Oh ok. Well that makes sense then.
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Oh ok. Well that makes sense then.
If I am here, in this infinitely huge Universe, why can't there be any other forms of life sitting around as well? You can't say to me there are 10,000,000,000,000,000,000,000 Stars in the universe, But there are only 6,900,000,000 intelligent Lifeforms sitting on 1 star in the entire Universe.
Now whether they can get here, and have been here is an entirely different issue..........
We're on a star? Holy fuck dude....
LOL awesome! :cackle:Quote:
Originally Posted by tommo
You're looking at this too much like a mathematician.Quote:
Originally Posted by Xei
What I'm arguing is that you cannot predict how many factors for life to exist, life could come about with very few factors in place. Life comes about with a temperature range, water and time for all we know.
But he was just saying it could be possible that there are more than just a few factors. Which would lower the probability of life occurring dramatically.Quote:
Originally Posted by Omnis Dei
Not that there actually is more than a few factors.
I've never seen an alien, so I'm not going to assume I know what factors make life and which don't. But I'm falling back on the research I've seen of basic AI models where computers, given no other directive, would still work toward more complex systems (duplication).
Do you think nature really goes by these exact maths though? I'd hesitate to treat the factors for life as completely separate. Maybe the factors are interconnected enough to appear together more often then not, like a certain amount of surface water on a planet suitable for life would more often then not suggest the amount of sunlight or certain kind of atmosphere on a planet suitable for life, then the maths would be a little different I suppose.Quote:
Originally Posted by Xei
But such programs are not modelling the universe in general; they are modelling whichever parts of it can exist as discrete units, carry information, duplicate themselves, and vary. In other words they are modelling natural selection, which requires life to already exist. The probability that such a thing should arise is a major unknown, because it is not known exactly what such a molecule has to be, and it is not known exactly which processes can bring it into existence.
What's the difference between 'a few' and 'a moderate number'? If you know how many conditions there are along with their likelihoods, you know far more than any other scientist in the world.Quote:
Originally Posted by tommo
Yes exactly. The whole thing is far far more complicated. But I'm just highlighting the basic nature of probability and how it can decease quickly.Quote:
Originally Posted by Wayfaerer
That's true.Quote:
Originally Posted by Omnis Dei
This video talks about exactly this. And Xei, i know this video will bore the shit out of you. I've seen a post of you somewhere and it showed me how much you know about the subject i probably don't have to tell you. But just spend a few minutes checking out this video that highly interested me if you want. Lee Cronin: Making matter come alive | Video on TED.com
What the hell are you talking about??Quote:
Originally Posted by Xei
The second bit - Well, yes we do. We know there must be Carbon, Oxygen, Nitrogen, Sulphur, Hydrogen and Phosphorous.
And actually some of those can be swapped around for other chemicals.
For life in the first place to arise, it has been shown that you only need water, methane, ammonia and hydrogen and electricity.
No, that's for amino acids to arise. Amino acids aren't life.
They form life. Therefore are necessary for it afawk.
So when you said that we know how many conditions there are along with their likelihoods, what you actually meant was that we know a few conditions that may or may not be necessary and may or may not be sufficient, and we don't know their probabilities? I'm struggling to see how you disagree with me.
According to the experiment there were actual microscopic living organism arising spontaneously. And even if it was just DNA, having DNA organize spontaneously would still be a big deal.Quote:
Originally Posted by tommo
What's the difference between 'a few' and 'a moderate number'? If you know how many conditions there are along with their likelihoods, you know far more than any other scientist in the world.Quote:
Originally Posted by Xei
You just said that before, and I don't know why. Which is why I said "what the hell are you talking about?"
I never said we know every condition or their likelihood.
All I said regarding the probability is that we know there are many Earth-like planets, we know the likely factors needed, based on observations of Earth only.
I don't know why you thought we disagreed anyway based on that post.
Basically I think there is more life out there, because I don't think life really is very complicated. And there could be more factors we don't know of, but I don't think they'd be very rare factors.
And even if there were more factors than we know already, there are enough planets for those factors to occur together probably 10's of thousands of times.
Yes, it would ruin all of our science probably. Good thing it didn't happen.Quote:
Originally Posted by Tranquil Toad
Well there are more known factors than you listed for a start. I can name others, but a major one is the probability of an RNA molecule forming that is capable of self-catalysis. The probability of this happening is a huge unknown because we have no idea which class of molecules can do this. The minimum could be ten acids long; it could be a hundred. This corresponds to an absolutely colossal difference in the probabilities of life. You really have zero basis for your assertions that we have good reason to suspect there are few factors and their probabilities are low... I'm not asserting anything here, but you seem pretty insistent to conclude that life is common on principle.Quote:
Originally Posted by tommo
There is also the issue of complex life. The discovery of self-replicating systems would be cool, but a much more interesting question is whether or not there are complex aliens out there. For the vast majority of Earth's existence, life was happy to stay simple. It's not known what factors caused the rapid emergence of complexity around 500 million years ago.
Something that can be said about complex aliens with relative certainty however, is that there is no life within our galaxy that is technologically advanced (only a blip beyond our abilities) that wants us to know it exists. This is a sad idea that I've yet to hear any rebuttals to.
Look, this is exactly what I've been arguing about. 'There are so many stars that it must be true' is a qualitative statement, when this is a quantitative issue. The difference between no life and 10,000 instances is life is only a few orders of magnitude, and the whole point of what I'm saying is that it is orders of magnitude (the logarithm) that is pertinent, NOT the absolute value. The difference between 0 and 10,000 is just a handful of factors, and we have absolutely nowhere near enough knowledge to ascertain the probability that accurately. It's the difference between the first life molecule being 50 units long and being 55, and as we have absolutely no clue how long it has to be, your statement is just completely untenable.Quote:
And even if there were more factors than we know already, there are enough planets for those factors to occur together probably 10's of thousands of times.
Xei certainly seems to know what he's talking about here. All discussion based on the probability of life have all come down to the same conclusion, that being we can't know wether or not aliens exist to a 100% certainty. It is interesting to exchange opinions however.
I personally like to believe Aliens do exist. Events in our history scream "Aliens exist!" in my opinion. One example, the pyramids. They couldn't have been built by Egyptians, each stone used in the construction of each colossal structure weigh at least a ton. Their hieroglyphics depict endless amounts of detail about their history and culture, but not one detail concerning the construction of the pyramid. Also within their hieroglyphics, they describe the sky opening up, bright lights or beings descending to earth and giving them wisdom. Some hieroglyphs even look like aliens and UFO's - strange beings with strange apparatuses over there heads, and strange looking vessel-ship-things.
Our existence would be far more exciting (in my opinion) if aliens existed, so to answer this forum post's question, yes I do believe aliens have made contact with earth. Ultimately though, no one will ever know.
I assume the OP is referring to ETI's. So I say definitely not. The nearest stars to us is Proxima Centauria which is 4.22(Ly) away and Alpha Centauri A and B (the close binary companions) which is about 4.36Ly. These particular stars fail to meet the basic fundamental requirements which constitutes the supportive ability for complex life chemistry. Now here lies the problems. First, sentient physical beings requires a habitat which would be Earth-like. One that orbits a "Solo" middle-aged star closely resembling our parent star. This particular planets orbit cannot be eccentric and must be nearly circular. The planet must also have a shielded plane or planets in it's vicinity in the likes of colossal companion(s) Like Jupiter and Saturn, ultimately alleviating asteroid bombardment but not to be boomeranged around by the protectors planets gravitational pull either. There are tons of other criteria's but I think the just of the point is made.
Now here is the data. Not one single star detected within 50(Ly) away from Earth can meet these specific requirements. The majority of the star systems detected are normally binary or triple star systems, while those detected with a similar mass akin to our Sun are either too old or too young to burn with adequate stability. They also normally have accompanying huge nearby extra-solar planets that would disrupt the orbit of any Earth-like planet dwelling within the goldilocks zone of that system. Now, lets assume that intelligent beings are occupying a star system within a 50(Ly) distant. In order to safely make it to Earth, they would have to travel a course erratically through multifarious galactic hazards to reach this planet, making their trip considerably longer. They would have to dodge the gravity and deadly radiation of super-gaint stars, neutron stars, eruptions of nova and supernova, and even worse, the remnants of such eruptions. They would have to deter away from the dense gases, dust, and comets within the spiral arms of the Milky Way, as well as the territories of late-born stars (stars which has developed during the past 5 billion years). They would also have to stay within the plane of the galaxy. Any departure from the plane would expose the travelers to the deadly radiation that streams from the galactic core. Evasive maneuvering to avoid such hazardous conditions would prolong the minimum distance to at least 75(Ly).
If we look at SETI's data where a research group scanned a little over 200 (solar type stars) within 155(Ly) away from Earth and not one intelligible signal has ever surfaced anywhere within the cross-vicinity of each star examined. Based off these findings we can then make the determination that the minimum distance of any ETI's would be 250(Ly) away. (1.something quadrillion miles away) is not a walk in the park for any type of inter-galactic traveling. Not to mention according to the laws of physics, permanence anywhere within the confines of the universe will be finite and not infinite. Nevertheless, life spans inevitably decrease with constant exposure to radiation such as what one will undergo during inter-galactic travel yields. The complexities of carbon-based biochemistry (which is the only possible chemistry for physical sentient beings to exist) set any carbon-based entity's life limit at about a thousand years even if extraterrestrial beings were to suspend consciousness for extreme long periods of time. So I say definitely not.
Here you go.Quote:
Originally Posted by Theta
http://www.youtube.com/watch?v=ziE0MANlbxU
Not principle. It is just chemistry. It's not some special circumstance that couldn't happen somewhere else. Given the billions of chances it has. It just doesn't seem possible that it wouldn't happen more than once. I don't know exactly what happened, no. But it can't be so rare that it only happened once.Quote:
Originally Posted by Xei
Also I don't think self-catalysis is the correct term. Self-replicate, yes. Using other chemicals as the catalyst.
You keep saying "it's not known". When there are obvious, good and valid theories.Quote:
Originally Posted by Xei
When we look at the history that we have good records for, we can see that evolution always goes in leaps and bounds. Just like our technological advancements.
Only when there is enough "food" (energy sources) around, can the organisms spread more and develop ways to eat/move/procreate etc. that don't need to adapt to use low levels of energy.
Then once they spread too much and consume all the food (because of their adaptations which used lots of energy because they didn't need to be efficient), the ones that did become more efficient survived, and the ones that didn't die. And evolution slows down again.
Lolzor.Quote:
Originally Posted by Xei
This is one galaxy in billions.
Billions. Maybe even trillions, I don't know. As a "mathematician" I would have thought you could understand large numbers.
Maybe not. And besides, our radio signals will take, for example, 2.3 million years to reach Andromeda. Not surprising someone else hasn't sent us signals by now. Or maybe they have sent some this way but we didn't have the receivers yet.
Again, you're going on the assumption that it isn't just basic chemistry, but something special happened on Earth. Which is ridiculous.Quote:
Originally Posted by Xei
If you have 10's of thousands (not 10,000 as you said) planets that are very very similar to Earth, maybe differing in size or something, there is no way life would only arise on one. Assuming nothing special happened on Earth, like one random chemical which just happened to help create life. Which is very fucking unlikely.
Well er... Neyo I stated they didn't have to be ETIs, just anything not from what we commonly establish to be Earth. There could be parallel earths, or what have you.
Besides apparently our universal speed limit may be imaginary.
If they're not ETI's then these other life-forms possibly making contact with us is unlikely if they do happen to exist.
Perhaps, but even if it is imaginary the criteria's I listed would make things worse for inter-galactic travel at faster than the speed of light.Quote:
Originally Posted by Omnis Dei
Yes but you're still acting as though they have to get here the long way. The idea that the shortest length between two points is a straight line only works in a 2 dimensional environment.
It's impossible to know anything to a %100 certainty, but your logic is sound. They probably haven't made contact.Quote:
Originally Posted by Ne-yo
I never made the statement of anything moving through a straight line to get anywhere. The description of inter-galactic travel I've spoke of would consist of more than 2 dimensions. You're a carbon based life-form. How many dimensions can you intelligently move through?Quote:
Originally Posted by Omnis Dei