by Larry Klaes, space exploration enthusiast, science journalist
How Might They Vanquish Us?
We have now looked at the most obvious motives (to us at least) for an alien species to want to crush humanity and found most of the feared concepts wanting. Now it is time to explore the ways in which said alien marauders might take us out of the galactic picture. Ironically, while the potential motives for invasion and destruction are often outright implausible, the methods available to a smart but aggressive species that might want us gone are often even more likely and effective than the usual imagined scenarios for the conquest of Earth.
If asked to visualize how an alien race might come after humanity, the scenario that seems to jump to most people’s minds is of giant spaceships hovering over major cities (Skyline is just the latest incarnation of that scenario), or a whole fleet of shiny silver spinning disks carrying alien hordes wearing shiny silver spacesuits and gripping laser rifles in their clawlike hands.
Now while one cannot entirely rule out the possibility that one day Earth’s skies will be filled with large and dangerous alien vessels up to no good for us, the idea that more advanced beings would engage in a battle for Earth and against humanity in a manner similar to the scenarios described above seems about as efficient as targeting our world for its supply of water with all the much easier and more effective alternatives available.
If you want to get rid of humanity and don’t care if most of the flora and fauna inhabiting our globe also gets destroyed in the process just so long as the planet remains intact, all you need to do is attach some rockets to a collection of planetoids and aim them at Earth. Humanity could be doing this with some of the smaller varieties of space rocks in just a few decades if we choose to, so a species that has actually made it to our Sol system via starship would be able to do the same.
Depending on the size and mass of the planetoid and where the ETI would target it, our civilization if not our very species could be rendered helpless in short order in a style reminiscent of the dinosaurs 65 million years ago. Indeed, a number of small planetoids have recently come close to Earth. Astronomers discovered them just a few days before their close encounters, leaving too little time to develop any countermeasures had they been on an intercept course. And these objects were guided only by forces of nature! A deliberate use of planetoids to smash us into submission or worse is a scenario that has been discussed and written about, but a real organized defense system is still decades away.
An even more frightening concept is to use a starship itself as a weapon. A large vehicle moving at relativistic speeds, even a fraction of light speed, could hit Earth with more force than humanity’s entire nuclear arsenal at its peak in 1990 (55,000 nuclear bombs). Such a weapon would be very hard to track and virtually impossible to stop with our present technology.
The details on this scenario, along with a very interesting discussion as to why an ETI might do such a thing to us and others (take out any potential aggressors/competition before it does the same thing, in essence) may be found on Winchell Chung’s fascinating Web site.
Keep in mind that while Chung does make some very compelling arguments, he is also a very big space war gamer. Having a galaxy full of mature, peaceful, and altruistic beings may make for a nice place to live on a cosmic scale, but a rather dull RPG. Going on the offensive with other species is also a pretty good guarantee that even an advanced ETI that gave up aggression and war ages ago may not like being threatened or seeing others in such a state and may take action against such a paranoid and self-serving race.
Another method for taking us out is one that has probably happened naturally across the Universe since the first stars came along: Supernovae. An exploding star would not only vaporize the members of its system but also spread deadly radiation for hundreds of light years around. Earth has obviously survived having its native life forms become completely extinct by many stellar explosions over the last four billion years. We can even thank a supernova for being here in the first place, as it was the violent death of an ancient star some five billion years ago that kick-started the cloud of dust and gas that became our Sol system, along with giving the elements needed for the evolution of life.
However, if an advanced species knew how to trigger and control a stellar detonation, they could fry our entire galactic neighborhood. Other methods of sterilizing whole solar systems includes smacking two black holes together and directing galactic jets, which are streams of particles and radiation thrown out by massive black holes in the cores of some galaxies. One hopes it won’t be possible to harness such energies, but who knows what beings that can survive and grow for eons in this Universe might be capable of?
Another cosmic weapon that fascinates and frightens is known as the Nicoll-Dyson Beam. Dyson Shells are a fascinating concept in their own right: Freeman Dyson envisioned a society taking apart its solar system and building a vast swarm of communities around its sun to collect as much energy from it as possible (right now 99% of Sol’s energy gets “wasted” into space). From a distant vantage point, anyone monitoring such a system would see its star gradually dim in the optical realm and brighten in the infrared region of the electromagnetic spectrum.
Being able to collect and utilize so much energy from a sun has many benefits for an advanced technological society – and a few dangers for others as James Nicoll would later point out. Dyson Shells would be able to focus and redirect the solar energy they collect into tight and powerful beams called a phased array laser. The beams could easily destroy whole worlds many light years from the Dyson Shell.
Whether Dyson Shells actually exist and if their makers would use them as galactic-scale weapons is another matter, though there have been actual SETI programs which attempted to find these astroengineering projects. This page from the Orion’s Arm web site gives an interesting visual and text description of this idea.
Is SETI Itself Dangerous?
There have been many who warn about sending greetings and other messages into the Milky Way and beyond. The idea behind METI (Messaging Extraterrestrial Intelligences) is that since it may be hard for an alien species to find Earth and humanity among the 400 billion star systems of the Milky Way, we should increase the chances for detection by broadcasting into deep space towards what we think are favorable cosmic places for intelligent life. The idea behind SETI is that alien beings are conducting their own METI programs, since that is probably the easiest way for humanity to detect another society in the galaxy at present.
The main and obvious issue with METI is that we do not know what other kinds of beings are out there. Folks such as Carl Sagan have speculated that aggressive species tend to wipe themselves out before they can achieve space travel. However, this has the flavor of painting an alien race with the traits and behaviors of our species. What if there were species which cooperated as a unit and still decided that other beings must go before they become a threat to them? Or what if they felt that other species, being viewed as inferior, were in need of a serious “makeover” that would effectively destroy whatever made the target species unique?
Some have speculated that an ETI might take out humanity and any other species at our stage of development by operating a METI program that carried what we might call an artificial virus. The target species would pick up the alien “message” and in the process of decoding it would unleash a program that could do all sorts of dangerous and deadly things, from taking down our technology to giving us the plans for a superbomb that would detonate once we built it from the instructions given in the message. Other potential scenarios involve converting humans into puppet slaves or replicating the alien species on Earth to take over and then aim more such messages at other potential worlds to continue the galactic conquest.
Of course it would seem easy to make sure that this never happens by simply keeping the alien message isolated or just never building the design plans. However, the combined excitement of detecting an ETI signal and the often wild, vast, and intricate nature of the Internet could bring about the spreading of the virulent message and be released by those who feel it is their right to have and know such information. In addition, as we see in the news on a regular basis, there are those groups of humans who might deliberately want to open up this cosmic Pandora’s Box to spread death and destruction across our planet for their own purposes.
This Web site goes into detail about the possibilities for an alien species to take out Earth without ever having to leave home either in person or even through a robot vessel:
This essay began thanks to Stephen Hawking’s well-publicized views on alien intelligences which he thought would not be a good thing for us to encounter any time soon. While there is of course the possibility that we might encounter an alien species that is a threat, I was unsatisfied and disappointed with Hawking’s version of this scenario. It struck me as not only being one-sided, limited, and old fashioned in thinking, but far too reminiscent of numerous recent Hollywood-style science fiction plots – an industry not exactly known for originality, deep thought or rigorous scientific accuracy.
Hawking’s take on alien life feeds into this negative, paranoid, and inward-looking attitude regarding the unknown that seems to be growing in human society these days. While it is prudent that we do not just jump into the galaxy without at least having some idea who and what is out there, focusing on the idea that all alien beings are hostile monsters and that we should dismantle our radio telescopes and hide under our beds are not exactly the actions of a healthy, maturing society. Besides, if an ETI were out to get us, remaining ignorant of the Universe and trying to be undetectable is not the way to go.
As I have pointed out in this essay, an advanced alien species would be able to destroy us in short order and we would have little recourse to stop them at present. The fact that it has not happened may mean they simply haven’t found us yet, but it may also mean that we are either lacking in large numbers of intelligent galactic neighbors or that taking out another species that has barely gotten its feet wet in the cosmic ocean is not the way to behave as a galactic society. We still have far more to worry about from members of our own species bringing down civilization than any hypothetical alien species.
Another thing I do know about human nature: No matter how many warnings and precautions and even laws that get thrown up to control people when it comes to what society thinks is in its best interests, there will always be individuals and groups of people who defy these rules either because they disagree with them or because it is in their nature to go against the grain.
This will apply to voyaging into space as much as anything else. The only reason it hasn’t happened already is due to the technological difficulties in making a deep space mission a reality. However, once we establish a serious foothold in space in our Sol system, I know there will be groups that will not want to remain confined to our celestial neighborhood but will want to venture to those countless stars surrounding us. This will keep happening for as long as humanity lasts.
This is the eventuality we must prepare for, because I will agree with Hawking on one thing: If life’s evolution is similar everywhere, then it is likely that some other species will also share our drive and desire to see what it out there beyond their home world. It may be only a matter of time before we are visited. How we respond to them depends not only on their intentions but on how much we have learned and evolved when it comes to understanding the Universe as well. Hopefully we will not let our fears turn a potential friend into an enemy.
Images: 1st, a meteor strike (Virgin Media); 2nd, a radiotelescope transmitting DNA to the galaxy (Jon Lomberg); 3rd, Jeriba Shigan (Louis Gossett, Jr.) and Willis Davidge (Dennis Quaid) in the film version of Barry Longyear’s novella Enemy Mine.