Slashdot Mirror

this story is sad. poor guy has obviously lost his marbles. unfortunately, 77 yrs old will do that, even to the most accomplished human (clearly, as is the case here)
there are about 1,000 ways from here to sunday that suggest there must be intelligent, communicating life out there somewhere. I'm talking about life just like us. why? Cause we dont care about intelligent viruses. we only care about life just. like. us.
ufo's and alien visitations however are a completely different topic. if you are asking me to belive in ufos, you are in effect asking me to believe in the most wide-ranging, far reaching successful conspiracy of all time.
its not just governments that are looking up at the sky.
its not just evil NSA or NASA, for that matter, that have radar, telescopes, etc.
asking me to believe in ufos is like asking me to believe in santa: no i can't prove that santa don't exist. i CAN however prove that not a single piece of scientific evidence exists that suggests a santa.
so, UFOs are silly, visitations are silly, but Drake equation suggests many many intelligent communicating species in Milky Way. Thousands, even under the most conservative assumptions.
http://www.activemind.com/Mysterious/Topics/SETI/drake_equation.html

Perhaps the fL has been reached for this civilization.

N = N* fp ne fl fi fc fL
(fL = the fraction of the planet's life during which the communicating civilizations survives)
http://www.activemind.com/Mysterious/Topics/SETI/drake_equation.html

There is a v. useful framework for having an intelligent conversation in re likelihood of finding ET, the Drake equation:
http://www.activemind.com/Mysterious/Topics/SETI/drake_equation.html
N = N* fp ne fl fi fc fL
Basic probability estimate, useful because it considers each factor separately, based on the best estimate available. You can play w. it and apply your own set of assumptions (i.e. probability of intelligent life evolving, etc).
One fascinating implication (illumination?) of this approach is you see what a HUGE impact time scales have. 50yrs is nothing, not even a blink of an eye, when you are talking about finding some evidence of intelligent communicating life. Frankly, i think the 1 aspect of SETI that is insane is that anyone should expect anything but 0 in next several centuries. E
My most pessimistic estimate calc'ed is about 1,000 intelligent communicating ALIVE races. Milky Way is 100K light years across. So maybe 1 intelligent communicating race per 100 light years on average?
awesome.

I think you need to recheck some of your facts.

Our solar system moves in and out of the spiral arms as well as up and down through the galactic plane. We go through the galactic plane about every 35 million years, and through the spiral arms about every 100 million years. Some postulate that these timescales coincide with various mass extinctions that occurred.

The axial tilt of the Earth changes all the time. The tilt angle varies between 22 and 25 degrees over a period of about 41000 years. There is also precession of the orbit that happens on a 22000 year timescale. The changing tilt angle changes the severity of the seasons (length of seasons, ice ages, etc.), but it doesn't have anything to say about whether the planet could harbor life.

There isn't anything magical about our molten core and magnetosphere. We usually expect large rocky planets to have them, so we find it unusual if a planet doesn't have a magnetosphere.

I wouldn't say that the asteroid belt has protected us. The asteroid belt is basically a planet that either didn't form, or didn't survive. Its existence is probably one of the biggest threats to our survival on this planet. It is a race to see whether a large asteroid or comet hits our planet and wipes us out. Nobody doubts that it will happen again in the future; we just don't know when it will.

The Moon actually causes a drag on the planet that is slowing down the Earth rotation. I don't recall hearing what an ideal rotation rate for the Earth is to sustain life.

Once one gets their head around how many stars there are in just our own galaxy, many people consider it a given that there is life all around in the galaxy. Even if you take the most pessimistic odds for life to develop, once you multiply that by the number of stars out there it would seem to be very likely. The most famous statement of this is the Drake Equation. Of course, once you consider the extremely large distances between any two stars it is easy to come to the conclusion that all this life will not come in contact with each other (the intelligent life, that is).

What you're exploring has been standardized in the drake equation:
http://www.activemind.com/Mysterious/Topics/SETI/d rake_equation.html

Note that I think ne is ridiculous, I would expect that to be a fractional quantity.

You have to make a slight modification if you want to find out if there are alien visitors in UFOs hanging around (add a couple of extra fractional multipliers).

it is good that the liqid question is answered, as liquid methane is somthing that some view as possible environ of life, just as those who believe water on Mars means likely life. The issue though is whether conditions were ever favorable enough, long enough for life to develope. If we establish Titan's parameters, and Mar's parameters, we might come up with some of the values in drakes equation http://www.activemind.com/Mysterious/Topics/SETI/d rake_equation.html the answeres might not be what we want, however

I don't know why anyone finds negative SETI results offensive. Nobody ever suggested the search would be easy. The occurrance of extraterrestrial civilizations is still mapped by the Drake Equation. Certain parameters (fc, fi, fL) are being adjusted down by the SETI effort. At the same time the success of planet hunting and planetary mission results are positively effecting others (fp, ne). A negative result, although less exciting, is still a result.

The standard evolutionary model says that Earth had a bunch of Primordial Soup that cooked for hundreds of millions of years until some of it did stuff that was interesting enough to photosynthesize, which started radically changing the chemistry of the planet's atmosphere and the Soup until more of it started doing more interesting stuff and eventually it was interesting enough that we can declare that "It's Alive!" The probability that stars will have planets, and that they'll have the right conditions to let this happen (temperature, available atomic mixtures, gravity, etc.) are pretty low, and people who like to speculate about how heavily populated the universe is and when we'll find aliens come up with estimates like Drake's Equation to try to guess how rare we are.

Interplanetary Panspermia suggests that not only did Earth have to have the right mixture of chemicals and temperature/pressure conditions in the Primordial Soup for all this to happen, but that Mars or maybe Venus also had to have a (presumably different) batch of soup cooking that had either become Alive or else pretty close, and something had to cause a Big Splash to get some Martian Soup mixed in with the Earth Soup at a time that both of them were in the right conditions. If the Earth had been running too far ahead or behind in time, or the Big Splash hadn't happened at the right time or hadn't been big enough, then the Martians would have been told No Soup For You, Next Billion Years , Earth wouldn't have been alive, and Mars would have done the Cosmic Wimpout without us evolving to see it today. Drake's Equation looks much more dodgy under those assumptions. If that's what it takes for life to evolve, I don't expect any space aliens to show up any time soon.

Interplanetary Panspermia doesn't really solve any problems about how life could have evolved, though I suppose it *could* have happened, but it seems much less likely than Earth's Primordial Soup doing the job on its own. Interstellar Panspermia seems much much less likely to me, for reasons I noted above. There's a huge amount of stellar evolution that had to happen just to get the right elements into the Solar System, since some of them only get formed inside supernovae or similar stars. Friendly Space Aliens deliberately seeding the place begs the question of how *they* evolved, but strikes me as no less likely than Interstellar Panspermia happening by accident. You'd think they'd have also left a message, but maybe they were just shooting stuff out at likely stars on spec, hoping that something would work even if they weren't around four billion years later when we were ready to Phone Home, or maybe they really *are* hanging around on the Dark Side of the Moon working on the next chapter of their cookbook before they drop in for a visit.

It would be much more than important. It would be the biggest discovery in the history of humanity.

Why?

Because if we know there are even a few cells living off of Earth that there is just such a vast expanse to the Universe that this would mean life was everywhere.

While it seems completely logical life would be everywhere, without the proof of it somewhere else, we just don't know.

With how many galaxies there are out there, and knowing life is so common that a planet right next to us also has it, it changes everything.

The Drake Equation getting an increase in the propensity of life elsewhere from it being next door would be profound. You can actually plug into that equation this event. Every extra planet we would find in our solar system increases the number of likely civilized societies able to communicate in our galaxy by 1000.

So if Mars has life, it is very likely a few moons of Jupiter would, and maybe Titan in some fashion. This would mean there may be thousands of civilazations in our own galaxy able to communicate.

What youre looking for is the Drake Equation.

I can only imagine that those people have never even tried to comprehend even an infintesimal fraction of just how damn big a galaxy is, let alone The Universe, or the possibility of other things in that grey area between science fiction and experimental science (i.e. the things we know nothing about at the 'end' of the universe - depending on whether it's signed or unsigned, has a wraparound, a wall, so on). If someone couldn't conclude that statistically there almost has to be something out there then that must be an awfully bleak world... um, universal view.

Wasn't there the Drake Equation? This takes the number of planets expected to be out there orbiting at a similar distance from a star as the Earth is from the Sun, divide by the likelihood that it is predominantly water, and the result gives the minimum number of planets which could reasonably be expected to sustain life. It ends up going into intelligence and civilisation, but I'm not going to be the one to make some jibe about the number of people believing in no intelligent life in the Universe.

Oh, and here is a link to a brief article about the so-called canals on Mars. It mentions Lowell, the U.S. astronomer who spent much of his life looking for these canals, but it also credits Schiaparelli with starting the furor over canals on Mars in the first place. (My first exposure to this issue was Carl Sagan's TV series Cosmos -- I think it's discussed in the episode entitled "Blues for a Red Planet." There's a companion book also called Cosmos which gives even more detail about the history of astronomical observation of Mars.)

"when any Platonic character relates a myth which none of the other characters are aware of, the myth is likely to be completely contrived by Plato. I say this as a hunch, mostly because Plato likes to make a point of talking about where information came from"

Plato does actually state where he heard it from. One of the other characters in the book, Solon, heard the story from Egyptian Priests. There is a belief that any reference to Atlantis which the Egyptian Priests may have had, would have been burned at the Library of Alexandria when it burned down the first time. (Thanks to Julius Caesar).
I own five books by Plato, but not this one. Here it is on the web. Timaeus and Critias .

Aristotle didn't believe Plato though, and thought he had made the story up, but he does site one source in "Constitution of the Tegaeians" where the people of Arcadia claim to have been descendants from Atlantis. So at least by Aristotles time (and he was taught by Plato), the Arcadians had at least heard of the Myth and were using it as a reason to claim the lands they lived on.

Of course that is why Drake's equation is a joke. You can't calculate anything with a sample size of one. There is not one number is his equation that we can even estimate.

And it really isn't that hard to get to actually less than one. There's a calculator here.
I did some very reasonable estimates and came up with 0.2475.

The two dialogs of Plato's which describe Atlantis are the Timeaeus and Critias. It is on-line at: Atlantis

The Timeaeus only refers to Atlantis in two paragraphs. The Critias has a longer description, but it ends in the middle of the dialogue.

You can draw your own conclusions.

The only existing written records which specifically refer to Atlantis where written by Plato

The story is about the conflict between the ancient Athenians and the Atlantians 9000 years before Plato's time. How likely is it that this actually exists?

Plato wrote about a conversation between Socrates, Hermocrates, Timeaus, and Critias.
How likely is it that any of those four people knew about a civilisation 9000 years before them ... how much do we KNOW about anything that happened 9000 years ago.. and we have a lot of technology to aid us now that did not exists during those times...

I don't believe that there is anything worth looking for.. but then again, just my opinion.. I accept the fact that I could be wrong, although I find this highly unlikely.

The only existing written records which specifically refer to Atlantis where written by Plato

The story is about the conflict between the ancient Athenians and the Atlantians 9000 years before Plato's time. How likely is it that this actually exists?

Plato wrote about a conversation between Socrates, Hermocrates, Timeaus, and Critias.
How likely is it that any of those four people knew about a civilisation 9000 years before them ... how much do we KNOW about anything that happened 9000 years ago.. and we have a lot of technology to aid us now that did not exists during those times...

I don't believe that there is anything worth looking for.. but then again, just my opinion.. I accept the fact that I could be wrong, although I find this highly unlikely.

Micah, I have enjoyed our conversations but find that like other Christians you ignore what you can't explain. Review what I have posted to you in the past, you will see that I have addressed every single one of your arguments adnausem. Gain some understanding of the nature of the Universe, and realize that we are likely not as rare as you think. Your table of statistics can be countered with other statistics. Just start with the Drake equation. A conservative estimate using the Drake equation puts 1000 planets with intelligent (capable of communicating) life IN OUR GALAXY. There is an estimated 125 billion galaxies. Even being extremely conservative and saying one in 10 galaxies has the potential for life, we are still saying there are 12.5 billion planets like ours. Get as conservative as you'd like and you would see that it is just not likely that we are the only life bearing planet in the UNIVERSE. Please, just google for the size of the known universe. Do you really believe being such an infintismal speck on some far flung planet in some average galaxy really suggests with any kind of certainty that we are truly the only life in existence? If you believe this, you are not only uneducated but arrogant as well. Read a book besides your bible, and quit wasting my time until you get some true facts. As long as you argue with me with your bible or some other related text as a source, I will consider your argument flawed.

No, and neither have you or anyone else.

Bullshit. Ever heard of the Drake Equation?

N = N* fp ne fl fi fc fL

where:

N* represents the number of stars in the Milky Way Galaxy (Current estimates are 100 billion.)
fp is the fraction of stars that have planets around them (Current estimates range from 20% to 50%.)
ne is the number of planets per star that are capable of sustaining life (Current estimates range from 1 to 5.)
fl is the fraction of planets in ne where life evolves (Current estimates range from 100% (where life can evolve it will) down to close to 0%.)
fi is the fraction of fl where intelligent life evolves (Estimates range from 100% (intelligence is such a survival advantage that it will certainly evolve) down to near 0%.)
fc is the fraction of fi that communicate (10% to 20% ?)
fL is fraction of the planet's life during which the communicating civilizations live (This is the toughest of the questions. If we take Earth as an example, the expected lifetime of our Sun and the Earth is roughly 10 billion years. So far we've been communicating with radio waves for less than 100 years. How long will our civilization survive? Will we destroy ourselves in a few years like some predict or will we overcome our problems and survive for millennia? If we were destroyed tomorrow the answer to this question would be 1/100,000,000th. If we survive for 10,000 years the answer will be 1/1,000,000th.)

When all of these variables are multiplied together when come up with:
N, the number of communicating civilizations in the galaxy.

(The info above stolen from here

You asserted that the probability of life randomly arising somewhere in the universe is unknown. That's certainly true for our current scientific state, since we can't yet claim to know all the intimate details of every single function of cellular life.

However we do know enough to make some interesting calculations. For example, all proteins in all living things known today are made up exclusively of 19 chiral and one non-chiral amino acid. On average, roughly 8% of bacterial protein amino acids are glycine (the non-chiral one). So in a smallish protein of only 450 amino acids, there are (0.92)*(450) or 414 chiral amino acids.

There is no natural process outside living cells that generates amino acids of one chirality; everything generates nicely racemic (equally L and R) mixtures.

It is fairly simple to calculate just how likely it would be to get just one protein to form randomly (proteins form sequentially, and since they need more than one copy of each amino acid, this must be done by the probstat model of "with replacement") from an unlimited supply of amino acids. To make the case easy, and to heavily tilt the odds towards the formation of proteins, let's ignore the energy gradient in aqueous solutions (which tends towards dissociation of proteins, not their assembly). So to calculate the odds of getting all 414 amino acids that are chiral to all be the correct chirality is one in 2^414 (or one in over 10^124).

To give some concept of that number, consider the assumptions made by fans of the Drake equation for example, and be generous. They estimate 200 billion (2*10^11) stars in our galaxy, and 20% of those having planets, with 3 to 5 possibly life-bearing bodies per star that has planets. Let's just say 10^12 possible planets, an order of magnitude higher than the upper limit of those Drake numbers. Also consider that the universe at 20 billion years is less than 10^18 seconds old. Let's say the earth has 10^50 atoms in it (slightly higher than estimates). So if you have one protein formed per each atom on every habitable planet in the galaxy (10^50*10^12 == 10^62) every millisecond since the big bang (10^18*10^3 = 10^21) you'd have 10^83 proteins formed. So the odds of getting one properly chiral protein by having 1000 formed per second per atom on all habitable planets and moons in our galaxy since the big bang would be 124-83 = one in 10^41. The universe is 10^28 inches across...

Now consider the odds of getting just one protein to have a particular sequence, which is immensely harder than the above which just focussed on getting the chirality alone correct. Plain fact is, random chance alone just will never be anywhere near adequate to explain the origin of life.

The Drake Equation would make a great title for a science fiction book, though.

The real value of the Drake Equation is not in the answer itself, but the questions that are prompted when attempting to come up with an answer. Obviously there is a tremendous amount of guess work involved when filling in the variables. As we learn more from astronomy, biology, and other sciences, we'll be able to better estimate the answers to the above questions.

Plato seems to have made up a lot of myths that his characters claimed to have been true, but that were intended by him (Plato) to be taken as illustrative moral lessons. The myth of Er at the end of Republic comes to mind as one example. Atlantis sounds like a utopian version of contemporary Persia when you read the accounts of it.

The stories of Atlantis come up in Critias and Timaeus, two of Plato's early-middle dialogues, when he was still recording Socrates' critiques of morality and ethics (with more or less embellishment depending on who you ask) and they crop up as historical legends designed to teach morality. Atlantis in particular shows what happens when corruption infects mankind.

I don't really see how people can take them all that seriously, to be honest. You might as well take the Legend of Er to be true.

-Seraph