Scientists suspect alien structure around star.

[jwl]

I newer quite understood the excitement about discovering aliens. Like, say we get 100% confirmation that 1500 ly from us there is in fact an advanced alien civilization. Like, a probe reaches us or something. So what? That's still 1500 years away at the highest speed there is. None of us alive today are ever going to meet one of them, talk to them, shake their hand or anything. It simply does not change our lives in any meaningful way. The world we live in is changed more every time a new model of mobile phone hits the market. So what's the excitement about?

If they have a Dyson sphere-like object? With better telescopes we can analyse the Dyson sphere and use it to work out how to make the technologies that lead up to it and ultimately one of our own.

[salm]

That said, it's probably the comet thing.

Actually it probably is not that comet thing. Just like it probably is not that alien thing. Both are just speculations which no body has proven wrong yet.

[Simon_Jester]

Hm... jwl, I'm not sure we could learn much useful about it with current technology.

However, if we had, say, massive ground-based observatories on the dark side of the moon that use synthetic array technology to have mirror/lens sizes hundreds of meters across... that might do the trick.

And it would actually be reasonable for us to try to accomplish this by 2100. A bit tricky by 2050, but doable. Maybe even 2040.

I newer quite understood the excitement about discovering aliens. Like, say we get 100% confirmation that 1500 ly from us there is in fact an advanced alien civilization. Like, a probe reaches us or something. So what? That's still 1500 years away at the highest speed there is. None of us alive today are ever going to meet one of them, talk to them, shake their hand or anything. It simply does not change our lives in any meaningful way. The world we live in is changed more every time a new model of mobile phone hits the market. So what's the excitement about?

For one, a lot of people who aren't sociopaths and who have more fertile imaginations than you care about what happens to their distant descendants or their distant ancestors. The existence of these aliens might not cause direct consequences for the human species for another three or four thousand years, but that doesn't mean it's irrelevant.

Now, once you start caring about long timescales and the future of the human race...

1) The existence of aliens who own a Dyson sphere implies certain things about what our own species can aspire to accomplish. Interesting things. To do that would require that this species somehow overcome the challenges of space flight and (what is to us) advanced technology. That they can spread out through one or more solar systems, rendering their species immune to all sorts of environmental disasters and cultural problems. It's nice to know someone else can accomplish these things, because it sets a precedent for us accomplishing them.

2) It gives us a standard to compete against. These aliens are likely to remain ignorant of our whereabouts for at least another 1500 years, and if they decide to do anything about us it will probably take at least another 1500.

How much can we do, in three thousand years, to prepare for their actions? Even if those actions are just a radio message? Or a single starship? Perhaps we could have a Dyson sphere of our own in that time, and all the resources it implies. IF we prepare.

[GrandMasterTerwynn]

I newer quite understood the excitement about discovering aliens. Like, say we get 100% confirmation that 1500 ly from us there is in fact an advanced alien civilization. Like, a probe reaches us or something. So what? That's still 1500 years away at the highest speed there is. None of us alive today are ever going to meet one of them, talk to them, shake their hand or anything. It simply does not change our lives in any meaningful way. The world we live in is changed more every time a new model of mobile phone hits the market. So what's the excitement about?

I'll start with the tl;dr version: No evidence for advanced aliens suggests that civilization-building intelligence is an evolutionary dead end. Which means we're all fucked, and our fucking will probably come within the next few centuries at worst, and within a few thousand years at best.

Long version: Because it should be absolutely terrifying that we haven't. There are up to forty billion habitable terrestrial planets in this galaxy, according to extrapolation from Kepler data, and current theories about planetary formation. Since the age of the average Sun-sized star in our galaxy is a billion or two years older than the Sun ... everything indicates that we should have some evidence that there are other advanced civilizations out there. And yet, we have none. So the question becomes: Why is there no evidence for advanced, civilization-building, alien intelligence?

The profound optimist would suggest that it's because we're first, or we're unique. However, given Earth should be younger than the average planet in this galaxy, and huge swaths of our own solar system are either currently habitable (at least if you're a creature that makes its living on seafloor hydrothermal vents,) or used to be habitable at some point in the past, should discount the "first", or "unique" hypotheses.

In which case, what's left is the notion that life never advances far enough to become a civilization that generates readily-detectable signs of its existence detectable on interstellar scales. There's nothing in the laws of physics that would stop a civilization from coming that far. Nothing says we can't disassemble the planet Mercury and use its silica to build a Dyson swarm detectable from across the galaxy (plus a swarm of O'Neill cylinders that could also be detectable from across the galaxy.) Nothing says we can't use all that electricity to power billions of supercolliders to make enough antimatter to build a rocket capable of reaching Alpha Centauri B (the closest star with at least one confirmed planet) in only fifty years of flight time ... whose drive flare would also be detectable over interstellar distances. For that matter, if we had that sort of industrial capacity, we could afford to spam our entire fucking neighborhood with antimatter rockets.

So advanced alien civilization ... really advanced alien civilization is readily detectable. And many alien civilizations would have strong imperative to become advanced. Thanks to our aging Sun, our own planet stops being habitable for multicellular life in a billion years or so. For very large forms of life, like humans, that point comes a lot sooner ... if adaptability is what you're after, it doesn't pay to be big. Long, long before that point, however, an alien civilization would rapidly exceed the carrying capacity of its home planet. At which point, it either expands beyond its home planet, or dies suffocating in its own shit.

At this point, the pessimist would point out that we haven't detected any signs of advanced alien civilization because civilization-building life because, based on a sample size of one (us), it probably suffocates in its own shit before becoming advanced. There are other reasons, of course: We might not see them because something else has come along and murdered them. Or they might be hiding from whatever comes along and murders advanced civilizations (implying an eugenics and population control regime that might even make you pause.) Or maybe they only become a little advanced and, for whatever reason, fizzle out. Or else, they get bored and eventually commit mass-suicide. All of these other options, by the way, are terrible.

[Purple]

I newer quite understood the excitement about discovering aliens. Like, say we get 100% confirmation that 1500 ly from us there is in fact an advanced alien civilization. Like, a probe reaches us or something. So what? That's still 1500 years away at the highest speed there is. None of us alive today are ever going to meet one of them, talk to them, shake their hand or anything. It simply does not change our lives in any meaningful way. The world we live in is changed more every time a new model of mobile phone hits the market. So what's the excitement about?

If they have a Dyson sphere-like object? With better telescopes we can analyse the Dyson sphere and use it to work out how to make the technologies that lead up to it and ultimately one of our own.

Ultimately is just another way of saying a long time after we are all dead.

For one, a lot of people who aren't sociopaths and who have more fertile imaginations than you care about what happens to their distant descendants or their distant ancestors. The existence of these aliens might not cause direct consequences for the human species for another three or four thousand years, but that doesn't mean it's irrelevant.

Across those time ranges it might as well be if for no other reason than because we don't even know if there will be a human race that far down the line. This isn't 2-3 generations forward we are talking about. It's ten times as much. We are more likely to hit peak oil, peak water or peak atomic holocaust than we are to stay on this planet for that long.

1) The existence of aliens who own a Dyson sphere implies certain things about what our own species can aspire to accomplish. Interesting things. To do that would require that this species somehow overcome the challenges of space flight and (what is to us) advanced technology. That they can spread out through one or more solar systems, rendering their species immune to all sorts of environmental disasters and cultural problems.

Why does it imply any of these things? Why do you need to spread out across more than one solar system to do that? And why do you think it solves any cultural problems at all? Technological and economic progress do not necessarily imply social progress.

It's nice to know someone else can accomplish these things, because it sets a precedent for us accomplishing them.

How does that matter? I mean, if Messi can play really well does that set a precedent that you might one day as well? Of course not. It only establishes that it's theoretically possible for someone to do it. Which frankly is not really worth much.

2) It gives us a standard to compete against. These aliens are likely to remain ignorant of our whereabouts for at least another 1500 years, and if they decide to do anything about us it will probably take at least another 1500.

You forgot to add the part where the image we have of them is at least 1500 years old to begin with. For all we know they might already be gone or we might be gone before they get to us, or we might send someone to get to them only for both them and us to be gone before they arrive etc.

How much can we do, in three thousand years, to prepare for their actions? Even if those actions are just a radio message? Or a single starship? Perhaps we could have a Dyson sphere of our own in that time, and all the resources it implies. IF we prepare./quote]
Are you listening to your self?
1) You imply some sort of unity on part of the human race. There is no reason to expect this will ever happen beyond wishful thinking. Of course, there is no reason to think it won't eventually. But one need not prove a negative.
2) You imply with certainty that the human race will exist by that point. Which again is not guaranteed.
3) You imply that the human race, which fails to do simple things such as fix the massive wealth inequality that leads some nations to throw food away whilst millions in others starve is somehow going to come together for a millennium long project.

I just don't see it.

I'll start with the tl;dr version: No evidence for advanced aliens suggests that civilization-building intelligence is an evolutionary dead end. Which means we're all fucked, and our fucking will probably come within the next few centuries at worst, and within a few thousand years at best.

I thought this was established fact already. What with the way we multiply without control, consume the resources around us like locusts, destroy the environment and can't spend a year without some place on earth erupting in war. Oh and we have atomic weapons trained on one another for good measure. What do you think will happen when we hit 9 billion, and than 20 and than 50? Do you think we'll stop having sex before that happens? Or that we'll give up on plastics and cars before we run out of oil? Or that the human race will accept going down to 3rd world living conditions across the board in order for our existence to remain remotely sustainable? Or do you think we'll keep going as we are blindly rushing to our doom for the sake of a better mobile phone every year?

I know which I find more likely.

[The Romulan Republic]

No, it is obviously not "established fact" that humanity will destroy itself, much less that this is universal for all technological life, your ironically smug and self-indulgent misanthropy aside.

Also, I might be wrong, but I'm fairly sure the consensus is not that human population will go up endlessly until we die out. Birthrates have already gone down in much of the world. Sex does not equal children, your false assumption to the contrary notwithstanding. We have these things called "sex education" and "birth control" and, as volatile a topic as it is, "abortion".

You know, if you hate all human beings, that's your business. But do not have the arrogance to treat your biases as objective fact.

[The Romulan Republic]

Edit: On population growth, I found this:

http://news.nationalgeographic.com/news ... om-africa/

Warning: The 21st century may get a lot more crowded than previously thought.


In a paper published Thursday in Science, demographers from several universities and the United Nations Population Division conclude that instead of leveling off in the second half of the 21st century, as the UN predicted less than a decade ago, the world's population will continue to grow beyond 2100. (Read "Population Seven Billion" in National Geographic magazine.)

And for the first time, through the use of a "probabilistic" statistical method, the Science paper establishes a range of uncertainty around its central estimate-9.6 billion Earthlings in 2050, 10.9 billion by 2100. There's an 80 percent chance, the authors conclude, that the actual number of people in 2100 will be somewhere between 9.6 and 12.3 billion.

A photo of hundreds of thousands of people in Lagos attending a convention at the Redeemed Christian Church of God.
NG STAFF. SOURCE: UN
That range "is the truly innovative part," says John Wilmoth, head of the UN Population Division and one of the authors of the Science paper. "It's a much more plausible analysis of uncertainty—but we may still be off by two billion."

According to other demographers, the UN has missed the mark by just about that amount. In a paper in press at Global Environmental Change and in a forthcoming book, Wolfgang Lutz and his colleagues at the International Institute for Applied Systems Analysis (IIASA) in Vienna, Austria, use a very different method—one that involves canvassing a large group of experts—to argue that population is likely to peak at 9.4 billion in 2075 and fall to just under 9 billion by 2100.

The UN team estimates there's no more than a 5 percent chance of that rosier scenario coming to pass.


Both groups foresee India becoming the world's most populous country, with its numbers peaking around 2070 and declining to around 1.5 or 1.6 billion by 2100. Where they differ most is in their estimates of the coming population decline in China and of the coming population explosion in Africa south of the Sahara—where most of the world's growth is going to occur.

According to the UN, the population in that region could quadruple, from less than one billion to nearly four billion. Africa in 2100 would be as densely populated as China is today.

"These are not predictions," says Wilmoth. "These are projections of what will happen if current trends continue. There is still an opportunity to intervene."

A photo of hundreds of thousands of people in Lagos attending a convention at the Redeemed Christian Church of God.
Hindu pilgrims bathe in the Ganges River in Allahabad, India, which is projected to become the world's most populous country.
PHOTOGRAPH BY STEFANO DE LUIGI, VII
A Change of Heart

A decade or so ago, the UN's demographers had a more optimistic view. The message back then, says Hania Zlotnik, who was chief of the UN Population Division at the time, was that "the population problem is essentially over, because fertility is coming down automatically. We know now that was wrong."

A country's total fertility—the number of children the average woman bears in her lifetime—is the key variable in the "demographic transition" that every developing country is expected to go through. At the outset of the transition, high death rates and low life expectancies are balanced by high birth rates, as women bear many children, knowing that some will die.

As the country acquires modern agriculture, sanitation, and medicine, its mortality rate can fall rapidly, especially in children. But it takes at least a generation for couples to adjust to the new reality and have fewer children. In that interval, the population booms—and the size of the boom depends on how long it takes for fertility to fall.

When Western countries went through this transition in their pasts, both mortality and fertility fell gradually over a period of a century or more. Beginning in the 1960s, demographers were shocked to see how fast the transition was happening in Asia and Latin America. "It was a total surprise," says Gilles Pison of INED, the French National Institute of Demographic Studies.

In countries like China and Brazil, it took just three or four decades for the fertility level to plunge from more than six to less than two—the number of kids it takes for a couple to replace itself, and for a country as a whole to maintain a stable population.


The experience in Asia and Latin America, says Pison, led demographers to expect a similarly rapid transition in Africa. Now they've been surprised again—unpleasantly this time.

Over the past decade or two, it has become clear that fertility is falling much more slowly in some countries in sub-Saharan Africa than it did on other continents. That realization has come gradually because vital statistics in Africa are so poor. As new data come in, researchers revise their estimates not only of the future, but also of the recent past.

Between 2010 and 2012, for instance, UN demographers raised their estimate of how many babies African women had recently been having by a quarter of a child per woman. Population grows like a bank account with compound interest; a quarter child more per woman today generates 600 million more Africans in 2100, according to the UN projections reflected in the Science paper.

Nigeria is a crucial country: Its population, already Africa's largest at 174 million, will more than quintuple by 2100, to more than 900 million. Of the people added to the planet in this century, according to the UN, one in five will be Nigerian.

"I think everybody has had trouble facing the reality of that many people in that quantity of land," says Wilmoth. "It's hard to imagine. People have trouble wrapping their heads around it."

A Range of Possible Futures

The small adjustments that demographers made in 2012 to Nigeria's recent fertility data added some 180 million people to the projection for that country—suggesting that the statistical model used is quite sensitive to such adjustments.

The model uses fertility data from all the world's countries going back to 1950 to generate a number of projections "that reflects the range of possible experiences," explains Adrian Raftery of the University of Washington, Seattle, one of the model's creators and a co-author of the Science paper.

By randomly generating tens of thousands of projections for each country, the model attempts to capture the full range of uncertainty about the future—barring a meteorite impact or a nuclear holocaust. (There are no examples of those in the demographic data since 1950, so the model can't imagine them.)

In contrast, Lutz and his colleagues from the IIASA attempt to model uncertainty in a completely different way: by surveying hundreds of demographers to get their subjective but expert answers to targeted questions about the demographic future of each country. The range of opinions gives a different set of possibilities.

There are three main reasons why the IIASA's projections, unlike the UN's, suggest the world's population will stabilize before 2100, Lutz explained by email. First, the UN assumes that China's fertility level, which has already fallen to 1.6 or so, is going to start rising again—an assumption, Lutz says, "that has no scientific basis, nor do trends point in this direction."

Second, the IIASA projects that Nigeria's population will triple but not quintuple in this century. The UN projections "on some African countries ... are simply too high," Lutz says.

And finally, the IIASA model incorporates data on a crucial variable that's not contained in the UN or other demographic models: the level of education in a given population. Educating girls in particular has been found to be one of the best ways of bringing down fertility, at least in the long term.


Lutz believes that improvements in education that are already happening-in Nigeria, he points out, half the women aged 20 to 24 have had a high school education, compared with a quarter of the women aged 40 to 44—will help keep the world's population from reaching 11 billion in 2100.

On the other hand, people will still have to figure out how to feed nine billion—a threshold that both the IIASA and the UN agree we'll cross before 2050.

A photo of hundreds of thousands of people in Lagos attending a convention at the Redeemed Christian Church of God.
New apartment blocks are rapidly being built in Beijing, China. Currently the world's most populous country, China is projected to experience population decline this century.
PHOTOGRAPH BY MARCUS BLEASDALE, VII
Choosing a Path

So who's right about 2100? "We'll find out in a hundred years," says Gilles Pison. He created an ingenious simulator, posted on the INED website, that allows you to become a godlike demographer, choosing your own population path for each country, and for the world as a whole, by dialing fertility and mortality up and down at will.

The UN's Zlotnik doesn't doubt the importance of educating women, but she questions Lutz's faith that it will keep us off the population trajectory traced by the UN. "No one knows, neither he nor us, what's going to happen," Zlotnik says. "In order to get to a different future, you have to change the now." Education is slow, she says: What governments in Africa and elsewhere need to do is make contraception more widely available, now.

"The important message is that governments need to react to the realities of population change," agrees Wilmoth, Zlotnik's successor at the UN. "At an individual level, women need access to family planning, and they need education. This study is a reminder of the importance of emphasizing both of these as we move forward."

Alarmism of the title not withstanding, there's disagreement on the subject, and the picture doesn't seem quite as bleak as the one you tried to paint, Purple.

[The Romulan Republic]

Edit: On population growth, I found this:

http://news.nationalgeographic.com/news ... om-africa/

Warning: The 21st century may get a lot more crowded than previously thought.


In a paper published Thursday in Science, demographers from several universities and the United Nations Population Division conclude that instead of leveling off in the second half of the 21st century, as the UN predicted less than a decade ago, the world's population will continue to grow beyond 2100. (Read "Population Seven Billion" in National Geographic magazine.)

And for the first time, through the use of a "probabilistic" statistical method, the Science paper establishes a range of uncertainty around its central estimate-9.6 billion Earthlings in 2050, 10.9 billion by 2100. There's an 80 percent chance, the authors conclude, that the actual number of people in 2100 will be somewhere between 9.6 and 12.3 billion.

A photo of hundreds of thousands of people in Lagos attending a convention at the Redeemed Christian Church of God.
NG STAFF. SOURCE: UN
That range "is the truly innovative part," says John Wilmoth, head of the UN Population Division and one of the authors of the Science paper. "It's a much more plausible analysis of uncertainty—but we may still be off by two billion."

According to other demographers, the UN has missed the mark by just about that amount. In a paper in press at Global Environmental Change and in a forthcoming book, Wolfgang Lutz and his colleagues at the International Institute for Applied Systems Analysis (IIASA) in Vienna, Austria, use a very different method—one that involves canvassing a large group of experts—to argue that population is likely to peak at 9.4 billion in 2075 and fall to just under 9 billion by 2100.

The UN team estimates there's no more than a 5 percent chance of that rosier scenario coming to pass.


Both groups foresee India becoming the world's most populous country, with its numbers peaking around 2070 and declining to around 1.5 or 1.6 billion by 2100. Where they differ most is in their estimates of the coming population decline in China and of the coming population explosion in Africa south of the Sahara—where most of the world's growth is going to occur.

According to the UN, the population in that region could quadruple, from less than one billion to nearly four billion. Africa in 2100 would be as densely populated as China is today.

"These are not predictions," says Wilmoth. "These are projections of what will happen if current trends continue. There is still an opportunity to intervene."

A photo of hundreds of thousands of people in Lagos attending a convention at the Redeemed Christian Church of God.
Hindu pilgrims bathe in the Ganges River in Allahabad, India, which is projected to become the world's most populous country.
PHOTOGRAPH BY STEFANO DE LUIGI, VII
A Change of Heart

A decade or so ago, the UN's demographers had a more optimistic view. The message back then, says Hania Zlotnik, who was chief of the UN Population Division at the time, was that "the population problem is essentially over, because fertility is coming down automatically. We know now that was wrong."

A country's total fertility—the number of children the average woman bears in her lifetime—is the key variable in the "demographic transition" that every developing country is expected to go through. At the outset of the transition, high death rates and low life expectancies are balanced by high birth rates, as women bear many children, knowing that some will die.

As the country acquires modern agriculture, sanitation, and medicine, its mortality rate can fall rapidly, especially in children. But it takes at least a generation for couples to adjust to the new reality and have fewer children. In that interval, the population booms—and the size of the boom depends on how long it takes for fertility to fall.

When Western countries went through this transition in their pasts, both mortality and fertility fell gradually over a period of a century or more. Beginning in the 1960s, demographers were shocked to see how fast the transition was happening in Asia and Latin America. "It was a total surprise," says Gilles Pison of INED, the French National Institute of Demographic Studies.

In countries like China and Brazil, it took just three or four decades for the fertility level to plunge from more than six to less than two—the number of kids it takes for a couple to replace itself, and for a country as a whole to maintain a stable population.


The experience in Asia and Latin America, says Pison, led demographers to expect a similarly rapid transition in Africa. Now they've been surprised again—unpleasantly this time.

Over the past decade or two, it has become clear that fertility is falling much more slowly in some countries in sub-Saharan Africa than it did on other continents. That realization has come gradually because vital statistics in Africa are so poor. As new data come in, researchers revise their estimates not only of the future, but also of the recent past.

Between 2010 and 2012, for instance, UN demographers raised their estimate of how many babies African women had recently been having by a quarter of a child per woman. Population grows like a bank account with compound interest; a quarter child more per woman today generates 600 million more Africans in 2100, according to the UN projections reflected in the Science paper.

Nigeria is a crucial country: Its population, already Africa's largest at 174 million, will more than quintuple by 2100, to more than 900 million. Of the people added to the planet in this century, according to the UN, one in five will be Nigerian.

"I think everybody has had trouble facing the reality of that many people in that quantity of land," says Wilmoth. "It's hard to imagine. People have trouble wrapping their heads around it."

A Range of Possible Futures

The small adjustments that demographers made in 2012 to Nigeria's recent fertility data added some 180 million people to the projection for that country—suggesting that the statistical model used is quite sensitive to such adjustments.

The model uses fertility data from all the world's countries going back to 1950 to generate a number of projections "that reflects the range of possible experiences," explains Adrian Raftery of the University of Washington, Seattle, one of the model's creators and a co-author of the Science paper.

By randomly generating tens of thousands of projections for each country, the model attempts to capture the full range of uncertainty about the future—barring a meteorite impact or a nuclear holocaust. (There are no examples of those in the demographic data since 1950, so the model can't imagine them.)

In contrast, Lutz and his colleagues from the IIASA attempt to model uncertainty in a completely different way: by surveying hundreds of demographers to get their subjective but expert answers to targeted questions about the demographic future of each country. The range of opinions gives a different set of possibilities.

There are three main reasons why the IIASA's projections, unlike the UN's, suggest the world's population will stabilize before 2100, Lutz explained by email. First, the UN assumes that China's fertility level, which has already fallen to 1.6 or so, is going to start rising again—an assumption, Lutz says, "that has no scientific basis, nor do trends point in this direction."

Second, the IIASA projects that Nigeria's population will triple but not quintuple in this century. The UN projections "on some African countries ... are simply too high," Lutz says.

And finally, the IIASA model incorporates data on a crucial variable that's not contained in the UN or other demographic models: the level of education in a given population. Educating girls in particular has been found to be one of the best ways of bringing down fertility, at least in the long term.


Lutz believes that improvements in education that are already happening-in Nigeria, he points out, half the women aged 20 to 24 have had a high school education, compared with a quarter of the women aged 40 to 44—will help keep the world's population from reaching 11 billion in 2100.

On the other hand, people will still have to figure out how to feed nine billion—a threshold that both the IIASA and the UN agree we'll cross before 2050.

A photo of hundreds of thousands of people in Lagos attending a convention at the Redeemed Christian Church of God.
New apartment blocks are rapidly being built in Beijing, China. Currently the world's most populous country, China is projected to experience population decline this century.
PHOTOGRAPH BY MARCUS BLEASDALE, VII
Choosing a Path

So who's right about 2100? "We'll find out in a hundred years," says Gilles Pison. He created an ingenious simulator, posted on the INED website, that allows you to become a godlike demographer, choosing your own population path for each country, and for the world as a whole, by dialing fertility and mortality up and down at will.

The UN's Zlotnik doesn't doubt the importance of educating women, but she questions Lutz's faith that it will keep us off the population trajectory traced by the UN. "No one knows, neither he nor us, what's going to happen," Zlotnik says. "In order to get to a different future, you have to change the now." Education is slow, she says: What governments in Africa and elsewhere need to do is make contraception more widely available, now.

"The important message is that governments need to react to the realities of population change," agrees Wilmoth, Zlotnik's successor at the UN. "At an individual level, women need access to family planning, and they need education. This study is a reminder of the importance of emphasizing both of these as we move forward."

Alarmism of the title not withstanding, there's disagreement on the subject, and the picture doesn't seem quite as bleak as the one you tried to paint, Purple.

[Purple]

notes:
- The text bellow is written using numbers made up to demonstrate a point and not actual measurements. They are probably off, but in the generally correct ballpark.
- The above text contains figures of speech and metaphorical language. Do not dissect the words them self literally but the meaning of the entire sentence and paragraph.

---

No, it is obviously not "established fact" that humanity will destroy itself,

Really? I figured that given the fact we are heading that way it was only a matter of time.

Also, I might be wrong, but I'm fairly sure the consensus is not that human population will go up endlessly until we die out. Birthrates have already gone down in much of the world.

Much of being bits of Europe and North America. The majority of the human population in places such as Africa and Asia meanwhile are happily breeding away.

Sex does not equal children, your false assumption to the contrary notwithstanding. We have these things called "sex education" and "birth control" and, as volatile a topic as it is, "abortion".

It's was a figure of speech. You need not take everything 100% literally.

You know, if you hate all human beings, that's your business.

I don't hate anyone. I just don't live in a fantasy land where education will suddenly magically prevail and fix all our problems, our population magically stops because the people in Africa, India etc. stop wanting to have children, where 3rd world countries won't want to develop into 1st world ones and reach our unsustainable living standards, where we will magically stop consuming the earths resources, fix all the problems in Africa and unite into a world union to prepare for an alien invasion. That's just wishful thinking.

But do not have the arrogance to treat your biases as objective fact.

You have the arrogance to be an optimist in face of reality.

Alarmism of the title not withstanding, there's disagreement on the subject, and the picture doesn't seem quite as bleak as the one you tried to paint, Purple.

The problem isn't if there will be 7, 8 or 9 billion people in 100 years time. The problem is that all of those people will want to reach the unsustainable economic standards of the 1st world. As we stand now we have maybe 1 billion people living very rich lives, unsustainably rich. Another billion or two living lives that are basically the 1980's but with smartphones and the rest living in various degrees of abject poverty. As it stands now thus, those 1 / 7 of our population are doing most of the damage. What do you think will happen when the other 6 catch up? And they will catch up because not only can the 1st world do nothing to stop them but it would be extremely immoral, evil and disgusting to do so.

Also, there is the issue of the time frame. 100 years is nothing compared to the 1500 being talked about. If history is any indicator there is no reason to believe our civilization will last that long if for no other reason than because no other has. Assuming we still exist by than what ever becomes of our species in that time will probably be as unrecognizable to us as our world would be to an ancient Roman.

[Ziggy Stardust]

You have the arrogance to be an optimist in face of reality.

You are confusing pessimism with intelligence, Purple.

This is not surprising, because you have a documented track record of being a misanthropic troll who has expressed confusion over simple concepts like "fun" and "hobbies".

None of us alive today are ever going to meet one of them, talk to them, shake their hand or anything. It simply does not change our lives in any meaningful way. The world we live in is changed more every time a new model of mobile phone hits the market. So what's the excitement about?

Simply the confirmation that there is intelligent extraterrestrial life has massive philosophical and scientific ramifications. The fact that you personally are too unimaginative and cynical to care about such things does not detract from the ability of millions of other well-adjusted human beings to want to explore these issues.

I mean, what is even the point of your comment anyway? Are you trolling to get a reaction or is this some sort of posturing, because you think being super-cynical makes you seem intelligent and thoughtful (here's a hint: it actually has the opposite effect)? With your posting history, I harbor no illusions that it was actually an honest question on your part, because you don't often pose those. It would be like going into the thread discussing the movie "The Martian" and complaining that the events never happened so won't materially impact our lives in any way, so how could people enjoy it?

In the words of George Bernard Shaw, a man infinitely more thoughtful than you can ever hope to be, "A pessimist is a man who thinks everybody is as nasty as himself, and hates them for it.”

[Simon_Jester]

Ultimately is just another way of saying a long time after we are all dead.

You only say this because you're a sociopath whose imagination is pretty sterile and dead about such matters; it doesn't apply to the average intelligent sane-ish member of the human race. Therefore, I am not going to continue to try to explain this to you at the moment; I have enough trouble trying to teach morality and caring to amoral uncaring fools at work without having to do it on the weekend too.

Across those time ranges it might as well be if for no other reason than because we don't even know if there will be a human race that far down the line. This isn't 2-3 generations forward we are talking about. It's ten times as much. We are more likely to hit peak oil, peak water or peak atomic holocaust than we are to stay on this planet for that long.

Since this completely misses the point of what I wrote later, I do not think any response is necessary.

1) The existence of aliens who own a Dyson sphere implies certain things about what our own species can aspire to accomplish. Interesting things. To do that would require that this species somehow overcome the challenges of space flight and (what is to us) advanced technology. That they can spread out through one or more solar systems, rendering their species immune to all sorts of environmental disasters and cultural problems.

Why does it imply any of these things? Why do you need to spread out across more than one solar system to do that? And why do you think it solves any cultural problems at all? Technological and economic progress do not necessarily imply social progress.

"Cultural problems" as in "our problems are caused by our culture."

If everyone lives in the same self-contained world (such as a planet), one culture can do something stupid, nihilistic, arrogant, or destructive and kill everyone.

If there are many self-contained worlds (multiple terraformed planets, huge numbers of self-contained space habitats), then it becomes far more difficult for any one culture or group to kill everyone. The resources to survive and ride out a disaster are more available and more distributed.

In the Iron Age, the actions of one culture could not kill everyone on Earth because they couldn't reach everyone on Earth. There were isolated places where everyone died due to self-created ecological disaster, or where everyone killed each other off, but no one group could do that to the whole Earth because the Earth was (effectively) subdivided into many separate habitats for humans, all of which were (effectively) independent of each other and of anything humans could do to them.

Modern technology allows one group of humans to reach and affect every part of the Earth at once, so this protection is lost. Advanced technology might well recreate the protection, but in a new form, with many habitats protected by being far away in outer space.

It's nice to know someone else can accomplish these things, because it sets a precedent for us accomplishing them.

How does that matter? I mean, if Messi can play really well does that set a precedent that you might one day as well? Of course not. It only establishes that it's theoretically possible for someone to do it. Which frankly is not really worth much.

It's not worth much to you because your imagination is sterile, and I feel sorry for you, but there's nothing I can do to fix that. Sorry.

2) It gives us a standard to compete against. These aliens are likely to remain ignorant of our whereabouts for at least another 1500 years, and if they decide to do anything about us it will probably take at least another 1500.

You forgot to add the part where the image we have of them is at least 1500 years old to begin with. For all we know they might already be gone or we might be gone before they get to us, or we might send someone to get to them only for both them and us to be gone before they arrive etc.

Or they might not; the point here is quite simple and it's amazingly obtuse of you to miss it. Rather than plan on the assumption that an advanced alien civilization will disappear, or that we will all willfully destroy ourselves for stupid reasons... would it not pay to at least consider the possibility that we will still be around?

This gives us a reason NOT to screw around and pointlessly damage ourselves- because at some point in the next million years, advanced aliens might come to our star system, and we today are the ones who get to decide whether they encounter another advanced species, or a bunch of random cavemen squatting in the ruins of what used to be an Atomic Age civilization.

How much can we do, in three thousand years, to prepare for their actions? Even if those actions are just a radio message? Or a single starship? Perhaps we could have a Dyson sphere of our own in that time, and all the resources it implies. IF we prepare./quote]
Are you listening to your self?
1) You imply some sort of unity on part of the human race. There is no reason to expect this will ever happen beyond wishful thinking. Of course, there is no reason to think it won't eventually. But one need not prove a negative.

I am not implying political unity, I am simply referring to the set of all humans as 'we.' Who knows or cares whether 'we' will be politically united? It doesn't matter for purposes of this discussion.

2) You imply with certainty that the human race will exist by that point. Which again is not guaranteed.

I do not imply it with certainty, you are failing at reading comprehension. But I discuss it because we have interest in what may happen if future humans are alive, and none in what may happen after all future humans are dead.

Why plan for a scenario that defeats all plans?

Conversely, why become obsessed with the ONLY scenario that defeats all plans, instead of the ones where planning and taking right actions now might actually help?

3) You imply that the human race, which fails to do simple things such as fix the massive wealth inequality that leads some nations to throw food away whilst millions in others starve is somehow going to come together for a millennium long project.

I just don't see it.

Who knows what the path between here and a Dyson sphere looks like? I don't. I know broadly what has to be done, but that doesn't mean it can only be done by a united species, or a species which knows how to feed everyone when food is moderately-not-scarce anymore. Or maybe our species needs to continue to develop its philosophies and ideas over this span of time- we today have a lot of good ideas and techniques that did not exist a thousand years ago. Savagery and cruelty and ignorance and indifference to the fate of strangers were all present in the humans of a thousand years ago, more so than today- maybe the future humans of the year 3000 will do better than we do, just as we do compared to the humans of the year 1000.

I thought this was established fact already.

Nothing is established fact until it already happens, you are assuming the things you wish to prove in order to support your arguments. We do not know what crises the future will contain, but there is literally zero evidence that they will overcome us.

Your smug nihilism, cynicism, and sociopathy are not a substitute for real thought, either about the present or about the future.

[Channel72]

Even if we don't detect any Dyson swarms out there, I really think it would be worth it to try to build our own. A precedent would be encouraging, yeah, but it might simply be that K2 civilizations are simply so rare that there's, on average, less than one per galaxy. So can we please at least fucking try to be that one K2 in the Milky Way?

[Borgholio]

It would change how we view the universe in a philosophical and religious manner. For the longest time, we felt we were special, the center of the universe, above all other lower lifeforms and basically owned whatever we set our eyes on. If we learn we're actually not the top of the totem pole, that would disrupt the worldview of a great many people. Religious people would question the idea that God made us in his image (since these guys could potentially have evolved first). It could lead to more cooperation between nations as governments realized that there could be an alien threat that requires us to work together (hey, sometimes government hysteria proves useful). So it would change our perspective on a great many things.

[Sky Captain]

I think simplest explanation why we haven't detected signs of other civilizations is because it could be that development of intelligent species is a freak event extremely rare in the universe. Humans are around only few million years. Earth has life on it going for 3,5 billion years or longer, large land animals theoretically capable of having advanced brain for several hundred million years so even here on Earth humans are freak occurrence.

Maybe even step from single cell life to multicellular life is extremely rare given most of Earth history life consisted of single cell organisms. If on average there is only one advanced civilization per galaxy unless physics allows some sort of intergalactic FTL drive we may never encounter signs of another civilization.

[Darmalus]

That, and space is a dangerous place. As far as I know we have been close enough to a supernova and another stellar event (who's nature escapes me at the moment) in our recorded history that night was turned into day twice. A little closer and we'd be a dead, irradiated rockball. If it happened today we could kiss the digital age goodbye as we experienced a world-wide EMP.

So even if intelligent life is fairly common, it may not last long enough to survive such events. All the more reason for our species to show some hustle.

[jwl]

I newer quite understood the excitement about discovering aliens. Like, say we get 100% confirmation that 1500 ly from us there is in fact an advanced alien civilization. Like, a probe reaches us or something. So what? That's still 1500 years away at the highest speed there is. None of us alive today are ever going to meet one of them, talk to them, shake their hand or anything. It simply does not change our lives in any meaningful way. The world we live in is changed more every time a new model of mobile phone hits the market. So what's the excitement about?

If they have a Dyson sphere-like object? With better telescopes we can analyse the Dyson sphere and use it to work out how to make the technologies that lead up to it and ultimately one of our own.

Ultimately is just another way of saying a long time after we are all dead.

Yes, I don't think it would lead us to building a dyson sphere in my lifetime. But that doesn't mean it's not going to be useful in that timespan. Going by Simon_Jester's figures, we are looking at 35-85 years before we start seeing applications, and the lower end of that is probably within my lifetime.

But I think we will start seeing technologies earlier. If this were to be confirmed as a dyson sphere, suddenly astronomers all over the world will be wanting to study this object, more people will be inspired to go into astronomy, and astronomy would suddenly gain a large boost of funding. Yes, at the moment it will just be a point of light, but there are things you can do with a point of light. The first thing to look at would be what is it made of? There are probably all sorts of exotic materials in and on the dyson sphere, and while we would be puzzilng how to make some of them, I could easily see some relativly simple molecule that can be made in 24 hours in any chemistry lab turning out to superconduct at 2 degrees Celsius.

And as soon as the technologies start rolling out, we will have better technology to build better telescopes, we'll discover new science to make better technology to build better telescopes, and more people and funding will flow into astronomy. This will feed back into more technologies coming from observation of the dyson sphere, and so on.

I think if this really is a dyson sphere-like object, the civilisation that made it probably did the same thing. If there was one K2 civilisation in our galaxy, there is probably a thousand that were like us. Some of these thousand would notice that K2 civilisation and work out how to build similar technologies. Then some other civilisations will notice them, and so on, resulting in the vast majority of K2 civilisations becoming second- or third- hand.

[Guardsman Bass]

Yes, I don't think it would lead us to building a dyson sphere in my lifetime. But that doesn't mean it's not going to be useful in that timespan. Going by Simon_Jester's figures, we are looking at 35-85 years before we start seeing applications, and the lower end of that is probably within my lifetime.

That's probably too soon. I don't see a purpose for it unless you're either trying to launch starships or running an almost unimaginably huge space computer network requiring incredible amounts of photovoltaic power, and both are pretty far-off and speculative at this point. Even more conventional space solar plants have the issues of either prohibitively high launch costs or very versatile worker robots required, as well as the ground infrastructure (plus the question of whether you want people building giant orbit-to-ground microwave beam emitters).

Modern technology allows one group of humans to reach and affect every part of the Earth at once, so this protection is lost. Advanced technology might well recreate the protection, but in a new form, with many habitats protected by being far away in outer space.

Do you keep a second house on a remote island in the Arctic Ocean in the off-chance that your house might get burned down in an arson attack?

It's an excessive use of resources to deal with problems you'll have to deal with anyways for most of the population. If we're afraid of a major pandemic outbreak, for example, we take steps to respond and deal with an outbreak - as well as research into cures and treatment. You don't build a space base to keep 200,000 people alive unless you're really, super-sure that the threat is real and unstoppable.

[Darmalus]

Modern technology allows one group of humans to reach and affect every part of the Earth at once, so this protection is lost. Advanced technology might well recreate the protection, but in a new form, with many habitats protected by being far away in outer space.

Do you keep a second house on a remote island in the Arctic Ocean in the off-chance that your house might get burned down in an arson attack?

It's an excessive use of resources to deal with problems you'll have to deal with anyways for most of the population. If we're afraid of a major pandemic outbreak, for example, we take steps to respond and deal with an outbreak - as well as research into cures and treatment. You don't build a space base to keep 200,000 people alive unless you're really, super-sure that the threat is real and unstoppable.

I don't think anyone's talking about keeping a reserve supply of humanity around excursively as a backup. My impression was he was talking about civilization spreading out and the very nature of space habitats providing such protection. Colonists on Mars or in orbit around Jupiter might be there for their own reasons, but if a near-lightspeed asteroid or super-plague shows up and turns Earth into a graveyard it does mean the species keeps going even if that was never part of the design document or mission statement.

[Simon_Jester]

It's not like ancient peoples created colonies and spread into new lands so that their culture would survive or to preserve the human species- but that was sometimes the effect.

[Channel72]

At this point, the pessimist would point out that we haven't detected any signs of advanced alien civilization because civilization-building life because, based on a sample size of one (us), it probably suffocates in its own shit before becoming advanced. There are other reasons, of course: We might not see them because something else has come along and murdered them. Or they might be hiding from whatever comes along and murders advanced civilizations (implying an eugenics and population control regime that might even make you pause.) Or maybe they only become a little advanced and, for whatever reason, fizzle out. Or else, they get bored and eventually commit mass-suicide. All of these other options, by the way, are terrible.

I never buy these "doom and gloom" interpretations of the Fermi paradox. All this "maybe they all commit suicide" speculation leaves out the most obvious possibility: that natural occurring large brains are simply very, very rare. I mean it took 500 million years after the Cambrian explosion for anything capable of doing simple arithmetic to appear on Earth. And there's no Darwinian reason why large brains should necessarily be a common outcome, given the starting point of sexually reproducing multicellular organisms. They certainly were not a common outcome on Earth. Most evolutionary pathways in the Animal Kingdom have not resulted in large brains capable of higher reasoning - only higher primates and to a lesser extent, cetaceans. The possibility that we're simply the first civilization capable of space travel in the Milky Way is a much more plausible explanation than the idea that countless other industrial civilizations exist, but they all fizzle out for some reason. Just because we don't observe other advanced civilizations by no means indicates that we are somehow logically fated to amount to nothing.

[Guardsman Bass]

I don't think anyone's talking about keeping a reserve supply of humanity around excursively as a backup. My impression was he was talking about civilization spreading out and the very nature of space habitats providing such protection. Colonists on Mars or in orbit around Jupiter might be there for their own reasons, but if a near-lightspeed asteroid or super-plague shows up and turns Earth into a graveyard it does mean the species keeps going even if that was never part of the design document or mission statement.

Fair enough, although I've heard on multiple occasions the "off-world backup" argument for building colonies off-world. It's presumably because other reasons to build them right now are rather weak - there's neither a strong economic case nor any private/public/non-profit group with the combined financing and desire to do so (Mars One doesn't count because they don't have the money even if they have the desire).

That said, it could certainly change over time. Robots could do most of the work for you in the future, although if those robots are that versatile they could also do most of the work you might want to do in space - you'd essentially be going into space to live permanently in space (or on another planet/moon/etc).

The possibility that we're simply the first civilization capable of space travel in the Milky Way is a much more plausible explanation than the idea that countless other industrial civilizations exist, but they all fizzle out for some reason. Just because we don't observe other advanced civilizations by no means indicates that we are somehow logically fated to amount to nothing.

I wouldn't rule out the "fizzling out" factor, although I don't think of that as a collapse so much as civilizations settling into a rather comfortable state of technological and economic maturity (especially if they figure out the technology to modify themselves to be long-lived and peaceful). The fewer civilizations there are, the more likely it is that you get a scenario where none of them have bothered to do much traveling outside their home systems in the Milky Way. Interstellar exploration is extremely expensive in energy terms, after all, even if you're only sending what will become a robotic probe weighing a few thousand kilograms at the destination. You'd have to really want to get away from the home system, and be tolerant of the unavoidable communication lag.

[jwl]

Yes, I don't think it would lead us to building a dyson sphere in my lifetime. But that doesn't mean it's not going to be useful in that timespan. Going by Simon_Jester's figures, we are looking at 35-85 years before we start seeing applications, and the lower end of that is probably within my lifetime.

That's probably too soon. I don't see a purpose for it unless you're either trying to launch starships or running an almost unimaginably huge space computer network requiring incredible amounts of photovoltaic power, and both are pretty far-off and speculative at this point. Even more conventional space solar plants have the issues of either prohibitively high launch costs or very versatile worker robots required, as well as the ground infrastructure (plus the question of whether you want people building giant orbit-to-ground microwave beam emitters).

I'm not talking about us imminently using it to build dyson spheres or anything close to resembling Dyson spheres, I'm talking about us using the technologies and materials they used to build dyson spheres, or other materials and technologies that society just happen to have. Although ultimately (and as Purple noted, this is a long way off) it may lead to one. You don't build a dyson sphere with reinforced concrete and JCBs, there will be other technologies involved. And if you give reinforced concrete and JCBs to Archimedes for example, he isn't going to build the Hoover Dam straight away, but he is going to find some use for it.

[Simon_Jester]

I don't think anyone's talking about keeping a reserve supply of humanity around excursively as a backup. My impression was he was talking about civilization spreading out and the very nature of space habitats providing such protection. Colonists on Mars or in orbit around Jupiter might be there for their own reasons, but if a near-lightspeed asteroid or super-plague shows up and turns Earth into a graveyard it does mean the species keeps going even if that was never part of the design document or mission statement.

Fair enough, although I've heard on multiple occasions the "off-world backup" argument for building colonies off-world. It's presumably because other reasons to build them right now are rather weak - there's neither a strong economic case nor any private/public/non-profit group with the combined financing and desire to do so (Mars One doesn't count because they don't have the money even if they have the desire).

That said, it could certainly change over time. Robots could do most of the work for you in the future, although if those robots are that versatile they could also do most of the work you might want to do in space - you'd essentially be going into space to live permanently in space (or on another planet/moon/etc).

Well, yes.

At the moment, launch costs to LEO are staggeringly expensive (cheap, efficient drives for getting OUT of low orbit exist, but they don't solve that problem because they can't produce the two or three gravities of acceleration you need to get to orbit in the first place). There is effectively no orbiting infrastructure to support, well, anything- no established refueling facilities, no habitats or stations large enough to do maintenance on your spacecraft, no tugs, no nothing. We've experimented with many of these things but as yet they simply do not exist.

In that context, the costs of building a colony on the Moon or Mars just seem unthinkable. We could do it if someone were willing to budget, oh, five or ten billion dollars a year, every year, for a number of decades; investments add up. But we're so far from being there that the distance between 'here' and 'there' seems impossible to bridge.

So obviously, no one is in a good position to provide a cost-benefit analysis that looks favorable at the moment.

The question, and the challenge, is whether smaller-scale ventures can bring in enough rewards (of scientific data or wealth, either or both) to justify creating infrastructure. If we already had the techniques to, say, tow asteroids into Earth orbit and start tapping into them for metals, with all the facilities that would imply, then something like lunar colonization would start looking a lot less prohibitive.

[Sky Captain]

That, and space is a dangerous place. As far as I know we have been close enough to a supernova and another stellar event (who's nature escapes me at the moment) in our recorded history that night was turned into day twice. A little closer and we'd be a dead, irradiated rockball. If it happened today we could kiss the digital age goodbye as we experienced a world-wide EMP.

So even if intelligent life is fairly common, it may not last long enough to survive such events. All the more reason for our species to show some hustle.

Don't even need distant space borne disasters, there are plenty of things that can go wrong on the planet itself and kill advanced life before it has a chance to spread out into space.

A planet may also lack resources for development of industrial civilization. Imagine if Earth had little or no easily usable deposits of fossil fuels. Industrial revolution likely would not have happened and we would be stuck in 18th century tech level.

Or a planet that is mostly covered with oceans with little to no dry land. While very intelligent dolphin equivalents may live there they are not going to build technological civilization and spacecraft any time soon.

[Channel72]

The possibility that we're simply the first civilization capable of space travel in the Milky Way is a much more plausible explanation than the idea that countless other industrial civilizations exist, but they all fizzle out for some reason. Just because we don't observe other advanced civilizations by no means indicates that we are somehow logically fated to amount to nothing.

I wouldn't rule out the "fizzling out" factor, although I don't think of that as a collapse so much as civilizations settling into a rather comfortable state of technological and economic maturity (especially if they figure out the technology to modify themselves to be long-lived and peaceful). The fewer civilizations there are, the more likely it is that you get a scenario where none of them have bothered to do much traveling outside their home systems in the Milky Way. Interstellar exploration is extremely expensive in energy terms, after all, even if you're only sending what will become a robotic probe weighing a few thousand kilograms at the destination. You'd have to really want to get away from the home system, and be tolerant of the unavoidable communication lag.

True - although I find it hard to believe that, over a period of millenia, the "it's too expensive, we're content to sit around and do nothing" attitude could possibly remain stable, given that:

• (A) curiosity seems to be a natural Darwinian trait among higher-reasoning, cognitive organisms
  (B) the pay-off is so extreme

In terms of (B), I mean the wealth and resources that could be extracted from the asteroid belt alone would justify the expenditure. Right now, sitting here in the early 21st century like a bunch of idiots, when we have zero infrastructure to even begin to dream about doing anything like that, it may seem really far-fetched. But it really isn't that far-fetched if you're thinking about timescales over thousands or even millions of years. I mean, extracting oil from the ground requires a very expensive infrastructure - once we realized it was worth it, we built that infrastructure. Granted, mining materials from asteroids is an order of magnitude more expensive, but it has to happen in baby-steps over centuries or millenia.

I mean the Romans, for example, would not be capable of setting up a typical ExxonMobil oil rig - their materials technology and engineering ability was so far behind us that they couldn't extract such resources from the Earth even if they knew about them. Now, we find ourselves in a similar position in regard to extracting resources from extraterrestrial objects. But again - it has to happen in baby steps. It's likely that commercial space flight merely for the fuck of it, along with space-based defense initiatives from private companies like SpaceX, will be the first baby steps towards some kind of permanent space infrastructure.