Given that essentialy every star we look at has planets or will do you thin we are alone at leas within 500 light years? 

Tough question, it has been said so many times, that given what we know now about the size of our Universe, to assume that we are the only life in the Universe to me is just downright arrogant.

The Drake equation has been brought up by others using very small values for our Galaxy alone, and  yet it still yields some astonishing results, even though there are to many unknowns to properly input the values, to me it still has me wondering.

Quite a few people bring up Fermi's Paradox, http://en.wikipedia.org/wiki/Fermi_paradox

 Microscopic life, I would have to say yes, probably either in the past or present, intelligent life within our own Galaxy, probably not, but who is to say for sure?

I find it hard to believe that given the shear numbers of visible Galaxies that life has not evolved elsewhere at some point in time. its one of the biggest questions that Astronomy is trying to answer.

May I ask, why did you limit your radius to only 500 light years?

Dennis

 

 

 

 

spacedoc:

Given that essentialy every star we look at has planets or will do ...

Where did  you get that idea? It's hardly a given.

It may be true that many stars have planetary systems. We have observational evidence of a couple hundred exoplanets, at present.

While it's still only conjecture, it may turn out to be true that most stars form in a manner which would be conducive to forming planets, or at least planet-like bodies, as well.

But we don't know that.

Your ultimate question is not one we can answer scientifically just yet, other than to say the answer is non-zero (us). However, since we now know there are not just a few exoplanets, but many of them, the odds are getting better all the time ...

As Carl Sagan famously said, if there are no other forms of life in the Universe, then it's an awful waste of space. Space, he also said, is a mighty big place ... so I feel the probability is pretty good there is life of some sort out there.

"There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy.." The very definition of "life" may also be at issue. There might be things so far our of our paradigm of human existence that we simply can't imagine what they are, much less define them. I kind of take it as a given that there's "life" of some form out there, but don't think we'll ever do more than wonder at it. Can they visit earth? Do they look suspiciously like people and are they visiting and snatching rednecks up on their way back from Domino's pizza, then taking them to a garden of Freudian tortures involving situations suspiciously reminiscent of one's inner fears of the doctor/dentist? Highly unlikely IMHO. Always thought it was interesting how "aliens" today function the same way that demons, devils, witches, and other supernatural phenomena functioned in previous era. (Abduction, molestation, bizarre experimentation...the occasional benevolent transcendence...) This points, to me, to an inherently human issue/delusional experience, seen through the lens of one's culture, although your hardcore UFO types obviously think that it proves aliens have always been here and their nature has been simply misunderstood throughout history. (Read "The Gernsback Continuum" by William Gibson in Burning Chrome for a fun story on the same...)

spacedoc:

Given that essentialy every star we look at has planets or will do you thin we are alone at leas within 500 light years? 

Welcome to the discussion group, spacedoc.

 

Yes, and that’s not arrogance as Star Dragon implies.  I’ve given my reasoning countless times in numerous threads already started on this message board regarding this same topic.  The optimistic fudge factors plugged into the Drake Equation by Drake himself reflect his own hopes and wishes.  My estimates and those of many others reduce the result to virtually zero in this galaxy; although of course it has to be at least one.  Sagan’s waste of space comment is clever but odd.  It’s implies a purpose for the universe based on the motivations of a life form or perhaps even a creator.  Sagan was not a creationist; he was an evolutionist, atheist and generally a skeptic except for this pet issue of his.  In any event, I’ve grown quite weary of this matter and won’t say anymore in this new thread.

 

If the Universe Is Teeming with Aliens... Where Is Everybody? Fifty Solutions to Fermi's Paradox and the Problem of Extraterrestrial Life

http://www.amazon.com/exec/obidos/ASIN/0387955011/crastro-20

 

Extraterrestrials: Where Are They?

http://www.amazon.com/exec/obidos/ASIN/0521443350/crastro-20

 

 

I am coming to believe that the only life in the universe is right here on earth.  There is nothing arrogant about thinking that if there is a Creator and He set it up that way.  And if that Creator is a loving one, we are certainly not alone. 

Astronomy http://jimcolyer.com/papers/entry?id=2

 I certainly hope so! We have enough troubles here on Earth that we can't seem to resolve, never mind some nasty ETs visiting. If they are friendly, I'm sure them seeing what a mess we made of this Earth will for sure send them packing with no forwarding address

 Oh NO - a green humanoid is knocking at my door. Could it be....?

 

  All's O.K.. It was only a man in black. He wants to take me for a ride in his vintage black Olds. I'll be back later, I hope
 

 

Yes, and that’s not arrogance as Star Dragon implies.  I’ve given my reasoning countless times in numerous threads already started on this message board regarding this same topic.  The optimistic fudge factors plugged into the Drake Equation by Drake himself reflect his own hopes and wishes.  My estimates and those of many others reduce the result to virtually zero in this galaxy; although of course it has to be at least one.  Sagan’s waste of space comment is clever but odd.  It’s implies a purpose for the universe based on the motivations of a life form or perhaps even a creator.  Sagan was not a creationist; he was an evolutionist, atheist and generally a skeptic except for this pet issue of his.  In any event, I’ve grown quite weary of this matter and won’t say anymore in this new thread.

 

I'm in complete agreement with Curt on this issue.  While there is likely a good chance of microbial and perhaps even more complicated life elsewhere in the galaxy, that certainly does not necessarily mean that there are other technologically advanced civilizations currently in existence.  There is no consensus among biologists that evolution operates towards a "goal" of producing intelligent beings, let alone ones capable of high technology. 

 

http://en.wikipedia.org/wiki/Drake_equation (see Current estimates of the parameters)

 

Sagan's comment always puzzled me somewhat given his extraordinary claims require extraordinary proof frame of mind.

 

Dave Mitsky 

  I just finished Poundstone's bio of Sagan.  He was a very complicated perosn.  He was extremely intelligent, and refused to be pigeonholed--a common mark of high IQ.  In his private moments, he was as giddy as a school(boy) regarding ETI.

  When he and Drake went down to Arecibo for the first listening session of SETI with the dish aimed at Andromeda, he was dispondent when they didn't pick up any signal-- after a few hours!!  He was that sure that the galaxy was teeming with ETI and beaming messages!  What a woo, eh!?

   He was concerned during the Viking mission that macrobiological entities would be missed by the slow scanning cameras onboard.  He believed that small/medium sized creatures could approach the lander and flee without ever being seen.  So, he argued, they should check for tracks on the ground!!!  This was 1976.  Woo woo! 

  On the other hand, he dismissed UFO believers as crazy because travel at interstellar speeds was impossible, but spent a large protion of his adult lifetime investigating and promoting research and design of interstellar spacecraft!

  What was good for the goose wasn't good for gander...  Scientists out of the media limelight are as human as the rest of us...

  Life is a complicated affair.  Sagan contributed much to understanding planetary atmospheres, promoting robtic exploration, and basically creating the field of astrobiology.  He worked with Urey and other seminal researchers.   Of course, 'Cosmos' did more to promote science funding and education than an arena full of creaking windbag researchers, yet he was not so subtly vilified for it by his jealous and SNOBBY, less talented peers.

  He promoted progressive politics and nuclear arms control.  His ideas concerning nuclear winter in the 1980s-1990s influenced climate studies today.

  All in all, if we could all be as skeptical, energetic, creative, and yet curious as Sagan, and as precise in our communication, what a wonderful world it would be!

Hi - I am new to this message board and apologies if I am repeating things that have been hashed out ad-infinitum already.

However, the Phoenix mission has gotten me thinking about this quite a bit.  I am beginning to think that the "follow the water" approach is highly unlikely to result in finding any signs of life elsewhere in the solar system.  The reason for this feeling is based entirely on armchair science, and I welcome corrections from more knowledgeable posters. 

The "follow the water" approach seems to be based on the observation that life is teeming in a watery environment on earth and so if we can find similar situations elsewhere, whether in the past on Mars or the present at the bottom of an ocean on Europa, the chances are decent that we will find signs of life.

However, if one considers earth, where the conditions for the formation of life are believed to be pristine - and have been probably for the past two billion years or so - it is impossible to point to the generation of any "new" life.  If it is so (relatively) easy for life to appear on earth, why haven't we seen any evidence of new organisms?  I suppose there are several potential answers to this: Firstly, the current belief that all living organisms come from a common ancestor several billion years ago may be incorrect.  This would allow us to infer that several strains of independently generated life resulted in the broad diversity of life on earth.  Secondly, the current form of life on Earth might be superior from an evolutionary standpoint and might have "choked out" competitors who have left no record of their existence on earth.

At any rate, the absence of evidence for the continuous generation of new life on earth leads me to conclude that the figures plugged into, say, the Drake Equation are far too optimistic about the possibility that life will start given the right environment.  I believe the current figure for this is a 13% chance.  It seems to me that it might really be much, much lower.

Of course, the potential for life to form in what we would consider a hostile environment is certainly not affected by this.  The problem with the "follow the water" approach is that it might lead us to overlook these other environments.

 As I said, I would welcome corrections to this, because I honestly find it depressing.

 Regards

  I think you are misreading the evidence and Darwinian evolution.  Do you think new species jump out of momma's womb?  New species are in the process of evolving even as we speak!  this process takes hudreds to millions of years, and is incremental.  In fact, given the recent spike in selection pressure for many species, I would argue that differentiation is actually speeding up right now.  Changes on this sort of time scale are difficult to register.

  If physics is essentially the same all over the universe-and we assume it is-- then "follow the water" is a very safe and logical first great step into the exploration of astrobiology.  We can expand and refine our ideas as we learn. 

   Give it time.

 

   Lots and lots of time!!

  I would suggest reading Rare Earth (Brownlee and Ward), and Intelligent Life in the Universe (Ulmshlaeger?? Spelling...) as well as any intro textbook on astrobiology and a book on established evolutionary theory. 

  These should answer many of your questions, and enrich your understanding of NASA's aims...