Are we alone in the universe? Maybe so.........

No I wasn't joking stuh505. They really are stars I can see with my eyes. Have you ever tried looking at the dark night sky? Those little pinpricks of light aren't holes in the firmament, they are (mostly) stars that give off electromagnetic radiation of various frequencies, some of it visible to the human eye. And you know we can learn a lot by examining this light with various sophisticated instruments. Spectroscopic analysis and comparison of the relative shift in elemental absorption frequencies can tell us how fast other bodies are receding from us. And similar analysis can tell us what the stars are made of. Things today are a bit more sophisticated than just looking with a large telescope for signs of life. [For instance we might be able to use the gravitational lens effect generated by large masses to see much further into the Universe than was hitherto thought possible]

Re: Are we alone in the universe? Maybe so.........



I submit that it is possible if not probably that in order to obtain a remotely similar evolutionary path we do not need to so exactly duplicate our planet as much as duplicating very similar conditions. Had a meteor not wiped out the dinosaurs we may have still eventually evolved into what we are now. Since our solar systems 9 planets have moons it is likely that many planets in our known universe have a moon but having a bigger or smaller moon or two moons would not negate the possibility that we would still have evolved as we are. I agree that the more similarities between two planets the more likelihood of there being a similar evolutionary path but I don't see it in my head as to why it is not just as likely to assume that humanoid based evolution may not be the norm and not the exceptions.

Lets pick a rough number of the 70 septillion stars in the known universe that there are 250,000 planets very similar to earth out of the possible 1 million that support habitable life. Taking out of your question (and I do apologize if it was important to the point) the requirement that this has to be now and not 500,000 years ago or 2 million years from now, I would submit that most habitable planets would produce a dominant intelligent species able to harness electricity, build magnificent structures, machines, and vehicles. etc. etc. and control the destiny of all other living creatures on each of their planets.
So if most habitable planets produce an intelligent dominant species it is not unlikely to assume they would walk upright, have 2 arms, 2 eyes, 2 ears etc. That may make them humanoid in a vague sense of the word but I think you were looking for aliens that could mate with a human from this planet and produce a human offspring. So of 250,000 possible planets that may be like Earth if we became dominant and we are what we are then I don't see why it is so far fetched to assume that most of those planets would not produce beings very similar to ourselves.

I submit that we evolved into what we are because we obtained early in our evolutionary process the ability to become dexterous with our hands. Having opposable thumbs and being able to grasp a stick or a bone and hold it both parallel and perpendicular to our forearm allowed us to use this as a tool. Using tools was the catalyst that sparked our path towards intelligence. The more we used tools the more we evolved and began to create better tools and then began to use language and as we used language our intelligence grew even faster. There is no reason in my mind not to assume that on any habitable planet during the course of each species evolution there would not be a creature who started using tools and developed language and evolved into the dominant intelligent species. How many of those were primates, I can't fathom but my instinct leads me to believe that more of them were primates then were not .

Nice post, nipok. A couple of points:

As I recall my college biology, early Earth had an ocean that was populated by 3 groups: arthropods, or insects; mollusks, sponges and other invertebrates; and vertebrates, or that marine life which possessed spines and ribs.

Although the insects were dominate for awhile, it was the vertabrates that eventually grew to the size to be most-dominate on the planet.

As for other 'earths', I would say that these 3 types might be common in a planet's early ecology. IF[/u] vertabrates became dominate, I agree that primates might be once again the species to eventually attain intelligence.

But how little change might be required for a drastic change in anatomy and chemistry? If there is no moon, hence no tides, would 3 main types of life evolve in ocean waters? A small thing like minerals in the water could cause a massive difference, I think...

I am not arguing that there are habitable worlds with dominant intelligent species able to build machines, understand quantum mechanics, harness electricity, travel into space that did not evolve from primates. Who knows, it is possible there are an infinite number of different types. And yes I agree that the number of variables that come into play that made us what we are astronomical. But when you take into account the number of stars in the universe and try to guesstimate the number of habitable planets you end up with a huge likely number of habitable planets inside our own little space-time continuum. If our pocket of space time is just a drop in the bucket of an infinite number of similar space time pockets then the number of habitable planets could be infinite (but this thread is not the place for that discussion). I just think it is illogical to assume that our human form is unique in our little speck of dust we call our universe. It would seem to me to be much more logical that even if primate to humanoid evolution is not the norm as I feel it is, then it still must account for some percentage of the other habitable planets out there. It just does not make sense to think that our evolutionary path was so unique that it is impossible to have been duplicated on other planets.

there was an article i read recently where some scientists stated that if seti didn't discover any extraterrestrial signals in the next twenty years they would conclude that we are currently alone....

doesn't seem far-fetched to me....

the nearest star other than our sun is 4.3 light-years away.....even if we ever reach that star we will never leave the milky way galaxy....in my opinion anyway.....

it would take 110,000 light years to cross our galaxy from end to end....

am i right to believe that organic matter can not survive even a fraction of light speed???

even if wormholes exist, what reason do we have to think that organic matter could survive a trip through one....

so....have aliens visited our planet???? in my opinion, not a chance.....i personally don't think they exist at all....

If there isn't a grand intelligence altering natural selection....

Then one can expect life to develop in the right circumstances - but its very tricky and you need alot of factors very finely tuned to achieve this. Previous posts on this subject 8 months ago covered this very well.

Intelligent life is alot harder, but can evolve by the same process. An entity that is aware of itself and the Universe and can think, plan and organise for a better future.

Now the thinking goes even if the chances are remote - the Universe is so big the circumstances could be right and the coin flip falls the right way somewhere else, sometime else.

I will offer a few thoughts on this.

1. The chances for intelligent life seem to be far smaller than the lay person expects

2. The natural lifespan for all but the most advanced civilisations may well be tied to how long their Sun lasts, which is not forever

3. The Universe is so big its 60% + casully disconnect under relativity - draw a hubble sphere 13.8 billion light years around where you stand and that's the maximum you can see or be affected by the Universe today. That sphere is a small fraction of the Universe current size due to inflation - its probably less than a 1/6 of the existing Universe.

4. The chances for intelligent life are modelled by scientists to be ridiculously low like 1 : 10 ^ 20,000 against, so the chance it occurs in our civilisation's lifespan, within our Hubble Sphere, and close enough to be observed since modern man existed is much smaller than the odds above.

5. Personally I'd imagine a modern Sun must be at least half way through its life cycles - say 5 - 6 billion years old, before it might have a planetary system capable of supporting life. For life to germinate add 1-2 billion years, possibly double or half for intelligent life. So that leaves 1-4 billion years to do your stuff before the lights go out. In Galactic terms that is not very long.

I missed the thread from 8 months ago, as I did not find this amazing forum until recently. Very interesting topic here.

Re your statement about a planets sun:

Would a hotter/longer living sun allow life to develop over a longer period of time? A planet would obviously have to be further away from its sun as Earth is from our sun if the planet was to have liquid water (or closer if the sun was smaller); what if instead of only 1-4 billion years to develop life, it actually had 5-8 billion, as some suns do? Might the odds go up a bit?

What I find most interesting is the potential a long-lived civilization might have; we have a few decades of technology under our belt; what would we have with 1-4 billion years? It boggles the mind......

Isn't there a current theory about stages of a civilization? I recall that it has something like 4 phases, with the second phase characterized by a society able to control its planets energy, third the Sun's, 4th.... I can't recall the whole thing, if somebody could help out?.....

All this, and alot more is contained in the thread I started 6 months ago asking - Why is the Universe so Big? (which grew to 23 pages)

http://www.able2know.com/forums/viewtopic.php?t=20276

Pages 5, 7 and 13 of that thread very clearly answer you questions (Type I, II or III civilisations, chances of life and 33 preconditions needed to support life, athromorphic (strong/weak) principle, colour of the Universe etc everything!

Some shortcuts to good links within it

http://www.konkyo.org/english/seti.html
Does life exist on any other planet in the universe? Another look at SETI

http://www.aish.com/spirituality/philosophy/The_Design_Argument.asp
Does the intricate design of the universe serve as evidence for the existence of God?

Of my over 10,000 posts over the internet - the above thread is IMHO one of my 5 best!

Somehow I lost track of this thread last year before I had a chance to reply; good stuff!

The SETI link you provided was excellent. It certainly addresses the main questions I had.....