Of course I would accept it.DROBNJAK said:Basically, you would not accept existence of UFOs even in the case you had seen one?
fp = fraction of stars with planets around them:5%
Basically, you would not accept existence of UFOs even in the case you had seen one?
VooDooX said:5%?! you right i would assume almost EVERY star has planets since there all formed the same way or most of them are anyways from what i observe here with 1 star with 8 planets and 1000's of asteroids and maybe millions of objects in the ort cloud and the Kuiper belt honestly do you believe all but 5 % of stars have nothign around them...
mikelepore said:Many parts of the galaxy have almost no metal atoms, therefore stars in those regions can have only gas planets, no solid surfaces. (Ward and Brownlee, _Rare Earth_, paperback, 2004, page 29)
Nope.Pattonias said:wouldn't the distribution of heavy elements be fairly uniform, or present wherever there are stars.
DaveC426913 said:Nope.
There are different generations of stars. Ours is a Population I type star. Older stars are Population II and are metal poor. But really old stars were the first stars made, when there were no metals to be had. They are almost entirely H and He. These are Population III stars.
http://en.wikipedia.org/wiki/Metallicity#Population_I_stars
Actually, we don't. If you read the article I linked to, you will see that Pop III stars are thought to exist near the centres of galaxies, generally obscured from view.WhoWee said:I find it amusing that we can be so certain on this point
Count Iblis said:I think intelligent lifeforms will last only for a short period in a biological form. Organisms with a large enough brain to develop a civilization will very soon develop intelligent machines. These machines will then take over control of the planet.
Why? It just a technical feat.mathman44 said:Interesting opinion but I doubt that we will ever make machines as clever as ourselves,
mathman44 said:and if we somehow do, I would assume that we would also be smart enough to make them controllable.
DaveC426913 said:What makes you think we could control them? (OK, I guess your first statement answers that. If you think we won't ever make machines as clever as ourselves, then it's not hard to keep control of them.)
No, it's simply a tangent about the longevity of hypothetical alien races, spawned by Count Iblis in https://www.physicsforums.com/showpost.php?p=2452118&postcount=896".baywax said:Is this all getting at some kind of speculative attempt to prove that alien machines have visited earth?
DaveC426913 said:No, it's simply a tangent about the longevity of hypothetical alien races, spawned by Count Iblis in https://www.physicsforums.com/showpost.php?p=2452118&postcount=896".
DROBNJAK said:I would tend to agree. Understanding nature on the level of quantum mechanics and theory of relativity is definitely mold braking point in terms of maturity of knowledge. Economic forces definitely favor globalization, so on the scale of next 100 to 300 years, there is to be more integration between the nations, rather than less. Most likely to the point where nations become irrelevant.
Interstellar travel needs a push from global economy, no nation will be ever rich enough to do it on its own.
N468989 said:we are visitors... simple as that.
Schrodinger's Dog said:Prove it?
N468989 said:I can only imagine, life itself most certainly formed on earth, due to our conditions in which we survive, but by what means can we prove that we are not from somewhere else. It's like someone lives in country XYZ, and was born in ABC, does it mean that, where they live now is where they have always been?
You say "Prove A" and i say "Prove !A".
We cannot prove that, since there isn't proof yet or may never be, maybe the absence of proof is proof itself!
We can't find the missing link.
Schrodinger's Dog said:Why?
Isn't that just a strong anthropic principle? And thus begging the question endlessly.
N468989 said:We can only imagine it's that way, due to our limited understanding of our being. We might be capable of understanding someday, but not today. What we know as valid today, tomorrow can be invalid. Didn't we believe the sun circled the earth?
Proof is there but we haven't been looking hard enough.
Is there life in the universe? Yes, we are part of the universe, so there is life!
Has it visited earth? Without proof, the answer in our living days is no...now its a matter of "to believe or not to believe".
Schrodinger's Dog said:How do you induct that?
How do you know we aren't alone?
N468989 said:To fully understand if we are, or not alone, we must first define what we understand by alone.
Beforehand, we must understand who we are, what is our meaning of existence (if there is such), and what is our purpose.
We can't find the missing link.
N468989 said:To fully understand if we are, or not alone, we must first define what we understand by alone.
Beforehand, we must understand who we are, what is our meaning of existence (if there is such), and what is our purpose.
DaveC426913 said:Why?
"Just as the pigment chlorophyll converts sunlight into chemical energy that allows green plants to live and grow, our research suggests that melanin can use a different portion of the electromagnetic spectrum - ionizing radiation - to benefit the fungi containing it," said co-researcher Ekaterina Dadachova.
Investigating further, the researchers measured the electron spin resonance signal after melanin was exposed to ionizing radiation and found that radiation interacts with melanin to alter its electron structure. This, they believe, is an essential step for capturing radiation and converting it into a different form of energy to make food.