The universe is a big place. In the 6th century BC Anaximander suggested that other worlds were endlessly forming and disintegrating in a universe of infinite size. In the 5th century BC Democritus, a Greek philosopher argued that there were countless other worlds containing countless other lives. Into the medieval ages and beyond, telescopes became more and more powerful, yet still the edge of the universe could not be found.
Today we can watch stars forming in the nebulae of dust and gas, and from the Hubble telescope a snapshot of 10,000 galaxies- each containing billions of stars. And the theory is we are still only seeing 95% of what there is out there. Statistical extrapolations for the 1000 potentially “Goldilocks planets already identified lead to the conclusion that there are about 20 billion earth-like planets in our galaxy.
Yet… we have never found evidence of extraterrestrial activity. It was eloquently put by Enrico Fermi in his book “5 billion years of solitude: “Where the hell are they?!”
If we assume that there are many planets capable of having intelligent life spawn on them, and that those planets will allow civilisations to develop for at least as long as our human ones, then why indeed have we not had any contact from them? One theory is that the distances between earth and other earth-like planets are simply to vast to be traversed. If we can never travel faster than the speed of light, and there aren’t thinks like wormholes in space, then we should resign ourselves to the fact that even if we are not alone, we will never meet another extra-terrestrial species.
The other theory is more interesting. They are avoiding us. For whatever reasons (and maybe we don’t look very nice as a species from our history) intelligent life out there has no wish to contact us. Perhaps they consider that species should rise and fall without any foreign intervention. Perhaps they are afraid of us. Perhaps they just wish to make us remain in splendid isolation, less we taint others with our warlike tendencies. Maybe they have evolved to another level of life where physical bodies have been dispensed with and we would not be able to see or understand them even if they were skimming past earth.
Whatever the reasons, we still spend a lot of time, money and effort in trying to see if there is intelligent life beyond earth. Perhaps as science develops apace in the next few hundred years we will have made some progress towards extra-terrestrial contact. Or perhaps we are just doomed to having another 5 billion years of solitude.
While the generally supported theory is that a freak asteroid hit lead to the demise of the dinoasurs, alternative theories suggest that it was no accident.
Consider the likelihood that there is intelligent life on other planets. Most scientists now think that even if life is as rare as hen’s teeth, the number of stars makes it likely that there will be Goldilocks planets circling some of them, and that some of those planets are a lot older than earth. It is also feasible that a new form of propulsion might have been discovered by some of those alien races that enable them to traverse the gulf of space and develop interstellar travel. Be it some form of ion drive, or wormhole jumping, it is not beyond the realms of possibility that these advanced aliens came upon the Solar System many years ago:
They see a young world that has almost arrested development. Dinosaurs have been the dominant species on the planet for million of years. Evolution is so painfully slow, that it is unlikely they will ever devlop into intelligent life even given many more millions of years. Intervention?
Some might argue that an advanced alien race would have a “no interference” policy when coming across inhabited worlds, much as wildlife documentary makers don’t interfere when a lion brings down a gazelle, or a pack of hyenas ambushes a baby giraffe. But what if they have some higher, more lofty goal? What if they believe that they should encourage the development of intelligent life on planets in the multiverse? It might be some quasi-religious drive that spurs this apparent altruism towards giving worlds a helping hand towards more advanced development. Rather like in the film 2001:A space Odyssey, they trigger a rush in progress of apes to man- except that this race visited earth long before the mammals, at the time of the dinosaurs. And perhaps they realised that mammals would never become dominant, and that dinosaurs could never develop into intelligent life. What to do?
Rightly or wrongly they decided to end the dinosaurs. Deflect a metoer to cause extermination of almost all life, but allowing mammals a chance to flourish. Did that really happen? Did aliens play God? No evidence, but it’s a plausible story. One wonders what we earthlings would do if we developed interstellar travel. Would we just leave a planet and its inhabitants to evolve (or not) or would we try to encourage creation in our own image? Well, we can put that question on hold until after we’ve developed a practical means to travel to the stars. Unles there’s life on Mars….
We all know how close we came to getting wiped off the solar system map before we even made an appearance on earth, when an asteroid smashed into earth and wiped out the dinosaurs. Curiously it was that close shave that actually enabled mammals, and eventually humans, to become the dominant species on earth.
But it seems another planet out there might have not had such a lucky escape as out own: Astronomers studying a dying star have discovered the mashed-up remains of a water-rich asteroid. This suggests that hundreds of millions of years ago that start system may have harboured a “goldilocks” planet, with conditions not disimilar to our own, that could well have had intelligent life on it. The research appears in the latest issue of the journal Science.
Given that the conditions for life to have flourished on earth are so rare, and must include water and an atmosphere, to find evidence that there seems to have been another planet at one time, is both uplifting and concerning. Uplifting in that it may point to us not being alone in the Universe, concerning for two reasons: What happened to the inhabitants- unless they were sufficiently advanced to develop interstellar travel, they would have perished when their sun went through the final cycles of its life. Scientists believe that the star would most likely have had a number of planets in its system before the star, expanded to become a red giant, burning everything on any planets, and then shrinking and eventually going cold.
This is also the likely fate of our planet, assuming we don’t get hit by another giant asteroid. Our sun too will become a red giant and then a white dwarf, and finally a black dwarf- a dead star emitting no heat.
Astronomers studying the light emitted by the asteroid, known as GD 61, located 150 light years away from the Earth, detected an abundance of “rocky” elements such as magnesium, silicon and iron. They also found oxygen in quantities that indicated a very large amount of water. Only a water-rich massive asteroid, or minor planet, can explain the observations. GD61, at least 90 kilometres in diameter, would have been drawn in by the white dwarf’s powerful gravity and ripped apart. It is highly likely that rocky, water-covered, Earth-like planets also existed in the system.
Dr Jay Farihi, from the Institute of Astronomy at Cambridge University, said:
“The finding of water in a large asteroid means the building blocks of habitable planets existed – and maybe still exist – in the GD 61 system, and likely also around substantial number of similar parent stars. These water-rich building blocks, and the terrestrial planets they build, may in fact be common – a system cannot create things as big as asteroids and avoid building planets, and GD 61 had the ingredients to deliver lots of water to their surfaces. Our results demonstrate that there was definitely potential for habitable planets in this exoplanetary system.”
US Radio astronomer Frank Drake developed the Drake equation so he could estimate the possible/probable number of planets containing intelligent life in the galaxy. He did this by taking into consideration the factors listed below, in preparation for one of the first “serious” discussions about the probability of life on other planets in the early 1960s. The factors are
N = the number of civilizations in our galaxy with which communication might be possible;
R* = the average rate of star formation per year in our galaxy
ƒp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
ƒℓ = the fraction of the above that actually go on to develop life at some point
fi = the fraction of the above that actually go on to develop intelligent life
ƒc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time such civilizations release detectable signals into space.
Thus, what the Paradox is saying is that if so many planets exist or have existed with intelligent life, why is there a lack of contact between the intelligent life and us and why is there such a lack of physical evidence of said intelligent life here on earth, or elsewhere in the observable galaxy? The paradox exists in that the Drake equation statistically indicates life should be abundant and yet physical evidence says otherwise. In other words “where is everybody?”
To be fair the Drake Equation was only concocted to promote discussion and interest in the Search for Extraterrestrial Intelligent Life (SETI) and not to “prove” the existence of abundant life in the galaxy.
Opponents and critics of the Fermi Paradox say that there is evidence of extraterrestrial life, on this planet, now and throughout our history, and also from astronomical and other observations of space. But these have been suppressed by governments for a variety of reasons….
We have now sent something man-made beyond the reaches of our solar system.
35 years ago Voyager 1 was launched with the intention of exploring the major planets. The then US President, Jimmy Carter, said;
“This is a present from a small distant world, a token of our sounds, our science, our images, our music, our thoughts, and our feelings,”
Using the sling-shot method of propulsion (using the gravity pull of each planet in turn to gain momentum) no-one expected the small craft to keep on going. But it did. It has now travelled 11 billion miles, trailed at 9 billion miles by its successor, Voyager 2.
Voyager 1 has entered interstellar space- the first man-made object to do so. It is now heading towards another sun; star AC+793888. But it won’t reach it. In 15 years Voyager 1’s plutonium generator will cease producing electricity and its transmitter will stop functioning.
But as we wave goodbye to this intrepid little craft, there is always the possibility that it will be found by alien intelligence, and if they recognise and understand the symbols and information contained on and in the craft, then we may get an outer space hello from them. Either that or we’ll be invaded. Hmmm- was it wise to indicate on the craft exactly where it originated from? Time will tell…