Instigator / Con

Aliens could quickly and easily invade Earth


The debate is finished. The distribution of the voting points and the winner are presented below.

Winner & statistics
Better arguments
Better sources
Better legibility
Better conduct

After 2 votes and with 4 points ahead, the winner is...

Publication date
Last updated date
Number of rounds
Time for argument
Three days
Max argument characters
Voting period
One month
Point system
Multiple criterions
Voting system
Contender / Pro

We are of course assuming the aliens have a technological head start.

Victory condition: subdue human civilisation by taking control of Earth's surface

BoP is shared.

Round 1
Thank you, PRO, for accepting this debate.

  • to enter for conquest or plunder
  • causing or involving little difficulty or discomfort
  • requiring or indicating little effort, thought, or reflection
  • fast in development or occurrence
  • done or taking place with rapidity
  • to have power over

Meaning of the resolution: Aliens could in a rapid way conquer humanity by gaining power over the surface of Earth; This invasion would not involve difficulty, thought or effort

PRO: Prove that the resolution is true
CON: Prove that the resolution is false

PRO has to provide evidence that shows how such a quick and easy invasion would be possible for aliens.

CON has to provide evidence that this invasion would require difficulty, effort, thought or time.

I wish PRO good luck.

The aliens we are talking about are of course aliens with technology as the description says. No nonsensical magical or supernatural beings would fit the meaning of the word technological. The aliens of this debate are scientifically speaking bound by the laws of physics. That includes the speed of light, the E=MC^2 formula, the laws of movement and inertia, the laws of thermodynamics, quantum mechanics, general relativity and so forth. These are the boundaries that limit the possibilities of technology in our physical universe. Many technologies seen in movies break these laws of physics. Most apparently is teleportation, time travel and FTL travel. None of these technologies is possible in the real world, and none of these technologies could be used by aliens to invade humanity.

Having clarified the actual science on which this debate is built, I proceed with my arguments.

The universe is vast. The nearest star to our sun is named Proxima Centauri and lies 4.24 light-years away from Earth [Britannica]. This means that communication between our sun and this star would have a delay of 4.24 years. Mind you a journey from Proximal Centauri would take way longer. Stars that aren't Proxima Centauri are much farther away, and the aliens we are discussing would have a journey of hundreds of thousands of years to reach our solar system. Furthermore, it would take multiples of that timeframe from the time we send our first signals and their arrival after detecting us.

Technology delay
The time delay would mean that our technology would be far more advanced than today when the aliens arrive. With enormous distances, they would only detect us hundreds of thousands of years after we send our signals. Even while their fleets are travelling towards us we develop our technology. In essence, they experience a technological delay. If our Earth is 100.000 years behind theirs in terms of technology, but the distance to their planet is 100.000 lightyears, then our technology would always be superior to that of their closest space fleets. The only way the aliens win this type of invasion is through prolonged war, which would mean that the resolution fails.

The immense distances of space make it impossible for an invasion to be quick. Not only does it take immense time to reach our planet, but the technological delay causes the aliens to never have the upper hand. Therefore, no quick and easy invasion is possible if the aliens have to first detect and react to our presence.


Advantage 1: Preparation
The communication between spaceships in different solar systems would take years, decades or centuries, which gives us plenty of time to prepare if one of their ships discovers our planet. Furthermore, since the aliens have a technological headstart, their first radio signals will reach us before ours reach them. We will thus know about them far before they do us. Also, their spaceships cannot move faster than light which means that they too will be detected and identified by us long before they arrive. With the trip from their homeworld taking so many years we too will have years of preparation. Even today, America has a team in place with the specific purpose of training the military for space battles [futurism]. There are even laser systems in place to protect against potential Russian attempts at destroying satellites [bigthink]. In short, human civilisation is preparing itself for war in space anyways. With detecting an alien invasion, the world would easily join forces under the threat of a common enemy. Within a short timeframe, our defensive measures would be formidable.

Advantage2: The planet itself
A planet like Earth is capable of sustaining heavy bombardment. The Earths atmosphere can defend us well enough that even a 25-meter thick meteor would burn up and not do any damage at all [nasa]. Scaling this up, our planet can survive the impact of gigantic meteors without cracking; the only damage being to the environment which evolution and especially human ingenuity can adapt to. Furthermore, many types of radiation from the sun are deflected by the magnetical field of the Earth. A spaceship does not have an atmosphere or similar magnetical field protecting it from these dangers. Earth is itself a fortification that no feasible spaceship can match. Its immense size also makes this advantage even more formidable. 

Advantage 3: Proximity to base
A fleet of spaceships attacking Earth would be unimaginably far away from their planetary supply chain, and thus would not be able to effectively replenish their food, materials or weaponry. They also have no possibility of urgent assistance due to the communication delay. Repairing a damaged spaceship is near impossible as the initial impact which caused the damage would immediately destroy the ship and leave the passengers exposed to the deadly outer space. However, human civilisation can rebuild itself while fighting. Not only do we have plenty of infrastructure and resources nearby, but we also have factories and scientists working day in and out. The American military budget is only about 3.4% of its annual GDP [], and most nations spend way less on their military. With the urgent threat of alien invasion, a fast and effective resource allocation to the military would drastically increase our ability to produce and engineer defensive measures. Militarising NASA and Roscocosmos would also be an option. The advantage of having everything we need to create defences just lying around is that we can quickly sway the tides of war if needed, while the aliens can't.

Advantage 4: Numbers advantage
A planet like Earth is unbelievably big when compared to any spaceship. The population of Earth amounts to billions and is only increasing. No spaceship can match the Earth in size, this is due to a scientific principle. "For massive objects, gravitational and rotational forces overcome rigid body forces, resulting in round bodies with low topographic relief." [astronomy]. The aliens cannot bring a spaceship large enough to match our human population without breaking with this principle.

Advantage 5: Fine-tuned weaponry
Human technology works perfectly fine on Earth. Yet taking our tanks and fighter planes to Mars would be unfeasible. Our aeroplanes and missiles would crashland rather than work properly. Gravity, atmospheric pressure and air friction would be different, resulting in our technology acting differently than it does on Earth. It then comes as no surprise that the aliens face the same problems. No matter how good their technology is, they have not developed it on Earth. A camel would certainly be more effective in a sand dessert than even the best of race cars. Similarly, alien technology would be inferior to that of humans with regards to functioning on Earth. 

There are so many advantages for the defending side in a space war that it would be dubious to claim that superior technology is enough to make an invasion quick and easy.

Even if the aliens broke the laws of physics and teleported to our solar system right now they would still face immense threats. In orbit around Earth, the aliens would be extremely vulnerable. There are about 20.000 trackable pieces of space debris in orbit around Earth, and multiples of that number are untrackable [nasa].  In any collision, "the damage can be substantial if not catastrophic." [ibid]. This is true even for small pieces of debris, due to their insane speed. When the aliens enter orbit this will immediately be their main problem. Humans could easily exploit this by intentionally releasing weaponised debris, essentially blocking the path of the alien invaders. Even without our direct planning, this is a problem though. If even one of their spaceships is destroyed, it would create much more debris. Essentially, staying in orbit would be exponentially riskier for the aliens. This also means the aliens can't destroy our satellites. Doing so would be detrimental to their own forces and would not be a viable strategy.

If the aliens attempt to simply land their spaceships, then the airforce, as well as ground and sea-based systems, could fire tactical missiles at the spaceships. Mind you such an impact would damage the alien spaceships in the most crucial moments, quickly causing them to malfunction. At the very least the impact would destroy important sensors, shock the aliens inside and throw the entire descent of balance. If the aliens have a bad day their spaceships are destroyed in the descent and everyone dies. Regardless of the result, the aliens will not be in good shape to fight once they land. Furthermore, they would need to land in the ocean unless they were planning to descent slowly. The aliens thus either land in the water and face our fleets, or they descent slowly and get bombarded even more.

Alien missiles
Israel has invented an anti-misle system called Iron Dome. "the Tamir interceptor travels at “2.5 times the speed of sound, guided by the ground-based radar. However, as the three-meter-long missiles close with the targeted projectile, their nose-mounted electro-optical sensor takes over to provide more precise terminal guidance...Since 2011, Iron Dome has intercepted more than 2,500 enemy rockets, more than 90% of those fired at Israel. " [jewishvirtuallibrary]. This system is not reliant on satellites to track and hit targets moving at incredible speeds. Israel has been selling this system to other nations for quite some time now. Coupled with the many other types of missile defence systems, the Iron Dome would be used to intercept alien missiles, landing pods or aircraft.

Surface battle
The aliens would most likely have no chance at fighting us on our own planet. Not only are they limited with regards to the material and army they can bring, but they also lack sufficient intel, battle plans and organization after a chaotic and dangerous descent. Humans could utilize thousands of aircraft and warships; nuclear warheads as well as conventional weaponry. We even have submarines, stealth bombers and camouflaged tanks. We have millions of troops equipped with lethal weapons. We have a wide array of tactics proven to work on Earth, as well as every advantage one could ever ask for.

Nukes kill. Nukes are heat-based, not penetration based. No armour could protect against nukes. We could merely nuke or bomb their spaceships right after they land.

The alien invasion would require time, effort, difficulty, thought and reflection
  • Distance in space ensures the invasion can't be quick.
  • The aliens would face multiple extreme dangers. The aliens would fight humanity equipped with lethal weapons and with a massive defenders advantage. 
  • Human ingenuity and pre-knowledge ensure we make a proper battle plan and set up our defences -- preventing a quick and easy invasion from being possible.
The resolution fails.

I am out of space.

Good luck, PRO

Thank you CON for giving me the opportunity to participate in this debate as a PRO.
Objective- To Invade Earth quickly and decisively.

The size of Observable Universe is 93.016 billion light years ( Source- Google), whereas the Radius of Earth is 6378 km. The farthest known celestial body discovered is a Quasar 13 Billion Light years away. However, even within this 13 Billion light year domain, researchers have barely discovered anything compared to the vast size.

I will begin my argument now. 


 I disagree with CON on the point of technological delay, as I believe with time the celestial invaders will progress in technology as well. NASA and CNSA both have been working on projects to establish research centre on space. These kind of projects ensure advancement of technology even in space. The same principle can be said for the celestial Invaders. An invasion which may take 100,000 years to arrive on Earth, these celestial invaders will definitely come with adequate resources  planned for a very long journey. With advance space research centres and industries, this technological delay factor will be eliminated.
 The progress of technology is independent of distance.

 Detecting an invasion itself is a near impossible thing for human in the current era. Even in future it will be like finding a needle in haystack. Generally, optics and wave related methods are used to detect celestial bodies. However, these method have drawbacks, that its dependent on a “reference” that maybe a star. Also, detecting spaceships which will be size of football field or even  a country will not be possible with these methods. We lack the technology to detect an invasion, which will be surprise factor.
  If an invasion is already en route, and expected to be here within few 100 years, then currently we have a very weak constitution. USAF has been detecting presence of unknown flying objects, which can possibly be scout for the aliens to keep track on humans.
 We will be outnumbered and out of all the possibility, alien invasion is the least expected threat and merely a serious issue for humans which we will fail to detect.
1) The invasion doesn’t need to be a direct confrontation.  Aliens don’t even have to set foot on the planet. Drones/Robots will be involved in major confrontation. Drones capable of carrying weapons of mass destruction able to manoeuvre with the help of artificial intelligence will cause colossal damage.  We are not talking about figures in thousands, we are talking about millions/billions of drones. Fighting against such a force will cause no casualty to the Aliens, however humans will suffer casualty and deplete their supplies.
2) The planet wont serve as a robust defence system. I would like to point out that the meteors which enter Earth’s atmosphere indeed end up burning, but this phenomena is more dependent on its trajectory. Many space shuttles enter the Earth’s atmosphere from space which have heat shield installed and in specific projectile motion. Its more about physics which obliviously will be known to the invader species. The magnetic field intensity of Earth is 25 to 65 μT. Spaceships equip with magnetic field generator can produce their own magnetic field and protects itself from the radiation and solar flare of sun.
3) The spaceships are built with hull to sustain heavy bombardment from an advanced enemy fleet else they will not serve the purpose of battle for which they are built. Space debris will be snowfall for such ships. Despite that they will also be equipped with defence system to destroy small meteor/space debris. Humans may be in numbers but its still not enough to cover all the grounds in planet. Landing a spaceship will be final resort of invaders after they have attained victory over humans which they can achieve even without entering Earth’s orbit. These aliens can launch lasers (not just 5-6 but in thousands) travelling at speed of light from outside the solar system. We will not be having weapons that can reach outside the solar system and nor we will have enough firepower to cause considerable damage to an army of billions.
 4) There is no denial that humans will have better weapons and technology in upcoming years, however, this progress of weapons and technology will be a competition between different nations. This race will be based on thinking that enemies are human itself from other nation. Satellites will be equipped with missiles, laser weapons, nuclear warheads, etc. All of this will be limited to a short distance of some hundred of thousand miles (approx. figure) to counter other nation missile, meteor, which can be evaded in this short distance domain. These systems wont be ready to be used on targets beyond Mar's orbit which will be handicap for humans while facing enemy launching offense beyond this domain.
 5) The current defence system like Iron Dome, S-400 and other defence systems which are best in the world, are obsolete compared to an alien ship. These defence systems will be outmatched by the speed of spaceships which will be travelling at 10+ Mach speed. Keeping in mind that even aliens will be having counter measure for such defence system which they might have developed in their primitive years.
 6) All the tactics, aircraft, naval fleet, army  will be futile if the invaders launch offense from outside the Earth’s Orbit. Humans will be on back foot and will only be in defence position without launching a counter attack on aliens.
 7)“Experience is the teacher of all the things” Julius Caesar. Since it’s an  alien invasion, these invaders might be a Galactic Empire with a robust experience of space wars, which humans have never experienced before. The tactical knowledge wont be bounded to one planet. Experiencing countless war against different civilization both advanced and primitive than humans, these invaders will be having mastery in warfare.
 8)High- Power Microwave with high effective range will fry the electronic equipments installed in various structures like naval ships, industries, medical facilities, RADAR, etc. Which will cut down the firepower, communication system and overall performance, thus hamstringing humans. Entire system will collapse due to which proper information transfer wont take place between humans, thus breaking the coordination. It will be a heavy setback for the Earth defence forces and it will lead to immediate defeat.
 With the equipments fried up, stranded apart from each other in total blackout, a pre-emptive strike from space via drones/robots will destroy majority of Earth defence in quick span of time. Casualties will be mounting up for humans, there will be poor reaction time, technological gap, lack of experience and being outnumbered, which will result in humanity to surrender itself to the Celestial invaders.

 Objectives achieved
1> Minimum Casualty
2> Minimum loss in assets
3> Quick Victory
Hence the Objective accomplished that is quick and decisive victory over humans.
My 2 cents.
Thank You

Round 2
Thank you, PRO.

First thoughts
Drones do not solve the problem of effort. Effort can be measured in how much else you could achieve had you used your resources differently. Billions of drones, battleships to carry them and enormous amounts of energy and costly weapons of mass destruction aren't cheap or easy to come by. You could have colonised more than a hundred non-inhabited planets with less effort than PRO's aliens used to merely beat one planet. Thousands of years are used to make the travel, making the invasion non-quick even on alien scales. Even once completed, the aliens don't control the surface of Earth. Humans have no way to communicate a surrender, and no incentive to do so either. Survival instincts call to fight with bravery, not surrender to an unknown enemy.

For the resolution to be true, aliens must land and invade the surface of Earth. It is here humanity has every advantage possible. Alien tech doesn't work on Earth, their descent is dangerous and their landing locations easily nuked by nuclear warheads hidden away from any first strike. The battle on the surface, I claim, cannot possibly be won by aliens. They lack sufficient vehicles, numbers and supplies to effectively fight humans on the surface. We have a lot of technology that doesn't rely on electronics and millions of people who are ready to use them. PRO never addressed those issues. In short, PRO's argument doesn't sufficiently prove the resolution.


Technological advantage
PRO is simply assuming that the aliens have millions upon millions of years as a technological advantage. The resolution doesn't state that as an assumption, it is merely PRO's own claim, and requires evidence or arguments from his side to be considered possible. More probable than not is it that humans are pretty early in the technological party, seeing as not a single sign of alien life or technology has reached us. Furthermore, Earth is the perfect planet for rapid evolution with large biological diversity. Not a single planet as suitable (or more suitable) for life has been found, signalising that the aliens we are talking about are most certainly very far away from us.

Position of Earth
PRO is simply assuming that the alien space fleet arrives today or in the very close future. But that is simply not within the boundaries of possibility. We aren't assuming that the aliens are given our exact coordinates; they have to detect us before they can attack us. Therefore, PRO's comparison between current-day humanity and a space fleet fails, because he is ignoring that it would take millennia before the aliens even detected our planet as inhabited by sentient creatures, and far longer before their fleets arrived here.


Technological delay
Doing research in space and developing technology in space are two very different things. Developing technology requires much time and resources to design and test new innovations. Designing and testing weapons, drones, engines and so forth is impossible to do on a spaceship due to lack of space, resources and ability to test your innovations safely and efficiently. Time-dilation in fast-moving objects means that even if we ignore that developing technology in spaceships is impossible, it still would go slower and thus technological development IS dependent on distance.

Early warning system
The list of these "needles in the haystack"s include black holes, gravitational waves, quasars, Hawking radiation, neutrons stars, exoplanets and literally every other scientific endeavour. If humanity discovered these so-called "undetectable" phenomenon in a short time span because of human ingenuity and technology, surely we will be able to detect smaller objects like spaceships in the very near future.

Furthermore, we DO have the technology to detect aliens. "The Panoramic Survey Telescope and Rapid Response System – Pan-STARRS – uses a 1.8-metre telescope and a 1.4-billion-pixel digital camera to survey the visible sky in visible and near-infrared wavelengths, on the lookout for transient, variable and moving objects, including asteroids that might be on a collision course with Earth." [astronomynow]. This is only the beginning of human cataloguing our entire galaxy. This system ensures we understand the position of every object in space. The closer alien spaceships come to us, the easier it for us to detect them. Even more conclusive is the fact that alien infrastructure and communication systems in space are easily spotted. Their radio signals were sent before ours were, and thus we detect theirs before they do ours. Thus, early warning for us.

Human progress and defences
Human progress would take a different path in our scenario where aliens exist. Humanity will not be so incredibly stupid not to defend the solar system. Not only would we focus all resources on space-military, but we would also ensure our technology can defend against such invasions PRO talks about.  We will install defence systems and especially recognisance stations in different places in the solar system, effectively transforming it into an impenetrable defence system. The alien invaders would be detected by our space probes long before they enter the solar system. Once they arrive, they would be bombarded from many angles immediately, and such an ambush isn't countered merely by technological superiority. With hidden launching platforms on big asteroids, the moon, Mars and other objects, the aliens certainly would not be safe in their orbit, not even after launching their first strike. Once again this is the unsurmountable defender's advantage that is incredibly impactful in a space war.

Space debris
Maybe with a strong hull, an alien spaceship won't be torn to pieces by normal space debris, but the damage isn't negated in the way PRO claims it is. The laws of momentum are similar for aliens. Since the speed of space debris is insane, the impact is enormous, and due to the small size of the debris, it will easily cut through any armour.  A weaponised version of space debris especially could never be countered, as the requirements of sufficient armour would far surpass any material physically possible. Heavy objects like stones could easily destroy any ship on impact, and later burn up in the atmosphere without harming humans. PRO's "billion of drones" would certainly not have sufficient armour, and they would be destroyed like flies, thus becoming space debris themselves and accelerating the downfall of the alien weapons.

Failure of alien tech on Earth
PRO asserts alien spaceships can fly at Mach 10+. Yet that would not be the case in our atmosphere. Our missile systems would do short work of any of their weapons. As I explained in R1, any alien technology would be inferior to ours with regards to working on planet Earth. The drones, spaceships and weapons PRO talks about would not be able to function properly without being perfectly fitted aerodynamically to Earths atmosphere. The alien drones were not constructed and tested on Earth, therefore they don't fit our conditions; thus they are useless and would crash rather than systematically fight.

AI learns by a long process of trial and error, they can't quickly adapt to new situations []. Assuming that drones with AI would function in our solar system on the first try is certainly not a reliable assumption for PRO to make. Especially on Earth, the environments are quite new, complex and chaotic -- making it impossible for AI to learn quickly.

First and foremost, water droplets in the atmosphere scatter and absorb most microwaves []. Not every part of the world could be taken out at once since it rains many places in the world. Furthermore, every single military submarine would be safe as well. Humanity sure would have nuclear capabilities even after a first strike by the aliens. 

But PRO's alleged "first strike" is actually not possible.  The atmosphere and magnetic field of Earth do indeed protect us against this first strike. More troubling for PRO's case is the fact that the sun actually releases sudden bursts of microwaves in solar flares. If PRO is correct in his assessment that a long-range microwave ray could destroy the Earths electronics then why isn't our entire world collapsing every solar flare? Unless alien spaceships are more powerful than the sun it would be absurd to claim that they could direct a beam at Earth and take out our electronics.

These kinds of electronic weapon are currently being developed by humans. "EMP weapons, streams of microwaves, electromagnetic railguns, and high-power lasers offer new ways to bring down swarming drones, sink ships without explosives, and disperse formations of soldiers" [defenseone]. These technologies, while not being effective at the ranges PRO needs them to be, are still effective in taking down large swarms of drones. Thus humanity could in the near future have such weapons installed, meaning PRO's drones don't have any chance. Even worse, with humans having this technology we will surely create countermeasures and ways to avoid total blackout in case of such a first strike.

Experience is on the human side. We know our solar system. We have preparation on Earth, and we know how to easily beat any invasion on the surface. PRO's claim that aliens have experience with wars fails. Even if aliens fought wars, this experience could only move at the speed of light, and most of it would never reach the alien fleet in time.

The size of the universe is very interesting. 94% of the observable universe is beyond a horizon of no-return due to the expansion of the universe [kurzgesagt]. Only a small region of space is close enough for us to ever interact with. PRO has to argue that the aliens are within this boundary and able to invade us before they fall into the horizon. That in and of itself is a challenge. But coupled with the lack of signs of alien life, this information undermines PRO's claim. I make an appeal to the fermi paradox, which is a principle in astronomy that suggests the reason for no signs of aliens is that their civilisations die too quickly to be detected.

Interstellar travel
PRO has not proven that aliens are able to traverse space when the distances are so large that even light uses thousands of years. Assuming that their first space ships sent towards Earth will succeed in surviving seems like an incredible and nearly impossible achievement in and of its own. Putting weapons of mass destructions, which are innately unstable, on billions of drones doesn't seem to be a possible choice of actions for intelligent species. Neither does it seem possible for them to reach fractals of lightspeed with the deadweight of drones, armoury and huge energy storage merely for a one-time microwave beam that most certainly won't work. In short, PRO's invasion is physically impossible or at the very least incredibly dangerous and pointless. Nothing suggests intelligent aliens could even get such an idea. We aren't a threat, as us invading them is even more impossible than them invading us. Thus, aliens couldn't traverse space to kill us, especially not without thought and reflection.

  • It might be impossible for aliens to even exist and travel in space. Nothing suggests aliens can form empires and reach us with heavily militarized spaceships. Especially not when the universe is expanding too quickly for even light to keep up.
  • PRO's scenario is unfeasible and based on flawed assumptions. It also would require both effort and time in preparation and execution
  • An alien invasion as described by PRO is not enough to beat humanity.
  • Technological delay and pre-warning are still advantages of humanity. We would be preparing our defences while the alien fleet falls behind technologically.
  • The resolution fails

Good luck, PRO.

Thank you CON
My 2 cents regarding CON’s claim on my “Flawed assumptions”. The entire debate is based on assumptions. There are no facts or practical proofs which can support either of the ends. The proof about alien existence itself will be a scientific breakthrough and  worth to be nominated for noble prize. The CON is trying to mold the situation by eliminating the possibilities as per his needs.  What I am presenting are the theories  as stated by researchers after years of study.
The universe is 13.77 billion years old as confirmed by astronomers. Age of Earth is 5.53 billion years old.  The first humans as per researchers came into existence 2 million years ago. Compared to the age of universe or Earth itself, its a very minute proportion. From referring these figures, there have been many civilizations birthed before  humans in exoplanets. Dinosaurs crawled the surface of Earth 245 million of years back (source- google). The epoch of multicellular organism started way before homo sapiens came into existence.
Humans’ “first contact” with aliens is likely to be with a civilization much more technologically advanced than ours, according to a new NASA-funded study into the search for intelligent extra-terrestrial life (SETI). The era of homo sapiens started way late compared to the age of Earth.
One of the most interesting planetary systems astronomers have found in our own Galaxy is Kepler-444  which consists of five rocky planets orbiting a star which is 6.6 billions years older than our own solar system, meaning that it formed only 2.6 billion years after the Big Bang! This shows that planetary systems have formed way earlier than our solar system. Humans might have come into existence when other alien civilization would be making breakthrough in science. As per my data above, a civilization formed at Era of dinosaurs, would be millions of years advance than what humans are now.
CON is simply making assumptions that Earth is “Ideal Planet” for  rapid evolution. The CON needs to provide evidence to support this claim. Scientist have found 24 Super habitable planets which  offer more conditions suitable for life than Earth. These planets will host lifeforms which will be cycles ahead of us in evolution.
CON has failed to justify on how humans aren’t in the detection zone of aliens. As per my point in R1, USAF and other nation military have detected UFOs all around the orbit of Earth. Failing to provide a valid explanation and denial of accepting it as one of its own, it indicates that our existence is known to other civilizations. We might be well under their radar.
Research and developing technology is a  onerous activity, but its not an impossible one. A civilization which is technologically advance and have fined the space industries wont find it cumbersome to develop technology in space. Millions of years of head start advantage exists. It took 2 million years for humanity to reach where we are today. A 100 of million years of evolution will be a sorcery for humans. Hence, these kind of civilizations might be  having mega structures(industries, scientific centres) in space which can be part of their flee. Hence my point stands technological development is independent of distance.
 Celestial bodies are needle in the haystack, but detecting  a fleet, at a distance of 100,000 of light years away wont be possible through the observational equipment's which we use today. Also even if humans manage to pinpoint a alien fleet light years away, it will be obsolete data as that data would be years old and not unto date.
This “short span” of time which took humanity to detect these heavenly bodies is 2 million years.
The current EWS system to detect asteroids have a very short limited range and fail to detect any asteroids beyond Saturn’s Orbit. If an invasion takes place during this century, missiles, laser weapons will be fired from outside of solar system and by the time these EWS system detect these incoming attacks which will be at a close proximity of Saturn’s orbit, not enough resources , planning and preparedness is there to withstand such attacks.
CON believes that an alien invasion will be a blatant entry of alien ships just heading towards Earth like hungry hogs. The situation in real life will be quite different than those in movies. It will be red alert situation for both Earth Defense Forces and for Celestial forces. Both the forces will be on their high guard. Before invasion, aliens will scout the solar system. It would take 140 hr for a photon emitted by sun to reach edge of solar system. This creates a time gap in exchange of information. Even if the aliens are bombarded at different angles, the defense system equipped in alien ships will overpower the defense system humans due to technological head start and human defense  will fall short to counter billions of enemy forces.  Having their own share of experience in space warfare, they might be well aware about defense/tactics of Earth Forces and have better offensive tactics.
These Billion of forces compared to human will a very “Vast” number but compared to our galaxy cluster, or even galaxy itself is a very small figure.
Projectile weapons having a high momentum is a ramming force, but having experience space warfare where such weapons will be part of “basic” defense system, their  hulls would be strong enough. With anti ballistic/projectile system installed on ships, these space debris will be vaporized miles away before it reaches the ship. The drones would be equipped with defense system to withstand any offense and be offensive when required. Else the attack drones wont serve the purpose for what its designed.  A material designed by MIT chemical engineers can react with carbon dioxide from the air, to grow, strengthen, and even repair itself. These kind of technology will play major role. Despite taking damage, the ships will be equipped with self healing technology.
Lamborghini has created the world's first self-healing sports car. The Terzo Millennio, which translates as third millennium in Italian, has the ability to detect and repair cracks in its body work.
SOURCE- telegraph uk
Survival instincts as claimed by CON is not just  being brave, fight and survive. It also includes laying down arms and running away. Whenever there is shootout the  reaction observed from public is that they run away from point of incident. Even the animal kingdom follows the same principle. Bravery, Survival and Fighting are suitable dialogues for movies but not for Nature.
On seeing such a heavy figure of drones, psychological factors will come into play where many humans will start questioning their stand and creating a division, one who will stand and fight and the ones who will lay down arms so that they themselves, their family wont have to suffer.
NASA’s X-43 was able to fly in Earth’s atmosphere at speed of Mach 9.6. CON believes that Earth has some special aerodynamics, condition which might be alien to the aliens.
On November 4, 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of Sun-like stars and red dwarf stars within the Milky Way Galaxy. The nearest such planet may be 12 light-years away.
Having fought many civilizations in all different terrains and kind of atmosphere, many of which are “Earth-Like” these drones, AI system and ships will be an unstoppable force during invasion. The Earth is a habitable planet unlike Venus/Mars which have a very harsh terrain and climate. Even if the Earth’s terrain is new to AI, it wont make them go haywire as CON claims.
CON has claimed the pre-emptive strike by aliens will not be possible due to Earth’s magnetic field and atmosphere. CON has failed to provide support/evidence regarding this claim.
“The biggest solar storms can cause ripple effects in our power systems, heating and even destroying electrical infrastructure. That can send electronic communications haywire, and it's happened several times before.”
Source-business insider
Earth’s Magnetic Field protects Earth from severe effects of solar flare. However, it doesn’t protects us from the HPM weapons. These weapons loaded on drones, ships will be fired inside Earth atmosphere. Drones, Missiles will  loaded with HPM, which will activate once it reaches inside Earth’s Atmosphere. It will be quite ironic if alien invaders wont have defense system for their own weapons.
  Having just submarines with loaded nuclear weapons isn't a very reliable defense system. Its more like self destruction.
CON asserts that having experience of a very small domain in space is a head on advantage in a space warfare. Years of experience which will be passed on to the next generation in form of knowledge will keep the war spirit and experience alive  in invader species. If the invasion to take place in few years, humans wont be having sufficient experience to defend against invasion
I have no where mentioned drones equipped with nuke or one time super microwave beam. I have laid the principles on which Alien weapons will be based on. Again, proving light speed travel or even alien existence is impossible and can only be assumed as they have a tag of technologically advance species.


The entire debate is based on hypothetical situation where we believe aliens existence is proven.

The defense system as said by CON fails in every aspect.

Experience, technological superiority and quantity will lead to a quick and decisive victory.

The resolution is success.
Good Luck  CON

Round 3
Thank you, PRO.

PRO's admission:

It will be the red alert situation for both Earth Defense Forces and for Celestial forces. Both the forces will be on their high guard...Before invasion, aliens will scout the solar system.
 If you need to be on the red alert then your invasion does indeed involve thought, strategic planning and reflections and thus isn't easy. Scouting every asteroid to find all of humanity's hidden missile silos won't be quick. The solar system is large and would take an incredible time to fully scout; thus, PRO's invasion is not quick. Furthermore, what requires careful planning and preparation is not easy. Thus, PRO's own quotes show that his invasion will neither be quick nor easy.

  • causing or involving little difficulty or discomfort
  • requiring or indicating little effort, thought, or reflection
PRO admitted that the aliens will take the invasion extremely seriously, thus conceding that it would involve thought, discomfort, effort and reflection. PRO kind conceded.


Evolution - rebutal
PRO claims super-inhabitable planets exist and are better suited for life than Earth. Yet "None of them met all the criteria the researchers drew up for super-habitable planets" []. In fact, only two of the planets met two criteria. Yet Earth seems perfect in every way. According to, our planet not only has a perfect distance to the sun, water levels and etc, but also the orbits of other planets and the moon are necessary to add the stability needed for life to evolve -- even the specific existence and orbit of Jupiter is important. All in all, the Earth is still unique and no comparable planet has been found that matches the Earth. Evolution happening quicker on other planets is still unthinkable.

Alien infrastructure
An alien civilisation with millions of years of headstart would have created large celestial structures easily spottable, and also built large communication systems emitting signals travelling at lightspeed. The complete lack of human detection of these things can only mean that the aliens are too far away to be detected, and thus are too far away to ever reach us (see next point). Alternatively, the reason that we don't detect aliens infrastructure might be that humanity is indeed more technologically advanced or at the very least on par (or almost on par) with the aliens.


Size and expansion of the universe
The complete lack of alien signals and radio communication detected on Earth shows us that the head start of the aliens (measured in years) can't be greater than the distance to Earth (measured in lightyears, since if that was the case we would today detect alien radio signals and alike. Because of this fact, the technological delay will ensure aliens would never have technological superiority after travelling for years to reach Earth. In R2 I provided evidence that almost the entire universe is eternally lost behind a horizon of no return because of the expansion of the universe, thus any aliens living there can't ever reach us.

Impossibility of reaching high speeds
If you accelerate a spaceship to fractals of the speed of light you require near-infinite energy as well as diminishing returns. Reaching even a quarter of lightspeed with a large spaceship or piece of space infrastructure would literally be impossible or at the very least inefficient to the point where not even advanced aliens could achieve it with ease. Not only that but the deadweight of attack drones and sufficient armour, like PRO's invasion needs, would drag this plan down into absurdity. With speeds that aren't even significant fractions of the speed of light, the mere travel phase of the invasion would take huge multiples of the time light travel would take, thus increasing technological delay.


Aliens shouldn't be the default explanation for weird stuff in the sky. []
This article debunks the idea that UFO's are alien spaceships or "spies" as PRO claims.

PRO has no evidence that multiple aliens civilisations exist in close proximity and are able to fight wars. That would leave detectable traces, and the absence of such evidence disproves his claim that the aliens in question are a great empire with much experience. Even if that was the case a single fleet can't utilize this experience, similarly to how a general can't magically improve the performance of his soldiers. The experience of the specific fleet is what matters, and this one fleet certainly has not invaded dozens of Earth-like planets before.

Realistically, humans have the advantage with regards to experience as we have always lived and studied our solar system, and we have our technology perfectly fitted to our domain. While Usain bolt certainly runs faster than me, there can be no doubt that I would be faster than him at finding my way to my kitchen. Similarly, human technology and experience excel over aliens as long as we stay in our own domain.

Technological delay
PRO asserts the alien can create technology in their spaceships because large space structures are possible. I object. One cannot improve one's own spaceship while moving, and one certainly can't develop and test weapons of mass destruction inside one's spaceship. That would be suicide. Only a planet can provide the needed resources, space and security needed to develop the technology. Indeed, the technological delay is a factor, even more so since aliens can't travel at lightspeed. Technology IS dependent on distance.

PRO fails to address my argument that alien civilisation will be detected. If aliens build anything large enough, we will detect them. The alien fleets, PRO claims, is large enough to bring billions of drones as well as huge research facilities -- yet is undetectable. Now that's some BS right there. Moving quickly through space will inevitably create friction because space isn't empty. Friction creates heat that humans can detect. The ability of humanity to map space and detect new and smaller phenomenon has increased exponentially over the last couple of decades, and this trend isn't ending. In the very near future 

The "it was designed this way"-argument fails because one could use it to justify time machines, faster than lightspeed travel and other impossible technologies. Sufficient armour might not be literally impossible but it is virtually impossible. Humanity could simply release sand, rocks of different sizes and alike into orbit, and the sheer number and energy of impact would destroy any spaceship, no matter the design. Self-heal does not work without extra (read: otherwise wasted) materials, and also is too slow to repair a damaged hull after massive impact before the ship collapses and the crew dies. Once again, nukes in space are heat-based and even PRO's impossible armour could not protect aliens from nuclear weapons. Even if we simply assume that for some reason the big spaceships can intercept most human missiles the billions of drones certainly don't all have anti-missile systems installed. For this reason, billions of drones are reduced to ashes before they even reach Earth. Humans can also use their own high-energy-microwaves to take out the alien anti-missiles thus allowing the human nukes to reach the alien fleet from several directions and harm or destroy the aliens and their ships. 

Electronic warfare
Solar flares do not have the capacity to hamstring humanity. "130 million people would be likely to lose power and 350 transformers would be at risk for permanent damage" [solar-flares]. Little to none electronics or military equipment is damaged by even the strongest solar flares. PRO's aliens do not have a pocket sun inside their spaceships and because of that PRO's claim that their electronic weapon hamstrings humanity is absurd. 

It will be quite ironic if alien invaders wont have defense system for their own weapons.
Exactly. If you have a weapon, then you also develop countermeasures. Since humanity is developing this EPM technology as per my R2 evidence, we will also have countermeasures. The implication of PRO's claim is that not only aliens but also humanity will have defensive measures against EPM, thus rendering the alien first strike harmless.

PRO claims the aliens have billions of drones. He claims that these drones are loaded with weapons of mass destruction and that they have self-healing armour protecting them against weaponised space debris. Apart from the impossibility of transporting this number of drones, there are other problems. Not only does the "armour" weigh far too much, the mass creates inertia which does not allow for manoeuvres, but it also weighs too much to be useful. A single nuke could destroy a vast number of drones no matter their armour, and thus the drones themselves become space debris -- and drones crashing into drones would create the chain reaction described in R1 and R2.

Thus the billions of drones are nearly useless. Most of them will die like flies in orbit of Earth. Those that manage to safely enter the atmosphere will be destroyed by human missile systems because they are too heavy and their AI too untrained and their design not working on Earth --- thus they can't dodge human missiles no matter their speed. 

Because of the advantages of humans on planet Earth, the aliens simply can't invade Earth without at the very least their spaceships being nuked into oblivion and their remaining forces facing a well trained and well-equipped army that also is both prepared and have experience with fighting on Earth. Any alien invasion of Earths surface will involve difficulty, effort, thought, reflection and time. In fact, not a single alien can safely land on Earth, not even after a successful first strike and drone bombardment.

The alien invasion is extremely costly when you think of all the other and more useful things resources could be used for. Alien time and effort are wasted and they risk dying or losing their drones in a pointless struggle against defenders advantage which includes pre-warning and technological delay. Certainly, any sane and intelligent alien would avoid conduction PRO's plan. The invasion is neither quick nor easy when you consider the applicable definitions. Ultimately, PRO's invasion plan is not even guaranteed to be successful. Similarly to the German invasion of France during WW1, this invasion is not reliable in any way and most certainly would not work as intended. Theoretical scenarios about quick and easy victories nearly always fall flat when the first sign of resistance appears, they end up as blatant failures and new plans and improvisation is needed. 

PRO's arguments rely on an impossible favourable scenario for the aliens. In contrast to my argument, he makes multiple assumptions like the aliens being an empire, and he never provides adequate evidence for such claims. Quite the contrary, his arguments contradict the very data humanity observes in space. His arguments imply impossible and contradictory feats of alien technology. My argument relies on testable facts and the reliable laws of physics described by science. Furthermore, PRO's invasion can't adequately prove the resolution as even the best-case scenario for aliens require thought, reflection, effort and involves difficulty, time and danger.

PRO also kinda conceded by agreeing that the invasion will involve alien discomfort and thought with the red alert. 

We are not sure that an alien invasion is even possible. However, we can know with absolute certainty that an alien invasion won't be quick and easy.

The resolution fails. Vote CON!

Good luck, PRO.

Round 4
I was looking forward to PRO's argument. Unfortunately, due to unknown circumstances, he forfeited.

These were my R3 rebuttals:
  • Earth is the perfect planet for life and rapid evolution -- meaning alien millions of Head start is implausible
  • Self-healing armour is neither sufficient armour nor possible in space without wasting tonnes of resources and manoeuvrability
  • Alien first strike isn't possible -- the energy of even the sun isn't enough to hamstring humanity, and we will surely have defensive measures in no time
  • UFO's aren't aliens not even in our scenario
  • Human local experience is better than the dubious experience of alien invaders -- and even the experience of aliens is limited by the travel time of the fleet
  • Technological delay is a fact -- developing technology in space is neither possible and especially not as efficient as on a planet
  • Pre-warning is a fact -- the alien structures and radio signals will be detected, as well as their fast-moving ships (especially when they are close)
  • Drones are useless because of space debris, nukes and misilles which destroy every single one of them before they can reach Earth
Due to the forfeiture, I will have no chance at responding to his R4 defence, which means my R3 rebuttals can't be considered debunked by new points PRO might make in R4. 

My rebuttals stand.

There are multiple scientific barriers to interstellar travel in general, namely travel time, space debris and the expansion of the universe, as well as communications delay and the time difference between perceived reality and actual reality because of lightspeed being relatively slow in space. Especially, it is nearly impossible to conclude that heavy weaponry can be put on a spaceship without it being slowed down or requiring impossible amounts of energy; armour on said ships also make this problem more prevalent.

Human technology and ingenuity mean our space defence will quickly become formidable, and the time delay between our ascent as a technological civilisation and the alien detection of us is necessary to large to allow for the aliens to invade us before we put up defences. In a very short time after we discover alien civilisation, our solar system will be transformed into an impenetrable area protected by advanced defence systems not easily countered; the alien technological difference is limited, because we all are limited by the same laws of physics and alien technology can't be magical; and also technological delay ensures any initial advantage is counteracted or even reversed.

Human defences, coupled with many defenders advantages that in space are insurmountable, create a situation in which no alien efforts could defeat us in our solar system.

Even if we simply assume, as PRO implied, that the aliens too far away to be detected suddenly teleport to our solar system and start attacking us --- that still is not an easy victory. The alien first strike can't work as not even the strongest solar flares can hamstring human technology, thus the aliens will face a humanity with advanced weaponry, many of which are capable of destroying cities, and burning a space fleet or swarm of drones will be a piece of cake. Not only that, but human misiles are fast and precise enough to beat alien technology, especially considering that they are perfectly fitted to Earth. Thus, humanity can win a fight against aliens, especially with incredible numerical advantage; after all, the fight is between an entire planet and a few spaceships and drones --- technological advantage can't overcome this disadvantage, one can only put finite (read: very small) amounts of weaponry on ships, meaning the aliens don't have enough war equipment to take down humanity.

The victory condition of the aliens was clearly stated as being "to subdue human civilisation by taking control of Earth's surface". PRO has mostly ignored this victory condition and assumed alien only need to bombard Earth from space. Since his plan does not prove any way for the Aliens to destroy human nuclear capabilities (especially not submarines), PRO has not proved how aliens could even land on Earth safely --- and thus the argument from PRO is insufficient to prove the resolution, as the aliens have not been proven capable of achieving the victory condition set up for this debate.

Furthermore, a project like the invasion PRO claims could defeat humanity would require incredible amounts of resources, time, preparation and thought. Such an operation clearly does not qualify as being "quick and easy". PRO's invasion, therefore, does not qualify as being quick and easy, if it can even be called possible. Since PRO also assumes alien empires exist -- an assumption contradicted by lack of any sign of alien infrastructure -- PRO's argument simply does not prove the resolution correct.

The nature of space makes it impossible for quick and easy invasions to take place. An alien invasion of Earth, if possible at all, cannot be both quick and easy. The resolution fails.


Thank you, PRO, for an interesting discussion.