Do you believe in possibility of life in other galaxies?

bearnard1616

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With over a hundred billion galaxies in the universe. It is hard for me to believe that there is not at least one other solar system with life. Especially, when some scientists claim that they have already found some exoplanets that can be like Earth.
 
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It depends on your view of the probability of life coming or evolving from non-life. It also depends on how you define, and how much faith, you have in many probability studies.

The last I checked, there was zilch probability, that life could have evolved on earth. Hence the comet life seeding theory.

But the thinking changes from decade to decade. It seems to be more of a want, than an answer. Because the ONLY evidence of life elsewhere.......is probability.

Can probability, prove probability?
 

bearnard1616

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It depends on your view of the probability of life coming or evolving from non-life. It also depends on how you define, and how much faith, you have in many probability studies.

The last I checked, there was zilch probability, that life could have evolved on earth. Hence the comet life seeding theory.

But the thinking changes from decade to decade. It seems to be more of a want, than an answer. Because the ONLY evidence of life elsewhere.......is probability.

Can probability, prove probability?
I`ve read an article that the Earth-like planet was found. "Earth Like Planet Found orbiting Proxima Centauri" by Al Paslow, published Sept.1, 2016; updated June 12, 2017, Mystic Sciences. Amazing detailed online article with artist illustration. So on some of those exoplanets that have been discovered by scientists some forms of life can live. I guss there is such possibility. Unfortunately we cannot check it(
 

bearnard1616

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I`ve recently watched the video about NASA`s the most expensive telescope. James Webb Space Telescope is considered to be the most technological and most advanced space telescope that is made for discovering exoplanets. I guess such project gives us the possibility to study those exoplanets and possibly it will help us find some forms of life on other planets. https://en.wikipedia.org/wiki/James_Web ... _Telescope
 
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I`ve recently watched the video about NASA`s the most expensive telescope. James Webb Space Telescope is considered to be the most technological and most advanced space telescope that is made for discovering exoplanets. I guess such project gives us the possibility to study those exoplanets and possibly it will help us find some forms of life on other planets. https://en.wikipedia.org/wiki/James_Web ... _Telescope
I'm not quite sure how the James Webb Telescope will be able to detect life, as it has been designed to detect light in a relatively narrow range in the mid-infrared, at wavelengths ranging from 0.6 micrometers to 28.5 micrometers, for the following reasons:
  • high-redshift objects which have their visible emissions shifted into the infrared
  • cold objects such as debris disks and planets which emit most strongly in the infrared
  • this band is difficult to study from the ground or by existing space telescopes such as Hubble
But trying to assess the possibility of extraterrestrial life, it is unknown how abundant such life is across the universe, or whether such life might be complex or intelligent.

On Earth, the emergence of complex intelligent life required a preceding series of evolutionary transitions such as abiogenesis, eukaryogenesis, and the evolution of sexual reproduction, multicellularity, and intelligence itself. Some of these transitions may be seen as extraordinarily improbable, even in conducive environments. The emergence of intelligent life late in Earth's lifetime is thought to be evidence for a handful of rare evolutionary transitions, but the timing of other evolutionary transitions in the fossil record is yet to be analyzed in a similar framework. Using a simplified Bayesian model* that combines uninformative priors and the timing of evolutionary transitions, we demonstrate that expected evolutionary transition times likely exceed the lifetime of Earth, perhaps by many orders of magnitude.

The original argument, suggested by Brandon Carter, concerns the idea that intelligent life in the Universe is exceptionally rare, assuming that intelligent life elsewhere requires analogous evolutionary transitions. Arriving at the opposite conclusion would require exceptionally conservative priors, evidence for much earlier transitions, multiple instances of transitions, or an alternative model that can explain why evolutionary transitions took hundreds of millions of years without appealing to rare chance events. Although the model is simple, it provides an initial basis for evaluating how varying biological assumptions and fossil record data impact the probability of evolving intelligent life, and also provides a number of testable predictions, such as that some biological paradoxes will remain unresolved and that planets orbiting M dwarf stars are uninhabitable.

One of the oldest arguments against SETI is the biological contingency argument (Simpson, 1964): the evolution of anything similar to humans has a minuscule probability since biological evolution is dominated by contingency, is radically open-ended, and has no determinism or tendency toward intelligence. Even in similar environments, the chance of getting “humanoids” is minimal, and most environments will be vastly different. This is the same argument used by Mayr in his debate with Sagan: out of the approximately 50 billion species on Earth, only humans evolved intelligence, suggesting a low probability (Mayr, 1995a, 1995b, 1995c).

Carl Sagan (1995) countered by noting that if there are enough possible pathways, even individually very unlikely paths can in sum give a high probability of an intelligent outcome. He also noted that extrapolating from our case is either valid, and we should expect Earth to be an average sample, or it is improper to extrapolate, in which case Mayr's argument fails. While the biological contingency argument can be attacked in other ways, for example, by emphasizing convergent evolution (Puccetti, 1968; Morris, 2003), and supported by noting the lack of convergent evolution toward human-like intelligence in the fossil record (Lineweaver, 2009), the key issue is how representative the Earth's biosphere history is (Rospars, 2013).

Brandon Carter proposed a simple model of evolutionary transitions to describe the process of intelligent life emerging. The model proposes that intelligent life requires n “critical steps,” each of which occurs at some rate λ. He further stipulates that λ−1 > τ⊙, so that the probability per unit time of the critical step is low enough that the time it takes for each critical step will typically exceed the lifetime of the star. A number of interesting properties follow from this model. First, the probability that the final transition occurs at time t is proportional to tn, so that the final critical step is likely to occur toward the end of habitable time remaining. Second, the amount of time remaining will be roughly equal to τ⊙/(n + 1), allowing one to estimate the number of critical steps that occurred in Earth's evolutionary history simply by knowing the amount of time left in Earth's habitable lifetime.

When Carter originally proposed the model, it was thought that the biosphere could last for another 4 billion years, which in turn suggested that there were likely only one or two critical steps in our evolutionary history. Subsequent improvements in climate models led to additional research that suggested that the time remaining is substantially shorter, on the order of 1 billion years (Caldeira and Kasting, 1992). A number of researchers have returned to Carter's critical step model and re-estimated the number of critical steps predicted by the remaining lifetime of the biosphere. Watson (2008) found that the best fit was with four critical steps, while Carter (2008) suggested between five and six. Waltham (2017) went further to demonstrate that models up to 12 critical steps still fall within a 95% confidence interval. Using the Carter model without further hard steps [e.g., just abiogenesis, as in Lineweaver et al. (2002) and Spiegel and Turner (2012)] produces significantly different estimates from including hard steps (Flambaum, 2003). The hard step model can also be combined with estimates of the window length (Lingam and Loeb, 2019), or even possible early windows for abiogenesis that later close (Lineweaver and Davis, 2003).

There are a number of reasons why the probability of an evolutionary transition could change over time. Perhaps most importantly, some evolutionary transitions may have required high oxygen concentrations as a source of energy, and oxygen concentrations have changed dramatically over Earth's history (Holland, 2006). The fact that oxygen concentrations have became high enough to support humans only in the past 800 Myr or so has led to some speculation that a planetary oxygenation time is the primary rate-limiting step to intelligent life (Catling et al., 2005). Relatedly, complex life on land requires shielding from ultraviolet radiation, and the emergence of an ozone layer has also been hypothesized to be a rate-limiting step that is correlated with stellar evolution, undermining Carter's original argument (Livio, 1999).

To test this, we adjust our model so that the transition rates change over time. The most dramatic example of this is a model in which the final evolutionary transition to intelligent life has a probability of zero until vertebrates on land emerge (340 million years ago), and that transition has probability zero until Phanerozoic oxygen concentrations are reached (800 million years ago). This model essentially tells us that these transitions occurred fairly rapidly once oxygen concentrations were high enough, and the results show a much larger peak around fast rates, suggesting a higher probability of intelligent life emerging in the right conditions. However, even these faster transition times are not enough to exclude extremely slow rates. Overall, accounting for a changing environment in terms of oxygen concentrations does not seem to be sufficient to overturn our key results.

after oxygenation.jpg

Posterior distribution if we assume two transitions that were made possible only after high oxygenation levels. Given the late oxygenation of Earth's atmosphere, these transition times are short, resulting in higher posterior probability on faster rates. However, arbitrarily slow rates are still not excluded. (Bottom) Posterior distribution if we adopt the self-indication assumption, and weight all parameter combinations by their probability of obtaining intelligent life. Only parameters that are consistent with intelligent life are assigned high probability, and extremely slow rates are ruled out entirely. Color images are available online.

It took approximately 4.5 billion years for a series of evolutionary transitions resulting in intelligent life to unfold on Earth. In another billion years, the increasing luminosity of the Sun will make Earth uninhabitable for complex life. Intelligence therefore emerged late in Earth's lifetime. Together with the dispersed timing of key evolutionary transitions and plausible priors, one can conclude that the expected transition times likely exceed the lifetime of Earth, perhaps by many orders of magnitude. In turn, this suggests that intelligent life is likely to be exceptionally rare. Arriving at an alternative conclusion would require either exceptionally conservative priors, finding additional instances of evolutionary transitions, or adopting an alternative model that can explain why evolutionary transitions took so long on Earth without appealing to rare stochastic occurrences. There are a number of other testable predictions, including that M dwarf stars are uninhabitable, that many biological paradoxes will remain unsolved without allowing for extremely unlikely events, and that, counterintuitively, we might be slightly more likely to find simple life on Mars.

We can conclude that intelligent life is exceptionally rare and that we may possibly be the only intelligent civilization within the observable universe, so long as we assume that intelligent life elsewhere requires similar evolutionary transitions. Although this may seem like a large assumption, there are good reasons to believe that many evolutionary transitions have universal properties (Levin et al., 2017). It also follows if we reason that our civilization is typical. If there were substantially easier evolutionary pathways to intelligent life that did not require such evolutionary transitions, we should expect to observe this easier evolutionary history instead. Although it is hard to show beyond doubt the absence of extraterrestrial intelligence, so far all of our astronomical data are consistent with being alone (Tipler, 1980).

* Bayesian statistics is a particular approach to applying probability to statistical problems. It provides us with mathematical tools to update our beliefs about random events in light of seeing new data or evidence about those events.

In particular Bayesian inference interprets probability as a measure of believability or confidence that an individual may possess about the occurance of a particular event.

We may have a prior belief about an event, but our beliefs are likely to change when new evidence is brought to light. Bayesian statistics gives us a solid mathematical means of incorporating our prior beliefs, and evidence, to produce new posterior beliefs.
Bayesian statistics provides us with mathematical tools to rationally update our subjective beliefs in light of new data or evidence.
This is in contrast to another form of statistical inference, known as classical or frequentist statistics, which assumes that probabilities are the frequency of particular random events occuring in a long run of repeated trials.

A Bayesian analysis of transition times

The objective is to estimate evolutionary transition rates, given how long it took to complete each transition. This can be found by using a Bayesian update as follows:



where t is the sequence of transition times t1,…,tn, β denotes our β parameters, and P(β) is a prior density over the expected transition time parameters. The term P(t|β), the probability of observing transition times t given the parameters β, is equivalent to the likelihood function as follows:


However, this likelihood function needs to be renormalized to account for the fact that we can only observe these data if all evolutionary transitions occurred before the end of Earth's lifetime. Accounting for this sample bias can be done by dividing the likelihood L(β|t) by the probability that all transitions occurred within the lifetime of Earth. If L is the lifetime of Earth, then our adjusted likelihood function is as follows:



where
is the probability that all transitions occur before the end of Earth's lifetime.

See: https://dailygalaxy.com/2021/03/the-aliens-before-us-we-are-not-the-first-technological-civilization-or-are-we/#utm_source=rss&utm_medium=rss&utm_campaign=the-aliens-before-us-we-are-not-the-first-technological-civilization-or-are-we

See: https://www.liebertpub.com/doi/10.1089/ast.2019.2149

See: https://www.quantstart.com/articles/Bayesian-Statistics-A-Beginners-Guide/

See: https://www.mathworks.com/help/stats/bayesian-analysis-for-a-logistic-regression-model.html;jsessionid=651855aa7c4c808bdf0975efb713

We have come a long way from Frank Drake's original equation on the probability of extraterrestrial intelligence. Which is the following:

{\displaystyle N=R_{*}\cdot f_{\mathrm {p} }\cdot n_{\mathrm {e} }\cdot f_{\mathrm {l} }\cdot f_{\mathrm {i} }\cdot f_{\mathrm {c} }\cdot L}

where:

N = the number of civilizations in our galaxy with which communication might be possible (i.e. which are on our current and past light cone) and where:

R∗ = the average rate of star formation in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fl = the fraction of planets that could support life that actually develop life at some point
fi = the fraction of planets with life that actually go on to develop intelligent life (civilizations)
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space

See: https://www.seti.org/drake-equation-index

andromeda m31.jpg

The Andromeda Galaxy. Image credit: Ivan Bok / CC BY 4.0.

When we look up in the night sky and the Andromeda Galaxy, M31 or NGC 224, swims into view in our field glasses, will someone on a planet in one of the habitable zones orbiting a stable G 2 star like our sun be looking back at the Milky Way, or whatever they call our home, wondering the same thing? Will they also have a forum where they can question the many possible pathways life has taken from RNA to intelligence contemplating the cosmos? Or are we, as I fear and they might also, alone.

Hartmann352
 
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I`ve recently watched the video about NASA`s the most expensive telescope. James Webb Space Telescope is considered to be the most technological and most advanced space telescope that is made for discovering exoplanets. I guess such project gives us the possibility to study those exoplanets and possibly it will help us find some forms of life on other planets. https://en.wikipedia.org/wiki/James_Web ... _Telescope

I can't wait til Webb gets operational. I predict it will confirm my earlier predictions. The farther we look, the denser it gets.
 

bearnard1616

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NASA`s the most expensive telescope James Webb Space Telescope will be able to detact forms of life on some of exoplanets but still, it give us a hint at probably some planets that can have life
 
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At the present time we have absolutely no evidence of life anywhere else except on the Earth. So if we use evidence as our criteria then I'd have to say 'No'. Using statistics and probability of billions and billions of galaxies, containing billions and billions of stars, that contain billions and billions of planets is just, conjecture. But then your question did ask, do you 'believe in the possibility' of life in other galaxies, which I would have to then answer 'Yes', there is always the 'possibility' of life in a different galaxy. The conundrum is a religious person could counter there is as much evidence for an Almighty God as there is for alien life. Both involve a belief system.

I was answering the question posed "Did I Believe There Was Life In Other Galaxies" My analogy to God was just an analogy, and was not meant to be a referendum on religion or does God exist. Many highly intelligent people believe there is intelligent life 'out there', yet those same people deny the existence of God even though the evidence for both is the same., or some people could legitimately argue maybe even a bit stronger for God because there is varied life here. When evidence for 'life out there' is cited, it's always cited as a statistical and probability of so many galaxies x so many stars x so many planets must = life. I don't agree that that's evidence, it's just conjecture! As for believing in God, I have found most people are taught this concept as children, and not a belief they come to by and in of themselves thru judging the evidence. Again, the thread was "Did I Believe There Was Life In Other Galaxies".

With over a hundred billion galaxies in the universe. It is hard for me to believe that there is not at least one other solar system with life. Especially, when some scientists claim that they have already found some exoplanets that can be like Earth.
bearnard,
Your belief seems to be the majority belief and for the reason you stated, yet it's still just statistical and probability, not evidence. just conjecture.
 
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bearnard1616

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bearnard,
Your belief seems to be the majority belief and for the reason you stated, yet it's still just statistical and probability, not evidence. just conjecture.
Unfortunately, I cannot show you any evidance, of this theory. Talking about life on the exoplanets that can be Earth-alike it`s just a conjecture. These planets are too far and we don`t know it for sure the only think we can do is presume and make some hypothesis.
 
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JacobCooper21

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Well, we live on Earth in Solar System. At least one planet in our system is habitable, right? Why can't other planet systems and galaxies have a similar structure and contain habitable exoplanets with people like us or other forms of life? I think yes, there's a possibility of life in other galaxies, but, unfortunately, we can't check this yet.
 
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bearnard1616

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Well, we live on Earth in Solar System. At least one planet in our system is habitable, right? Why can't other planet systems and galaxies have a similar structure and contain habitable exoplanets with people like us or other forms of life? I think yes, there's a possibility of life in other galaxies, but, unfortunately, we can't check this yet.
I like your point and assumption. The chance of it really exists, however, we don`t now for sure the structure of other galaxies, they might be not the same or familiar to the Solar system.
 
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JacobCooper21

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What do you think when we can travel at least to the nearest galaxies searching for extraterrestrial life? I understand that it's too early to make any assumptions as to it, but I want to know your opinion.
 
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bearnard1616

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What do you think when we can travel at least to the nearest galaxies searching for extraterrestrial life? I understand that it's too early to make any assumptions as to it, but I want to know your opinion.
To invent such kind of technology we need a lot of time. Just imagine what a huge leap we must take making space technology more advanced. Now we cannot even trawel to Mars or to other planets in the Solar system and I don`t think it will happen soon. The gap we need to bridge is too big
 
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Nobody knows for sure but it's possible. That's a fantastic question, bearnard1616– and one scientists are desperate to answer. The short answer is that we simply don't know.

I appreciate you Hartmann352 for sharing this wonderful thought!
 
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With over a hundred billion galaxies in the universe. It is hard for me to believe that there is not at least one other solar system with life. Especially, when some scientists claim that they have already found some exoplanets that can be like Earth.
I am of the same opinion and as others have posted it comes down to how you use the statistics and known information whilst sprinkling in a bit of personal belief but some things to consider that are need-

A planet with a iron core of a particular size to generate the required magnetic field to protect against solar winds; have a sufficiently large planet to 'vacuum' up the majority of space debris before it reaches your planet with one migrating towards the centre before being drawn back out by another massive planet forming; have a star that creates the required 'Goldilocks' zone for liquid water and favourable conditions; no quasars within light years of your planet; have had sufficient ice based asteroids and comets to allow water to arrive; have a secondary planet of the right size and mass to collide so as to create a 22deg (ish) angle and rotation for seasons whilst creating the moon to hold the planet's axis steady; have plate tectonics and weather to allow recycling of the land; have sufficient heat in the core to have a conveyor belt of molten rock to allow the plate tectonics...

Now we need to go onto what happened on Earth including the right amino acid composition to start life; favourable land areas for life to move to land, an asteroid to not wipe life completely but allow for mammals to take the Earth and evolve; no further major event such as asteroid impact, supervolcano (Tambora was close!), disease or predator; chance discoveries to progress a civilisation and then the leap into the future of no war and a population accepting that all funding should go into stellar exploration as unfortunately Earth does have an expiry date.

Perhaps the real question is, will we reach a position to establish if there is life away from Earth (not of our creation e.g. contamination).
 
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I am of the same opinion and as others have posted it comes down to how you use the statistics and known information whilst sprinkling in a bit of personal belief but some things to consider that are need-

A planet with a iron core of a particular size to generate the required magnetic field to protect against solar winds; have a sufficiently large planet to 'vacuum' up the majority of space debris before it reaches your planet with one migrating towards the centre before being drawn back out by another massive planet forming; have a star that creates the required 'Goldilocks' zone for liquid water and favourable conditions; no quasars within light years of your planet; have had sufficient ice based asteroids and comets to allow water to arrive; have a secondary planet of the right size and mass to collide so as to create a 22deg (ish) angle and rotation for seasons whilst creating the moon to hold the planet's axis steady; have plate tectonics and weather to allow recycling of the land; have sufficient heat in the core to have a conveyor belt of molten rock to allow the plate tectonics...

Now we need to go onto what happened on Earth including the right amino acid composition to start life; favourable land areas for life to move to land, an asteroid to not wipe life completely but allow for mammals to take the Earth and evolve; no further major event such as asteroid impact, supervolcano (Tambora was close!), disease or predator; chance discoveries to progress a civilisation and then the leap into the future of no war and a population accepting that all funding should go into stellar exploration as unfortunately Earth does have an expiry date.

Perhaps the real question is, will we reach a position to establish if there is life away from Earth (not of our creation e.g. contamination).
 
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I found that last year the University of Nottingham published a study in The Astrophysical Journal that has taken a new approach to this problem.

Using the assumption that intelligent life forms on other planets in a similar way as it does on Earth, researchers obtained an estimate for the number of intelligent communicating civilizations within our own galaxy — the Milky Way. They calculated that there could be over 30 active communicating intelligent civilizations in our home Galaxy.

Professor of Astrophysics at the University of Nottingham, Christopher Conselice who led the research, explains: “There should be at least a few dozen active civilizations in our Galaxy under the assumption that it takes 5 billion years for intelligent life to form on other planets, as on Earth.” Conselice also explains that “The idea is looking at evolution, but on a cosmic scale. We call this calculation the Astrobiological Copernican Limit.”

Author Tom Westby explains: “The classic method for estimating the number of intelligent civilizations relies on making guesses of values relating to life, whereby opinions about such matters vary quite substantially. Our new study simplifies these assumptions using new data, giving us a solid estimate of the number of civilizations in our Galaxy.

The two Astrobiological Copernican limits are that intelligent life forms in less than 5 billion years, or after about 5 billion years — similar to on Earth where a communicating civilization formed after 4.5 billion years. In our criteria, where the metal content equal to that of the Sun is needed (the Sun is relatively speaking quite metal-rich), there should be around 36 active civilizations in our Galaxy.”

et distance.jpg

The research indicates that the number of civilizations depends strongly on how long they are actively sending out signals of their existence into space, such as radio transmissions from satellites, television, FM and AM radio, etc.

However, the average distance to these civilizations would be 17,000 light-years away, making detection and communication very difficult with our present technology.

Professor Conselice explains: “Our new research suggests that searches for extraterrestrial intelligent civilizations not only reveals the existence of how life itself forms, but also gives us clues for how long our own civilization will last. If we find that intelligent life is common then this would reveal that our civilization could exist for much longer than a few hundred years, alternatively if we find that there are no active civilizations in our Galaxy it is a bad sign for our own long-term existence. By searching for extraterrestrial intelligent life — even if we find nothing — we are discovering our own future and fate.”

And isn't our fate akin to a bell curve, and aren't the fates of all these civilizations, real or imagined, to be found on similar bell curves?

org stability.png

In any case, the distances involved, even at a paltry 17,000 light years by galactic and inter-galactic standards, makes communication, let alone reception, rather difficult when each side of these conversations are separated by such long, almost infinite in human terms, pauses. And what of travel to these distant outposts?

Imagine undertaking such a mission with a Project Orion* type of propulsion.

NASA-project-orion-artist.jpg
NASA-project-orion-artist

Later studies indicate that the top cruise velocity that can theoretically be achieved by a Teller-Ulam thermonuclear unit powered Orion starship, assuming no fuel is saved for slowing back down, is about 8% to 10% of the speed of light (0.08-0.1c). An atomic (fission) Orion can achieve perhaps 3%-5% of the speed of light. A nuclear pulse drive starship powered by Fusion-antimatter catalyzed nuclear pulse propulsion units would be similarly in the 10% range and pure matter-antimatter annihilation rockets would be theoretically capable of obtaining a velocity between 50% to 80% of the speed of light. In each case saving fuel for slowing down halves the max. speed. The concept of using a magnetic sail to decelerate the spacecraft as it approaches its destination has been discussed as an alternative to using propellant, this would allow the ship to travel near the maximum theoretical velocity.

At 0.1c, Orion thermonuclear starships would require a flight time of at least 44 years to reach Alpha Centauri, not counting time needed to reach that speed (about 36 days at constant acceleration of 1g or 9.8 m/s2). At 0.1c, an Orion starship would require 100 years to travel 10 light years. Carl Sagan suggested that this would be an excellent use for current stockpiles of nuclear weapons.

See: https://uber-facts.com/scientists-say-there-could-be-36-alien-civilizations-in-the-milky-way/

* Project Orion, See: https://infogalactic.com/info/Project_Orion_(nuclear_propulsion)

Distance and its relationship to time appear to render realistic communication with and travel to the galactic location sending out intelligent signals nearly impossible. However, since I first saw the Outer Limits, Season One, Episode One, 'The Galaxy Being' from 1963 with Cliff Roberts, I have always hoped that one day such communication would be feasible.
Hartmann352

"Those who dream by night in the dusty recesses of their minds, wake in the day to find that it was vanity: but the dreamers of the day are dangerous men, for they may act on their dreams with open eyes, to make them possible." -- T.E. Lawrence
 
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its a lot of probability to life on other galaxy's and i personaly think that must life on other galaxys we cant see means they donot exist.
 
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I like your point. I guess there is a chance that some forms of life ( even intelligent ) can exist on some planets that were called by scientists as exoplanets and according to scientists' statements they can remind Earth.
It does little good to worry about life, single cell, multi-cellular or intelligent, existing so far away away and separated by so much time that even if it does exist the possibilities of contact render its existence so minuscule in the aggregate as impossible to gauge.
Hartmann352
 
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Isn't modern science amazing? They teach us that matter can not reach c, because it would take an infinite energy. In other words, c for matter is impossible.

And then, they turn around and say the universe is accelerating at multiple c rates. We should have graduate degrees in fork tongue rhetoric.

Our science is based on ignorance and filled in with lies. It's all snake oil.

Starlight redshift is caused by gravity, not acceleration. Take any oscillation. Slide it thru a gravity field.....the frequency changes. Everyone knows this, but they insist velocity is the cause.

Our star trek scientists need super c speeds......for the dream of travel. More likely more funding for research. Like CERN, astronomy is a complete scam. We still can't measure a base line for parallax.

Understanding reality starts with understanding light. And no modern scientist understands light.

All light has a relative velocity. They just don't know how to measure it. Once you understand light, matter can be understood. And see that the standard model and QM is from kindergarten intellect.
 
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There are three main categories of statistically independent signals (isotropic, narrow beams, and rotating beacons) needed to calculate the average number NG of emission processes present in the Galaxy and the average number of them crossing Earth, k¯⁠, which is a number amenable to statistical estimation from direct observations. We show that k¯ coincides with ND (Drake's number*) only for isotropic emissions, while k¯ can be orders of magnitude smaller than ND in the case of highly directional signals. We further show that while ND gives the number of emissions being released at the present time, NG (Galactic number) also considers the signals from no longer active emitters but whose emissions still occupy the Galaxy because they still remain in transit at light speed. We find that as long as the average longevity of the emissions is shorter than about 105 yr, NG is fully determined by the rate of emissions alone, in contrast to ND and k¯ which also depend on the emission longevity. Finally, using analytic formulas of NG, ND, and k¯ isn be determined for each type of emission process considered, and a comprehensive overview of the values of these quantities can possibly achieve the functions of the emission birthrates, longevities, and directionality of the civilizations sending these signals..

The contribution of each type of emission to the total number of processes crossing Earth's orbit strongly depends on the relative abundance of signal types and their longevities. As shown in the chart below, the contribution to k of isotropic processes and lighthouses in 2D would likely dominate over other types of emissions of similar birthrates.

Screen Shot 2021-07-16 at 2.15.30 PM.png

Under the assumption that the emission birthrates did not change during the recent history of the Galaxy, we have shown that k = ND only for isotropic processes and for emissions originating from rotating beacons sweeping the galactic disk. In all the other cases considered (beamed signals directed randomly and lighthouses with tilted rotation axis) k can be orders of magnitudes smaller than the Drake number, showing that the historic ND may largely overestimate the possible occurrence of signals that can be detected.

See: https://academic.oup.com/mnras/article-abstract/500/2/2278/5960163?redirectedFrom=fulltext

See: https://arxiv.org/pdf/2011.14147.pdf

* Drake's number:
{\displaystyle N=R_{*}\cdot f_{\mathrm {p} }\cdot n_{\mathrm {e} }\cdot f_{\mathrm {l} }\cdot f_{\mathrm {i} }\cdot f_{\mathrm {c} }\cdot L}

where:
N = the number of civilizations in our galaxy with which communication might be possible (i.e. which are on our current past light cone);
and
R∗ = the average rate of star formation in our galaxyfp = the fraction of those stars that have planetsne = the average number of planets that can potentially support life per star that has planetsfl = the fraction of planets that could support life that actually develop life at some pointfi = the fraction of planets with life that actually go on to develop intelligent life (civilizations) fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space L = the length of time for which such civilizations release detectable signals into space.

While Drake's equation was a superb starting point when it was first presented in 1961 by Frank Drake to estimate the number of galactic civilizations, it has been fine tunes since then, most notably and recently by Claudio Grimaldi in his paper of 28 November 2020 "Demography of galactic technosignatures". He fully fleshes out his additions, such as failed or destroyed civilizations whose radio output is still traveling across the galaxy at the speed of light whose messages may cross the Earth's orbit at some future time. I find these ideas fascinating. As far as reaching the seat of these broadcasts, is it even possible - physically or financially to do so? Once sent, would we ever expect to hear from these pioneers again?
Hartmann352
 
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Jul 29, 2021
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The optimistic point is that from several approaches (astrology, astrobiology, philosophy) there is continuous ideas, theories and calculations emerge.

Together with Fermi Paradox and SETI [may have] messages to be re-analysed, commonly discussed within the extraterrestrial life subject, there are some more spots that could be considered.
  1. This is as far as our knowledge and data is available. There might be a chance with Big Data and Data Science technologies to overlook all collected messages?
  2. Life evolution and reproduction is not following common entropy, it creates an order, but this should result in the intelligence self-destruction (assuming analysis of human evolution).
  3. Life and intelligence have no exact definition (at least they may have a set of definitions, according to astrobiologists).
  4. We might have a chance with an AI approach of definitions? Which could be believed/predicted as another evolution phase. Another intelligence form, that doesn’t need DNA reproduction and probably entropy contradiction.

P.S.: Stephen Hawking mentioned that we might start our life occurrence in the universe thinking by making a hypothesis: “the universe exists for life being here” and “if not our planet, why another one”.


There is no yes/no answer, rather than philosophical approaches. Even now we are not sure of planet 9 in our solar system.
 
Apr 5, 2021
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It depends on your view of the probability of life coming or evolving from non-life. It also depends on how you define, and how much faith, you have in many probability studies.

The last I checked, there was zilch probability, that life could have evolved on earth. Hence the comet life seeding theory.

But the thinking changes from decade to decade. It seems to be more of a want, than an answer. Because the ONLY evidence of life elsewhere.......is probability.

Can probability, prove probability?
Hayseed, I quite agree.

It appears that many [but not all] of the people who believe in ET base their belief in 'probability & statistics', not in a shred of evidence other than here on Earth. The fact that 8 planets comprise our solar system with 3 possible planets in the 'habitable zone for life' [Venus, Earth and Mars] in our Milky Way Galaxy, and that billions of stars comprise each galaxy, and there are billions of galaxies seems to be the rationale for this belief.

Not to sound religious, I'm not, but I find many of the 'scientists' who are atheists have this belief in ET, yet reject a Supreme Being 'God' when there is probably more evidence for a Supreme Being because we do have intelligent life here on Earth and there have been so-called 'miracles' ascribed to such a Supreme Being. Just a thought, not a rationale.

Speaking of Earth, so many different things happened, that if even one single thing didn't happen life 'may' not even have been possible here, from Saturn stopping Jupiter from coming into the inner solar system to Theia slamming into Earth, [BTW why is this never mentioned as a source for 'life' and 'water'] to having a tilt and our Moon, etc., etc., etc.

Dennis
 
Mar 4, 2020
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Hayseed, I quite agree.

It appears that many [but not all] of the people who believe in ET base their belief in 'probability & statistics', not in a shred of evidence other than here on Earth. The fact that 8 planets comprise our solar system with 3 possible planets in the 'habitable zone for life' [Venus, Earth and Mars] in our Milky Way Galaxy, and that billions of stars comprise each galaxy, and there are billions of galaxies seems to be the rationale for this belief.

Not to sound religious, I'm not, but I find many of the 'scientists' who are atheists have this belief in ET, yet reject a Supreme Being 'God' when there is probably more evidence for a Supreme Being because we do have intelligent life here on Earth and there have been so-called 'miracles' ascribed to such a Supreme Being. Just a thought, not a rationale.

Speaking of Earth, so many different things happened, that if even one single thing didn't happen life 'may' not even have been possible here, from Saturn stopping Jupiter from coming into the inner solar system to Theia slamming into Earth, [BTW why is this never mentioned as a source for 'life' and 'water'] to having a tilt and our Moon, etc., etc., etc.

Dennis

I believe that because of the obvious uniqueness of life only here, life should be classified as super natural. And the recognition of a life force.

In some way, this life force can re-configure and manipulate and animate, non-living matter.....into UN-natural combinations that we call living matter. Only here.

This living force goes thru cycles and has to be passed on. It consumes and propagates. Only here.

I do not believe man will ever find this life source, but I do believe we can understand natural forces, and understand natural matter.

Hopefully in the future, with better imaging techniques, we might strobe an electron, and put this silly modern science to rest. It's not a waveform, it's a real thing, a structure of matter.

But neither a life force or a particle structure are searched for. Or even recognized.

A bell curve of probability is not a structure.
 

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