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How many earths in our galaxy .....

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#26 astroneil

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Posted 20 February 2015 - 04:56 PM

 

 

The fact that we haven't explained abiogenesis does not negate the fact that it occured. 

Abiogeneis is impossible. You would need far more time than the age of the cosmos and far more matter than is contained in the cosmos to get anything viable. Most folk don't understand that.

 

We are here for a reason.

 

There is no need to debate it either; all one need do is sit back and watch as new discoveries come to the fore.

 

We need to get used to being alone.

 

Best,

 

Neil. ;)

 

 

Neil, I respectfully disagree. For the past five semesters it has been my unhappy duty to teach undergraduate engineering majors Thermodynamics II, and we occasionally handle this problem of life and self organization of matter as a bonus problem or mini-project. I will skip the mathematical description for now and say that what distinguishes life from non-life is its self organizing orderedness (as a measure of both entropy and its enthalpic content) and reproduction. It is bounded very much by the enthalpic curve. Of course, the universe has many pockets of low entropy. Consider a star for example. Eta Carinae represents an extreme measure of orderedness but it does not reproduce. One reason why serious astrobiologists who understand some of the physical sciences and thermodynamics are optimistic about the possibility for simple life on other worlds (meaning prokaryotic life = bacteria) is that prokaryotes represent a fairly low amount of orderedness (their enthalpy content is fairly small). Which means that since we see many pockets of high orderedness in the universe, it seems likely we will find simple life in many places. This is also true in our best detailed estimates of catalytic RNA type processes which are the probable  methods by which life arose around 3.8 billion years ago.  So, as to your concerns, current supercomputer simulations show that rather than being a very, very rare event, abiotic life processes leading to simple cells should actually be pretty common.

 

As to the question Ian is asking about Earth like worlds, that is very much harder to guesstimate. The reason is that once very simple prokarya evolved, the best evidence indicates that the next 3.2 billion years life continued to remain one celled (either as prokarya or as eukarya starting perhaps 1.5 BYA). This makes sense because for life to assume mulit-cellular organization, it must make a huge jump up in orderedness. This is thought possible if a star begins putting out more light than in past epochs (the sun grows about 10% more luminous every 900 million years) or an exothermic window is opened (such as the build up of oxygen around 600 MYA). Because of these possible conditions, Earth underwent a very strange and still unexplained explosion of life over a very short period of time (the Cambrian Explosion). (and that has never been repeated since) Life exploded onto the scenes from simple single celled eukarya and simple colony forms to true multi-cellular forms of many different body plans.  Because this represents a much more ordered state, this means the pockets of enthalpy where this exists are likely to be less.

 

And finally, in the quest for Earth like worlds and possible ETs, consider that most university educated professional biologists estimate that 99 to 99.9% of all life that ever lived is now extinct. If we assume the lower bound, then this means that if Earth currently holds about 10 - 15 million species that there have been about 1,200,000,000 species that have lived on Earth. (although, remember, only perhaps 400 to 500 million of them eukarya) (also to be fair, some biologists believe that Earth has held up to 750,000,000,000 species). Since natural selection pressures have only given rise to sapient life once (or possibly a few if you consider dolphins, chimps, etc...) out of hundreds of millions of environments, then we have a very, very strict bound on high ordered intelligent life developing.

 

And that is the reason why many serious professional scientists from the physical sciences who hold a doctorate estimate that bacterial like life out among the stars is probably pretty common. Worlds where you have simple eukarya like colonies may also be fairly abundent. But worlds with six legged horses and intelligent exosaurs might be very rare.

 

Time will tell, my friend. ;)



#27 Crow Haven

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Posted 20 February 2015 - 05:01 PM

Time will tell....

Hasn't it already?
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#28 llanitedave

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Posted 20 February 2015 - 05:12 PM

There is a recent book I can recommend to help those interested in grappling with this old chestnut;
 
Origins of Life; Biblical and Creation Models Face Off by Hugh Ross and Fazale Rana. They are Christians with backgrounds in astrophysics and biochemistry, respectively.
 
http://www.amazon.co...howViewpoints=1
 
Please don't be offended by their faith (as opposed to 'superstition'); but the arguments they use deserve to be heard by as many people as possible.
 
I direct you to the reviews of this book. That should get you started.
 
Hope this helps,
 
Neil. ;)


Helps a lot. I'm quite familiar with Hugh Ross, actually. I've read much of his stuff.

His scientific credibility is zero. He's an apologist, nothing more.
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#29 jrbarnett

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Posted 20 February 2015 - 05:16 PM

Time will tell....

Hasn't it already?

Bazinga!

 

That is probably the wittiest thing I've ever read on CN!

 

Well done!

 

:bow:

 

- Jim



#30 astroneil

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Posted 20 February 2015 - 05:17 PM

 

There is a recent book I can recommend to help those interested in grappling with this old chestnut;
 
Origins of Life; Biblical and Creation Models Face Off by Hugh Ross and Fazale Rana. They are Christians with backgrounds in astrophysics and biochemistry, respectively.
 
http://www.amazon.co...howViewpoints=1
 
Please don't be offended by their faith (as opposed to 'superstition'); but the arguments they use deserve to be heard by as many people as possible.
 
I direct you to the reviews of this book. That should get you started.
 
Hope this helps,
 
Neil. ;)


Helps a lot. I'm quite familiar with Hugh Ross, actually. I've read much of his stuff.

He's an apologist.

 

;)



#31 Rick Woods

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Posted 20 February 2015 - 06:45 PM

 

Trick question!

Real answer: One.

The probability of that being the real answer is equal to the probability of being struck dead by a meteor whilst being attacked by a Great White shark and simultaenously flipping a quarter landing seventeen consecutive "edge" flips (i.e., neither heads nor tails) on the very day you also won a half billion Dollar jackpot in the Powerball Lottery.

 

But your answer reminds me that I have a business proposition for you.  I have some ocean frontage to sell you in Flagstaff for a very good price.  Interested?

 

:grin:

 

- Jim

 

 

Tiresome sarcasm aside, you miss the point: There is only one Earth. There may be many similar worlds, but they are not Earth. There is only one you and one me.

 

(I can't believe I had to explain that!)


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#32 maugi88

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Posted 20 February 2015 - 07:23 PM

Trick question!

Real answer: One.

I was going to say the same thing. There may be hundreds, thousands earth like planets in the galaxy, but there is only one earth.


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#33 jrbarnett

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Posted 20 February 2015 - 09:00 PM

 

 

Trick question!

Real answer: One.

The probability of that being the real answer is equal to the probability of being struck dead by a meteor whilst being attacked by a Great White shark and simultaenously flipping a quarter landing seventeen consecutive "edge" flips (i.e., neither heads nor tails) on the very day you also won a half billion Dollar jackpot in the Powerball Lottery.

 

But your answer reminds me that I have a business proposition for you.  I have some ocean frontage to sell you in Flagstaff for a very good price.  Interested?

 

:grin:

 

- Jim

 

 

Tiresome sarcasm aside, you miss the point: There is only one Earth. There may be many similar worlds, but they are not Earth. There is only one you and one me.

 

(I can't believe I had to explain that!)

 

I agree that for practical reasons we and anyone tracing lineage to any of us contributing to this thread will ever know whether or not there is other intelligent life in the Universe, and therefore we are alone in the sense that we will never interact with extraterrestrials or colonize/terraform a life-bearing exoplanet.  To the extent that was the intent of your response, then I apologize for the teasing.   Probability, however, favors millions of Earth-like worlds teaming with life, sapient and non-sapient, that sadly we'll likely never meet.   :grin:

 

- Jim


Edited by jrbarnett, 20 February 2015 - 09:04 PM.


#34 Rick Woods

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Posted 21 February 2015 - 01:00 AM

 

 

 

Trick question!

Real answer: One.

The probability of that being the real answer is equal to the probability of being struck dead by a meteor whilst being attacked by a Great White shark and simultaenously flipping a quarter landing seventeen consecutive "edge" flips (i.e., neither heads nor tails) on the very day you also won a half billion Dollar jackpot in the Powerball Lottery.

 

But your answer reminds me that I have a business proposition for you.  I have some ocean frontage to sell you in Flagstaff for a very good price.  Interested?

 

:grin:

 

- Jim

 

 

Tiresome sarcasm aside, you miss the point: There is only one Earth. There may be many similar worlds, but they are not Earth. There is only one you and one me.

 

(I can't believe I had to explain that!)

 

I agree that for practical reasons we and anyone tracing lineage to any of us contributing to this thread will ever know whether or not there is other intelligent life in the Universe, and therefore we are alone in the sense that we will never interact with extraterrestrials or colonize/terraform a life-bearing exoplanet.  To the extent that was the intent of your response, then I apologize for the teasing.   Probability, however, favors millions of Earth-like worlds teaming with life, sapient and non-sapient, that sadly we'll likely never meet.   :grin:

 

- Jim

 

You still miss my point.

I agree, there are most likely trillions of worlds teeming with life. Maybe we'll interact, maybe not.

But none of them are Earth, save this planet. This is the ONLY Earth. The others are Mongo, or Vulcan, or Blothar, or whatever; but they aren't Earth. Nobody on any of those other worlds is me, or you.

It's a very simple concept. Earth is unique. All those other inhabited worlds are unique, too. I don't know how else to put it.


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#35 goodricke1

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Posted 21 February 2015 - 07:52 AM

But, um, er, well, where did the first mover come from?   :lol:  If the first mover was infinite, why couldn't the purported creation, instead, have been infinite. - Jim

Where did infinity come from so?? :grin:  Admit it Jim, you don't have a clue what you're talking about - like the rest of us.



#36 dyslexic nam

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Posted 21 February 2015 - 08:55 AM

This is a forum for scientific discussion, and one prevalent and recurring topic is cosmology.  Similarly, there are theology forums where folks can posit whatever mystical entities they want.  Maybe I am in the minority, but I would rather discuss cosmology here on CN without any reference to the sky wizard - either explicit or implied.


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#37 maugi88

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Posted 21 February 2015 - 09:06 AM

I agree to the extent of this forum, it should remain scientific and I say that as a religious person. I have no problem discussing the origins of it all from my perspective, in other forums or by PM, as long as those who don't agree aren't insulting, but this forum should be left to the study and understanding of the universe from a scientific standpoint. In this context such topics tend to get heated anyway so it's best to leave them alone.

 

Enough of that from me. Carry on.


Edited by maugi88, 21 February 2015 - 09:53 AM.

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#38 Rick Woods

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Posted 21 February 2015 - 09:45 AM

+1.

All this started out as was, basically, just a discussion of how the Drake equation might be updated. Let's keep the metaphysics out of it.

 

Except for my crystal.


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#39 Qwickdraw

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Posted 21 February 2015 - 12:14 PM

The fact that we haven't explained abiogenesis does not negate the fact that it occured.  At some point in earth's history, earth's "stuff" changed from disorganized non-living material to organized living material.  Setting aside a few theories that are completely outside the realms of science, it is reasonable to conclude that there is some scientifically explainable way this occured.   And unless we find evidence that there was something extremely rare and exceptional about early earth, then it makes sense to expect the same result when the experiment is repeated over trillions of planets in the universe.

 

That IS logical.  

 

 

Sorry but that is just one big assumption. We don't know how life developed on Earth. Potentially, abiogenesis didn't occur on Earth at all.


Edited by Qwickdraw, 21 February 2015 - 12:14 PM.


#40 TomCorbett

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Posted 21 February 2015 - 12:39 PM

I really do enjoy reading this banter back and forth.

 

I usually read with an astronomy book in one hand and a theology book in the other--searching for a happy medium. Which I think is there.

 

Seek first to understand, before seeking to be understood .

 

There, that is my speech.

 

...Bob


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#41 maugi88

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Posted 21 February 2015 - 12:54 PM

To topic; I suspect that earth like planets with liquid water, a thriving ecosystem that supports life, as we know it, are exceedingly rare. Having said that, in the scale of things, among the billions of planetary systems in our galaxy, exceedingly rare could still mean hundreds even thousands of earth like planets. We may have spotted a couple with Kepler already.

 

I just think there must be some out there.


Edited by maugi88, 21 February 2015 - 12:56 PM.

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#42 Crow Haven

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Posted 21 February 2015 - 01:22 PM

+1.

All this started out as was, basically, just a discussion of how the Drake equation might be updated. Let's keep the metaphysics out of it.

 

Except for my crystal.

Rick, you'd better get a fluorite crystal, calcite really causes double trouble. :eyecrazy:

 

What can we do with updating the Drake equation with larger numbers, though?  I've already let my meager imagination run wild with ideas of other life forms and habitats, even their possible technology...and I'm right back into sci-fi, confusing the issues with the facts we only are aware of today. It's good for writing stories, art and film, but is it going to change anything?  Does humanity want it to?  What do we seek to change through possibly discovering extraterrestrial life forms?  A mindset?  What might be the unintended consequences?


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#43 TomCorbett

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Posted 21 February 2015 - 01:24 PM

I just think there must be some out there.

 

I hope you are correct.

 

...Bob



#44 snork

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Posted 21 February 2015 - 01:30 PM

I think it is very egotistical on our part to believe that we are so special that we are the only life in a universe with countless possibilities. The materials needed for carbon and non-carbon based life exists abundantly in the universe...stealing a line from someone else but the truth is probably stranger than we can imagine. I think we are not alone but we may never know.


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#45 dyslexic nam

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Posted 21 February 2015 - 01:38 PM

 

The fact that we haven't explained abiogenesis does not negate the fact that it occured.  At some point in earth's history, earth's "stuff" changed from disorganized non-living material to organized living material.  Setting aside a few theories that are completely outside the realms of science, it is reasonable to conclude that there is some scientifically explainable way this occured.   And unless we find evidence that there was something extremely rare and exceptional about early earth, then it makes sense to expect the same result when the experiment is repeated over trillions of planets in the universe.

 

That IS logical.  

 

 

Sorry but that is just one big assumption. We don't know how life developed on Earth. Potentially, abiogenesis didn't occur on Earth at all.

 

 

 

If abiogenesis is understood as the transformation of matter from a non-living state to a living state, with the timeframe left undefined, I don't really see the alternative.  We know that in earth's early history, it is very unlikely that life could evolve in those conditions, given everything we know about it.  Rampant volcanism, no liquid water, intense radiation, etc.  To me, it isn't unreasonable to think that evolution likely wasn't underway at that point.  Yet later in geologic time, life started to be prevalent. 

 

I suppose there are the Panspermia theories and comet seeding, but that simply removes the problem a step.  That comet originated in a place that at some point went from a state of non-living matter to living matter.  And once again, to relate this back to the original point, almost any physical environment and set of conditions that can be conceived in the universe, including those where abiogenesis (as previously defined) can occur, likely occurs a multiplicity of times given the sheer scope and diversity of the observed universe.

 

To me, these aren't a series of maybe-maybe-not assumptions.  They are a series of reasonable deductions based on everything we have seen in the observable universe.  There are still many many variables that are absolutely left unresolved, but I don't see the alternative to thinking about the issue in any way other than what is loose described above.


Edited by dyslexic nam, 21 February 2015 - 01:40 PM.


#46 maugi88

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Posted 21 February 2015 - 01:40 PM

I recently saw an online article about life starting up to a billion years earlier than first thought. I will see if I can find it.



#47 Crow Haven

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Posted 21 February 2015 - 01:57 PM

Abiogenesis... so that relies on the "time is on my side" ingredient for life to occur?

So you take the "non-living" components and then "somehow" over billions, trillions, etc. of what we measure as time, bingo, and at that point "life" is kick-started? I'm stuck at the "how" is all.

#48 Qwickdraw

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Posted 21 February 2015 - 02:20 PM

I really do enjoy reading this banter back and forth.

 

I usually read with an astronomy book in one hand and a theology book in the other--searching for a happy medium. Which I think is there.

 

Seek first to understand, before seeking to be understood .

 

There, that is my speech.

 

...Bob

 

Well then Bob, you may enjoy this Heisenberg quote...

 

β€œIn the history of science, ever since the famous trial of Galileo, it has repeatedly been claimed that scientific truth cannot be reconciled with the religious interpretation of the world. Although I am now convinced that scientific truth is unassailable in its own field, I have never found it possible to dismiss the content of religious thinking as simply part of an outmoded phase in the consciousness of mankind, a part we shall have to give up from now on, Thus in the course of my life I have repeatedly been compelled to ponder on the relationship of these two regions of thought, for I have never been able to doubt the reality of that to which they point.”
― Werner Heisenberg


Edited by Qwickdraw, 21 February 2015 - 02:22 PM.

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#49 jayhall0315

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Posted 21 February 2015 - 02:45 PM

Abiogenesis... so that relies on the "time is on my side" ingredient for life to occur?

So you take the "non-living" components and then "somehow" over billions, trillions, etc. of what we measure as time, bingo, and at that point "life" is kick-started? I'm stuck at the "how" is all.

 

 

Not over billons or trillions. Over perhaps a few hundred million years. Computational complexity work on the surface chemistry of the early Earth (which was very much different than the blue ocean world we inhabit today) show that catalytic RNA (early ribosomes) form in several energy wells in a kinetic high heat environment (assuming a random Monte Carlo random walk approach). The physical chemistry (and computational chemistry) of the early Earth is not a black box into which no one can look, but it does require many of the lessons typically learned during the first two years of a undergrad physical sciences major, which is a real hurdle for many Americans.

 

The real question is why do reasonable scientific simulations of abiogenisis not hold weight with those who favor religious explanations? Well, have you seen the latest issue of National Geographic? It is much like climate change or people who believe vaccines may cause autism or that the moon landings are fake. Once their heart is made up (often by influences of those in the same social tribe), then even though the mind can understand a mounting stack of scientific evidence for a topic, it will still remain unconvinced. 

 

(The real reason behind this is the limbic filter of human neural networks which adds and weights incoming data in terms of emotional content. Many times, continuing to be on good social standing with your tribe is far more beneficial (and adaptive) than being right. This is part of the natural selection pressure for a limbic input to high order neural networks. It is hypothesized but not yet proven that humans of high reasoning ability or higher intelligence are able to better separate the limbic processing from the cortical inputs (meaning from the cortex).  This is also one of the principal reasons why some prominent neuroscientists suspect that witchcraft is primarily the abode of the easily lead (low IQ), with religion not far behind and that on the other end of the scale with guys like Aristole, Euclid, Ptolemy, Spinoza, Von Neumann, etc...you find a strong preference for agnosticism, pantheism, and atheism. It is also the most probable reason why when modern day graduate students are sampled regarding their religious views, you find the least amount of religious views among physical scientists, astronomers and engineers.  Call it the Spock filter. :) )


Edited by jayhall0315, 21 February 2015 - 03:01 PM.

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#50 Crow Haven

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Posted 21 February 2015 - 02:52 PM

I think there are scientists who also believe in religious teachings. That's their prerogative.

It's just not what answers my questions in a concrete way. It doesn't give understanding, in my view, to simply say "poof" and then it/life just happened when humanity accepts, even depends on, scientific thinking and it's discoveries in every other category.

So scientific approaches to questions suddenly don't work on the question of how life began on our planet and possibly many others? We have to give up on that question and settle on a "miracle"?


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