Why have aliens never visited Earth? Scientists have a disturbing answer

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We are not supposed to get into religious discussions here, so I will try to tread carefully in responding to the idea that "special creation ", as an alternative to abiogenesis, has any effect on the probability of life occurring elsewhere. Special creation could occur in other places if it occurred here, and maybe with even more likelihood.

My point is that not believing in abiogenesis, or even somehow having proof that abiogenesis is impossible, still does not result in a logical basis for claiming that life cannot exist somewhere else, too.

The idea that there is not absolute proof that abiogenesis occurs is just as ineffective as claiming that there is no proof that special creation occurred. What we have proof of is that something did occur here, and we have no data or logical basis for arguing that whatever that was could not occur elsewhere, too.

So far, we have no proof that live did or did not ever occur anywhere else, all we have is proof that whatever put life here on Earth can happen.
 
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Helio, whoever or whatever owns the acres, this postulate requires modification to Drake equation. Let me know when that is done :)
Agreed, but perhaps minimal tweaking would be required.

Give me a million acres and I’ll likely find several garden-like areas existing. But I might elect to add one or two more, yet I would place them in the more favorable areas in accord with their evolved circumstances.

I’m speculating, of course, but planetary bodies are now better understood as “evolving”, as well. It’s hard, at this point, to imagine a percentage of these, albeit tiny, would not be either gardens or garden-ready environments.
 
So far, we have no proof that live did or did not ever occur anywhere else, all we have is proof that whatever put life here on Earth can happen.
Right, yet we have more than this.

Having now learned that there are as likely as many planets as stars, and with the means to determine many of these are in the HZ, along with the abundance of water in star systems, we can argue circumstantially far more more today for life elsewhere than just 2 decades ago.

We must, however, still be careful to not let scientific momentum take us too far from the road.
 

rod

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Then I will rephrase:

" If abiogenesis never took place or does not take place in nature, things fall apart quickly."

Then what is the alternative?

Cat :) :) :)
The alternative in science is to provide necessary demonstration that abiogenesis took place, and still does in nature today. Galileo and heliocentric teachers had to meet this standard to show the Earth moved around the Sun, necessary demonstration. What we do see operating in nature on Earth, life comes from life, not non-living matter.
 
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Catastrophe

"There never was a good war, or a bad peace."
.Rod, frankly, I am not interested in medieval precursors of philosophy.

Science does not have to go back to the Big Bang. It does not have to replicate the Big Bang, indeed that would be rather difficult. No theory is 'absolutely true', but the Big Bang appears to be the best theory we have at present.

By the same token, we are here. Science holds that we are here as the result of abiogenesis.
Abiogenesis is the only scientific explanation of our presence here.
This is a science forum and should be and, indeed, is, limited to scientific explanations.

Cogitas ergo sum. Likewise the Universe.


Cat :)
 

rod

Oct 22, 2019
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.Rod, frankly, I am not interested in medieval precursors of philosophy.

Science does not have to go back to the Big Bang. It does not have to replicate the Big Bang, indeed that would be rather difficult. No theory is 'absolutely true', but the Big Bang appears to be the best theory we have at present.

By the same token, we are here. Science holds that we are here as the result of abiogenesis.
Abiogenesis is the only scientific explanation of our presence here.
This is a science forum and should be and, indeed, is, limited to scientific explanations.

Cogitas ergo sum. Likewise the Universe.


Cat :)
Cat, to clarify here. Is your post suggesting that abiogenesis is supported as well as the Big Bang theory when it comes to observations of the natural world used to support the paradigm?
 
Then I will rephrase:

" If abiogenesis never took place or does not take place in nature, things fall apart quickly."

Then what is the alternative?

Cat :) :) :)
Abiogenesis, like claims of a t=o singularity, are still subjective views, not hard science. Other subjective views come from both philosophy and religion.

For the cause behind BBT, the non-science view held by perhaps the majority of the world, is for a Creator. Something from a super intelligence makes a fine-tuned universe look like it was engineered. Something from nothing makes very little sense. Regardless, addressing this beginning is only in the magisteria of philosophy and religion (and math), so arguments are not that welcome in science forums. But they are legitimate ideas that may, or may not, come to fruition because of future science,

But for abiogenesis, science offers circumstantial evidence that gives some favor in accepting it over a supernatural one. Granted, neither is disproven. If science keeps improving the arguments for abiogenesis, or if abiogenesis becomes demonstrable, then any philosophical or religious view will fade, or worse, will look silly when argued.

How did I do? ;)
 
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rod

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Abiogenesis, like claims of a t=o singularity, are still subjective views, not hard science. Other subjective views come from both philosophy and religion.

For the cause behind BBT, the non-science view held by perhaps the majority of the world, is for a Creator. Something from a super intelligence makes a fine-tuned universe look like it was engineered. Something from nothing makes very little sense. Regardless, addressing this beginning is only in the magisteria of philosophy and religion (and math), so arguments are not that welcome in science forums. But they are legitimate ideas that may, or may not, come to fruition because of future science,

But for abiogenesis, science offers circumstantial evidence that gives some favor in accepting it over a supernatural one. Granted, neither is disproven. If science keeps improving the arguments for abiogenesis, or if abiogenesis becomes demonstrable, then any philosophical or religious view will fade, or worse, will look silly when argued.

How did I do? ;)
One problem, demonstrating abiogenesis. When did abiogenesis first start operating on Earth and when did abiogenesis stop operating and creating life on Earth? We do not see abiogenesis operating today, life comes from life.
 

Catastrophe

"There never was a good war, or a bad peace."
abiogenesis, the idea that life arose from nonlife more than 3.5 billion years ago on Earth. Abiogenesis proposes that the first life-forms generated were very simple and through a gradual process became increasingly complex. Biogenesis, in which life is derived from the reproduction of other life, was presumably preceded by abiogenesis, which became impossible once Earth’s atmosphere assumed its present composition.

OK, life arose here, or arose elsewhere in the Universe. My understanding is a (without) bio (biological) genesis (beginning). If there is a wider definition "arose from nonlife elsewhere in the Universe", I would be grateful if you would please enlighten me.


Cat :)
 

Catastrophe

"There never was a good war, or a bad peace."
Cat, to clarify here. Is your post suggesting that abiogenesis is supported as well as the Big Bang theory when it comes to observations of the natural world used to support the paradigm?
Encyclopaedia Britannica:
"While the hypothetical process of spontaneous generation was disproved as early as the 17th century and decisively rejected in the 19th century, abiogenesis has been neither proved nor disproved."

In common with the Big Bang and most other major ideas.

Cat :)
 

Catastrophe

"There never was a good war, or a bad peace."
Abiogenesis, like claims of a t=o singularity, are still subjective views, not hard science. Other subjective views come from both philosophy and religion.

For the cause behind BBT, the non-science view held by perhaps the majority of the world, is for a Creator. Something from a super intelligence makes a fine-tuned universe look like it was engineered. Something from nothing makes very little sense. Regardless, addressing this beginning is only in the magisteria of philosophy and religion (and math), so arguments are not that welcome in science forums. But they are legitimate ideas that may, or may not, come to fruition because of future science,

But for abiogenesis, science offers circumstantial evidence that gives some favor in accepting it over a supernatural one. Granted, neither is disproven. If science keeps improving the arguments for abiogenesis, or if abiogenesis becomes demonstrable, then any philosophical or religious view will fade, or worse, will look silly when argued.

How did I do? ;)
See parallel post. Abiogenesis has been neither proved nor disproved. Encyclo Britann
 
To answer Rod, Helio and Cat:

Why believe that it must be either abiogenesis or "special creation"? Just because you can't think of it does not mean it can't happen. Yes, it might appear to be "magic" if it happened in front of us by a process that is beyond our comprehension. But, life here on Earth doesn't "fall apart" just because you (and I) don't understand it at this time, so it doesn't "fall apart" anywhere else it might be, either. Life here is proof that life will be somewhere. Does "special creation" require it to be only here? Where is the proof of that? And, if that is the theory, then I will simply propose an equally unproven theory that the same creation occurred on multiple planets by exactly the same process it occurred here.

It also strikes me as a sort of circular argument that nobody that is "extraterrstrial" could have ever visited us because only we were created specially. Wouldn't that creator qualify as "extraterrestrial", whether a deity or a super-powerful species who created us as an experiment?

All I am seeing in this part of this thread is people going in illogical circles.

Can we please get back to something more scientific, such as discussing parameters of the Drake Equation or some expansions of it?
 

Catastrophe

"There never was a good war, or a bad peace."
Unclear Engineer and all others present.

I do appreciate your comments, and I am trying to keep this on a scientific basis.

You posted "Why believe that it must be either abiogenesis or "special creation"? Just because you* can't think of it does not mean it can't happen."

*Assuming you mean "one", "rather than "you" (as in "me"), I do accept your point - however, I would regard this as a philosophical question. In science, we do the best we can utilising the means we have available.

I am only suggesting that, in order to abide by the rules, we keep discussion here on a scientific basis. If anyone wishes to discuss philosophical or other non-scientific matters, would it be too much to ask, very politely, that they find a more suitable forum. There are those of us here who want to discuss scientific matters, not confused by philosophical arguments.

Thank you all for your kind consideration.

Cat :) :) :)
 

rod

Oct 22, 2019
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abiogenesis, the idea that life arose from nonlife more than 3.5 billion years ago on Earth. Abiogenesis proposes that the first life-forms generated were very simple and through a gradual process became increasingly complex. Biogenesis, in which life is derived from the reproduction of other life, was presumably preceded by abiogenesis, which became impossible once Earth’s atmosphere assumed its present composition.

OK, life arose here, or arose elsewhere in the Universe. My understanding is a (without) bio (biological) genesis (beginning). If there is a wider definition "arose from nonlife elsewhere in the Universe", I would be grateful if you would please enlighten me.


Cat :)
Cat provides a timeline now for abiogenesis operating on Earth. More than 3.5 billion years ago until the Earth atmosphere is like today. This all takes place in the Precambrian age. What fossil record evidence from the Precambrian shows abiogenesis shut down when our modern atmosphere appeared?
 

Catastrophe

"There never was a good war, or a bad peace."
Rod,

You ignored the second paragraph:

"abiogenesis, the idea that life arose from nonlife more than 3.5 billion years ago on Earth. Abiogenesis proposes that the first life-forms generated were very simple and through a gradual process became increasingly complex. Biogenesis, in which life is derived from the reproduction of other life, was presumably preceded by abiogenesis, which became impossible once Earth’s atmosphere assumed its present composition.

OK, life arose here, or arose elsewhere in the Universe. My understanding is a (without) bio (biological) genesis (beginning). If there is a wider definition "arose from nonlife elsewhere in the Universe", I would be grateful if you would please enlighten me."

Cat :)
 

rod

Oct 22, 2019
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Rod,

You ignored the second paragraph:

"abiogenesis, the idea that life arose from nonlife more than 3.5 billion years ago on Earth. Abiogenesis proposes that the first life-forms generated were very simple and through a gradual process became increasingly complex. Biogenesis, in which life is derived from the reproduction of other life, was presumably preceded by abiogenesis, which became impossible once Earth’s atmosphere assumed its present composition.

OK, life arose here, or arose elsewhere in the Universe. My understanding is a (without) bio (biological) genesis (beginning). If there is a wider definition "arose from nonlife elsewhere in the Universe", I would be grateful if you would please enlighten me."

Cat :)
No Cat I used that second part you point out. I asked if there is fossil record evidence from the Precambrian that shows abiogenesis shut down when the atmosphere became N2O2, "which became impossible once Earth’s atmosphere assumed its present composition." No fossil evidence cited to support this claim so I must assume none exist to document this dramatic shutdown of abiogenesis working on Earth when it did for perhaps 2 billion years or more. It seems a failed lab experiment stands by such statements about abiogenesis stops. So we have a failed lab experiment that did not create life from non-living matter and no fossil record to support such a dramatic shutdown in abiogenesis too. This methodology is something I do not accept.
 

Catastrophe

"There never was a good war, or a bad peace."
Rod,
Thank you for your suggestion, but to me it is totally illogical to think even for a nanosecond that, in all the billions of galaxies, and trillions of stars, life originated only in this pathetic little backwater.

To me it is blatantly obvious that in every galaxy there are billions (at least) cases of primitive life (starting from microbiological) and, at any one time, probably at least hundreds of cases of 'intelligent' life, to various degrees.

Evolution of life seems to me to be as obvious as evolution of stars.

Cat :) :) :)

P.S. I have just seen program on UK TV in the last hour, containing the estimate of galaxies in the observable universe as 2 trillion (galaxies).
 
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The universe is really, really big, with distances to even near stars being enormous; expecting to obtain samples and direct observations at a distance, let alone visits and direct contact is unrealistic. The circumstances that would allow us to find directly observable evidence of extraterrestrial life are exceptional - seems like it's transmissions on purpose or incidental or observation of atmospheric chemicals of planets that pass between their star and us. The possibility of actual visits - if our current understanding of physics is close to correct - is extremely, infinitesimally low even for any hypothetical alien species that has space capabilities.

We may indeed not have contact with aliens because no other life, let alone technology using ones exist. It is a possibility. Lack of observation, when we have barely begun looking with what tools we can devise, is not evidence they don't exist. It is evidence of the fact that we don't have the ability to look directly. Yet lots of knowledge is built around phenomena we cannot observe directly.

Abiogenesis is not proven false by the absence of observable occurrences, and life on Earth is potentially an example; Abiogenesis is still the most credible path to life we can conceive. We are unlikely to prove it by any direct observation of that abiogenesis occurred or is occurring on Earth - in this case it is not distance in space but distance in time that prevents observation of the former. The latter is more a case of evolution of existing life making a quick and easy meal of proto-life forms - they will be too vulnerable to being out-competed by more developed life forms.

I think we will see more chemistry modeling as the principle tool, with experiments to demonstrate specific chemical pathways - whilst arranging the conditions for those to occur, ie will not be random or unassisted. When those pathways are compatible with the conditions and abiotic chemistry of early Earth it will still be compelling evidence for abiogenesis.
 
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Catastrophe

"There never was a good war, or a bad peace."
News:

I have just seen program on UK TV in the last hour, containing the estimate of galaxies in the observable universe as 2 trillion (galaxies).

Just to remind you, In the U.S., one trillion is written as the number "1" followed by 12 zeros (1,000,000,000,000).
That gives around 2,000,000,000,000 galaxies only in the observable universe.

Now, how many stars per galaxy?
"Averaging out the types of stars within our galaxy, this would produce an answer of about 100 billion stars in the galaxy. This is subject to change, however, depending on how many stars are bigger and smaller than our own sun. Also, other estimates say the Milky Way could have 200 billion stars or more."
Source: How many stars are in the universe? | Space

Just take, say, 100 billion stars per galaxy. (100,000,000,000 or 10^11)
Than gives 2 x 10^12 multiplied by 10^11 or 2 x 10^23 stars in the observable universe.
For those who do not like scientific notation, that is:
200,000,000,000,000,000,000,000 stars.

And some might have you believe that life got started only on this puny backwater of only what we can see of the Universe.

Isn't this just a teeny bit anthropocentric, or perhaps medieval is an adequate description?

Cat :)

For those wishinng to pursue this matter as the presence of life in the Universe, other than in relation to visits by aliens, I have started a new thread under Cosmology:

New estimate of galaxies in the observable universe | Space.com Forums

Cat :)
 
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