Much has been written about this subject, and particularly in recent years the discussion has moved somewhat further into mainstream science. Therefore I feel compelled to publish main own musings about this topic here - mind you these are my own thoughts and opinions, and you, the reader, must understand that I am not a qualified scientist, so I claim no authority in this field whatsoever.
First of all the hard facts :
For all you UFO fanatics - once all is said and done there is still absolutely no hard physical evidence in the public domain for the existence of any form of extraterrestrial life. Sorry lads !!!
For all you sceptics - Just because we can't see it at the moment, and just because it has not come to us as per yet, does not necessarily mean it is not there.
For decades now people have speculated about how likely or unlikely it is that other life outside earth's biosphere exists; tools like the Drake Equation have given us some interesting models to work with, but no answers. The problem seems to be that we simply do not have the necessary scientific knowledge to give accurate probability predictions for some of the variables in the Drake Equation - e.g. : one of the variables within that equation represents the likelyhood of planets that can potentially harbour life to go on and actually bring forth some form of life. We do not currently know the exact mechanisms that need to be present to evolve life on a newly formed, habitable planet, therefore it is not possible for us to accurately estimate the value of this variable.
What comes out at the end of the Drake Equation is the number of extraterrestrial civilizations with which we might potentially enter into some form of communication, using our technological capabilities ( this would mostly be optical or electromagnetic means ). I seem to remember having read somewhere that, using input data that would conform to our current understanding of the universe and its workings, the equation yields a number of about 2 or 3; so that would mean that there are 2 or 3 civilizations out there with whom we could potentially establish communication.
So, some of you will immediately say, where are they ?? As far as we know, no alien signals have been detected so far. Does that mean we are alone after all ?
Hm, I think there are several problems with that reasoning. First and foremost the Drake Equation is a relation of probabilities, and not of scientifically measurable quantities; it does not produce results that are scientifically testable per se, and was never intended to do so.
Next, this models attempts to make a statement about the number of contactable civilizations, and not about life in general. For me it is entirely conceivable that there is indeed not a single contactable civilization within - say - our galaxy, yet the place might nonetheless be teeming with life. The can happen for a variety of reasons, for example :
- Life somewhere else might not have evolved to become intelligent
- Life may be highly intelligent, yet not able to communicate with us; they may have focused their intelligence on other areas, e.g. spiritual or mental development
- There is intelligent life, but they do not wish to communicate, or actively avoid detection
- A civilization may actively communicate, but by means that is very hard to detect or even undetectable by our own technology ( e.g. gravitational waves ? )
- Communication by some other civilization might already be in progress, and in principle detectable, but the mode or contents of the transmission might be so unusual/foreign that we simply do not recognize it as originating from an intelligent source
- The attempts at communication by another civilization may not have coincided with the period of time during which we have been listening ( i.e. the last couple of decades ). Signals could have gotten here 10,000 years ago, and lasted for a few centuries, but no one on earth would have listened or answered. Likewise, the signal might not yet have gotten to us, and might start tomorrow !
Other reasons and circumstances can easily be thought of. There are also a number of tacit assumptions worked into this model; let me give as an example that Drake assumed that all intelligent life actually does communicate, be it among members of its own species or as an attempt to contact other civilizations. It is in my mind entirely possible - though not necessarily very likely - that there exist civilizations within which the individuals do not communicate or interact at all ( and therefore entirely lack these capabilities ), yet each individual might be highly intelligent. Such a civilization would be hard to detect for us.
At the end of the day, it all boils down to the following : the absence of intelligent life means that no signals can be detected by us; however, the absence of detectable signals does not necessarily mean that there is no intelligent life out there ( it just makes it less likely ). The only way to rigorously establish the fact that we are not alone will be the discovery of hard evidence of the existence of extraterrestrial life ( i.e. communication, an artifact, or actual physical contact with a foreign life form ); given the sheer size of our universe as a whole it will however never be possible to conclusively determine that there is no one else out there, as we will not ever be able to visit every habitable place in this vast cosmos.
I personally believe that it is highly unlikely, though not impossible, that we are the only sentient, intelligent and/or conscious life form in this universe. The mere idea of us being utterly alone among billions upon billions of light years of mostly dark, cold and empty space utterly terrifies me, and even with our current limited understanding of the workings of the universe I would say that the probability of that being the case pales into insignificance given the sheer scale of everything. It is, however, conceivable that it might yet take a very long time before we stumble upon signs of another intelligence, provided humankind lives long enough to see that day at all.
Time only can tell.
First of all the hard facts :
For all you UFO fanatics - once all is said and done there is still absolutely no hard physical evidence in the public domain for the existence of any form of extraterrestrial life. Sorry lads !!!
For all you sceptics - Just because we can't see it at the moment, and just because it has not come to us as per yet, does not necessarily mean it is not there.
For decades now people have speculated about how likely or unlikely it is that other life outside earth's biosphere exists; tools like the Drake Equation have given us some interesting models to work with, but no answers. The problem seems to be that we simply do not have the necessary scientific knowledge to give accurate probability predictions for some of the variables in the Drake Equation - e.g. : one of the variables within that equation represents the likelyhood of planets that can potentially harbour life to go on and actually bring forth some form of life. We do not currently know the exact mechanisms that need to be present to evolve life on a newly formed, habitable planet, therefore it is not possible for us to accurately estimate the value of this variable.
What comes out at the end of the Drake Equation is the number of extraterrestrial civilizations with which we might potentially enter into some form of communication, using our technological capabilities ( this would mostly be optical or electromagnetic means ). I seem to remember having read somewhere that, using input data that would conform to our current understanding of the universe and its workings, the equation yields a number of about 2 or 3; so that would mean that there are 2 or 3 civilizations out there with whom we could potentially establish communication.
So, some of you will immediately say, where are they ?? As far as we know, no alien signals have been detected so far. Does that mean we are alone after all ?
Hm, I think there are several problems with that reasoning. First and foremost the Drake Equation is a relation of probabilities, and not of scientifically measurable quantities; it does not produce results that are scientifically testable per se, and was never intended to do so.
Next, this models attempts to make a statement about the number of contactable civilizations, and not about life in general. For me it is entirely conceivable that there is indeed not a single contactable civilization within - say - our galaxy, yet the place might nonetheless be teeming with life. The can happen for a variety of reasons, for example :
- Life somewhere else might not have evolved to become intelligent
- Life may be highly intelligent, yet not able to communicate with us; they may have focused their intelligence on other areas, e.g. spiritual or mental development
- There is intelligent life, but they do not wish to communicate, or actively avoid detection
- A civilization may actively communicate, but by means that is very hard to detect or even undetectable by our own technology ( e.g. gravitational waves ? )
- Communication by some other civilization might already be in progress, and in principle detectable, but the mode or contents of the transmission might be so unusual/foreign that we simply do not recognize it as originating from an intelligent source
- The attempts at communication by another civilization may not have coincided with the period of time during which we have been listening ( i.e. the last couple of decades ). Signals could have gotten here 10,000 years ago, and lasted for a few centuries, but no one on earth would have listened or answered. Likewise, the signal might not yet have gotten to us, and might start tomorrow !
Other reasons and circumstances can easily be thought of. There are also a number of tacit assumptions worked into this model; let me give as an example that Drake assumed that all intelligent life actually does communicate, be it among members of its own species or as an attempt to contact other civilizations. It is in my mind entirely possible - though not necessarily very likely - that there exist civilizations within which the individuals do not communicate or interact at all ( and therefore entirely lack these capabilities ), yet each individual might be highly intelligent. Such a civilization would be hard to detect for us.
At the end of the day, it all boils down to the following : the absence of intelligent life means that no signals can be detected by us; however, the absence of detectable signals does not necessarily mean that there is no intelligent life out there ( it just makes it less likely ). The only way to rigorously establish the fact that we are not alone will be the discovery of hard evidence of the existence of extraterrestrial life ( i.e. communication, an artifact, or actual physical contact with a foreign life form ); given the sheer size of our universe as a whole it will however never be possible to conclusively determine that there is no one else out there, as we will not ever be able to visit every habitable place in this vast cosmos.
I personally believe that it is highly unlikely, though not impossible, that we are the only sentient, intelligent and/or conscious life form in this universe. The mere idea of us being utterly alone among billions upon billions of light years of mostly dark, cold and empty space utterly terrifies me, and even with our current limited understanding of the workings of the universe I would say that the probability of that being the case pales into insignificance given the sheer scale of everything. It is, however, conceivable that it might yet take a very long time before we stumble upon signs of another intelligence, provided humankind lives long enough to see that day at all.
Time only can tell.
