We Haven't Been Visited? Examining Arguments Against ET Visitation.

tanka418

ZetaRediculian
I counter that this number represents biased speculation and not a real number since there is no known aliens from which to calculate a number.

Alas, this really shows the depth of your understanding. I have asserted before, and I will again, Extraterrestrials are not needed to estimate their probability. The "base line" for the probability of ET is 1 chance in the sample size (Earth being necessarily a part of the sample, and Earth has the kind of life we are looking for.)...so we start off with a "prior probability" for ET life...its sort of "built in". Thus your notion of "not having data" is wholly inappropriate, and acts as a "Bar" to further research.

Further, there seems to be extraterrestrials upon which to begin to build: Fresh claim for fossil life in Mars rock

Alas?

"This argument seems persuasive on its face, but Spiegel and Turner have shown it doesn't stand up to a rigorous statistical examination — with a sample of only one life-bearing planet, one cannot even get a ballpark estimate of the abundance of life in the universe.

www.princeton.edu...
seems to agree with this...

ZetaRediculian
I counter that this number represents biased speculation and not a real number since there is no known aliens from which to calculate a number.

Which quote besides your own can you provide that supports you?

Further, there seems to be extraterrestrials upon which to begin to build

"begin to build"? as in there was nothing to build from before? as in zero? I thought you had already built it. this "fresh claim" is from November 2009

ZetaRediculian

Which quote besides your own can you provide that supports you?

Oh sorry man, I use logic, as opposed to the opinion of those who may not have use all the available data. The value stated for a "default prior" is simply the logical value; a bit surprised YOU didn't see that. I'm sorry that I don't have a quote for you, but, with that value; you can have no argument.

But, allow me to further explain; You have a sample of stars with planets, with life on them. You, that is to say Sol / Earth are a part of that sample. Thus the probability is 1 / sample_size. Again, as a computer software type; you should already know this.

"begin to build"? as in there was nothing to build from before? as in zero? I thought you had already built it. this "fresh claim" is from November 2009

WHA??!?!! Do you not comprehend simple English? And, yes, begin to build. Bayesian Inference is an "updateable" system, in that as new data / knowledge is gained it can be used in our "original" computation. With this data updating either model the probabilities for the ubiquity of life are dramatically improved.

I'm not responsible for the title.

reply to post by tanka418

Oh sorry man, I use logic, as opposed to the opinion of

Joshua Winn, an associate professor of physics at the Massachusetts Institute of Technology

I use logic also which seems to be the same logic as

Joshua Winn, an associate professor of physics at the Massachusetts Institute of Technology

Do you not comprehend simple English? And, yes, begin to build

be·gin
1. start; perform or undergo the first part of (an action or activity).

As in the first part as in the part before that didn't exist or hadn't been started yet? OK. where's the camera?

tanka418

ZetaRediculian
I counter that this number represents biased speculation and not a real number since there is no known aliens from which to calculate a number.

Alas, this really shows the depth of your understanding. I have asserted before, and I will again, Extraterrestrials are not needed to estimate their probability. The "base line" for the probability of ET is 1 chance in the sample size (Earth being necessarily a part of the sample, and Earth has the kind of life we are looking for.)...so we start off with a "prior probability" for ET life...its sort of "built in". Thus your notion of "not having data" is wholly inappropriate, and acts as a "Bar" to further research.

Further, there seems to be extraterrestrials upon which to begin to build: Fresh claim for fossil life in Mars rock

Yeah im afraid if we use earth as the sole example thats not really a sample size. I have a feeling life is actually rare but i dont go trying to prove it by starting with the idea that it is either. If you use us as the sole example that is statistical bias its like me saying i own a mustang therefore everyone else must too.If my sample size is just me its a perfectly valid statement.

reply to post by ZetaRediculian


First you have to have a planet around a star in a habitable zone not to far not to close. This planet must contain water and needs to have a long lifetime. Even our solar system we came in very late in the game because earth will only be habitable for 5 billion years and we showed up at 4. Now alot of people dont realize this but our galaxy has a habitable zone as well. Which severely restricts the number of stars. For example the center of the milky way is packed with stars many many however theres a problem there are so many they are bombarded with huge amounts of radiation. So this means about 3/4 of the stars just in our galaxy would kill microbial life. Then if we pass those hurdles we then need to look at how long a species survives 99 percent of all the animals that ever existed on earth are now extinct. Then we move on to could they develop technology well that appears to be a 50 50 shot supposedly dolphins are close to us in intelligence yet they can't make anything. Than there is the fact when you get intelligence you also gain the knowledge to destroy the planet. We have had some very close calls on almost killing ourselves off already.

So if we get through all that than comes the final stage does the species actually want to explore the stars.And at that moment how many civilizations are still around remember countless would come and go the universe is really old. And apparently intelligent species never colonize a galaxy or we would see it. So they probably stay within a local area of maybe a couple of parsecs. Meaning intelligent life could be in your galaxy but youll never meet them. By the time its all said and done you probably have about a dozen species in a galaxy that could travel into space and maybe one close enough if you're lucky. Because even if we came up with warp drive the other side of the galaxy would still be unreachable just because of the shear time involved.

tanka418


Alas, this really shows the depth of your understanding. I have asserted before, and I will again,

This shows the depth of YOUR understanding... it's your ASSERTIONS that are in question.

draknoir2

tanka418


Alas, this really shows the depth of your understanding. I have asserted before, and I will again,

This shows the depth of YOUR understanding... it's your ASSERTIONS that are in question.

He knows that and has pretty much conceded all the points. He pretty much stated we haven't even started to build our knowledge of life outside of earth. He knows there is no knowledge base to draw any conclusions from and the hocus pocus of his Bayesian math has all but melted away. His only focus is me right now. He fancies himself a medieval magician or something and the first rule of magic is to divert attention.

Well, it's pretty much the same deal for the Drake Equation. Compounded assumptions add up to a really big assumption. It is not a mathematical equation, per se. Doesn't solve for anything. More of a thought experiment that believers like to trot out as "proof" of an unknown.

Blue Shift

waltwillis
The Pseudo-Skeptic is not a true Skeptic!

Labeling and semantics is the last refuge of scoundrels.

“Everybody is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid.”

waltwillis

Blue Shift

waltwillis
The Pseudo-Skeptic is not a true Skeptic!

Labeling and semantics is the last refuge of scoundrels.

“Everybody is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid.”

do you have any more videos?

waltwillis

Blue Shift

waltwillis
The Pseudo-Skeptic is not a true Skeptic!

Labeling and semantics is the last refuge of scoundrels.

“Everybody is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid.”

Judge a fish by it's willingness to strike at the exact same bait over and over.

draknoir2

This shows the depth of YOUR understanding... it's your ASSERTIONS that are in question.

Assertions like:

From the article at: arxiv.org...

The primary conclusion of this paper is incorrect.

The last paragraph of the conclusion;

We had to find ourselves on a planet that has life on it, but we did not have to find ourselves (i) in a galaxy that has life on a planet besides Earth nor (ii) on a planet on which life arose multiple, independent times. Learning that either (i) or (ii) describes our world would constitute data that are not subject to the selection effect described above. In short, if we should find evidence of life that arose wholly independently of us either via astronomical searches that reveal life on another planet or via geological and biological studies that find evidence of life on Earth with a different origin from us we would have considerably stronger grounds to conclude that life is probably common in our galaxy.

In my previous remarks I stated that life may have arisen more than once on Earth, I was referring to the event that formed the Moon, but was mistaken about "when" the Moon was formed, so I'm taking that off the table. However, I also mentioned that evidence of abiogenesis on Mars does exists, and, the latest conclusions are the micro-structures in question are NOT of geological origin, and are probably biological. I do believe this will satisfy the learning of (I) "we find ourselves in a galaxy that has life on a planet besides Earth." In this case Mars; This would appear to be rather strong evidence of abiogenesis occurring on Mars, probably around the time it happened on Earth. This has the effect of nearly negating that work and lending greater probability to my hypothesis that life is ubiquitous.

This single bit of data does significant damage to the "life is rare" hypothesis. Firstly, the hypothesis as presented is based on a single life model; Earth, and admittedly does not look or allow for life elsewhere. All this work ultimately does is provide a starting point; which while valuable, should not be taken as the "final result".

Bayesian inference is an "updatable" process, and this latest update would alter the conclusions dramatically.

reply to post by tanka418


Actually life may have started on mars and transferred to earth so there isnt two places it happened only one if this is correct. If true this means life on earth was a cosmic fluke and wasnt meant to be here.More to the point however due to the requirements of life it will be a very rare thing indeed.

www.bbc.co.uk...

dragonridr
reply to post by tanka418

 

Actually life may have started on mars and transferred to earth so there isnt two places it happened only one if this is correct. If true this means life on earth was a cosmic fluke and wasnt meant to be here.More to the point however due to the requirements of life it will be a very rare thing indeed.

www.bbc.co.uk...

interesting hypothesis. However, I'm not so sure. I suppose Mars could have gotten a bit of a "head start" due to the formation of the Moon, but, according to the research (admittedly quick) did today; Mars lost it atmosphere at around 700 million years, coincidently, that is around when life supposedly arose on Earth.

The Mars rock that contained the fossil was supposed to have been ejected from Mars some 15 million years ago. I would think that the probability of ejecta from Mars transporting life to earth would be something less than independent abiogenesis.

tanka418

dragonridr
reply to post by tanka418

 

Actually life may have started on mars and transferred to earth so there isnt two places it happened only one if this is correct. If true this means life on earth was a cosmic fluke and wasnt meant to be here.More to the point however due to the requirements of life it will be a very rare thing indeed.

www.bbc.co.uk...

interesting hypothesis. However, I'm not so sure. I suppose Mars could have gotten a bit of a "head start" due to the formation of the Moon, but, according to the research (admittedly quick) did today; Mars lost it atmosphere at around 700 million years, coincidently, that is around when life supposedly arose on Earth.

The Mars rock that contained the fossil was supposed to have been ejected from Mars some 15 million years ago. I would think that the probability of ejecta from Mars transporting life to earth would be something less than independent abiogenesis.

Actually makes sense when i think about it realize the inner planets at that time where constantly being bombarded with meteors. So its very likely a martian rock landed on earth.

ZetaRediculian

waltwillis

Blue Shift

waltwillis
The Pseudo-Skeptic is not a true Skeptic!

Labeling and semantics is the last refuge of scoundrels.

“Everybody is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid.”

do you have any more videos?

www.youtube.com... perfect storm

The Eye in the shy?

reply to post by tanka418

All this work ultimately does is provide a starting point; which while valuable, should not be taken as the "final result".

Bayesian inference is an "updatable" process, and this latest update would alter the conclusions dramatically.

I think this was pointed out in in my posts a while back and in a couple of the articles I referenced. Did you miss them? I don't see where you mentioned this prior to the paper being posted. Anyway, I am glad that you understand how this works now and how simple a concept it really is. It looks like a real discussion can happen now that basics are understood. Kudos to you for the effort.

dragonridr

Actually makes sense when i think about it realize the inner planets at that time where constantly being bombarded with meteors. So its very likely a martian rock landed on earth.

Some I suppose, but, I have difficulty getting past the idea that independent abiogenesis is a better explanation.

While Mars rocks have landed on earth (we have them as prof, there is no telling how long they were in space. The conditions in interplanetary space s rather harsh, and may well destroy all but the last chemical remains of anything attached to the rock when it gets ejected. Also, the ejection s very violent, and may well destroy virtually everything attached to the rock, and some of the rock as well. Then there is the rocks ingress to Earth, they would have the same fiery descent as any other meteor. Anything making it to the surface would be quite "lucky". But, we do know it has happened at least once...

dragonridr
reply to post by ZetaRediculian

 

First you have to have a planet around a star in a habitable zone not to far not to close. This planet must contain water and needs to have a long lifetime. Even our solar system we came in very late in the game because earth will only be habitable for 5 billion years and we showed up at 4. Now alot of people dont realize this but our galaxy has a habitable zone as well. Which severely restricts the number of stars. For example the center of the milky way is packed with stars many many however theres a problem there are so many they are bombarded with huge amounts of radiation. So this means about 3/4 of the stars just in our galaxy would kill microbial life. Then if we pass those hurdles we then need to look at how long a species survives 99 percent of all the animals that ever existed on earth are now extinct. Then we move on to could they develop technology well that appears to be a 50 50 shot supposedly dolphins are close to us in intelligence yet they can't make anything. Than there is the fact when you get intelligence you also gain the knowledge to destroy the planet. We have had some very close calls on almost killing ourselves off already.

So if we get through all that than comes the final stage does the species actually want to explore the stars.And at that moment how many civilizations are still around remember countless would come and go the universe is really old. And apparently intelligent species never colonize a galaxy or we would see it. So they probably stay within a local area of maybe a couple of parsecs. Meaning intelligent life could be in your galaxy but youll never meet them. By the time its all said and done you probably have about a dozen species in a galaxy that could travel into space and maybe one close enough if you're lucky. Because even if we came up with warp drive the other side of the galaxy would still be unreachable just because of the shear time involved.

Where is the current best REAL habitable zone for earth like life in our solar system (clue it's not Mars).

It's on the moons around Jupiter and Saturn. Which is not in the standard habitable zone!

That's right, the only places likely to have large bodies of water like on Earth are OUTSIDE the habitable zone.

Let's ditch the whole habitable zone idea here and now.