Are we alone?

[Tellie]

Ya know, only one planet can claim to be the first to have life in the universe. Why can't it simply be us? Or "It's a cook book"

[Yellowtulip]

Originally Posted by Tellie

Ya know, only one planet can claim to be the first to have life in the universe. Why can't it simply be us? Or "It's a cook book"

It took 4billion years for life to evolve on Earth, but the Universe is three times that age. So there’s been more than enough time for other life forms to appear (and disappear) in that time. Since there are billions of planets similar to Earth it’s highly likely that Earth-like life has evolved somewhere else first, let alone non-Earth like life.

[Tellie]

Originally Posted by Yellowtulip

It took 4billion years for life to evolve on Earth, but the Universe is three times that age. So there’s been more than enough time for other life forms to appear (and disappear) in that time. Since there are billions of planets similar to Earth it’s highly likely that Earth-like life has evolved somewhere else first, let alone non-Earth like life.

Maybe so. The universe is also a very violent place for life, so maybe not.

[GordMay]

Using the Drake equation*, the "Search for Extraterrestrial Intelligence" meeting (Green Bank, 1961) postulated that there were probably between 1000 and 100,000,000 planets with detectable civilizations (not including primordial or primitive life forms), in just the Milky Way galaxy.

It is extremely unlikely (statistically) that Earth hosts the only technological species, that has ever occurred.
If fewer than 1 in 60 billion habitable planets develop a technological species, there must have been at least a second case of such a species, over the past history of just our Galaxy.

* Even though the Drake equation involves speculation, about unmeasured parameters, it was intended as a way to stimulate dialogue, on these topics. Indeed, Drake originally formulated the equation merely as an agenda, for discussion at the Green Bank conference.

Of course, Fermi’s Paradox remains to be explained. "Where is everybody?"

“Are we alone in the universe? Revisiting the Drake equation” ~ by Leonor Sierra
“... a new paper [1] shows that the recent discoveries of exoplanets combined with a broader approach to the question makes it possible to assign a new empirically valid probability to whether any other advanced technological civilizations have ever existed.
And it shows that unless the odds of advanced life evolving on a habitable planet are astonishingly low, then human kind is not the universe’s first technological, or advanced, civilization ...”
Much more ➥ https://exoplanets.nasa.gov/news/135...rake-equation/

[1] “A New Empirical Constraint on the Prevalence of Technological Species in the Universe” ~ by A. Frank and W.T. Sullivan
➥ https://www.liebertpub.com/doi/pdfpl.../ast.2015.1418

If we expand the question, beyond technological intelligent life, to just intelligent life, we may not even be unique, on our planet.

[Yellowtulip]

Regarding Fermi’s paradox, we are looking for, indeed are only able to, detect life that is a) like ours and b) at a similar state of technological development as us. Suppose this state (call it the Radio Age) lasts for a thousand years before we discover better means of communication, then there will be an expanding sphere of radio traffic a thousand light years thick emanating from our planet and any other planet capable of it. In the context of the Galaxy, let alone the Universe, that is vanishingly thin. If such a sphere of alien radio broadcasts passed us by two hundred years ago we would know nothing about it.
But it may just be that life is rare and interstellar travel too difficult to be common. Fermi still has to be addressed, however.

[GordMay]

On the other hand:
“Our Improbable Existence Is No Evidence for a Multiverse” ~ by Philip Goff
Experts in probability have spotted a logical flaw in theorists’ reasoning
“We exist, and we are living creatures. It follows that the universe we live in must be compatible with the existence of life. However, as scientists have studied the fundamental principles that govern our universe, they have discovered that the odds of a universe like ours being compatible with life are astronomically low ...”
More ➥ https://www.scientificamerican.com/a...-a-multiverse/

[Yellowtulip]

Originally Posted by GordMay

On the other hand:
“Our Improbable Existence Is No Evidence for a Multiverse” ~ by Philip Goff
Experts in probability have spotted a logical flaw in theorists’ reasoning
“We exist, and we are living creatures. It follows that the universe we live in must be compatible with the existence of life. However, as scientists have studied the fundamental principles that govern our universe, they have discovered that the odds of a universe like ours being compatible with life are astronomically low ...”
More ➥ https://www.scientificamerican.com/a...-a-multiverse/

“...astronomically low..” very good. Do you think he meant it?
It’s possible, of course, that we are alone, or that life is so rare that we never find anymore. I hope not.

[Mike OReilly]

The problem with all this statistical speculation is that until we find actual life somewhere else, we still only have one confirmed incidence. As anyone competent in stats will say, it's impossible to know the probability of something using only one data point.

Given all we know about the immediate Universe around us, it seems unbelievable that life could have evolved in only one place. But until we confirm life is, or has, existed outside of the Earth's biosphere, the statistical question remains with a sample size of one.

This is why exploration of Mars, the asteroids, and perhaps the bigger moons of Jupiter and Saturn, are so neessary. I believe we're getting closer to that Ah Ha! moment. I expect it will come in the next decade. But until then, we can't really know if we are alone.

[hpeer]

If there are advanced civilizations out there then we wont need to find them, they will find us.

And maybe they have, and are keeping an eye on us.

Navy video does seem to suggest something is going on.

[Tellie]

Originally Posted by GordMay

Using the Drake equation*, the "Search for Extraterrestrial Intelligence" meeting (Green Bank, 1961) postulated that there were probably between 1000 and 100,000,000 planets with detectable civilizations (not including primordial or primitive life forms), in just the Milky Way galaxy.

It is extremely unlikely (statistically) that Earth hosts the only technological species, that has ever occurred.
If fewer than 1 in 60 billion habitable planets develop a technological species, there must have been at least a second case of such a species, over the past history of just our Galaxy.

* Even though the Drake equation involves speculation, about unmeasured parameters, it was intended as a way to stimulate dialogue, on these topics. Indeed, Drake originally formulated the equation merely as an agenda, for discussion at the Green Bank conference.

Of course, Fermi’s Paradox remains to be explained. "Where is everybody?"

“Are we alone in the universe? Revisiting the Drake equation” ~ by Leonor Sierra
“... a new paper [1] shows that the recent discoveries of exoplanets combined with a broader approach to the question makes it possible to assign a new empirically valid probability to whether any other advanced technological civilizations have ever existed.
And it shows that unless the odds of advanced life evolving on a habitable planet are astonishingly low, then human kind is not the universe’s first technological, or advanced, civilization ...”
Much more ➥ https://exoplanets.nasa.gov/news/135...rake-equation/

[1] “A New Empirical Constraint on the Prevalence of Technological Species in the Universe” ~ by A. Frank and W.T. Sullivan
➥ https://www.liebertpub.com/doi/pdfpl.../ast.2015.1418

If we expand the question, beyond technological intelligent life, to just intelligent life, we may not even be unique, on our planet.

"the Drake equation involves speculation"... Thus my simplistic "Maybe so, maybe not."



Maybe, if we can ever finally get the James Webb up there, who knows what new wonders or speculative confirmations we might be in for.

[barnakiel]

I think that "we are alone" is a religious thinking.



Given the number of habitable planets estimated, we are extremely unlikely to be alone.


" ... To make a calculation of how many habitable planets there might be then, we can take the estimate of 2.5% from the total number of planets (20 sextillion). That comes to 200 quintillion, or 200,000,000,000,000,000,000. ..."


https://skiesandscopes.com/habitable-planets




Cheers,
b.

[barnakiel]

We can assume that our green neighbours are very smart (well, they need to be to build an ufo to get here from there).


But if they are that smart, they will come, look, spit, and move on.


Only an idiot alien would like to make contact with idiots like us.


Why make contact with an aggressive species that is in the process of wiping itself off the face of its home planet?



barnakiel

[Old fella]

I reckon they arrived here a week or so ago, and the first thing they heard on the radio waves was a Donald trump speech. They turned around and got the hell out of there, I could have sworn I heard screaming noises coming from the sky that night.

[hpeer]

Originally Posted by barnakiel

We can assume that our green neighbours are very smart (well, they need to be to build an ufo to get here from there).


But if they are that smart, they will come, look, spit, and move on.


Only an idiot alien would like to make contact with idiots like us.


Why make contact with an aggressive species that is in the process of wiping itself off the face of its home planet?



barnakiel

To contain the contamination?

[BAD ORCA]

Originally Posted by Dave_S

I remember as a kid, looking at the night sky and wondering how far it goes and realising there is nothing in the heads of people on earth who can understand the answer to that question.

It's either infinity or it's not. Neither answer is within our comprehension.

I disagree. I think we understand the concept of what infinity is. Robert Thurman summed it up nicely i think. He described that infinity is not a thing but the concept of unlimited open ended possibilities. Thats not exactly how he said it but how i remember it. Theorists might call it granularity rather than thinking of infinity as something dimensional.