Extraterrestrial life

[12th Doctor]

I'm certain there are probably thousands, if not hundreds of thousands of planets in our galaxy that support life forms.  Of those, probably at least 10,000 support intellegent life forms and of those, probably at least half have reached roughly our plain of development with perhaps a few hundred or so being more advanced.

There was a guy who acctually wrote an equation to figure out how many intellegent spicies do exist.  Can't really remember much about it.

Anyway, I don't believe in Alien Abductions, at least not at nearly the frequency that are being reported.  While I think that they might have visited Earth, I do not think they are part of any "secret plots" or anything involving the government or Area 51.

[12th Doctor]

If the second is true, it is my belief that life is such an astounding
accident, requiring such perfect arrangements of chemicals to arise
under such perfect environmental circumstances, that there is no other
life anywhere else, let alone life intelligent enough to travel across
the vast expanse of space to visit us.

Perhaps not. The number of stars in the universe, and the number of planets, is astonishingly enormous.

The Drake equation, with even somewhat conservative estimates, would yield a relatively large number of planets with intelligent life, and an even larger number of planets on which life arose. Drake himself estimates 10,000 intelligent civilizations.

Yes, the Drake equation.  That is it.

[12th Doctor]

Drake fails to take into account the mind-boggling complexity of even the simplest possible lifeforms.  In order for a cell to form from lifeless matter, a process would have to take place akin to a tornado striking the junkyard outside of a Boeing factory and accidentally assembling a functional 747.

Not true at all.  We have good evidence that single celled lifeforms once existed on Mars, and we may soon discover that they, or even slightly more complex forms, still live on the moons of Saturn.

If Earth has taught us anything it is that life is highly adaptable and can form to fit many environments and functions.  Now, I do believe that we had some help in that, but I also have a hard time believing that God created all that crap that we call the Universe and never bothered to fill it with anything else.

[12th Doctor]

not in this galaxy.

Scientists estimate that it would take between 5 and 50 million years for a race to colonize the entire galaxy.  And we've yet to be colonized, and our sun is a relatively new star.  Therefore it's highly improbable that a very advanced civilization has arisen in our galaxy, unless they're long gone.

Not nessesarily.  Maybe they have a Prime Directive.    Or maybe they have other reasons for not coming here.  Scientists estimated that we would go to Mars by the 1980's.  And, I'm still waiting for my flying car and Fusion powered cities.  Maybe they have just developed differently from us.  Perhaps they are more introverted and prefer to stay in their own system.  Maybe some of their planets have been ripped apart by war.  Maybe they are so peaceful and docile that they advance much slower than we do.  Maybe other civilizations have clashed when they have met and are to preoccupied with that to visit our planet.  Remember, in galactic terms, our system is fairly remote.  Not only that, but a species managing to stay around and thrive for even 10 million years is a little unreasonable, let alone 50 million.

Or, maybe they visited here, once, a long time ago and saw a semi-intellegent spiecies developing, and either decided not to screw with the development of the planet, or simply weren't interested in this place, so they packed up and left.

[12th Doctor]

Drake fails to take into account the mind-boggling complexity of even the simplest possible lifeforms.  In order for a cell to form from lifeless matter, a process would have to take place akin to a tornado striking the junkyard outside of a Boeing factory and accidentally assembling a functional 747.

Not true at all.  We have good evidence that single celled lifeforms once existed on Mars, and we may soon discover that they, or even slightly more complex forms, still live on the moons of Saturn.

If Earth has taught us anything it is that life is highly adaptable and can form to fit many environments and functions.  Now, I do believe that we had some help in that, but I also have a hard time believing that God created all that crap that we call the Universe and never bothered to fill it with anything else.

I agree with Super, but let's factor God out for a moment.  It looks as if at one point something was alive on Mars.  We think that on one of Jupiter's moons, there might be water and possibly something alive, on a cellular level. 

Now, there are several reasons why we wouldn't see them.

1.  We are fairly close to the edge of the galaxy.   Even if we were closer to the center, half the galaxy is on the other side; most of civilizations might be over there.  We may not be on a trade route.  Further, perhaps the only reason they would seek us out is for raw material,  Any species capable of transversing space may have easier was of getting raw materials.

2.  We're looking for the alien equivilents of I Love Lucy, broadcasts.  This period might only last for about a century and a half of a technological culture.  Even today, we are increasingly using technologies that aren't broadcast, like satellite television.  In 50 years, there may be no more "accidental"  broadcasts coming from Earth.

Assume that a culture about 100 light years from here reached this point 200 years ago.  We might have gotten broadcast 100 years ago, but we were not looking.

3.  Third, is distance.  Assume that a planent is advaning at the same rate as the earth  We won't be getting their I Love Lucy] for another 50 years

All very true.  As we have both said, our solar system is probably one of the more remote in the galaxy, and thus we probably are not "in the line of fire" for much that would give clear signs of other intellegent life.

[12th Doctor]

not in this galaxy.

Scientists estimate that it would take between 5 and 50 million years for a race to colonize the entire galaxy.  And we've yet to be colonized, and our sun is a relatively new star.  Therefore it's highly improbable that a very advanced civilization has arisen in our galaxy, unless they're long gone.

Not nessesarily.  Maybe they have a Prime Directive.    Or maybe they have other reasons for not coming here.  Scientists estimated that we would go to Mars by the 1980's.  And, I'm still waiting for my flying car and Fusion powered cities.  Maybe they have just developed differently from us.  Perhaps they are more introverted and prefer to stay in their own system.  Maybe some of their planets have been ripped apart by war.  Maybe they are so peaceful and docile that they advance much slower than we do.  Maybe other civilizations have clashed when they have met and are to preoccupied with that to visit our planet.  Remember, in galactic terms, our system is fairly remote.  Not only that, but a species managing to stay around and thrive for even 10 million years is a little unreasonable, let alone 50 million.

Or, maybe they visited here, once, a long time ago and saw a semi-intellegent spiecies developing, and either decided not to screw with the development of the planet, or simply weren't interested in this place, so they packed up and left.

What if we were planted here? Much like a farmer plants a seed and sits back and watches it grow.

While I would not embrace such a theory, I suppose it is possible.  Star Trek Already explored that oen though. 

[12th Doctor]

not in this galaxy.

Scientists estimate that it would take between 5 and 50 million years for a race to colonize the entire galaxy.  And we've yet to be colonized, and our sun is a relatively new star.  Therefore it's highly improbable that a very advanced civilization has arisen in our galaxy, unless they're long gone.

I've got to disagree with the idea that an alien race would be interested in colonization.  Building out of system colonies is expensive (in terms of resources) and probably difficult to govern (or control). 

Assume that Galatic Emperor Sloob IV has an empire with 100,000,000,000 Gorfs; also assume that Gorfs are cabon based lifeforms that need air food and water.  If they are capable of interstellar flight, they are capable of doing many things.  They can build stations, settle other planets in their system, "terraforming" them.

They fill their own system up and decide to colonize.  They have a choice:  Planets in a 20 light year radius or earth 100 light years away.

There are probably a lot of planets within a 50 light year radius.  It will be expensive to colonize, because of terraforming, but its still work it.  Maybe there are one or two that are pretty much like Gorfia and don't need much work.

Sloob the Tyrant looks at the situation.  It's going to cost more to send people to Earth, 150 light years away, and ship supplies to it.  It's going to be harder to defend it, if the H'Dok'ofs start trouble (again), that it will be that nice one 5 light years away.  Further, if they revolt, it's going to be easier to supress the planet five light years away than 150 light years away.  He (or She or It) looks at the situation and decides, "Ah, we'll keep it close to Homeworld."

They may be able to keep 20 Billion in their own system, including other planets, space stations, moons, and move the rest into the ten or twelve systems closer to Gorfica.

There probably isn't anyone else within a 35 light year radius.

I agree, mostly, with what you have to say, but I have to say the number of people one could resonable expect to hold in the average inhabitable system should be more than you have supposed.  Using our technology and our system as a model (which is flawed, I know) we should be able to postulate that the average system might have 6-12 planets, of which, 2-5 are large gas giants (from what we can tell now the average system seems to have two) and 1-4 are in the habitable range (We have three, but thanks to Venus' atmoshpere, it posses a serious challenge to even the most advanced terraforming technology that we can concieve of at this point) and the others are either too close or too or too far away to be terraformed.  Also, you have moons that might be able to be terraformed, of which our solar system might have one (our own).  This is not to mention colonies that could be formed on every non-gas giant body in our system (including moons around Saturn and Jupiter.  Now, with advanced technology, in food production, sanitation, living space, matierials production, communication, transportation, environmental science and a stable social structure, I don't think it is unreasonable to think that you could fit as many as 20 billion people on an Earth sized planet alone.  In an entire system, it might not be unreasonable to think that as many as 50 billion people could live in our system alone.  Now, if you had a system with, say three Earth sized planets (Venus and Mars our both somewhat smaller than the Earth) or larger that have ecological systems or could be terraformed, and 4 or 5 smaller planets that could be terraformed and a coule of gas giants (life without larger planets in the way to keep large astroids from striking habited planets would be difficult to imagine) then you could perhaps situate as many as 100 million people in the same system.

[12th Doctor]

The Drake equation, with even somewhat conservative estimates, would yield a relatively large number of planets with intelligent life, and an even larger number of planets on which life arose. Drake himself estimates 10,000 intelligent civilizations.

Consider this very long list of criteria that have to be within very tight tolerences in order for intelligent, complex life to exist.  There are now 154 of them:

http://www.reasons.org/resources/apologetics/design_evidences/200406_fine_tuning_for_life_on_earth.shtml

Almost everything on that list is too elementary to warrent discussion, already assumed, not nessesarily so, irrelevant, taken care of by nature and chance (or a Higher Power) or simply too narrow minded a very of how life and advanced civilizations could blosom and flurish.

[12th Doctor]

This chart seems to assume that conditions that exist now in our galaxy, system and planet have always been as they are now.  the fact is, life forms have thrived on this planet when the continental shift was greater, when sunspot patterns were more frequent and more intense, when there was more iron in the oceans, when there was less oxygen in the atmosphere, when there was more nitrogen in the atmosphere, when gravitational poles were different in our solar system.  When certain stars and nebuli(sp) were closer or farther away, when there was less sediment, when the planet was colder, hotter and everywhere in between, when astroids strikes were more frequent, when the environment was more or less acidic... I can do this pretty much all day.  And obviously, other planets and, presumablly, star systems exist inspite of the sometimes hostile conditions of the Universe.