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Old 09-13-2019, 04:05 AM
 
Location: Swiftwater, PA
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Quote:
Originally Posted by Vasily View Post
What fraction of the 260,000 stars within 250 light years are old enough and stable enough to provide a Goldilocks zone where life could evolve? How many of that fraction contain worlds within their Goldilocks zones that support life? How many of those have progressed to multicellular life? How many of those have complex intelligent beings with technology surpassing our own?

Sobering facts: There was no life on Earth for the first billion years; and the Earth was 2.7 billion years old before multicellular life appeared; hominids have been on the planet for about 2 million years, and we developed space flight a few decades ago. If this applies to other planets, it's likely very few of those 260,000 stars host intelligent life that's beyond a stone age level. We may very well be the only technological civilization in our area of the galaxy.
You have to keep in mind, that if any one of them reaches our stage of development, we are quickly closing in on the 'Singularity'. We could possibly rush in our 'replacements' within the next decade or century. Once that happens, if AI's quest is to explore and conquer/acquire, who knows what could happen?

Remember Star Trek: The Motion Picture (https://en.wikipedia.org/wiki/Star_T...tion_Picture)? Perhaps we are poised to release V'Ger to search for its maker? Lieutenant Liia is barely mentioned in that Wikipedia link that I find strange since I remember her more than the other cast? It was shocking back then to have a bald head woman play a major role.
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Old 09-13-2019, 08:26 AM
 
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Quote:
Originally Posted by fisheye View Post
Here is a link to stars within 250 light years of earth: The Universe within 250 Light Years - The Solar Neighbourhood. There are some and that would mean that there is a possibility of life in that little 200 light year blip. That said it might take us another 50 or 100 years to hear back from any intelligent life form; if any do exist in our little blip.
1500 stars are within 250 light years from Earth. That would make it a pretty large bubble of space. I guess that would make it about 500 light years across. Those 1500 stars also happen to be the most luminous stars which are much brighter than the Sun. When considering stars that are similar to the Sun, the G-type stars, there are around 512~ of those within that distance of 250 light years. Our Sun is a G2 spectral type star. These G-type stars are the ones that are most suitable to host planets with life. That doesn't mean there couldn't be some form of life on planets in the habitable zones around highly luminous stars (which outnumber the G-types in our neighborhood), but it would be pretty unlikely due to the tremendous amount of radiation pouring out from them. In addition, highly luminous stars tend to be more massive, have shorter life spans, and can go out with a bang.
G stars within 100 light-years
https://www.astronomynotes.com/evolutn/s2.htm

Smaller red dwarf stars are thought by some to host planets within a habitable zone much closer to the star. The problem is that red dwarf stars tend to frequently shoot out flares that could engulf such planets that are close to it, reducing the chance for life to develop.

We're still in the very early stages of understanding the galaxy and the universe. We just don't know. What we are learning is that some of the stars with planets in habitable zones that were considered as potential for life, is turning out to be less likely to host life, at least for life as we know it. Just as there are habitable zones around stars, the galaxy itself may contain a habitable zone. Too close to the center and radiation would make life impossible. Too far out, and there might not be enough of the right materials to allow life to form. If that's so, then the number of likely places for life would be much less than the total number of stars in the galaxy. Although, it would still be a pretty large number to choose from.


I agree that IF there are some forms of intelligent life within that 250 light year range, it'd take up to over a century to hear from them, if we hear anything at all. I also agree, as you said, "...if any do exist in our little blip." That's very true. It's a really small blip indeed among the estimated 150 billion to 250 billion stars in the galaxy. The sampling of our stellar neighbors is far too small, nearly microscopic, to conclude anything, one way or the other, about the potential for intelligent life, or any kind of life, elsewhere in the galaxy.

There's a wide range of possibilities. It's possible life could be more abundant on the other side of the galaxy and rather barren on our side. Or it's possible we might be the only ones in an otherwise barren galaxy, meaning we just happened to hit the jackpot. It's also possible, even likely, that the galaxy has a habitable zone and that our solar system is with that range. Too close to the center of the galaxy means too chaotic and a flood of highly charged radiation. Too far out and there's less materials available. Our solar system is somewhat midway between the center and the outer edge of the galaxy.

Our best bet to increase the odds of extra terrestrial life, even if it's just microbial life, is whatever we can discover right here in our own solar system. That said, I do think we'll continue to develop and improve more powerful tools to learn in greater detail about other star systems and exoplanets.
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Old 09-13-2019, 10:55 AM
 
Location: The Driftless Area, WI
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Quote:
Originally Posted by Vasily View Post
What fraction of the 260,000 stars within 250 light years are old enough and stable enough to provide a Goldilocks zone where life could evolve? How many of that fraction contain worlds within their Goldilocks zones that support life? How many of those have progressed to multicellular life? How many of those have complex intelligent beings with technology surpassing our own?

Sobering facts: There was no life on Earth for the first billion years; and the Earth was 2.7 billion years old before multicellular life appeared; hominids have been on the planet for about 2 million years, and we developed space flight a few decades ago. If this applies to other planets, it's likely very few of those 260,000 stars host intelligent life that's beyond a stone age level. We may very well be the only technological civilization in our area of the galaxy.

That's assuming other potentially inhabited places are in synchrony with us. Our solar system is probably just a toddler compared to other "adult" or "senile" inhabited worlds.


The other inappropriate assumption we usually make is in thinking other worldly life forms live on a time schedule like us-- a lifetime is ~ 100 yrs. But even here, a bacterial lifetime is only 20 minutes, a mouse a few months etc. Maybe a little green man lives for 100,000,000 of our yrs, so a flight in his saucer to here is just like our trip to the 7-11 for some Cheetos.


BTW- why does other life require a planet? Couldn't it have evolved on a star and avoided the heat by hiding during the day and just coming out at night?
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Old 09-13-2019, 01:04 PM
 
Location: Madison, Alabama
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Quote:
Originally Posted by guidoLaMoto View Post
That's assuming other potentially inhabited places are in synchrony with us. Our solar system is probably just a toddler compared to other "adult" or "senile" inhabited worlds.


The other inappropriate assumption we usually make is in thinking other worldly life forms live on a time schedule like us-- a lifetime is ~ 100 yrs. But even here, a bacterial lifetime is only 20 minutes, a mouse a few months etc. Maybe a little green man lives for 100,000,000 of our yrs, so a flight in his saucer to here is just like our trip to the 7-11 for some Cheetos.


BTW- why does other life require a planet? Couldn't it have evolved on a star and avoided the heat by hiding during the day and just coming out at night?
Presumably the smiley face means you're kidding. That's like talking about the "dark" side of the moon.
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Old 09-13-2019, 03:12 PM
 
Location: Swiftwater, PA
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Quote:
Originally Posted by NightBazaar View Post
That said, I do think we'll continue to develop and improve more powerful tools to learn in greater detail about other star systems and exoplanets.
In 1989 we launched the Galileo mission which gave us most of our information on Europa. Many think that the ocean of Europa could be a cradle of extraterrestrial life. There are several missions purposed that might settle that question.

But the point I want to make and I think we are both on the same page; is that we know very little about space. Yes we are learning; but we are far from actually exploring. Until that time comes; it is very hard to say what we might find. Our "Giant Steps" look very small when considering the distances of space.
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Old 09-13-2019, 03:31 PM
 
Location: Greenville, SC
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A great detailed (very long) article on the Great Silence (aka Fermi's Paradox) and the Great Filter, by a prof of economics at GMU. A couple of decades old, but not much has changed significantly in our understanding in the years since it was written.

The Great Filter

Last edited by Vasily; 09-13-2019 at 03:43 PM..
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Old 09-13-2019, 08:58 PM
 
Location: Swiftwater, PA
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Quote:
Originally Posted by Vasily View Post
A great detailed (very long) article on the Great Silence (aka Fermi's Paradox) and the Great Filter, by a prof of economics at GMU. A couple of decades old, but not much has changed significantly in our understanding in the years since it was written.

The Great Filter
But doesn't that seem to support the 1968 book "The Population Bomb": https://en.wikipedia.org/wiki/The_Population_Bomb. That 2017 graph, included in the Wikipedia link, seems to bear out some of the fears that prompted the original book.

To me it appears that human life is similar to what happens when we have a sterile Petri dish and touch it and incubate it at the right temperature and humidity. The bacteria, from our touch, will eventually eat all the food and die. Of course that is a contained (confined) space; like our Earth. Of course we are not limited to just our Earth; we are acquiring the technology to reach out into our solar system and eventually beyond. If we ever do encounter another extraterrestrial life form will we be perceived as an 'infection' (like the bacterial we released in the Petri dish)?
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Old 09-14-2019, 10:30 AM
 
Location: Greenville, SC
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Quote:
Originally Posted by fisheye View Post
But doesn't that seem to support the 1968 book "The Population Bomb": https://en.wikipedia.org/wiki/The_Population_Bomb. That 2017 graph, included in the Wikipedia link, seems to bear out some of the fears that prompted the original book.
There were serious problems with Ehrlich's assumptions. They're discussed later in the linked article. The late 60s and early 70s were a period when people were freaking out that we were going to use up all our resources and breed ourselves out of existence. Limits to Growth is another product of that period - another work that has proved to be inaccurate in its predictions of what would happen in subsequent decades. Early editions of the Population Bomb (including the one I read way back then) started with this:

Quote:
The battle to feed all of humanity is over. In the 1970s hundreds of millions of people will starve to death in spite of any crash programs embarked upon now. At this late date nothing can prevent a substantial increase in the world death rate.


Big problem: this didn't happen. Not even close. The gloom and doomers of the late 60s and early 70s were wrong. (and note how similar this statement is to the "we only have 12 years left" drumbeat of the climate disaster crowd)

Quote:
To me it appears that human life is similar to what happens when we have a sterile Petri dish and touch it and incubate it at the right temperature and humidity. The bacteria, from our touch, will eventually eat all the food and die. Of course that is a contained (confined) space; like our Earth. Of course we are not limited to just our Earth; we are acquiring the technology to reach out into our solar system and eventually beyond. If we ever do encounter another extraterrestrial life form will we be perceived as an 'infection' (like the bacterial we released in the Petri dish)?
Here's the heart of the matter: we're not bacteria, and we're not living in a petri dish with a nonrenewable source of food. We're driven as organisms by social interactions, ideologies, and our psychological makeups as well as biological contingencies. Decades ago, techno-anarchist Murray Bookchin pointed out that populations whose standard of living has been raised to a certain point tend to show a reduced birth rate - to the point where they have to import labor to keep industry and commerce running. In general, the poorer the country, the higher the birth rate. You see this in Europe, Japan, the United States, and industrialized Asian and African countries.

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

A bigger threat to our civilization in my opinion is the tendency of large-scale agriculture to reduce the genetic variability in crops (monoculture) - making the world's agricultural systems more prone to disaster in the face of crop diseases and pests. The result can be disasters like the Irish potato famine (and the disease that's wiping out the monocultured Cavendish banana):

https://www.laboratoryequipment.com/...yet-be-learned
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Old 09-14-2019, 11:55 AM
 
Location: NYC
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I have a theory, that we've been placed here in the edge of the universe as other galaxies are moving away from us. Whichever entities placed us here don't want other civilizations to find us easily but some have found us just don't want to deal with us yet. Because we are so far away any signal would take thousands or millions of years to reach us and will be too weak to make any sense.

Hopefully we don't destroy this planet or kill each other before we make contact or some other species decides to come by and help us elevate beyond our current tech limits. It's documented throughout ancient history that we had extra-terrestrial help.
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Old 09-14-2019, 02:05 PM
 
Location: Swiftwater, PA
14,690 posts, read 11,988,402 times
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Quote:
Originally Posted by Vasily View Post
Big problem: this didn't happen. Not even close. The gloom and doomers of the late 60s and early 70s were wrong. (and note how similar this statement is to the "we only have 12 years left" drumbeat of the climate disaster crowd).
So they are off by a few years; that does not mean they were wrong. When you consider that we had about one billion people in the whole world in 1800 and we now seven and a half billion; that is a significant increase in a relatively short timeframe. When you look at the charts the population has skyrocketed. Of course there are some signs it is slowing down; but our mindset is "save the world" - feed them all. The more we save and the more we feed; the more that will need saving and feeding. Our solutions can be our next problems.


Quote:
Originally Posted by Vasily View Post
Here's the heart of the matter: we're not bacteria, and we're not living in a petri dish with a nonrenewable source of food. We're driven as organisms by social interactions, ideologies, and our psychological makeups as well as biological contingencies. Decades ago, techno-anarchist Murray Bookchin pointed out that populations whose standard of living has been raised to a certain point tend to show a reduced birth rate - to the point where they have to import labor to keep industry and commerce running. In general, the poorer the country, the higher the birth rate. You see this in Europe, Japan, the United States, and industrialized Asian and African countries.
The bacteria also want to survive; all living things do. For the time being; the Earth is our Petri dish. Once we have the first off world (self sustaining) colony that will not be the case. We might be close; but we are not there yet. Our economic system can only function if there is 'more'. Sure our birth rates might drop; but we open the doors to make up for what we perceive as a 'need'. We were never 'trained' to accept what we have and look for no more. That is the same as those bacteria do as they fight for the last drop of agar.

Quote:
Originally Posted by Vasily View Post
A bigger threat to our civilization in my opinion is the tendency of large-scale agriculture to reduce the genetic variability in crops (monoculture) - making the world's agricultural systems more prone to disaster in the face of crop diseases and pests. The result can be disasters like the Irish potato famine (and the disease that's wiping out the monocultured Cavendish banana):
In 1950 there were less than 50 dead zones in our world's oceans; today there are around 500: https://www.theguardian.com/environm...oxygen-starved. I know that it is hard to see; but, looking at that map in the link, do you notice that the shores of the US are surrounded by dead zones. Much of that was blamed on our modern use of fertilizer. But we have also been guilty of dumping anything and everything in our oceans in the past. There are plenty of other worries besides monoculture when talking about modern agriculture. However the increased population still strains everything.
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