galactic colonization.
So where are they? Where are our galactic neighbours? This is the paradox.
Professor Michael De Robertis, a lecturer in York’s Department of Physics and Astronomy, further elaborates: “Our sun and planets came on the scene many billions of years after the first stars and planets that formed in our galaxy. With a head start of billions of years, shouldn’t there be evidence for civilizations who came well before us? If any such civilization has survived to this point, it could easily have explored the entire galaxy many times over. In other words, it isn’t clear to me that the argument that the immense size of the universe (when combined with our own relative insignificance) suggests the universe must be teeming with intelligent life has any merit.”
Some refer to the Drake Equation, a formula derived in 1961 by Frank Drake of the National Radio Astronomy Observatory to take into account all the variables that surround the emergence, and proliferation, of intelligent life within our Milky Way galaxy.
According to the equation, there are seven variables: the number of broadcasting civilizations; the average rate of the formation of suitable stars; the fraction of stars that form planets; the average number of habitable planets per star; the fraction of habitable planets where life emerges; the fraction of planets where intelligent life emerges; the fraction of planets with intelligent life capable of interstellar communication; and finally, the years a civilization remains detectable.
When three researchers from Oxford University’s Future of Humanity Institute completed a draft study on all the papers they could find related to the equation’s variables, they found that approximately two thirds of them suggest that there may be 100 advanced alien civilizations within our galaxy. But other estimates they completed suggested that there may be as much as 100 million civilizations; as such, the researchers were left stumped.
In response, they reformulated each variable of the Drake Equation as a range of uncertainties, which resulted in a bell-curve distribution of results. The average probability that we are alone in the Milky Way galaxy came out to 52 per cent. As for the entire observable universe, the result was 38 per cent.
Though these results may come as a surprise to some, it should be noted that the universe we call home is unforgivingly cold, and incredibly catastrophic. How can one condense these complex sets of events into a single variable of a somewhat uncomplicated equation? What about the many variables associated with the emergence of life on any given planet? Or the plethora of incredibly powerful stellar events that occur across the cosmos, the explosions of energy that make nuclear warheads look like cherry bombs?
It took life 3.5 billion years to achieve a level of intelligence that could even imagine travelling to other planets; that’s 3.5 billion years of avoiding life-destroying asteroids, exploding supernovae, and highly-radiative solar flares.
There are even travelling stars, those that could come into contact with the rocky “Oort cloud” at the edge of our solar system. Such an interaction could hurl massive, planet-destroying comets in the direction of Earth.
Our own sun travels, and it takes us with it. If our solar system were to come into contact with higher levels of radioactive interstellar medium, and the heliosphere (a magnetic shield produced by the sun) was unable to protect us due to our gradual distancing from its protective reach, we would be left exposed, and vulnerable.
And let’s not forget the most terrifying of all monsters lurking amongst the sea of stars, the Kraken of the vacuum: the roaming black hole. There is a black hole that is moving (yes, you read that correctly) through our Milky Way galaxy. Though it is be unlikely that it will cross our path, there could very well be others out there, and if they were to arrive in our solar system, the result would be disastrous, to say the least.
Stellar events are not the only threat to life. Earth itself is capable of destroying life on its own. Approximately 444 million years ago, 86 per cent of all life was wiped out, possibly due to volcanic rock-weathering, the product of which (silicate rocks) drew CO2 from the air. This sudden drop in global CO2 levels was followed by a drop in temperature, which contributed to the destruction of life on Earth.
If the Earth doesn’t destroy life, then life itself may just do it. Approximately 251 million years ago, 96 per cent of all life died after a monstrous volcanic explosion dramatically increased global CO2 levels. Microbes that digest CO2 proliferated substantially, and unfortunately, produced so much methane that the atmosphere became toxic to living creatures.
And, of course, the white elephant in the room: humanity. Life forms that equal us in intelligence, may also equal us in stupidity. It may be that supposedly ‘intelligent’ life forms are predestined to bring upon themselves their own destruction, be it through climate change or war. There may not be anyone else out there, because they made the same mistakes we are making today.
But let’s hope for the best. It is our species after all, and if humanity can push (rather slowly) through its own astounding idiocracies of the past, it can certainly survive, and thrive, long enough through its present idiocracies to uncover the secrets of interstellar travel, and hopefully, subsequent colonization of extrasolar planets. Who knows, maybe we will be the first intelligent beings to conquer the universe.
Professor Alireza Rafiee, a lecturer and course director within the Natural Sciences Division at York, is teaching a course called Life Beyond Earth. When asked for the number of discovered habitable exoplanets that could one day be populated by our interstellar descendants, he said: “One of the first missions to systematically investigate for them was Kepler’s mission launched around 2009. Kepler detected many thousands of candidates (around 6000) and more than 3800 of them are confirmed exoplanets. Around 16 of them are within the habitable zone with some similarities in size and mass to that of our Earth. One can safely extrapolate this result to say that around 0.5 per cent of all exoplanets can be Earth-like and in the habitable zone.”
De Robertis believes the question requires more information, information we cannot acquire due to our technological limitations. “Astrobiologists take some liberties when defining ‘habitability.’ Exoplanets are so far away that we really can’t determine their individual properties very well. So what is done is to ask the question whether liquid water—an essential component for life as we know it—can exist on the exoplanet’s surface, given their distance from their host star.
“This isn’t the full story, since an atmosphere can enhance a planet’s temperature,” he explains.
But how will humanity reach the perfect planet without first mastering interstellar travel?
Professor Paul Delaney, a lecturer of York’s Department of Physics and Astronomy, feels that the chances are slim for any near-future trips to other worlds. “Even if we head for Proxima Centauri b, our closest exoplanet in the habitable zone, our technology is way too poor to consider such a trip with people.
“Accelerating up to a reasonable fraction of the speed of light to cut down travel time is not possible today, let alone building a vehicle that could sustain any number of people for up to decades. Most people suggest we are still the better part of a century away from attempting an interstellar ‘ark’ type journey,” continues Delaney.
If humanity achieves interstellar travel and reaches another world, the conditions of the planet may be hospitable enough to survive, but survival will be difficult. Establishing a colony on another continent was a daunting enough task for our predecessors, let alone another planet.
“Assuming you are talking about colonizing a planet like Earth, I would suggest it is not much different to the analogies of our world when European explorers and settlers headed off for new lands,” Delaney elaborates. “It will be tough to start out with relatively limited resources (what you brought with you initially), and overcome the natural challenges. Presumably you would settle in a location where temperatures and weather were moderate, free of major challenges such as tornadoes, hurricanes, etc.”
But that is no guarantee. As Rafiee explains: “You might wish for California-beach weather and lifestyle, but you might get Kalahari desert or North Pole weather and lifestyle. Those are still good for survival.”
But with a planet already covered in life, food, water, and all the air we can breathe, why do we insist on travelling to other worlds, instead of dealing with the problems we have here? In movies such as Christopher Nolan’s epic film Interstellar, where the Earth’s ecosystems have been irreparably destroyed as a result of anthropomorphic climate change, the protagonist Cooper (played by Matthew McConaughey) so eloquently said: “We used to look up at the sky and wonder at our place in the stars, now we just look down, and worry about our place in the dirt.”
Suffice it to say, our best chance of survival depends on the planet we currently inhabit: Earth. If we can overcome our challenges here, maybe we won’t have to worry about travelling to other worlds. Besides, Rafiee believes, in comparison to Earth, the weather on an exoplanet may hardly be worth the trip.
“You might end up with a more extreme condition and lifestyle than you can imagine. I can certainly tell you that no place is like our home planet. We better clean and protect our planet, since we may never find any place exactly as comfortable as Earth.”
