The Australia Telescope Compact Array (ATCA), at the Narrabri Observatory, 500 km north-west of Sydney, Australia.
Credit: ATCA/CSIRO
WHICH IS THE more shocking proposition: that our galactic neighbourhood is riddled with advanced alien civilisations? Or that we humans are a solitary beacon of intelligent life in a silent universe of almost incomprehensible vastness?
Either prospect is enough to keep you awake at night. Yet one of these two statements is likely true. We just don't know which one.
That's not to say we don't know anything about the likelihood of intelligent life existing in the universe. In fact, we know it does: the very presence of humanity means the probability of intelligence arising is greater than nil.
We just don't know how much greater than nil it is. It might be one in a million. It could be one in a billion. Or it could be a freak event, never to be repeated.
Consider the numbers involved: we live in a universe with billions upon billions of stars, many of which are very much like our own Sun, and each may well have a clutch of planets. So, even if the probability of intelligent life emerging is infinitesimally small, the sheer number of stars in the heavens makes it likely we're not alone.
One man who has maintained a life-long passion for solving this astronomical conundrum is Frank Drake, an American radio astronomer who now chairs the SETI Institute in the United States (SETI, a common acronym in the field, stands for Search for Extraterrestrial Intelligence).
According to Drake, his interest in the possible existence of extraterrestrial life started as a child. "I was eight years old and my father told me there were other worlds in space. To me that meant worlds with cities and people just like the Earth, and that fascinated me."
In the early 1960s, while working at the National Radio Astronomy Observatory in West Virginia, he and a few enthusiastic scientists became intrigued by the prospect of detecting evidence of extraterrestrial civilisations using the relatively new discipline of radio astronomy.
"In 1961, I was asked by the National Academy of Science to convene a meeting of scientists interested in SETI to explore what the possibilities were," says Drake.
"In preparing the agenda for the meeting, I listed all the factors one needed to know to predict the number of detectable civilisations in our galaxy. I recognised that if they were all multiplied together, one got an estimate of the number of detectable civilisations."
Thus the Drake equation was born. And it seems that ever since, Drake has spent his career in dogged pursuit of evidence for ET's existence.
While that evidence has yet to arrive, his equation lives on as a simple yet potent tool that gives us a road map of what we need to learn in order to solve this fundamental existential dilemma. So what's the equation like? Here it is:
N = R* x fp x ne x f1 x fi x fc x L
was Michael one of yours?
Dear Aliens,
Just wondering if Michael Jackson might have originated out in the heavens with you blokes, because he sure was one strange sort of a dood.
fascinating
Wouldnt it be fantastic if we could hear from another civilization. I really do hope that we are not alone and that we hear something within my lifetime. I can only hope...
X PRIZE
IS THERE AN X PRIZE FOR POSITIVE REPRODUCEABLE PROOF OF ET?
Drake's Equation is an
Drake's Equation is an excellent Mathematical model of the probabilities involved. There might, as yet, appear more factors to the equation; who knows?
The variables are quite wobbley and estimates between 1 and 200 seem reasonable. The Milky Way is a big place!
Evidence of alien contact
Assuming programs like SETI discover concrete evidence of extraterrestial civilisations existing outside our own solar system, what's stopping governments around the world from suppressing this information to the general public labelling any evidence, "Top Secret!".
Universe Silent Because Humans are Alone
The article is wildly optimistic about 1). The prospects of life originating from non-life (which is zero), and 2). The prospects of intelligent life arising and surviving.
To begin with, science has failed to accomplish biogenesis because biogenesis is impossible. If scientists cannot accomplish the task abiogenesis is likewise impossible.
Secondarily: Civilization has existed on the Earth for 10,000 years out of 4,600,000,000 years. SETI scientists try very hard to avoid the implications of this observation. I'll tell you what it means: Civilization may be considered as inevitable as the duck-billed platypus.
Thirdly, technological civilization sufficiently advanced for radio astronomy has only existed for 100 years out of civilization's 10,000 years. While some might consider this an evidence of technological civilization's inevitability, I shall remind you of the role of perpetual warfare in the advance of technology. Supposing an intelligent animal actually existed on another planet and that animal isn't perpetually engaged in warfare there isn't any reason at all to imagine that such a peaceful intelligent animal would ever invent radio telescopes.
Finally, the SETI advocated seem to operate on the notion that technological civilization is going to survive on the Earth forever. This assumption is wildly irrationally optimistic. Technological civilization is already dying, infrastructure eroding, resources depleting and climate change is poised to deliver the final knock-out punch.
If technological civilization survives for another century you may consider that a major miracle. Technological civilization isn't going to survive for another two centuries under any circumstance.
Technological civilization originated once and only once in this Universe. We're it. Humankind is alone in the Universe and there won't be any other.
David Mathews Nature Photos
Humans are alone in the Universe
The article is wildly optimistic about 1). The prospects of life originating from non-life (which is zero), and 2). The prospects of intelligent life arising and surviving.
To begin with, science has failed to accomplish biogenesis because biogenesis is impossible. If scientists cannot accomplish the task abiogenesis is likewise impossible.
Secondarily: Civilization has existed on the Earth for 10,000 years out of 4,600,000,000 years. SETI scientists try very hard to avoid the implications of this observation. I'll tell you what it means: Civilization may be considered as inevitable as the duck-billed platypus.
Thirdly, technological civilization sufficiently advanced for radio astronomy has only existed for 100 years out of civilization's 10,000 years. While some might consider this an evidence of technological civilization's inevitability, I shall remind you of the role of perpetual warfare in the advance of technology. Supposing an intelligent animal actually existed on another planet and that animal isn't perpetually engaged in warfare there isn't any reason at all to imagine that such a peaceful intelligent animal would ever invent radio telescopes.
Finally, the SETI advocated seem to operate on the notion that technological civilization is going to survive on the Earth forever. This assumption is wildly irrationally optimistic. Technological civilization is already dying, infrastructure eroding, resources depleting and climate change is poised to deliver the final knock-out punch.
If technological civilization survives for another century you may consider that a major miracle. Technological civilization isn't going to survive for another two centuries under any circumstance.
Technological civilization originated once and only once in this Universe. We're it. Humankind is alone in the Universe and there won't be any other.
David Mathews Nature Photos
Abiogenesis
If the chances of life arising from non-life are zero, then how did you manage to write your post, seeing as, by your own rules, you don't exist? Of course life arose from non-life. Amino acids form from inorganic matter:
http://en.wikipedia.org/wiki/Abiogenesis
Is someone controling the switch of life ?
surely the universe is far to immense for absoluty no life other than earth. life everywhere is switching on and off constantly, have we just switched on or are we close to switching off ? probably the later.
someone must be looking did they look before we switched on or will they look after weve gone ?
Perhaps we are just being avoided.
What Does Rate of Star Formation Have To Do With It?
Would someone smarter than me please tell me why this equations seems so deeply flawed? Why is the rate of star formation featured so prominently? If it happened to be zero, then N becomes zero. I hardly see how a zero rate of star formation means that billions of stars have a zero chance of harboring intelligent life. And where is the factor for the number of stars in the galaxy?
The way I see it the equation should be N = (# stars in the galaxy) x (# habitable planets per star) x (prob. of a habitable planet having life) x (prob. of life evolving into a communicating civilization) x ((avg. lifetime of a communicating civilization) / (age of the universe)) x (prob. of communicating in a manner that we can detect) x (prob. of detection)
Even this is flawed, because what if the civilization is at the opposite edge of the galaxy? The signal will be so weak that it would be overwhelmed by noise, not to mention the long delay (100000 years?) while we wait for it.
We should also consider that we know almost nothing about several of the factors, especially those concerning evolving intelligence, and anything about alien cultures. The only observed facts so far are these:
Habitable planets per star = at least 1
Communicating civilizations per habitable planet = 1
So the observed odds are 1 and 1 for each of those factors. Call me when we have more data.