10 Things You Should Understand About Fermi’s Paradox
Fermi’s paradox arises because of the contradiction between the size of the universe and the fact that we have no contact with alien civilizations. Fermi looked at the heavens and postulated that our Sun is a fairly typical star of its type, it is also young in galactic terms. As there are so many other stars in the sky, some much, much older than our Sun there is a high probability that manly of them will be orbited by earth like planets. Given the potentially large pool of potentially life bearing planets it is likely that some of them would develop life and on some planets that life would develop intelligence. Over time, he said those civilizations should learn to develop space travel.
Given the huge numbers involved in all these steps the galaxy should have been colonized through space travel but, to date, we have seen absolutely no evidence of any other intelligent life in the universe. Fermi’s paradox basically poses the question ‘where is everybody?’.
We use this article as an opportunity to explain the background to the paradox and explore some of the more interesting theories that have been put forward as potential solutions.
10. Fermi Is One Of The Fathers Of The Atomic Bomb, His Work In Physics Led Him To Develop His Paradox.
Although these days Enrico Fermi is best known for his famous paradox he was a gifted theoretical and experimental physicist. He won a Nobel Prize in Physics for his work on radioactivity in 1938. At around the same time he escaped Europe for the US to protect his Jewish wife from the rising tide of anti-Semitism. He was recruited to work on the Manhattan Project and led the design of the first ever nuclear reactor and then worked closely with Oppenheimer to produce the first atomic bombs although he opposed extensive development of nuclear weaponry on moral grounds.
Fermi was famous for his direct approach to complex problems and his ability to find quick answers to complex problems by a system of estimates often refeed to as being done ‘on the back of an envelope’. This is done by making a series of estimates that address the problem at hand and multiplying them together to calculate a solution. Fermi used this method to calculate the blast power of the test atomic bomb detonated in the Trinity Test. The method assumes that the answer will be incorrect but that it will give an indication of the range in which the accurate result can be predicted. It is this famous method of analysis that inspired Fermi to pose his paradox.
9. Fermi’s Paradox Was Inspired By The Theft Of Some Trashcans.
In the 1950s Fermi was working at the National Laboratory in Los Alamos. During lunch with some colleagues the conversation turned to recent UFO sightings and the men had some fun blaming aliens for the recent disappearances of some trashcans.
While the men were amused by the discussion they tuned their minds as to whether or not it would be possible for human beings to actually observe an object travelling faster than light within the next 10 years. The conversation started Fermi thinking about the probabilities of the existence of extraterrestrial life. He made a series of calculations to show that the galaxy should be full of intelligent life and that it should have visited Earth many times. This led him to formulate his famous paradox – If probability suggests that there are many different alien civilizations why have we not come across them?
8. The Fermi Paradox Is Closely Related To The Drake Equation And Has Been Discovered Four Different Times.
About 10 years after Fermi asked his question ‘where is everybody?’ and made his initial estimates as to the probability of extra-terrestrial civilizations Frank Drake developed the ‘Drake Equation’ to try systematically to address the probabilities for the existence of extra-terrestrial life. The equation is almost impossible to answer because out of a total of 7 estimates 4 are impossible to make with any reliability. This means that, depending on the estimates used, the equation can give answers varying from 1 to millions. Drake himself explained that the equation was not designed to give an answer to the paradox but rather to ‘organize our ignorance’ on the subject.
Enrico Fermi is not the only person, nor even the first person to pose the paradox. Konstatin Tsiolkovsky discovered the paradox in 1933 but determined that extra-terrestrial civilizations were leaving us alone to develop on our own. Fermi’s Paradox was given relatively little attention until, in 1975, the same question was again posed by David Viewing and Michael Hart.
7. All Attempts To Find Extra-Terrestrial Life Have Failed.
Humans have tried for hundreds of years to find proof of extra-terrestrial life. As we are unable to leave our own Solar System we have to rely on earth bound searches to accomplish this aim. Of course our searches are based on a very human centric view of the galaxy – we are searching for the type of evidence we ourselves might leave, whether or not aliens would leave the same type of signals we just do not know.
There is also tremendous potential for mistakes which allow us to think that we have discovered life when we have not. When Seyfert Galaxies were initially discovered it was thought that they might be unnatural in origin – it turns out that they are a completely natural phenomenon.
Projects like SETI have been set up to search for radio emissions from extra-terrestrial civilizations. SETI has searched for these tell-tale signals for many decades, in all that time only one unexplained transmission has been picked up. In 1977 a telescope called ‘Big Ear’ detected a powerful radio transmission (subsequently dubbed the ‘Wow Signal’) from the region of space near Sagittarius. The transmission was detected once and once only despite repeated attempts to search the same area of sky.
At the present time our ability to explore our own Solar System is limited by cost and the state of our technology. However, our telescopes are now sufficiently powerful to allow us to search for planets orbiting other stars. This search has, so far (March 2015) detected many different planets with the number increasing all the time. Despite this we have, to date, not found any evidence of extra-terrestrial probes or artifacts. Attempts have been made to communicate with or activate any hidden alien probes that have been sent to investigate us but these attempts have not met with any success.
6. Earth Is Too Mundane To Be The Only Planet To Host Life.
We all like to think that we are special but as very young children we are taught to consider others by being told that the world does not revolve around us. It turns out that not only are we not that special (except to our loved ones) but our planet is not that special either.
Astronomers search the night skies for evidence of other planets orbiting other suns, this is done by looking for variations in star’s light caused by a planet moving across the star. In just a small area of the Cygnus constellation NASA’s Kepler telescope found 3588 planets over a relatively short period of search time. Just over 50 of these were postulated to be Earth like; extrapolated to cover the entire galaxy this figure suggests that there could be more than 30 Billion Earth like planets in the heavens many of which are likely to orbit their suns at the optimum distance to permit life to flourish. This, combined with the discovery that Amino Acids (the building blocks for protein and essential for life as we know it) are relatively common in space, has been cited as support for the ‘Mediocrity Principle’. The principle is the belief that because in that our sun is relatively normal and we are in an unexciting part of the Milky Way, there is nothing special about the Earth that could lead us to believe that the evolution of intelligent life here is anything out of the ordinary.
5. Some People Believe That No Other Intelligent Life Exists In The Universe.
Many people believe that the fact the paradox exists is proof of the very fact that life is rare. We may not be the only civilization in our galaxy but if others exist they are so far away from us as to make us practically alone or they existed in the past and have since died out. This theory postulates that life is driven to colonize. It might start with considerable regularity but something somewhere, a great filter, along the way stops it from expanding very far beyond its point of origin.
Other people reject the mediocrity principle in its entirety and claim that the circumstances that gave rise to life on Earth were so unique that they could not be replicated elsewhere. Even if other planets exist that are capable of giving rise to life this does not mean that the unique conditions that allowed for this here on Earth would be replicated on these worlds. If life did exist on other planets, they claim, it would probably not be intelligent; after all only one truly intelligent species has evolved in all the time life has existed on Earth.
The fact that that our species was able to industrialize was driven by the easy availability of fossil fuel sources, such sources may not be available on other planets. Finally while Earth like planets may be common double planets such as the Earth/Moon pairing appears to be relatively rare. Without the presence of the moon we might not have had a warm core or a magnetic field. The moon also drives tides, without these life might never have moved from the sea to the land, The homogeneity of life in the sea means that animals are presented with fewer challenges to overcome and therefore less likely to develop problem solving technologies.
Of course other people believe that we are alone in the Universe because humans are unique and created in the image of God.
4. Some People Believe That Intelligent Life Exists Elsewhere But That The Universe Is Too Vast For Us To Communicate
Although we believe ourselves to be an advanced species it is almost impossible for us to communicate across interstellar distances. Probes that we send out to planets in our own Solar System take years to get to their destinations and experience a communications time lag when beaming information back to us. The distances, even in our own back yard, are unimaginable. We have made attempts to beam information out of the Solar System by radio and send it in physical form aboard Voyager. A message sent by radio telescope from Arecibo in 1974 will take 25,000 years to reach its destination.
There may be many other civilizations in our neighborhood but if they have a similar level of technology to us we may simply not be able to receive each other’s messages. Any message we do receive is likely to be extremely old indeed so even if we do receive a communication from another world the chances are that that civilization may be extinct, or will certainly have moved on from the point in time when we sent the message. If other civilizations are trying to communicate with us, for example by way of signals like the ‘Wow Signal’ then we have to be in the right place at the right time to intercept it and we may only get once chance. When we ourselves sent the Arecibo Signal we sent it to one small segment of space and sent it only once.
With this in mind we should also consider that humans have only been technologically active, in a manner that could be viewed from space, for very few years. The first radio transmissions too place less than 200 years ago and we have been searching for other life for less than 100 years. The radio transmissions that we use in our day to day lives, unlike targeted broadcasts to other stars, do not have the power to travel very far. This means that we may not have been looking for extra-terrestrial life long enough to have found evidence of it or, alternatively, that it searched our Solar System already, before humans were active and concluded that there was nothing of interest here.
In any event our period of high visibility radio use is now coming to an end, we have developed many alternatives to the use of radio waves and all of these are less visible from outer space. If extra-terrestrial civilizations follow a similar route of development to us then it is likely that they too would only use radio waves and other detectable means of communication for a very short period of time before developing alternatives. We would have to be extremely lucky to be searching the correct part of space at exactly the right time to pick up little more than 100 or so years of visible broadcast.
3. Some People Believe The Universe Is Full Of Life But That The Civilizations Do Not Wish To Or Can’t Communicate With Us
There may be many other civilizations out there but they could be, quite simply, antisocial. We currently choose to scan the skies but have made very few attempts to communicate with the outside galaxy. The SETI community on Earth believes that even if they do intercept a message from another world it would be irresponsible to respond unless there is consensus amongst nations as to when to send a message back and what to include in them. It would be almost impossible to gain consensus in the world as it stands. It is entirely plausible that other worlds are experiencing the same problems – we are all listening as passive participants but none of us wants to be active.
In order to complicate matters further we communicate in a very human way – our attempts at communication may not be understood by alien life and we may not be able to understand their efforts. It is always possible that the intelligent life on other planets has not chosen to pursue a technological society, or has perhaps evolved beyond one. A water world populated by sentient and sapient dolphin like creatures would have little incentive or desire to develop technology along the same lines as our own. Even if we identify a distant planet as capable of supporting life we would not know that life was intelligent unless it displayed markers of technology that we understood.
Our failure to find other life in the universe may be down to as simple a reason as the fact that we are broadcasting and/or searching on the wrong bandwidth. If we did receive a communication there is no guarantee that we would be able to decode it – many people talk of the universal language of mathematics but what if our math and their math is just too different.
With this in mind the universe could be teeming with other life and civilizations but we would not necessarily be able to intercept or understand their communications or we theirs.
2. Some People Believe That The Earth Has Been Quarantined, That We Are In A Zoo Or That All The Other Civilizations Have Destroyed Themselves
There are some very bizarre postulated explanations as to why we have not found other civilizations in our galaxy. Some people believe that highly developed extra-terrestrial civilizations are allowing us to develop on our own and at our own pace, in a sort of cosmic zoo or galactic equivalent of a National Park. This would require there to be a single, overarching, civilization in our part of the galaxy which controls access to Earth. An alternative explanation is that we are living in a giant simulation, a galactic equivalent of the Truman Show. This might possibly tie in with those who have the religious belief that humans are unique and created by God.
Still others believe that because most known instances of contact between civilizations on Earth has proved disastrous for one of the groups (eg the Caribbean Indians vs Columbus) alien civilizations actively choose to avoid initiating contact with others and try to hide their presence in the universe.
A rather depressing explanation for Fermi’s Paradox is that civilizations may well be the agents of their own destruction. The argument is that most societies that develop the technology necessary for space flight and interstellar communication will also have had to develop very destructive technology such as nuclear weapons which if not controlled can lead to catastrophe. Further, based on our own experiences we could postulate that advanced societies may be at risk of poisoning their atmosphere, using all their resources, changing their climate etc. Even if the civilization does not completely destruct it may have to evolve beyond technology in order to save itself and its home planet.
1. Some People Believe That Fermi’s Paradox Prevents Civilizations From Making Contact With Others
It is, sadly, possible that the very act of proposing the Fermi Paradox gives rise to it. Given that the paradox was independently discovered here on Earth on at least four separate occasions it is likely that every single extra-terrestrial civilization will have its own Fermi who poses the paradox. When a civilization realizes that no one else is attempting contact they may decide that it is best not to attempt it themselves!
So there you have it! From the atomic bomb to a paradox that has exercised some of the best minds on Earth (and possibly many other planets as well) for decades and will continue to cause us all to scratch our heads for decades to come. It is easy to wonder ‘where are they all’ and it is only human to be curious about whether or not we are alone in the world. However, we should ask ourselves whether it is a good idea to even try to make contact. While a passive search to find out if we need to protect ourselves is a good idea should we be broadcasting our presence to all and sundry? Should we give them detailed information about our mathematical understanding of the universe and the composition of our DNA.
It is comforting to think that extra-terrestrials capable of interstellar travel must be so technologically advanced as to be totally benign. However there is every chance that instead of calling ET to come to our home that we invite the lethal predator from Aliens in over our doorstep.