Re: are we alone in the universe?
 

I didnt come up with it myself.

It is based on the number of molecules in the most simple - single cell organisms

and the number that have to be right for the (DNA based) cell to live and reproduce.

This is not too hard to understand, since most people are familar with binary counting.

If a molecule has four atoms for example, and each location in that molecule could be oxygen or carbon, then there are 16 possible combinations

OOOO
OOOC
OOCO
OOCC
....
CCCC

or 2^length of the strand, in this case 2^4 = 16. This is not taking into account mirror image (reversed) combinations that look the same

if there could be 4 elements in each position, then you end up with 4^4 = 256 possible combinations. You can start to see how unwieldly this will get

if the molecule is 100 atoms long, and has 4 possible elements in each position, then there are 4^100 = 1.6E60 possible combinations. This is still a realitively small molecule, and you have already matched the number of atoms in the entire universe.

Im only giving a simplified answer here. The 1E350 number has many factors to take into consideration. I think you can google this subject and come up with several websites that go into more detail on the 1E350 number.

This has been part of the evolution vs creation ongoing debate. Some people say the incredible complexity of the most basic lifeforms requires a creator (the watchmaker argument). Some try to dispute the 1E350 number, saying atoms will have some inherent preference to form DNA cells on their own.

But if you take the discussion out of the creation vs evolution debate forum, and look at it strickly from a scientific method (as some people are starting to do), it leads us down a different path.

Scientists, to some extent, assumed the religious concept of life only existing on earth must be wrong, for the simple reason that the conclusion was based on religion and not on science. Drake assigning a very high probability of spontainious life on almost every possible planet was to some extent a knee jerk reaction - bleedover from the creation vs evolution debate.

If we get past the reactionary thought processes, and look at the data we have, then if life sprang into existance spontainiously it was an extreemly rare event.

Re: are we alone in the universe?
 

I'll add what I've been able to observe so far.
Life comes from life. Life doesn't just spontaneously occur.
Where did the first life come from? Thats metaphysics argue on.

To me life is an example of complexity ( a complex system). Complexity tends to be driven by the flow of energy from an area of high concentration to areas of low concentration. If the flow is high enough and there is a disturbance factor a complex system will form. Complex systems tend to be very durable as long as the energy flow rate is maintained. Could it be that the flow of energy from a star can only drive drive life to a certain limit of complexity and that limit is not enough to spread threw space. These thoughts come from chaos theory. You could build a religion out of chaos theory.

As to the post about their not really being anything in the universe that is an example of infinity. Humans are uncomfortable with the concept of infinity so we try not to deal with it. We yell and scream at the mathematicians to do something about the infinities. They raise their math wands and make the infinities go away. Then we have theories that kind of work but have holes or a whole set of solutions that aren't observed. But, heh there aren't any infinities to worry about. I believe Steven Hawkings first claim to fame was he made an infinity disappear.

Ill stop here before I really get on a philosophical rant.

Re: are we alone in the universe?
 

Im not sure what you are trying to say here?

mathematics is abstract - physics deals with reality

can you think of any real physical world characteristic that is infinite?

Re: are we alone in the universe?
 

The number of different polarizations a given photon is capable of having.

The number of paths that lead from one place to another.

The number of directions you can point from a given location.

The acceleration experienced by an object reaching the center of a black hole.

(Okay, we're not quite sure about that last one.)

Re: are we alone in the universe?
 

I'm sorry but the idea of not believing that their isn't life in the universe just because religion says its true is ridiculous. what would have happened if we didn't believe in antimatter just because it came from a patent clerk? (no I'm not comparing religion to Einstein I'm showing that just because an scientific idea come from a unusual source is stupid) besides now creationism (not that god created life but still life spontaneously forming) is the accepted reason for life on earth.

Re: are we alone in the universe?
 

if matter (and even time) is quantitized, is that really true?

I understood that space is digital, not linear. There is a minimun dimension below which you cannot make smaller increments- as if atoms or subatomic particles exist on a grid, with 'snap to grid' enabled ?

Re: are we alone in the universe?
 

But life began from simple amino-acids, with nothing more than a mixture of hydrogen, water, methane, and ammonia, all of which are common materials, no doubt found throughout the universe. Amino-acids have been created in a lab under conditions simulating the environment of early Earth. From another site:

Further studies showed that some amino acids would have combined with hydrogen cyanide (HCN), which is a byproduct of volcanic activity. This combination would form purines and pyrinidines, which are used to make nucleic acids, which in turn create DNA.

So essentially, atoms wouldn't have to form complex cells initially, but rather, start with more simple organic compounds, and combine/evolve into more complex molecules from there. This seems much more likely, and as it's been proven in the lab, is far from impossible to happen in other solar systems.

Re: are we alone in the universe?
 

This is targeted more toward the discussion in general than the issue at hand.

We all live in a delusional state. Actually, I haven't quite decided whether it's a delusion or an illusion. We see the world however we want to see it. If I want to believe that Microsoft is an evil corporate conglomerate, I’ll be able to find evidence to support it and I’ll be able to find a way to counter any evidence against my belief. (Do some research on dihydrogen monoxide if you’ve never heard of it before) We have a limited view of the world around us. We use what we can see to construct our delusion of the world. Let’s consider the following situation:

Ed walks into the other room. You hear the chop saw spin up, then Ed screams. As someone opens the door, you see red splatters all over the walls.

What happened? Well, it would be easy to assume that Ed cut his hand off. However, he didn’t. He wanted to get the ketchup out of the bottle, but didn’t realize that it would splatter all over the place when he cut into it. You didn’t have enough information to find the correct solution, but you did have enough to make a very good educated guess. If you never saw Ed again and never found out about the ketchup, you would have gone on believing that he’s missing a hand.

Anything you see can be interpreted in many different ways. With something on a large scale, like whether life exists anywhere other than earth, the number possible interpretations increases. Until we’ve checked every planet in the universe (or just find life elsewhere) this discussion will continue forever.

Re: are we alone in the universe?
 

that is what is so good about discusions. you see when we discuss our limited view evolves and changes and allows us to create a more educated opinion.

Re: are we alone in the universe?
 

The original post as stated is a question of metaphysics. And as such we can not apply the scientific method to it. All we can do is state our individual human feelings and perceptions on the subject. We can not quantify our common perceptions and apply the tool of mathematics to come up with a model that many can agree is a valid model of our common perceptions of reality.
This post is a great example of why every student who is going to go to college for the sciences should take a course in philosophy and study metaphysics and religions. Religions is plural. Part of doing good science is understanding what questions can be studied scientifically and what ones can't.

Re: are we alone in the universe?
 

I dont understand the assertion that the question of the extent of life spread through the universe is a matter of metaphysics?

We have no problem clearly defining what is alive here on earth, and what is not 'life'. Why should there be any difficulty determining the probability of finding life elsewhere, based on what we already know.

Is their any question of whether we have found life on the moon, venus, mars, jupiter? is there any question of whether we can reasonably expect to find life on the sun?

Life interacts with the physical world in a well established manner. When does the search for life stop being a matter of physics and probability, and start becoming a matter of philosophy or metaphysics? When does it stop being hard-core science? when we get to the nearest star? the next one after that? 100 light years away?

Im speaking of life as we know it: physical organismism that interact with the physical world.

Re: are we alone in the universe?
 

I agree that the first living cell could have been a combination of the right types of amino acids, but each molecule of that cell had to be the right type, in the right place, in the right sequence.

If you start with a swimming pool full of random amino acids, most of what you have in there will be tar or oil or other toxic substances, not the material you need to form protien, and then DNA.

Saying you will form DNA by forming the right amino acids first, and then combining them, doesnt diminish the probability of an entire cell forming by random. Its like saying I will guess this weeks lottery numbers, but I will guess them one at a time. It makes no difference. In the end, the odds are the same. The probability of that first cell forming spontainiously remains the same: astronomically small.

Re: are we alone in the universe?
 

i believe ken posted earlier that if their were life it would have DNA but i thought allot about that. if DNA is formed by specific amino acids and these in turn are created by specific reactions with certain chemicals than the only way aliens would have a similar form of DNA would for their to be similar conditions present. given the extremely distant probability of earth having a twin i doubt life will have similar building blocks. however how would other chemicals or the same chemicals form with completely different environmental stimuli (like extreme gravity or radiation). if we meet life biologist will have a field day and much of the founding blocks (DNA or even amino acids) will be insanely different from what we know. this of course assumes that the life we meet even has a chemical biology.

Re: are we alone in the universe?
 

How about this:

We've concluded that the probability of life starting in the first place is obscenely low. We know for a fact that it has happened at least once though. What if it happened ONLY once? Not necessarily here though. They've found what could be bacteria in meteorites... If I'm not mistaken, they've found such mereorites a couple times. Some planet with life blew up (possibly Superman style) and something landed on earth providing the beginnings of life here. I think we decided that evolution works? If so, to me, that seems probable. Actually, it seems more likely than life starting on multiple planets... Something else that doesn't seem unreasonable to me is some advanced civilization "seeding" earth. If we ever acquire some sort of interplanetary travel, I'm sure someone would try it. (wait...I think that was on an episode of Star Trek...yes it was...but that doesn't change the fact that it's possible) I don't even think we need interplanetary travel. I'm sure Voyager has all sorts of stuff on it. Think of what would happen if it crashes into some earth-like planet. We could probably launch a few thousand canisters of stuff into space. They'll eventually crash into something.

Re: are we alone in the universe?
 

The problem isnt crashing into something. Think about this. Take an ameba and put it on the moon how long will it last? How about mars? maybe neptune? The fact is that life is very picky about its home. I would like to see some articles about life in meteors. Ive also heard about this but I would like to know the extent of this life.