by Michio Kaku
Yet another problem facing a developed society was outlined in Asimov’s award-winning story “Nightfall,” where he envisioned scientists living on a planet that revolves around six stars. The planet is continually bathed in starlight. Its habitants, who have never seen the night sky with its billions of stars, firmly believe that the entire universe just consists of their solar system. Their entire religion and sense of identity centers around this core belief.
But then scientists begin to make a series of disturbing discoveries. They find that, every two thousand years, their civilization collapses into total chaos. Something mysterious happens to spark the total disintegration of their society. This cycle seems to repeat unending into the past. There are legends that people went insane because everything went dark. People lit huge bonfires to light up the sky, until entire cities went up in flames. Bizarre religious cults spread, governments collapsed, and normal society disintegrated. Then it would take two thousand years before a new civilization could rise from the ashes of the previous one.
Then scientists realize the sickening truth behind their past: that every two thousand years there is an anomaly in their own planet’s orbit, so that it experiences nightfall. And to their horror, they find that this cycle will happen again very soon. As the story ends, nightfall begins once again, and civilization descends into chaos.
Stories like “Nightfall” force us to contemplate how life may exist on planets under a totally different set of circumstances from our own. We are lucky to live on the Earth, where energy sources are plentiful, where fire and combustion are possible, where the atmosphere allows electrical devices to function without short circuits, where silicon is plentiful, and where we can see the night sky. If any of these ingredients were missing, it would make the rise of an advanced civilization very difficult.
FERMI PARADOX: WHERE ARE THEY?
But all this still leaves one persistent, nagging question, which is the Fermi paradox: Where are they? If they exist, then surely they would leave a mark, maybe even visit us, yet we see no real evidence of an alien visitation.
There are many possible solutions to this paradox. My thinking is as follows: If they have the ability to actually reach the planet Earth from hundreds of light-years away, then their technology is much more advanced than ours. In that case, we are arrogant to believe that they would travel trillions of miles to visit a backward civilization with nothing to offer. After all, when we visit the forest, do we try to talk to the deer and the squirrels? Maybe initially we might try, but since they don’t talk back, we would quickly lose interest and leave.
So for the most part, the aliens would leave us alone, looking at us as a primitive curiosity. Or, as Olaf Stapledon speculated decades ago, perhaps they have a policy not to interfere with primitive civilizations. In other words, they might be aware of us but don’t want to influence our development. (Stapledon gives us another possibility as he writes, “Some of these pre-utopian worlds, not malignant but incapable of further advance, were left in peace and preserved, as we preserve wild animals in national parks, for scientific interest.”)
When I asked Dr. Shostak this question, he gave me an entirely different answer. He said that a civilization more advanced than ours will most likely develop artificial intelligence, so they would send robots into space. We shouldn’t be surprised, he told me, if the aliens that we finally meet are mechanical rather than biological. In movies like Blade Runner, robots are sent into outer space to do the dirty work, since space exploration is difficult and dangerous. That, in turn, may explain why we don’t pick up their radio emissions. If the aliens follow our own technological path, they will invent robots soon after they invent radio. Once they enter the age of artificial intelligence, they might merge with their robots and have little use for radio anymore.
For example, a civilization of robots may be wired up with cables rather than radio or microwave antennas. Such a civilization would be invisible to the radio receivers of the SETI Project. In other words, an alien civilization may only have a few centuries in which they use radio, so perhaps that is one reason why we don’t pick up transmissions.
Others have speculated that maybe they would want to plunder something from our planet. One possibility is the liquid water from our oceans. Liquid water is indeed a precious commodity in our solar system, found only on the Earth and the moons of the gas giants, but ice is not. There is plenty of ice out there on comets, asteroids, and the moons orbiting the gas giants. So all an alien civilization has to do is heat up the ice.
There is another possibility, that maybe they would want to steal valuable minerals from the Earth. This is certainly possible, but there are plenty of uninhabited worlds out there with precious minerals. If an alien civilization has the technology to reach the Earth from vast distances, then they would have a selection of planets to exploit, and it would be far easier to strip a planet that is uninhabited than one with intelligent life.
Another possibility is that they want to steal the heat from the core of the Earth, which would destroy the entire planet. But we suspect that an advanced civilization has harnessed the power of fusion and hence there is no need to steal the heat from the core of the Earth. Hydrogen, the fuel for fusion plants, is after all the most plentiful element in the entire universe. And they can always capture energy from stars, which are also plentiful.
ARE WE IN THEIR WAY?
In The Hitchhiker’s Guide to the Galaxy, the aliens want to get rid of us because we are simply in the way. The bureaucrats among the aliens have nothing against us personally, but we are an obstacle that had to be removed so they can create an intergalactic bypass. This is a real possibility. For example, who is more dangerous to a deer: a hungry hunter armed with a powerful rifle or a mild-mannered developer with a briefcase who needs land for a housing tract? The hunter may seem more dangerous to a single deer, but ultimately the developer is more lethal to the species, wiping out an entire forest full of creatures.
In the same way, the Martians in The War of the Worlds did not have a grudge against earthlings. Their world was dying, so they needed to take over ours. They did not hate humans. We were simply in the way.
The same reasoning is found in the previously discussed Superman movie Man of Steel, in which the DNA of the entire population of Krypton was preserved just before their home planet exploded. They need to take over the Earth to resurrect their race. Although this scenario is certainly plausible, again there are other planets to plunder and take over, so one can hope that the aliens would pass us by.
My colleague Paul Davies raises yet another possibility. Maybe their technology is so advanced that they can create virtual reality programs that are far superior to reality, so that they prefer to live perpetually in a fantastic video game. This possibility is not so illogical, because even among humans, a certain fraction of our population would prefer to live in a hazy, drug-fueled state rather than face reality. In our world, this is an unsustainable option, because society would fall apart if everyone were on drugs. But if machines satisfy all our worldly needs, then a parasitic society is possible.
But all this speculation still leaves open the question, What will an advanced civilization, perhaps thousands to millions of years more advanced than ours, look like? Will meeting them usher in a new era of peace and prosperity, or annihilation?
It is impossible to predict the culture, politics, and society of an advanced civilization, but, as I mentioned, there is one thing that even they will have to obey: the laws of physics. So what does physics say about how a super-advanced civilization will evolve?
And if we do not encounter any advanced civilizations in our sector of the galaxy, then how might we advance into the future? Will we be able to explore the stars and eventually the galaxy?
Some scientists have proposed adding the category of a Type IV civilization that controls space-time well enough to affect the entire universe.
Why stop at one universe?
—CHRIS
IMPEY
There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
—MARK TWAIN
13 ADVANCED CIVILIZATIONS
The tabloid headlines blared:
“Giant Alien Megastructure Found in Space!”
“Astronomers Baffled by Alien Machine in Space!”
Even the Washington Post, not used to running lurid stories on UFOs and aliens, ran the headline, “The Weirdest Star in the Sky Is Acting Up Again.”
Suddenly, astronomers, who normally analyze boring reams of data from satellites and radio telescopes, were flooded with calls from anxious journalists, asking if it was true that they had finally found an alien structure in space.
This caught them by surprise. The astronomical community was at a loss for words. Yes, something strange had been discovered in space. Yes, it defied explanation, but it was too soon to say what it meant. This might just be a wild goose chase.
The controversy began when astronomers were looking at exoplanets transiting distant stars. Usually, a giant Jupiter-sized exoplanet, moving in front of its mother star, will dim its starlight by 1 percent or so. But one day they were analyzing the data from the Kepler spacecraft concerning the star KIC 8462852, which is about 1,400 light-years from Earth. They found an astonishing anomaly: something had dimmed the starlight by a massive 15 percent in 2011. These anomalies can usually be dismissed. Perhaps there was something wrong with the instruments, a spike in power, a transient surge in electrical output, or perhaps it was nothing but dust on the telescope mirrors.
But then it was observed a second time in 2013, this time dimming the star’s light by 22 percent. Nothing known to science can dim starlight regularly by that amount.
“We’d never seen anything like this star. It was really weird,” said Tabetha Boyajian, a postdoctoral fellow at Yale.
The situation became even more bizarre when Bradley Schaefer of Louisiana State University searched old photographic plates and found that the star’s light has been dimming periodically since 1890. Astronomy Now magazine wrote that this “has triggered a frenzy of observations as astronomers hurry to try to get to the bottom of what is rapidly becoming one of the biggest mysteries in astronomy.”
So astronomers made long lists of possible explanations. But one by one, doubt was cast on the usual scientific suspects.
What could possibly cause this massive dip in starlight? Could it really be something twenty-two times larger than Jupiter? One possibility was that it was caused by a planet plunging into the star. But that was ruled out because the anomaly kept reappearing. Another possibility was the dust from the disk of the solar system. As a solar system condenses in space, the original disk of gas and dust can be many times larger than the sun itself. So maybe the dimming of starlight occurred because the disk passed in front of the star. But this was ruled out when analyzing the star itself, which was found to be mature. The dust should have long since condensed or been swept into space by the solar winds.
After discarding a number of possible solutions, there was still one option that could not be easily dismissed. No one wanted to believe it, but it could not be ruled out: maybe it was a colossal megastructure built by an alien intelligence.
“Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build,” says Jason Wright, an astronomer from Penn State University.
Since the time elapsed between dips in starlight in 2011 and 2013 was 750 days, astronomers predicted that it would recur again in May 2017. Right on schedule, the star began to dim. This time, practically every telescope on Earth capable of measuring starlight was tracking the star. Astronomers from around the world witnessed the star dimming by 3 percent and then brightening again.
But what could it be? Some thought it might be a Dyson sphere, first proposed by Olaf Stapledon in 1937 but later analyzed by physicist Freeman Dyson. A Dyson sphere is a gigantic sphere around a star, designed to harvest the energy from its massive amounts of starlight. Or it could be a huge sphere orbiting a star that periodically passes in front of the star, causing starlight to dim. Perhaps this was something created in order to power the machines of an advanced Type II civilization. This last supposition tweaked the imagination of amateurs and journalists alike. They asked, What is a Type II civilization?
KARDASHEV SCALE OF CIVILIZATIONS
This classification of advanced civilizations was first proposed by Russian astronomer Nikolai Kardashev in 1964. He was not satisfied looking for alien civilizations without any idea of what he might be searching for. Scientists like to quantify the unknown, so he introduced a scale that ranked civilizations on the basis of energy consumption. Different ones might have different cultures, politics, and history, but all of them would require energy. His ranking was as follows:
1. A Type I civilization utilizes all the energy of the sunlight that falls on that planet.
2. A Type II civilization utilizes all the energy its sun produces.
3. A Type III civilization utilizes the energy of an entire galaxy.
In this way, Kardashev conveniently gave a simple method for computing and ranking the possible civilizations within the galaxy, based on energy use.
Each civilization, in turn, has an energy consumption that can be computed. It is easy to calculate how much sunlight falls on a square foot of land on Earth. Multiplying this by the surface area of the Earth illuminated by the sun and one immediately calculates the approximate energy of an average Type I civilization. (We find that a Type I civilization harnesses the power of 7 x 1017 watts, which is about one hundred thousand times the energy output of the Earth today.)
Since we know the fraction of the sun’s energy that falls on the Earth, we can then multiply to include the surface area of the entire sun, and we get its total energy output (which is roughly 4 x 1026 watts). This tells us roughly how much energy is utilized in a Type II civilization.
We also know how many stars there are in the Milky Way galaxy, so we can multiply by this number and find the energy output of an entire galaxy, giving us the energy consumption of a Type III civilization in our galaxy, which is roughly 4 x 1037 watts.
The results were intriguing. Kardeshev found that each civilization was greater than the previous one by a factor of between ten billion and one hundred billion.
One can then mathematically compute when we might rise up this scale. Using the total energy consumption of the planet Earth, we find that we are currently a Type 0.7 civilization.
Assuming a 2 percent to 3 percent annual increase in energy output, which roughly corresponds to the current average growth rate or annual growth in GDP for the planet, we are about a century or two away from becoming a Type I civilization. Rising to the level of a Type II civilization could take a few thousand years, according to this calculation. When we would become a Type III civilization is more difficult to compute, since it involves advances in interstellar travel that are difficult to predict. By one estimate, we will probably not become a Type III civilization for one hundred thousand years and possibly not for a million years.
TRANSITION FROM TYPE 0 TO TYPE I
Of all the transitions, perhaps the most difficult is the transition from Type 0 to Type I, which we are undergoing at present. This is because a Type 0 civilization is the most uncivilized, both technologically and socially. It has risen only recently from the swamp of sectarianism, dictatorship, and religious strife, et cetera. It still has all the scars from its brutal past, which was full of inquisitions, persecutions, pogroms, and wars. Our own history books are full of horrid tales of massacres and genocide, much of it driven by superstition, ignorance, hysteria, and hatred.
But we are witnessing the birth pangs of a new Type I civilization, based on science and prosperity. We see the seeds of this momentous transition germinating every day before our eyes. Already, a planetary language is being born
. The internet itself is nothing but a Type I phone system. So the internet is the first Type I technology to develop.
We are also witnessing the emergence of a planetary culture. In sports, we see the rise of soccer and the Olympics. In music, we see the rise of global stars. In fashion, we see the same high-end stores and brands at all the elite malls.
Some fear that this process will threaten local cultures and customs. But in most third-world countries today, the elites are bilingual, fluent in the local language and also a global European language or Mandarin as well. In the future, people will likely be bicultural, fluent in all the customs of the local culture but also at ease with the emerging planetary culture. So the richness and diversity of Earth will survive even as this new planetary culture arises.
Now that we have classified civilizations in space, we can use this to help calculate the number of advanced civilizations in the galaxy. For example, if we apply the Drake equation to a Type I civilization to estimate how plentiful they might be in the galaxy, it would appear they should be quite common. Yet we see no obvious evidence of them. Why? There are several possibilities. Elon Musk has speculated that, as civilizations master advanced technology, they develop the power to destroy themselves and that the biggest threat facing a Type I civilization may be a self-inflicted one.
For us, there are several challenges as we make the transition from Type 0 to Type I: global warming, bioterrorism, and nuclear proliferation, to name a few.