Interesting conversation on here. According to NASA, there could be millions of habitable planets out there.

My guess: millions of planets or more.

If they have enough water for clouds and storms and they will have some kind of life eventually. Not all planets are the same age. Suns are still forming from interstellar gas. I expect life to be plentiful.

It may or may not be interesting. How many planets with algae also have organisms that build flying saucers and fly between the stars? Possibly none. There is some possibility that visiting other planets is so costly that it is never done. It is possible that the only outcome is that we find life. There is nothing they have that justifies the cost of making the journey. Maybe civilizations make the trip once and figure out that any contact is lethal to both sides. One bacterium from our world finds their world full of "empty" living space, and one bacterium from their world likewise finds our world "empty." They replicate without control because nothing in the original world can metabolize the new chemistry. The world ecosystem crashes.

It may also be that there are many alien civilizations but they are so far apart that they might as well be alone in the universe. One civilization every 100,000 light years and no warp drive. The signals from our civilization are at best slightly over 100 light years distant. Also, the signals will be very faint at that distance because they did not have much power behind them (at least when measured on a cosmic scale).

It might be interesting to ask: given the power behind modern electronic signals, have we deployed equipment that is sensitive enough to detect that signal if it came from 10 light years away?

The question depends on the definition of life. Then the question should be changed to: How many Earth-like planets are there in the universe -- i.e. planets where life on Earth may be translated to and survive. The current answer is: The number is still unknown. Estimates range from only one (Earth) -- the extreme Rare Earth hypothesis -- to innumerable.

There are no others so far!

Depends on how picky one is about the definition. An exact duplicate, no. Things that are close within the limits of our ability to determine:

https://www.space.com/30172-six-most-earth-like-alien-planets.html

We need to be very careful about playing Star Trek and happily running around every planet we find unless our goal is to destroy all non-earth life in the universe. Look at what happens when we move organisms from one continent to another. Must we replay introducing small pox to the Americas, or infecting the citrus groves in the USA with Huanglongbing, gypsy moth, dutch elm disease, and the list goes on. Yes, I cannot prove that there will be any problem at all. Yet there is ample precident and if a problem develops it will be far too late after the fact. It could go the other way: we set foot on another planet and a microbe there finds our sugars and fats irrisistable.

Why use the word create in the first place? For some attempt to quantify in part your question, search for Drake "equation".

https://en.wikipedia.org/wiki/Drake_equation

Possibly billions of civilization exist and we dont know how to reach them with current technology.

or maybe we are alone .

but after analysing the contents that helpful to create life there are many planets . there life can exist ,in and outside our galaxy

Simply our technology needs to be far more advance techniques to get this answer

Do you mean "in the Universe" or "in the observable Universe"?

Missions like Kepler suggest that almost every single star has a planetary system and of the order of 1 in 104 has a planet in what we would consider the "habitable zone". Other factors might reduce the number that could support life by some factor but a typical large galaxy with 1011 stars might contain of the order of 105 life bearing planets. It is estimated that there might be 1011 such galaxies in the observable universe or say 1016 in total, but the universe as a whole is probably at least 1013 times larger, perhaps much more, so something like 1029 planets would be a conservative estimate.

Of course the majority of those planets might have no species more advanced than single-celled organisms, or perhaps our dinosaurs, and all but those within our own galaxy are beyond detection or communication.

Very interesting various conclusions, suggestions and scientific theses appeared in your discussion.

Your remarks, conclusions, conclusions, scientific considerations are very interesting and enrich the discussions in this topic. Thank you for participating in the discussion.

In your comments, there are different perspectives on the above issues, which significantly enrich this discussion.

I invite you to continue the discussion People interested in this subject.

The Drake equation (https://en.wikipedia.org/wiki/Drake_equation) deals with this, but the main problem of this equation is the correct input data. The Universe is extremely large, it consists from the same matter as we have here on Earth and in our Solar system, so (IMHO) existence of many many civilisations across the Universe is very probable. On other hand, as the Universe is very large in space and in time, we can easily miss other civilisation in space and/or in time. Probably we do not have mature civilisation in close vicinity (a couple of light years), but it is extremely complicated to find other civilisation if is very far from us, particularly if we consider other galaxy...

“The universe is a pretty big place. If it's just us, seems like an awful waste of space.”

― Carl Sagan, Contact

It is arrogant, but typical for Earthlings to think that they are the only ones. I would say the number is infinite.

There is, as far as we know, no reason to limit life to planetary systems similar to our own. So as far as "primitive" forms of life are concerned, the number of planetary systems that can or should have life on one or more planets is probaby as close to infinity as the number of planetary systems.

For more complex life forms, things are more complicated. It is known that primitive life forms existed on Earth even in the Hadean era, and complex life forms (sponges, etc) came into being only about 10% of that time ago. So it seems to take a long time to go from primitive forms to things that most people would have any interest in. In fact, a recent study of the rate of growth of complexity at the level of DNA suggests that even Hadean life was very complex compared to what might be considered the least complicated form of life, and suggests that extremely primitive life forms may have originated around 10 billion years ago, long before the formation of our Solar System, and have been spread throughout our galaxy as frozen organic material by comets and interstellar asteroids. If so, primitive life forms would be even more common than the suggestion in the first paragraph, BUT the time frame between the origin of life and of what we consider complex life then becomes more than twice as long as previously tought, in which case life forms now on the Earth may be the currently most complex in our entire galaxy.

So... for life in general, take the biggest number you can think of, and it's probably not big enough. But for complex life forms, depending on how complex you want it to be (e.g., capable of interstellar travel), the number could drop very close to zero.

I guarantee that the number is not infinite. If the number were infinite then there would be no room for anything else in the universe even if each alien civilization consisted of only one organism.

CS: There is, as far as we know, no reason to limit life to planetary systems similar to our own.

That is true, planets with hydrocarbon-based weather cycles could support life in forms of which we have no knowledge, but an estimate based on planets like our own can provide a good figure for a lower limit.

TAE: I guarantee that the number is not infinite.

I think we can assume that the density is finite, but you cannot guarantee that the universe is not infinite. In fact that is the simplest interpretation of the apparent flatness of the universe.

Actually it is easy.

If the big bang theory is correct (or even mostly accurate) then one would have to postulate an infinitely fast rate of expansion to get a universe that is infinite. "Unimaginably large" is not infinite. Just because I cannot walk from one end to the other in my lifetime does not make it infinite. Just because it is expanding faster than I can travel does not make it infinite.

You could be silly and say that I will fit an infinite number of alien civilizations into a finite space by making them infinitely small.

George's comment on the original post prompted a look at curvature of the universe.

https://en.wikipedia.org/wiki/Shape_of_the_universe

In retrospect my answer was not good. However, in an infinite universe, most of the universe will be unobservable. Alien civilizations beyond 14 billion parsecs (45.7 billion light years) do not count because even the light from their suns will never reach us.

https://en.wikipedia.org/wiki/Observable_universe

Within this fixed volume of space there are a countable number of galaxies, solar systems, and planets.

TAE: If the big bang theory is correct (or even mostly accurate) then one would have to postulate an infinitely fast rate of expansion to get a universe that is infinite.

Not at all. Curvature doesn't change sign so if it was zero or negative, both of which give an infinite universe, then there was never a time when the curvature was positive. That would mean it had always been infinite regardless of the rate of expansion.

I did not mean that the number of planetary systems is literally infinite -- merely so large that any finite number suggested is probably too small. And at least some kind of primitive life is probably found on several objects in any given planetary system (we have already had reasonable suggestions for present and/or past life on several objects in our own system), so almost any specific number suggested for the number of objects with some kind of living organism is almost certain to be an underestimate.

Nor do I think that the Universe is infinite in size, or that it ever will be. It is certainly far larger than the roughly 14 billion light year radius usually quoted in the press, and perhaps a zillion times larger than the roughly 50 billion light years that is the current distance of the most distant objects in the "Observable Universe". And since even the Cosmic Background is receding from us at the speed of light, the furthest parts of the current Universe (counting the part that lies beyond the Observable Universe) must be expanding away from us at a similarly zillions of times greater speed than light. And although the local density of galaxies is small compared to the space available, with that much space, there must certainly be an unimaginably large number of places where life can exist.

However, despite that "optimistic" attitude concerning the existence of extra-terrestrial life, I think that proving that it exists is going to be very difficult, and that I may not live long enough to read any credible proof that there is life anywhere else even in our own Solar System; and feel certain that there will be no proof of the existence of life outside our Solar System even if I live another 30 or 40 years.

I am sure that I have never been to this planet before, I love the planet earth, nature, animals, etc. but most of the humans that are here are too harsh, and unenlightened compared to where I came from. I remember at 8 years old, my sibling who was attending university and majoring in history, told me about how people warred on earth, and I said that I was happy that I was not born then, and she responded by telling me that history repeats. At that moment, at the age of 8 years old, I thought what kind of horrible planet have I been sent to? E.T.

So far, we don’t have any direct evidence for the existence of life in other solar systems or outside of our solar system. Further, we cannot rule out the possibility of life without hydrocarbon materials also.  Who are we to declare or conclude that a life must be formed with or in combination of hydrocarbon materials alone? Other solar system or universe may hold life in other form of materials.

Our understanding on life forms and universe is very limited. If we compare our understanding on every concepts during the past two centuries we can understand that we had a significant progress. Yet, our understanding is limited.  We don’t know the complete life style of thousands of insects or small creatures or even existence of certain creatures in our mother planet itself. That’s the reason we document or report the existence of new species, newer life cycles for existing species every year. We have only one mother planet (a finite) but the life forms are (infinite) due to lack of our understanding. Theoretically, we can say that the number of life forms exist in our planet must be finite. If so, then what is the final number of total species exist in our world. It is not possible to document each and every form of life exist in all forms of ambient and niches. It is like an attempt to provide precise measurement for sand grains present in the bottom of an ocean. Theoretically, we can provide a number but practically it is not verifiable. The primary reasons is it is in a continuous flux state.  We have superior technologies to measure the movement of an atom but we don’t have technologies to calculate and express such huge data derived from sand grains from single ocean. I would like to express this condition as “impossible to measure or calculate” even within limited time and space.

 Here, I would like to denote TAE expression “ Unimaginably large" is not infinite. Yes, it is practically observed in our civilization or in every field. The depth of an Ocean, height of an mountain which remain unknown in previous centuries are become known in the present century. However, the scenario of “impossible to measure or calculate” even within limited time and space disclosed our own limitation. Hence, the context of infinite applied for universe is “impossible to measure or calculate”

We cannot say that the universe is infinite because of ignorance and we cannot speculate that the universe is finite.  Hence, at present universe is infinite since we don’t have the evidence for finite universe.  Likewise, total number and size of universe and its life forms cannot be defined.  

The acceptance of our ignorance on the concepts (as infinite) will aid us to explore further about the finite features of the infinite. However, consideration of universe as finite will never allow us to progress since we need to define the final number or finite materials or finite dimension at the first step to measure other systems present within it. It’s like beginning the first step of a serious of arithmetic equations with wrong number or wrong signs. It may not be possible to verify due to massive number of steps, equations and iterations but at the end it is a wrong number.

Consider that there are 200+ billion stars in the Milky Way & somewhat more than 1000 exoplanets have been discovered; that's a ratio of 200 million to 1.

There are at least as many galaxies as there are stars in our galaxy so the probability of some form of life in the universe may be greater than zero.

So far, no radio studies have heard any signals that indicated an alien/intelligent origin. Some folks think the search is a waste of astronomical time...who knows?

RW

A subsidiary question is of all the planets harboring intelligent life how many are home to beings far more evolved with intelligence well beyond our own? Earth is only some 4.5 or so billion years old while the Universe is ~13 billion years old. That allows plenty of time for beings somewhere to evolve that are billions of years more advanced (or at least have been around longer) than us.

But, yes, the host stars of planetary systems also evolve as they consume their stores of nuclear fuels with consequences that may not be beneficial to their associated planetary systems and the living beings they support. Stars evolve through stages that may niclude expansion to giant and supergiant size in which they devour their planetary progeny as will our sun one future day.

https://www.researchgate.net/post/Do_you_think_that_there_is_intelligent_life_of_other_creatures_on_other_planets

One Strange Rock is a beautiful documentary series from National Geographic that explores our delicate and wondrous Planet. The series is hosted by Will Smith and strengthened by eight astronauts giving their personal experiences and perspective of Earth from a distance.

Episode 8 titled "Alien" gives a fine idea of the possibility of life elsewhere.

Episode 4 "Genesis", describes the difficulty, dynamic forces, coincidences and how everything had to fall in place for life to begin on Earth.

"For an alien planet out there to evolve over those billions of years and to be exactly like it evolved here on Earth... that's like rolling those dice and hitting a one a billion times in a row".

"The overwhelming probability if you find a planet with life on it, its probably going to be very simple life".

Interesting conversation on here. According to NASA, there could be millions of habitable planets out there.

La NASA afirma existen desde 10 a 40 años luz sistemas planetarios cercanos a nuestro sistema solar. Es edible vida similar con agua por los orígenes astrofísicos de los cuantiosos sistemas planetarios...

Nearly every star has a planetary system. The one's that have not are the minority. So I would think that if you knew how many stars are out there, within our Galaxy, and say you brught it back to 80%. Then multiply by a unlimited amount of galaxies. There answer lays somewhere there. Then divide by 100, to give you the amount of star systems that could have life. What would be really interesting to find out is, how many different type of planets are there and then be able to classify.

I don't think any bacteria-like organism was ever found on a meteorite from space (only the one from Mars?). Life like on Earth is extremely common in the millions of solar systems in our galaxy and the other millions of galaxies, but it is too far away. We still need to find a way to "go there" without actually travelling to there.

In the context of the above considerations, the following question is also current:

Why in spite of the many years of listening to radio waves emitted from various parts of the cosmos, did not there appear such, which would mean the possibility of existence in another cosmos of intelligent creatures?

For several dozen years, various astronomical programs have been running radio-frequency listening programs of various emission ranges to diagnose those that could be a testimony that somewhere in another constellation there is or has existed the civilization of other intelligent beings.

However, up to now, it has not been possible to diagnose such waves that could confirm the existence of other intelligent beings in the cosmos and thus other, developed forms of life.

Why has not it worked so far?

Why in spite of the many years of listening to radio waves emitted from various parts of the cosmos, did not there appear such, which would mean the possibility of existence in another cosmos of intelligent creatures?

Please, answer, comments. I invite you to the discussion.

Will the new generation of astronomical instruments ever reach the farthest corners of the universe, reach the edge of the universe and explain the essence of the boundlessness of what is possibly beyond the known Universe?

Perhaps someday in the future, thanks to the huge telescopes, we will discover the details of the distant planets in other planetary systems in other galaxies, i.e. exoplanets.

According to astronomers' forecasts, it will be technically possible to build such large telescopes in a few dozen years.

Astronomers have so far discovered a small part of the planets in our Andromeda Galaxy.

Billions of exoplanets existing in other constellations are still unknown.

However, even these known exoplanets are studied to a very limited extent.

In the case of the majority of exoplanets learned, apart from the knowledge of size and mass, little is known about them.

More and more perfect astronomical tools are being built, more and more telescopes provide new knowledge.

Thanks to more perfect astronomical instruments, we know more and more about the cosmos, but on the other hand we know that we still do not know more and more about the vastness of the Universe.

Will we ever know the answer to the question: Are there other forms of life somewhere in the universe and how does life look like?

Will the new generation of astronomical instruments ever reach the farthest corners of the universe, reach the edge of the universe and explain the essence of the boundlessness of what is possibly beyond the known Universe?

In view of the above, the current question is: Will the new generation of astronomical instruments ever reach the farthest corners of the universe, reach the edge of the universe and explain the essence of the boundlessness of what is possibly beyond the known Universe?

Please, answer, comments. I invite you to the discussion.

If so, when will new telescopes be constructed, thanks to which you will be able to see what is on the planets of other planetary systems in other constellations?

Every now and then more and more perfect telescopes are being built thanks to which photographs of other constellations and other galaxies are created.

Thanks to these photographs, the cognitive abilities in the field of astronomy are increased, among others the estimated amounts of stars, planetary systems and planets in specific constellations, galaxies.

Besides, thanks to these photographs, more and more perfect maps of the blue vault, collections of galaxies and specific segments of the cosmos are created.

For example, studies conducted in recent years based on new cosmic photographs show with previously unattainable accuracy the distribution of stars in the Milky Way Galaxy, in which there is a solar system with our Earth.

In April 2018, astronomers prepared a much more accurate than the current three-dimensional map of the Milky Way Galaxy.

This was done as part of a research project with a million dollars budget. As part of this research project and thanks to the space mission launched in 2013, the Gaia probe was developed a very accurate map of the Andromeda Galaxy and a new research material was created for the purposes of research into the analysis of the past and future of our Galaxy.

The research project was implemented by the European Space Agency. Based on this research project, the latest astrometric data set containing positions and self-movements of over a billion stars was made available.

Placed on Earth's orbit, the Gaia Probe has two optical telescopes and three scientific instruments that also allow to determine the brightness, temperature and chemical composition of individual stars.

In addition, the latest data set contains star colors that provide vital information about their surface temperature and age.

The Gaia probe also provided new data in the area of 13,000. asteroids circulating within the solar system.

In view of the above, the current question is: If so, when will new telescopes be constructed, thanks to which you will be able to see what is on the planets of other planetary systems in other constellations?

Please, answer, comments. I invite you to the discussion.

A very large number but we are unlikely to meet anyone who lives there.

The other issue is that we only see the past. If all worlds capable of intelligent life and capable of developing machines all evolve at the same rate, then the only civilizations that would be able to detect us are all solar systems within 100 light years, and at the edge of this sphere they would be listening in on some of our very first radio communications. The real noise from our world is all much closer to home. Say that the closest civilization is 400 light years distant. They will not hear us for another 300 years at best, and we will hear their response 400 years after that. I have not seen a calculation, but would be interested in knowing how far out we can go. Say there is an earth clone that is 300 light years distant. By the time their signal reaches us could we detect it above random noise of the universe? How about 1000 light years, or a million. What is the distance where the signal becomes too minute to detect?

We have not found any signals because we could only detect those carefully pointed at us. Similarly they could only detect us if we were to build a transmitter of immense power and feed it through a very large antenna and point the resulting narrow beam directly at one star. Since we don't know whether there is life on any planet orbiting that star or its level of development (our dinosaurs didn't build radio telescopes), we would have to transmit for a period longer than needed for their evolution, say 10 billion years perhaps.

We won't do that so why would we expect them to do it?

The only way to make contact is to send probes. A self-replicating Von Neumann fleet capable of putting a communications relay into each star system visited to create a pan-galactic network is the only practical approach.

Even at 100 light years the signal would be difficult to detect or interpret. Signals emanating from Earth would be massively attenuated by 100 light years.

The other factor is that the recipient would have to have complex radio transmission and reception technology including radio telescopes. We have only had that for just over half a century.

There could be thousands of civilisations within 20 light years from whom we cannot hear and they cannot hear from us. They could be at stages of civilsation approximate to ancient Egypt or 19th century Europe. They would neither be able to hear us or send us messages.

Random factors would suggest that many civilsations will be more advanced than we are. Many could have come and gone.

It is becoming clear that if there is anyone out there they are far away or, if they are aware of us they are simply ignoring us. It is all too clear that unless we have made some very fundamental errors in our understanding of physics they they will not be coming here or us going there.

Interesting conversation on here. According to NASA, there could be millions of habitable planets out there.

The above question inspired me to the following considerations:

Can other forms of life occur on other exoplanets?

Research is currently underway to answer what conditions are needed to create life in a situation of a different chemical composition that is potentially present in many exoplanets, i.e. planets in other planetary systems, in other constellations of our Andromeda Galaxy or in other galaxies.

Perhaps for the emergence of life it is necessary to have on the given planet, far from the Sun, many various other determinants, such as the occurrence of water and atmosphere with a specific chemical composition.

Therefore, perhaps life exists in the Universe on other exoplanets very rarely.

Theories on this topic among astronomers have changed significantly over the last several decades.

In the 1960s, most scientists claimed that in the entire Universe life was created only once, ie on Earth.

Some scientists then pointed to the groundlessness of searching for intelligent life outside Earth.

It was claimed because it was thought that the origin of life on Earth is a kind of unique case of chemical reactions that took place on Earth.

Chemical reactions with such a low probability that one should exclude the possibility of repeating such a large coincidence of the necessary determinants of the origin of life.

However, even then, in terms of the number of other planetary systems found in other constellations, in other galaxies, in the number of other exoplanets, a certain distance from their suns, these estimates were mistaken.

The emergence of better telescopes generated a change in these estimates.

This change consisted in thousands of galaxies being turned into billions of galaxies.

Similar to the number of planets in these galaxies.

Therefore, even if we take into account the statistics and the question of selecting random determinants determining the emergence of life on other exoplanets, if these potential exoplanets with favorable conditions for the emergence of life is not hundreds, thousands but millions, then the probability is much greater.

In the 1970s, the researcher Francis Crick wrote that "Nowadays the emergence of life seems almost a miracle, because for it to exist, a lot of conditions must be met".

Similarly, Jacques Monod wrote in a book published in 1970: "Case and necessity" wrote: "People finally know that they are lonely in the indifferent space of the Universe, in which they appeared by pure chance".

(continued in the comments).

In view of the above, the current question is: Can other forms of life occur on other exoplanets?

Please, answer, comments. I invite you to the discussion.

The eminent scientist Paul Davies claims that currently many scientists are in favor of completely different theories suggesting a large probability of the fact that life in the Universe was created in many places, on various exoplanets, ie many times.

In addition, many eminent scientists claim that various forms of life occur in various places in the Universe.

Some of the eminent researchers suggest that on some exoplanets, where there are various forms of life, there are also intelligent life forms.

Biologist Christian de Duve went further in this trend of scientific theory because he described life as a "cosmic imperative".

However, modern knowledge in the creation of life on Earth has changed little over the years, since the study of the evolution of life on Earth began to be studied.

Well, we know about the transition from inanimate to life-filled forms on the ground, almost as much as Charles Darwin, who wrote over 100 years ago: "Now thinking about the creation of life is just as silly as considering the origin of matter."

In the field of astronomical instrument technology, a lot of progress has been made over the past few decades.

Recent discoveries of hundreds of exoplanets are an important factor determining the validity of the search for extraterrestrial intelligence (SETI - search for extraterrestrial intelligence).

According to current estimates, there may be billions of exoplanets in our own Andromeda Galaxy in the form of planets similar in many respects to Earth.

There is probably a lot of exoplanets that can be colonized.

However, we still do not know the details of the complex process that led to the creation of life on Earth.

We do not know all aspects of the process that converts a mixture of organic or inorganic chemicals into the first life forms into a living cell.

According to Paul Davies, it is not possible to precisely calculate the probability with which life could be created on different exoplanets.

Carl Sagan once remarked that the birth of life can not be so difficult, because then it would not appear on Earth almost immediately after the conditions became appropriate.

Paul Davies also points out that the universal argument is the magnitude of the Universe: if it is so big, then life must appear somewhere. But what does this statement mean? By limiting ourselves to the observable part of the Universe, we will probably find in it 1023 planets. Yes, it is actually a large number. However, it is reduced by the tiny probability of even simple organic molecules being created by pure chance. If the path from chemistry to biology is long and complicated, it may turn out that life occurs less often than on one trillion trillion of planets.

The conviction that life is widespread is based on the silent assumption that biological evolution processes are not the result of accidental chemical reactions, but they contain a specific purpose.

This purpose lies in the development of targeted and increasingly complex self-organization.

The increasingly complex organized structures determine the superiority of the living forms over the inanimate.

Sometimes this is referred to as a kind of unwritten law of life or the purposefulness of creating and developing life with the possible creation of an intelligent being.

However, for now, such theories may arise and will remain only theories, because man has not yet developed research instruments, with the help of which such theories and research thesis could be verified.

Scientist Sagan claimed that life appears frequently in the Universe. He also claimed that perhaps life on Earth arose many times. Therefore, if there were many beginnings of life on Earth, then also in currently functioning ecosystems there should be organisms with a different origin of life.

If such a theory were to turn out to be true, it would mean that in some ecosystems on Earth there are life forms that have arisen in completely different origins of their initial life forms and create a biosphere within one ecosystem.

On the other hand, they have recently been discovered in meteorites that are burning fossils of something that may resemble bacteria.

So if the bacteria could bring life to Earth before billions of years, it would be the first significant evidence of the possibility of life on other exoplanets.

Moreover, it is interesting that in this period of the last few decades, ie when significant changes occurred in the astronomers' theories and in the answer to the question about the existence of other forms of life in the Universe, at the same time in the cinematography the presentation of these alternative alternatives has also changed. worlds, other life forms that may exist on other exoplanets.

It is from the 70s of the twentieth century that the form and content of the depicted cosmos and possible aliens in space in the subsequent films are changing.

The first of the films in which this issue was taken seriously is the movie "2001. Odyssey Space" directed by Stanley Kubrick.

The subject concerned space travel and not discovered, completely different forms of life, however, this film opened a new era in cinematography.

In the following years, more and more sci-fi movies were being made, in which the plot was somewhere in space with the participation of people meeting or even cooperating with other humanlike intelligent beings.

In one of these films, this subject was taken in the convention of typical entertainment as in the films from the saga "Star Trek" and "Star Wars" and in other films in conventions or catastrophic (hostile to Earth humans intelligent creatures from other exoplanets) or in a convention typical paranova , in which people in precisely planned space missions go to Mars (as in the films: "Mission to Mars", "Red Planet", "Martian", ...) or go outside the Solar System to colonize another exoplanet (film "Passenger").

Therefore, the convergence and correlation in the theories of scientists regarding the scale and the probability of other forms of life on other exoplanets and the observed changes in the presentation of the issues of space and life in the cosmos in the cinematography over the last few decades is an interesting one.

In view of the above, the current question is: Can other forms of life occur on other exoplanets?

Please, answer, comments. I invite you to the discussion.

I would guess that there are a few fundamental tasks that must take place for life to exist. The obvious one is that molecules must be able to replicate themselves. The molecules must be able to defend themselves either from other molecules or from the environment. They must be able to gather simpler molecules as building blocks. Finally they must have a source of energy and be able to transfer the energy from a collection point to a use point. We know that these processes can happen in a water environment. I am not so certain that it could happen in another liquid. Can I make a cell with a water membrane in a lipid sea? One can certainly make an inverse emulsion, but is it possible to make the water membrane complex enough to carry out cell functions?

The other issue with using something like liquid methane is that reactions would take place more slowly. My guess is that we do not have to worry about aliens swimming in methane seas. Of course there is some possibility that they were bioengineered to live there, though with that scenario almost anything goes.

Our best shot is a planet with liquid water. It might work to have a cold planet warmed by gravitational forces. The ice surface protects a liquid core and thermal vents on the sea floor provide the energy for life to exist. Mostly, we are looking for planets much like Earth. Fortunately, water is common in the universe. However, the planet needs enough water to have pools of water that are permanent at geologic time scales. Also there must be enough water to form clouds in the atmosphere to give rain and lightning. The planet must be young enough that the core has not become cold. The planet core must have enough magnetic material (iron, cobalt) to have a magnetic field.

In all the galaxies in the universe, there are many such planets. Thousands, maybe millions. The chance that one of these planets is within 20 light years of us is small.

The other problem is survival. So an organism has a will to survive and the ability to build tools. When a new technology is developed there is always the temptation to use it. Our experience with the atomic bomb could have gone much differently.

Timothy

To the best of our knowledge, based on observation once life starts it is damn nigh impossible to shut it down, save destroying quite literally the real estate it stands on.

Life 'sparked up' on Earth about 3.5 billion years ago at least. Modern theories suggest it had already started in the Hadean some 600 million years earlier. Its been around ever since in spite of unbelievable forces that we imagine should have snuffed it out.

The circumstances for life to form must be duplicated many many billions of times in the universe we inhabit. Our universe will be teeming with it.

Alternative Earths are going to be rare indeed but this one cannot be unique. The forces that formed it will have happened so many times that RG does not have enough noughts to express it.

Out there are countless people asking the same questions and a lot of them will have more answers than we do.

While I agree that life may be on even billions of planets, the chance that a civilization has developed in the same time frame as ours and that is close enough for us to say "Hello Universe" is very small. There are quite a few discussions similar to this one on RG and StackExchange (and elsewhere). Some have postulated that life could develop in any liquid environment, or parts of Gas giants. I simply don't see how the requisite chemical reactions can take place wherein energy is transferred through the system to enable movement, sensory input, or thought in a medium other than water. That said, I don't see this as restrictive because many planets have some water.

Timothy

Its all in the numbers. There are so many places out there someone some where, who does not live in this solar system is worrying about his football team.

We may never meet them but its sort of comforting to think about it.

Have you read Conway Morris's Life's Solution?

In view of the above, it is also important to include in the above discussion also the following issue: How is the unlimitedness of the Universe explained now?

In many cosmological theories, astronomers try to explain the essence of the unlimitedness of the Universe. But how can this unlimitedness be presented and defined in the most concise and clear way possible? What can be compared to the unlimitedness of the Universe? Or maybe the essence of the problem goes beyond the scientific definition of the concept of the unlimitedness of the Universe? The problem may be the understanding of this unlimitedness of the Universe by man, because everything that surrounds man in everyday life on Earth is limited.Do you agree with my opinion on this matter? In view of the above, I am asking you the following question: How is the unlimitedness of the Universe explained now? Please reply I invite you to the discussion Best wishes

The above question inspired me to the following considerations:

If space travel would be possible, what would one look for in other planetary systems?

Perhaps the human curiosity about learning about other planetary systems found in other galaxies results from the consciousness of the unlimitedness of the Universe. In many cosmological theories, astronomers try to explain the essence of the unlimitedness of the Universe.

The problem may be the understanding of this unlimitedness of the Universe by man, because everything that surrounds man in everyday life on Earth is limited.

Probably in the Universe in other planetary systems found in other galaxies there are many exoplanets similar to Earth.

Perhaps there is life there, other life forms, perhaps other intelligent life forms. Is human curiosity about getting to know the Universe, traveling in space mainly due to the desire to learn about these other exoplanets, other life forms, other biological ecosystems, other biological conditions to live?

Confirmation of this curiosity about exploring the Universe, traveling in space are many science fiction novels and movies, in which space travel, people travel to other planetary systems located in other galaxies, which for several decades have been created and find many fans.

Do you agree with my opinion on this matter?

In view of the above, I am asking you the following question:

If space travel would be possible, what would one look for in other planetary systems?

Please reply

I invite you to the discussion

Best wishes

I would not rely on NASA's opinions, commonly known as "Never A Straight Answer". They know a lot, but only issue things "they feel people should be allowed to know". In other words, forget their opinions.

Life elsewhere could take many forms, not necessary to have an Earth-like planet. For example the skeleton could be silicon not carbon-based. Oxygen is necessary for us, but is deadly for sulfur bacteria for example.

Carl Sagan sent out a radio message to space in 1974 and got a reply in 2001, but people hesitate to believe it. This means then that people are not really interested to find life elsewhere?

The message was probably a warning. It was sent to a star cluster 25,000 light years away and we got a reply in 27. Maybe they can travel faster than light, or bend time, or maybe they were only 13.5 light years away when Carl sent the message. As they have not made their presence known, they are probably living amongst us waiting for the right moment.

According to current knowledge of cosmologists and astronomers, there are millions of galaxies in the Universe, and millions of planetary systems in them, in which there are many exoplanets located similarly to Earth in the living zone, i.e. a certain distance from the sun and equipped with the necessary set of elements and chemical compounds, thanks to which life can exist on a significant proportion of these exopanets. Due to the possible different chemical composition of the soil and atmosphere on exoplanets, these may be completely different life forms not known on Earth. Currently, there is a prevailing opinion that, according to the theory of probability and knowledge of cosmologists, it is highly probable that on many millions of light-years away from Earth-like exoplanets there are various life forms. However, it is also highly probable that humanity will never get there and verify this issue personally. It is also highly probable that humanity may run out of time even to build huge, improved new generation telescopes capable of looking for other life forms on exoplanets located on millions of light-years of exoplanets. Man may run out of time if, as a result of an increasingly rapid global warming process, a global climate disaster occurs at the end of the 21st century. It would be a great irony of fate if, in a few million years, representatives of other life forms coming from exoplanets reach the Earth and study life forms existing on Earth, completely different from currently occurring species of flora and fauna, and establish archaeological sites to examine the remains of the former human civilization.

What do you think about this topic?

What is your opinion on this topic?

Please reply

I invite you to discussion

Thank you very much

Best wishes

Dariusz Prokopowicz

I am sure other life forms have already visited Earth and studied animals, plants and humans and have passed that knowledge around already.

In the crop circle studies, many instances where circular borings have been found on the ground. Samples have been taken out for study.

What about the numerous cases of animals that have been mutilated and precisely cut by surgical instruments. I was talking to some farmers who lost such animals (cows). They were afraid to go public because of ridicule. On the other hand, their loss of property and income is worrying them. That happened in my area.