Do Aliens exist?

May 30, 2018

8 minutes ago, bison said:

If the history of science teaches us anything, it is that we are not, on this planet, in some unique situation. We have often imagined that we were, only later to learn better.

Various nations once imagined themselves at the center of the (flat) world. It was once fancied that Earth was at the center of the entire universe. Not long ago, it was thought that planets were caused by rare events, and were very uncommon around other stars.

All these notions were wrong. Given the billions of Earth-like planets now believed to exist in our galaxy, it seems not unreasonable that a still large number of them will fulfill conditions suitable for life, intelligence and civilizations. If only one in one hundred thousand of those planets was suitable, that would still leave well over 10 thousand such worlds in our galaxy.

If we are talking about life being capable of visiting Earth, that number goes way down.

Life has existed on Earth for about 4 billion years. Life which can travel into space about 50 years. Life that can travel great distances in space 0 years. That is a small sliver and not even taking into consideration that our galaxy has been around for about 14 billion years. Plenty of time for life to have existed and died off. Just saying that life existing out there and life existing out there that is capable of visiting Earth are very different.

May 30, 2018

I would assume there are more Earth-like planets where intelligent life has not evolved on them than Earth-like planets where intelligent life has evolved.

I could be mistaken, but if I am correct, where does this leave a populated galaxy?

How difficult or easy is it for intelligent life to evolve?

May 30, 2018

Reply to StarMountainKid:

I proposed a scenario where advanced civilizations are quite rare. Only one in 100 thousand of the billions of Earth sized, habitable zone planets scientifically inferred to exist in our galaxy were assumed to have all the conditions suitable to foster an advanced civilization. that still leaves over 10,000. If one in a million, really rare, that still makes for 1000 advanced civilizations in our galaxy.

May 30, 2018

24 minutes ago, Myles said:

If we are talking about life being capable of visiting Earth, that number goes way down.

Life has existed on Earth for about 4 billion years. Life which can travel into space about 50 years. Life that can travel great distances in space 0 years. That is a small sliver and not even taking into consideration that our galaxy has been around for about 14 billion years. Plenty of time for life to have existed and died off. Just saying that life existing out there and life existing out there that is capable of visiting Earth are very different.

If civilizations in space are 'dying off' at a certain rate, there are also presumably new ones coming onto the scene at about the same rate. If, as is the case with much life on Earth, these civilizations expand into the available territory, in this instance, our galaxy, their nearest residence could well be within practical traveling distance of Earth.

May 30, 2018

24 minutes ago, bison said:

Reply to StarMountainKid:

I proposed a scenario where advanced civilizations are quite rare. Only one in 100 thousand of the billions of Earth sized, habitable zone planets scientifically inferred to exist in our galaxy were assumed to have all the conditions suitable to foster an advanced civilization. that still leaves over 10,000. If one in a million, really rare, that still makes for 1000 advanced civilizations in our galaxy.

Quite possible, we just don't know. How many of these intelligences exist at this present moment? Given the short time of human evolution, perhaps many evolved and died out, and many have yet to evolve, and on some undetermined number of Earth-like planets intelligent life may never evolve.

So, what are we left with?

.

May 30, 2018

8 minutes ago, StarMountainKid said:

Quite possible, we just don't know. How many of these intelligences exist at this present moment? Given the short time of human evolution, perhaps many evolved and died out, and many have yet to evolve, and on some undetermined number of Earth-like planets intelligent life may never evolve.

So, what are we left with?

.

We are left with the seeming probability that there are many civilizations in the galaxy at any one time. Since we have been at the business of civilization for quite a short time, it's likely that most of these civilizations are more technically advanced than we are.

Even at conservative, sub-light speeds, any, or many of these civilizations could have filled the galaxy long before now. Since we've been left largely alone, these civilizations would seem to have a peaceful attitude toward us. That was the question from the original post, which I attempted to answer.

May 30, 2018

39 minutes ago, bison said:

Reply to StarMountainKid:

I proposed a scenario where advanced civilizations are quite rare. Only one in 100 thousand of the billions of Earth sized, habitable zone planets scientifically inferred to exist in our galaxy were assumed to have all the conditions suitable to foster an advanced civilization. that still leaves over 10,000. If one in a million, really rare, that still makes for 1000 advanced civilizations in our galaxy.

I still think 1000 advanced civilizations in our galaxy is way too high. So many factors.

17 minutes ago, bison said:

their nearest residence could well be within practical traveling distance of Earth.

What do you consider "practical traveling distance"?

May 30, 2018

Nice conversation all around.

May 30, 2018

1 minute ago, Myles said:

I still think 1000 advanced civilizations in our galaxy is way too high. So many factors.

What do you consider "practical traveling distance"?

There's no telling what the practical traveling distance could be. Flesh and blood astronauts, or artificial intelligences? Long or short-lived ETs? Cryo-preservation? Generation ships? Near light-speed time dilation? Perhaps even some work-around to the relativistic light speed limit, such as warping space, which is now being seriously discussed among some scientists.

May 30, 2018

4 hours ago, bison said:

There is a good case to be made that many extraterrestrials would be more technically advanced than we are, and could reach this planet. Since our planet has not been taken over, or destroyed by such beings, it appears that, overall, they are peaceful.

And your evidence for this comes from where exactly? Or is this just your opinion?

May 30, 2018

What if for some reason, whatever it might be, we are the progenitors of life throughout the cosmos?

May 30, 2018

1 hour ago, Alien Origins said:

And your evidence for this comes from where exactly? Or is this just your opinion?

These questions have been long discussed in the scientific community, around the subject that has come to be known as the Fermi paradox.

We know from astronomical work that our solar system is relatively young in a much older galaxy -- 4.5 billion as against 13.5 billion years. That makes much older, more advanced civilizations in space a reasonable likelihood. We have every reason to suppose that many stars and planets suitable to host civilizations are much older than our solar system.

Further-- since our civilization is only a few hundred or a few thousand years old, depending on what criteria for civilization are assumed, we appear to be very near the bottom of the range of possible ages of civilizations.

We know, too, that if even a few, or even one of these civilizations sought to extend its territory out into the galaxy, they could have filled all available space within it, even at sub-light speeds, long before now.

This is the very basis of the Fermi paradox, which, in essence, asks: given the above considerations, where is the galactic civilization? Why is it not obvious to us?

My answer is that these extraterrestrial don't have any hostile designs on us, or we'd either know of it, or not be here at all !

Edited May 30, 2018 by bison
corrected mispelling

May 30, 2018

19 minutes ago, bison said:

These questions have been long discussed in the scientific community, around the subject that has come to be known as the Fermi paradox.

We know from astronomical work that our solar system is relatively young in a much older galaxy -- 4.5 billion as against 13.5 billion years. That makes much older, more advanced civilizations in space a reasonable likelihood. We have every reason to suppose that many stars and planets suitable to host civilizations are much older than our solar system.

Further-- since our civilization is only a few hundred or a few thousand years old, depending on what criteria for civilization are assumed, we appear to be very near the bottom of the range of possible ages of civilizations.

We know, too, that if even a few, or even one of these civilizations sought to extend its territory out into the galaxy, they could have filled all available space within it, even at sub-light speeds, long before now.

This is the very basis of the Fermi paradox, which, in essence, asks: given the above considerations, where is the galactic civilization? Why is it not obvious to us?

My answer is that these extraterrestrial don't have any hostile designs on us, or we'd either know of it, and not be here at all !

And yet SETI has discovered nothing.

May 30, 2018

10 minutes ago, Gaden said:

And yet SETI has discovered nothing.

Yes, contact with extraterrestrial civilizations is not being made overly easy for us to accomplish! That could well be by design.

Dr. Jill Tarter of the SETI Institute has compared the search, so far, to dipping a glass of water out of the ocean, finding no fish in it, and concluding that there were no fish in the ocean; an obviously premature conclusion.

There are many combinations of radio frequency, band width, signal strength, modulation types, and other factors, yet to be tried.

May 30, 2018

59 minutes ago, bison said:

These questions have been long discussed in the scientific community, around the subject that has come to be known as the Fermi paradox.

We know from astronomical work that our solar system is relatively young in a much older galaxy -- 4.5 billion as against 13.5 billion years. That makes much older, more advanced civilizations in space a reasonable likelihood. We have every reason to suppose that many stars and planets suitable to host civilizations are much older than our solar system.

Further-- since our civilization is only a few hundred or a few thousand years old, depending on what criteria for civilization are assumed, we appear to be very near the bottom of the range of possible ages of civilizations.

We know, too, that if even a few, or even one of these civilizations sought to extend its territory out into the galaxy, they could have filled all available space within it, even at sub-light speeds, long before now.

This is the very basis of the Fermi paradox, which, in essence, asks: given the above considerations, where is the galactic civilization? Why is it not obvious to us?

My answer is that these extraterrestrial don't have any hostile designs on us, or we'd either know of it, or not be here at all !

Or more likely, they have no idea we are here.

June 2, 2018

On 5/30/2018 at 11:08 AM, StarMountainKid said:

But the in search of resources part, well, there'd be plenty of near-by planets for them to find whatever they need..

Some resources yes. All resources no.

On 5/30/2018 at 11:08 AM, StarMountainKid said:

..instead of traveling all the way to Earth.

I would assume that anyone traveling to Earth would be doing so for a reason. Look, traveling thousands of light years at a time is going to require resources. I assume that any one with the technology to traverse the cosmos, is going to have the technology to search out what it is before they get there. Otherwise they are wasting resources flying around blindly thought the universe, crossing their fingers that the next planet they pass by will have the resources they are looking for. If they're coming to earth, then it is for a reason to be sure of. Even if they are friendly, how friendly would they be after we tell them that we cannot afford to give them what they want, or we would not have enough for ourselves. I imagen that space travel takes a lot recourses of many different kinds, especially if moving a lot of people. Would they not at that point just take what they want? after all it be a "us vs them" mentality. they will take what they need(imo)

June 2, 2018

What exactly would they want from Earth that they couldn't get from a million other planets?