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Mass Extinction and the Structure of the Milky Way (2013) (arxiv.org)
351 points by DrScump on May 8, 2017 | hide | past | favorite | 204 comments


As a non-astronomer, I hadn't thought of that but now that I read the abstract, it makes complete sense (assuming evidence supports the thesis)

- Might be related to why moon's surface is so scarred and yet in many centuries of recorded (astronomical) history (since the invention of telescope) we haven't seen any major lunar impact events.

- Also I was reading the other day how our solar system is going through a local "bubble" (region of unusually low interstellar density) but is heading towards a certain G-Cloud.

Mind blowing stuff. I guess once we have fixed the planetary mess (climate change) and biological-aging, we'd have a serious type-I [2] problem to worry about (and we can't even handle/track the inner solar system objects yet, NEO, asteroids, etc).

[1] https://en.wikipedia.org/wiki/Solar_System#Galactic_context

[2] https://en.wikipedia.org/wiki/Kardashev_scale


Are you familiar with the theory of the Late Heavy Bombardment? https://en.wikipedia.org/wiki/Late_Heavy_Bombardment


The predominant theory, though, is that the bombardment was caused by changes within our own solar system, not from outside - per your link


> Might be related to why moon's surface is so scarred and yet in many centuries of recorded (astronomical) history (since the invention of telescope) we haven't seen any major lunar impact events.

Except for that 1178 event then.

https://en.wikipedia.org/wiki/Giordano_Bruno_(crater)


If you read the section you linked it has some very serious - I would say fatal - objections listed to the theory that the impact occurred in 1178.


...half a millennium or so before the telescope was invented?


I can't comment on this specific event, but there are many accounts of astronomical events visible to the naked eye that were proven to be a useful resource for contemporary astronomy [0].

[0]: https://en.wikipedia.org/wiki/SN_1054#Chinese_astronomy


We can assume events of this magnitude can be seen with naked eye. It the the Moon after all. Apparently this is based on recorded eye witness testimony.


I find it interesting that the public has a good understanding of our solar system, and recognizes images of our galaxy as a whole, but if you ask them anything about the layout of what's in between, they have no clue.


What needs to be fixed about biological aging exactly?


The fact that I'm going to die. It's really annoying.

Also, ageing effects on the body, like brain plasticity reduction and various other bits that really suck when you get up in the morning and remember how easy it was 20 years ago.

Life is so totally freaking awesome, I want more of it.


>Life is so totally freaking awesome, I want more of it.

Life is amazing because it's finite. The sense of urgency, the foreknowledge of limited time, trying to get the most out of each moment but at the same time striving to enjoy the simple things, these are all incredible motivators. Take away death and what do you get?


"Take away death and what do you get?"

Nobody has any idea, because it's never been done. There's no support for your claims that life's amazing-ness comes from impending death. Meanwhile there's a lot of support for the claim that death causes a lot of suffering.

In any case, an actually infinite life is not possible as far as anyone knows. You'll eventually die when the universe undergoes heat death or the Big Crunch. Is living a mere ~10^34 years sufficient to remove the enjoyment of life?


> Life is amazing because it's finite.

How do you know that? Some pretty miserable people had finite lives too.

> Take away death and what do you get?

I don't think they'll forbid people to die. It will simply become optional.

As for more practical objections to your opinion - when you're young you live like you're going to live forever. I don't think kids and young people live less happily than old people.


>I don't think they'll forbid people to die. It will simply become optional.

You can't even euthanize yourself in most states. If you want to die, people consider you 'insane' and you get locked up at the govt's (and your) expense.

Life extension / artificial age reduction will purely be a benefit for the rich - the poor will just get injections so they live longer and work harder for their ageless overlords. It's not gonna be good.


You sort of described the plot of the movie In Time.

http://www.imdb.com/title/tt1637688/

Just because you can't age doesn't mean you can't die. I think if people started living forever there would be a lot of rebellion from the people who are not given that access. Assuming at that point they can't just use brute force to protect themselves from the masses.


> Take away death and what do you get?

You get lack of genetic diversity, which leads to death. If a species became immortal, it would have to stop reproducing, to prevent overpopulation. Without sex, the gene pool stops changing. Along comes some new infectious organism, and there are no individuals that can resist it. The species goes extinct.

Sex and death are both necessary.


Because there's no option other than just stopping and dying to super bugs? Biological immortality would have us push for the stars so much faster...


The probability of an accident (car accident, firearms accident, choking, tripping while carrying a knife, drowning, and so on) resulting in death would tend toward one, given a long enough life, so humans would still need to reproduce, we would just need to keep the rate quite low.


> lack of genetic diversity

> gene pool stops changing

The above two are incompatible. How can a gene pool decrease in genetic diversity if it never changes?


You really think a civilization advanced enough to cure aging can't stop a pathogen? Evolution sure isn't going to save us. Evolution happens on a timescale of tens of thousands to hundreds of thousands of years. The plague will come and go long before evolution can do anything interesting.


Tell that to the dandelions.


Even if you want to keep it finite, it would still be better to have the body of a twenty-five year old for ~sixty years and then die.


If you want to be incredibly vain, sure.

I think we'll see a huge backlash to artificial age reduction / life extension, much in the same way that plastic surgery / cosmetic enhancement is viewed as an indulgent activity.


No, nobody is going to object to feeling like a 25-year-old for their entire life. It's not about vanity. I would be totally fine with appearing to age, if I could run and jump, and recover the same at 70 as I did at 25.

Is there any more universal dream than eternal youth, or even youth for a lifetime?


Ironically, the whole point of the 'fountain of eternal youth' stories is that people wasted their entire lives looking for it rather than enjoying life / what they were given.

Age extension technology is going to be the doom of humanity as we know it. Death right now is the only equalizer we have to our own destructive and damaging tendencies to the planet and ourselves at large. Living longer just means more waste, more war, more inequality, all the behest of the richest who get access to life extension technologies first. Don't kid yourself.


> Ironically, the whole point of the 'fountain of eternal youth' stories is that people wasted their entire lives looking for it rather than enjoying life / what they were given.

On a meta level, perhaps those stories are an example of 'sour grapes'? :)


I think the greater irony is that the Fountain of Youth was sought by people who weren't going to actually live to what we would call today "old age" anyway. I'm not actually looking for it by the way, but if somebody else finds it, I would like to get in on that action.


If you want to be incredibly vain, sure.

You clearly haven't hit 50 yet. Many mornings when I wake up my back is so stiff I can barely stand. A bit of yoga stretching has me operational again, but too much stress through the day can make my knee pretty sore, too.

So no, it's not all about vanity.


At 37 I'm already beginning to feel it. I have to be careful with my back lest it decide to punish me (backs are quick to strain/injure and very slow to heal). Also, my knees no longer permit me to run more than about 3 times a week and I have to watch my diet closely because everything gives me reflux.

Not looking forward to 50 :( Unfortunately, like fusion power, the cure for aging seems to be perpetually "20 years away."


If you want to die it doesn’t mean all of us want to. To imagine those many geniuses and visionaries that have died in their peak just because they’ve aged is sad.


One way to clarify your thoughts on this is to imagine that the opposite were true -- that is, that we already lived for thousands of years -- and then ask yourself how you'd feel about artificially limiting that to ~70 years.


> Take away death and what do you get?

Overpopulation?


That is probably the best argument against it, but I still think it is a weak argument.

Countries with populations that live longer tend to have fewer children and care for them better. Look at Europe and even he United States, the average amount of children per pair of parents is 1.5 to 2.5 depending on where you look. If you pick poorer places that have way more kids.

I think its clear the mechanism at work here is wealth and not age directly. Richer countries make richer people and richer people live longer. Then something happens and they have fewer kids.

For many social and health issues it seems possible to go the either way. Some place increase wealth to get health, others increase health and get wealth. If someone poor today could be made to live until they chose to die, would the knowledge they accumulate in their unnaturally long life lead to increased wealth in their community? I think it would and I think it would lead to the same long term reduction having too many kids.


Or you could summarize it as: wealth and health are bidirectionally causal. In any given situation, one of them will be the limiting factor to increases in both.


If we can control our population growth that isn't inevitable. If we can't we'll get that with or without aging.


Ehh ... it needs to be eliminated? [1]

[1] https://en.wikipedia.org/wiki/Life_extension


I never understood the people who argue for indefinite life extension. Imagine a world with essentially no children. No generation of young adults growing up and spurring change in the world. I think it would not just take away a crucial part of the human experience, but our entire economic system would collapse. There's just too much of it tied into the constant churn of people.

(Of course, you might imagine indefinite life extension springing into existence only after we've started rapid colonisation of space; a pipe dream if I ever saw one. Even then, Earth would still be holden to what I describe.)

In two-three generations, most everyone alive in the countries where life extension was widely adopted would be old farts that didn't want to take up much further debt, with few new ideas and not much drive left in them. "Science advances one funeral at a time", as do many other fields key to human progress.

Meanwhile, the countries too poor to see mass adoption of life extension would out-grow and out-innovate our collective asses faster than you can say "collapse of Western civilisation".

So you'd live forever, but in increasing poverty (due the countries that produce most of the things you buy having much higher growth than yours) in a stagnant, crumbling society.

If we were to invent indefinite life extension that was affordable beyond the 0.1%, I think it would be the ultimate tragedy of the commons.


> In two-three generations, most everyone alive in the countries where life extension was widely adopted would be old farts that didn't want to take up much further debt, with few new ideas and not much drive left in them. "Science advances one funeral at a time", as do many other fields key to human progress.

But old farts are like that because they realise they are going to die.

Wouldn't you behave differently if you were going to live forever? You could learn new skills, invest for the really long term. Do multiple degrees, try out many professions. Start a game of Civilization on a huge map. Level up all your wow characters.


No, old fart are like that because they now "have it figure it out" and are happy with they point of view.

That's just how the brains work: it uses experience to create a map of the world, a paradigm. The older you get, the more experience you get, and the harder you can endure a paradigm shit.

Renewing the populating, beside the absolute biological necessity (you are adapted to your environment now, but probably not to the one in the future) is the only way nature manage to balance experience and flexibility.


Plenty of the older generation have adapted to paradigm shifts though. I mean we've seen enough of them in my generation alone:

* the adoption of mobile phones - being able to contact anyone, anytime and at any place. This wasn't the case as a kid.

* instant non-realtime communication via emails and text messages. Before we were reliant on the postal service so we learned to be patient

* online shopping, taking the dependency away from having to travel to the shops as often this is easier said than done when you're old

* linked to the above is global shipping - the ability to order something that isn't even available in this country

* online resources and, in the more broader sense, the decline of our dependence on libraries

* computers in general. I don't just mean portable devices like smart phones, tablets and laptops, but even BASIC-driven micro computers were a relatively new concept when I was born.

* the rise of quaternary industries. Tertiary industries were still on the rise when I was born with many people expecting to go straight into secondary (manufacturing) industries. In the last 50 years we've undergone 2 paradigm shifts in the industry landscape

* cheap air flights. Plenty of older people enjoy holidays abroad in ways they could only have dreamed about when they were kids

There will be others I've not thought about. But I do think it's highly unfair to tar all of the older generation as unable to adapt. Often the slow down is a result of failing mental and/or physical health reducing a persons ability to drift outside of their comfort zone. But if one had an infinite life span then you would hope that would also be in good health. If not, then effectively all we've done is brought about a zombie apocalypse where our bodies and mind fall into ill health while we lose the ability to die.


Those are the easy things. Technology. Pleasures. Services...

The hard paradigms are the ones challenging your believes, world views, and habits. Living with people with very different cultures, learning the universe is not working the way you though it is, seeing you are not the person you saw in the mirror, etc.


The world has changed a lot in recent years in that regard as well. Take the "old people are racist" stereotype for example. You see the same with younger people who are not actively exposed to people of different cultures. So it's not that surprising that older people are don't mingle with different cultures wouldn't be afforded the opportunity to have their prejudices challenged. And thus to go back to my previous point: if in an infinite life scenario where "older people" were just as mentally and physically capable as the younger generation of today, you would expect the older generation to be in the position to mingle in the same ways and thus have their prejudices challenged.

This is of course all hypothetical. But so is your argument that older people cannot adapt in the same scenario.


Parent's point might be better phrased not by "old people are racist" as "old people don't know they're racist."

The biggest difference between old and young people is depth of experience. The elderly aren't racist because they never met a person of another race: they're racist because that's how they were taught and trained to act towards other races.

And I think it's more difficult to argue that "undoing previously held beliefs" (old) is as easy as "forming new beliefs where none exist" (young).

Source: Extensive traveling in the rural American south, and I believe psychological findings back up the tendency to cling to preconceptions


You acknowledge that it is more difficult for the older generation to have their beliefs challenged than the younger generation but you fail to address why that it. This is the point I was addressing. Yes there will be an element of human conditioning to racism, however I was not discussing the direct cause of it but rather how said conditioning is often combatted. To discuss an infinite lifespan one would also have to assume good mental and physical health. That would mean that "old age" as we describe it would also be eradicated. This means there's more opportunities to have opinions challenged. It also means peoples outlook might change as well (eg an infinite lifespan might bring around boredom so people might welcome being pushed outside of their comfort zones more often). There's also the question of the maximum capacity of human memory: as we age in an infinite life we might forget some of conditioning we were taught earlier in our lives as new experiences take their place.

So the issue I have with both yours and the GP's position is I feel you fail to take into account that old age wouldn't exist (or at least "shouldn't" if we don't want to breed zombies) so we cannot assume the same phycology will apply with people who are 100 but physically and mentally 20 as currently applies with those who are 100 with failing physiology and cognitive functions.


>> "and I believe psychological findings back up the tendency to cling to preconceptions"

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

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

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

These are not things that humans do because they're old (and somehow less plastic / capable than the young). They do them because that's how our brains work once they've acquired information.

If you're going to argue against current neuroscience and psychology findings and beliefs, then you're welcome to cite some sources. "Good mental and physical health" is necessary but not sufficient for creating as many opportunities to have opinions challenged (as younger people).

In the absence of equivalent ability to be challenged and accept new ideas, parent's assertion that a society without death would look very different from our current "each generation overthrows some ideas of the last as they die" seems to stand.


I could counter your point with an article about peer pressure (https://en.wikipedia.org/wiki/Peer_pressure). For example there might be less stigma about old people dating young people or groups of friends with massively different age ranges due to the infinite life and good health factor allowing more diverse social groups. This would result in groups of people exchanging opinions and being influenced in ways that aren't as common currently.

I should stress though that I do feel you're missing my point. I'm not saying people give up attitudes easily. What I'm saying in an infinite life there is infinitely more opportunities for ones preconceptions to be challenged. I'm not saying it's easy for ones preconceptions to be challenged but it does often still happen and thus with an infinite life span there is both significantly more time and significantly more opportunity for this to happen.

What I'm suggesting is that where we don't observe significant adaptation in preconceptions within a shorter time scales, we might discover that humans are more capable to adapt over a much longer scale. We might even beg for change just out of pure boredom (eg I doubt many people could stand doing the same job for hundreds of years). Change pushes us outside of our comfort zone, into new social groups, and most importantly, change can often force us to evaluate our preconceptions through personal experience which is far more valuable to reconditioning than debate and 2nd hand reporting (which is what your articles focused on).

Ultimately though, and as I said to the GP, this is all speculative. However I would be amazed if infinite life + good health didn't affect human psychology given the massive impact it would have culturally and the significance that mortality, the fear of growing old and ill health, all play in human psychology. There are so many variables that would change (economic, social, psychological, etc) beyond just the numbers on our birthday cakes that I find it weird to assume our lives would just be the same but longer.


Selective exposure bias and cognitive dissonance absolutely do not only apply to information (in as you said "debate and 2nd hand reporting"). Their effects are equally documented on first hand experience.

Two people with difference beliefs experience the same thing and each walk away with their previous beliefs reinforced.

I hear and grant your argument ("What I'm suggesting is that where we don't observe significant adaptation in preconceptions within a shorter time scales, we might discover that humans are more capable to adapt over a much longer scale.").

But you're seemingly only using that to suggest that there will be one impact (towards more flexibility / change). You're ignoring the other side of the sword: what if more experience only deepens our beliefs because of our hardwired cognitive biases? E.g. if its difficult to overcome 20 years of racist enculturation, then what about 200?

The worries I have, and why I bet more on my future than yours, is that the majority of these biases stem from non-conscious processes in our brains. So there's no indication that taking a brain adapted for a 30 year human lifespan and extending it to 200 is going to radically change their physical, biological underpinnings.

However, if we gain the technology to indefinitely extend life, it seems probable that we'd also have the technical capability to modify these logical flaws. So it's possible we'd be able to "debias" brains to a greater degree.

Or, and I'd actually consider this more unlikely and harder, perhaps our understanding of human psychology and neuroscience will have advanced to the point where we can consciously override our own biases in a more reliable and passive manner (e.g. super mindfulness, Dune-esque psychoconditioning).

My main point is that indefinitely extending life and expecting our mammilian, product of evolution brains to just "get it" isn't a bet I'd be willing to take with humankind's culture hanging in the balance.


> But you're seemingly only using that to suggest that there will be one impact (towards more flexibility / change). You're ignoring the other side of the sword: what if more experience only deepens our beliefs because of our hardwired cognitive biases? E.g. if its difficult to overcome 20 years of racist enculturation, then what about 200?

Ohhh that's a very good point. I hadn't considered that.


Yeah, hard to know who's right before we get immortal. But nature can produce immortality and evolution didn't settle on it so we should wonder why.


Evolution doesn't work towards an end goal like that though. There are plenty of attributes we have which are sub-optimal. For example our eyes have a number of significant flaws many of which are not present in other, arguably inferior, species to ourselves.

You'd probably have a stronger case if you argued about natural selection instead but given the history of humans, it's hard to believe that many would reached the end of their natural lives before getting killed. Certainly not enough and over a long enough period for immortality to have come about.


As if evolution required reasons to settle on stuff.


> paradigm shit

Still works.


Accidental brilliance, even.


When you can't be brillant in any other way...


Transcendendal excremeditation.


> Wouldn't you behave differently if you were going to live forever? You could learn new skills, invest for the really long term. Do multiple degrees, try out many professions. Start a game of Civilization on a huge map. Level up all your wow characters.

This is like the people that thought TV and radio would bring Shakespeare and the classics to the general populace.

Instead you got weird reality TV.

It's a fantasy.


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

I think it's fair to say TV and radio did bring "Shakespeare and the classics" to the general populace, as well as a great deal more that was previously inconceivable. "Weird reality TV" is quite a small genre compared to the set of all audiovisual media.

More broadly, you seem to be saying that TV and radio have had a net negative effect on culture - that's a pretty big claim, though there are inarguably negative effects.

I don't think life extension would be fundamentally different from any other "life-improving" technology in that regard - some would have it and some wouldn't, and it would lead to both great things and dysfunctional effects. Impossible to predict the full impact ahead of time.

I don't think "immortality" is on the cards anyway, just living longer. Note that rich people already live longer anyway.


>More broadly, you seem to be saying that TV and radio have had a net negative effect on culture

I'm saying it didn't have the intended or predicted effect.


Intended? I don't think much technology is developed with long-term social impacts in mind. We're kind of careless like that. In the tech world we're only just starting to realise the importance of this, and then only because it's recently become apparent how frighteningly easy it is to reshape society with software. Most other industries' ethics stop at "don't kill people".

Predicted? It's impossible to predict perfectly. But a great many effects were predicted in one place or another - especially the negative effects. The Machine Stops, 1984, and Brave New World all deal with the themes of technologically networked society and mass visual media.


But you're incorrect, and the word "instead" in your original post is what makes you incorrect. We did get "Shakespeare to the masses" for whatever that's worth in general. It's not like his work is some objective benchmark of qualitative excellence - people just assert it is because they learn it from adoring fans during formal education.


I missed this at the top of the Wiki article:

"The Guinness Book of Records lists 410 feature-length film and TV versions of William Shakespeare's plays as having been produced, making Shakespeare the most filmed author ever in any language."

We didn't just get it - it's the definitive thing we got!


Is it? Did the percentage of people who cared about Shakrespeare and the classics in the, say, 1800s increase or decrease with each new media?

Because there's always going to be the unwashed masses that want low-quality sensory indulgences.


You embody my greatest fear and annoyance in this area.

I think it's perfectly possible that, within my lifetime, significant or indefinite life extension could become possible.

But I'd bet that fears about effects on society, as well as the arrayed forces of religious conservatism, will create so much strife on the matter that it'll be denied to people for long enough that I'll die unnecesarily.


If you're really worried about that, have you considered coming to China? The government keeps religion in check, and science is pretty free (although plagued with plagiarism); China's already trying to genetically modify children. If a technology with the potential for indefinite life expansion was found, there's no way the ruling class would let anything stand in the way of them prolonging their lives indefinitely.


I would consider going anywhere that could offer proven, real, relatively safe life extension.

A choice of leaving the country of my birth or leaving this mortal plane... I know which way I would go.


> I think it's perfectly possible that, within my lifetime, significant or indefinite life extension could become possible.

It's about as likely as having a sentient AI anytime soon. So, you can rest assured it's not going to happen despite all the hype.


> I think it's perfectly possible that, within my lifetime, significant or indefinite life extension could become possible.

It's weird that everyone believes this stuff will happen within their own lifetime. Like, no-one goes on about how life extension is going to happen 300-ish years from now, it's always conveniently within a timeframe where the speculator could personally become immortal.

Just like every loon in history has insisted that the Apocalypse is definitely, certainly going to happen within their own lifetimes too.


With the rate medical tech is advancing, almost as fast as computing, 300 years from now might be within our lifetime just by other means of extension.

We have many active and healthy 50, 60 and 70 year olds. This is unheard in cultures before the modern era.


> I think it's perfectly possible that, within my lifetime, significant or indefinite life extension could become possible.

We know so little about the human body that I find this claim very difficult to substantiate. We're only up to the task of extending 25% of mice lifespans, with no end in sight to resolving the adverse side effects of aging in humans so life extension doesn't become a horrid, protracted end of life grinding agony.

If our entire economic system was switched from the banking system having the first crack at newly-issued capital to the healthcare industry with special emphasis upon gerontology-oriented sectors (with the near-infinite demand for healthcare, the inflation could be impressive), then I would grant a possible doubling (which counts as significant when stacking up against "indefinite") breakthrough in the next 2-3 decades. But I would really like to see the pro-SENS argument we're really that close to such a magnitude breakthrough of extension with intact, restored vitality to 20's range.


Ironically your wish to "live eternally" kind of sounds like something out of the bible ;)


Not really, I said indefinitely. There's not really such thing as eternal.

For instance - in under a billion years the earth is likely to become too hot for liquid water to exist on the surface, likely seeing the end of (most) life on earth. Beyond that, much/most of the solar system gets destroyed when the sun goes red-giant. Unless interstellar travel is commonplace by then, it's pretty final.


Oh, come on. The reason we balk at interstellar travel these days is because it'll take thousands of years to get to the nearest star with current propulsion technology. But thousands of years is still far less than 1B years. If we're still around in several hundred million years and the Earth is getting too hot, and we haven't invented warp drive yet, then of course we're going to build a bunch of generation ships and take our chances in interstellar space. By that point, it really shouldn't be that hard to build such ships that are reliable enough to last indefinitely, powered by fusion reactors.


Exactly, which is why I will live forever...


I forget the author but there was a pretty cool sci-fi story that had legislation to "solve" this. Every 100 years, an individual "died" and was "reborn" legally. They lost all their stuff, were given a starter account with enough interest to live on for several years and exiled from their home continent. Most people went back to school.


> I never understood the people who argue for indefinite life extension.

I'd say admitting an inability to understand something is a good first step towards making progress. Don't lose hope.

Here's something to read in the meantime [1]

[1] https://carcinisation.com/2014/07/13/an-anti-deathist-f-a-q/


Great article. Would be better if the answers were written in a slightly more compassionate tone.


I think the tone is perfect.

- In questions, it represents a knee-jerk reaction of annoyance by a deathist who hasn't thought about this seriously or deeply.

- In answers, it represents an anti-deathist who is jaded after engaging in the debate hundreds of times, with almost every time the deathist being highly opinionated and yet completely lacking any convincing counter arguments.


You are assuming that life extension would produce lifeless old men - which of course wouldn't improve humankind. But this is not given.

Another, more optimistical way to look at life extension is that it is what neural networks are to genetic algorithms. Instead of randomized search for better parameters you get a more directed one (backpropagation). In other words, instead of waiting for the next generation to learn on the same mistakes previous ones made, we can skip this and transfer knowledge in the future much faster.

It all depends in what form the technology will surface, and what the people will use it for once it does. I am willing to bet it won't be all good, but also not all bad.


Yes but neural networks use experience to make decisions. The more experience it gets, the less creative and flexible it becomes.

This is why you need new individual:

- to not be blinded by a vision of the past;

- to ignorer status quo;

- to see things differently;

- to bring creativity;

- to bring a bit of chaos.

They are rare, those who, among us, can cumulate experience and a beginner's mind.


IMHO, this is a problem with the current education system, not with aging.

Imagine if Einstein, Tesla, Newton, Mozart, Beethoven, Gandhi, Martin Luther King, Nelson Mandela, Disney, Steve Jobs, etc. all lived for another couple hundred years. Do you truly believe they would stop trying to disrupt the status quo? It only takes one person to disrupt the status quo. Generally, it doesn't matter how many people are against something. Nothing can stop a great idea when its time has come.


You could equally point to examples of great minds who nonetheless objected to new (and correct) theories.

Einstein objected to much of QM. There's the history of the adoption (and rejection) of plate tectonics over much of the 20th century. Continued opposition to old-Earth geology, or biological evolution. The present conflict within physics over string theory. Likely others.

At some point, fixed mental models tend to get in the way, even if the minds containing them once made novel and useful contributions.


Much of Eistein's issues could have been due to degenerative issues. If he had everlasting youth, perhaps he would have had the energy and motivation to properly tackle the research in QM.

That and no one person is bigger than science, Even though Einstein opposed QM it kept making advancements. Imagine if Einstein spent even all this time opposing it, their theory would be even more rigorous and advanced. More likely we would have changed his mind at some point and actively contributed, why would a one time scientist be stubborn for many decades in the face of so much evidence?


Einstein opposed QM, but Einstein has never been the arbiter for all of physics. QM was created and promoted by his own contemporaries, after all, not people who came many decades later. Even if all those scientists of that time had managed to magically stop aging at 30 and live indefinitely, QM would have succeeded as a theory because of all the scientists who promoted it and tested it.


Yes, but you're missing the other aspect of life extension: control over effects of aging. People become "old farts" because of physical and cognitive decline. Consider evidence from rapid-aging disorders. So by preventing and repairing damage, there are no "old farts". And you get the advantages of both youth and age.


You would still loose:

- new DNA combinations entering the mix. They are quite damn important.

- beginners minds. Without it, systems will be stuck in what we assume are the best fit.

- disrupters. Newcommers, by lack of experience, misunderstanding or just because they are not blinded by the status quo have the tendency to change things.

Basically, even if you don't have "old farts", our system will get old.

There is a reason why nature promoted renewal of individuals inside a long living but dynamic group and not long living individuals inside a static small group.


> - new DNA combinations entering the mix. They are quite damn important.

Get a DNA profile done, throw up some random (or interesting) changes, simulate them. If you like it and have the balls, make a virus that implements it.


That supposes you know what DNA combination you need. But the whole purpose of diversity is to have a backup plan for things you don't know.


True, but it allows you to test and fix things that are predictable, something that current evolution does not.


If you want to prepare for unknown unknowns like we do now, then simulate a mating between you and X other people and implement them resulting DNA. Be your own biological child.


You get beginner's minds whenever someone who had a lifetime of experience doing A starts trying to do B.


Absolutely not. You get somebody trying to do B the A way. Not with a blank page. That's the problem.


But isnt that also interesting? They either fail to do B the A way, or they realize what things from A are applicable to B. In the latter case, we may all benefit from this cross pollination.


You don't get absolutely blank pages in any field, even now. Until somebody knows enough to contribute, they've been shaped tremendously by their teachers.


You're missing out on the effect that children will have in that system. Children will still be there, to keep the population stable, and because some people do like to have children, though maybe not as many as in today's system. And you're also forgetting the old people will die off, just not as fast as today, and not from old age: instead, they'll be dying from accidents and murder. We already lose a LOT of people these days just from car accidents (30k/year in the US alone last I checked).


People would still die, and new people would still need to be made. Granted, at rates far lower than today - but old age is only one cause of death (usually an indirect one).


Re new DNA combinations, do you have evidence? CNS development is a higher level of natural selection, involving on-the-fly variation. Rather like the immune system. There arguably hasn't been much biological evolution over the past few thousand years. Certainly not enough to account for modern civilization.

We all become disruptors when we switch fields.


Every mass extinction, a new DNA set is gaining traction.


That's quite a jump in time scale. The overall lifetime of the human species is miniscule, relative to the timing of mass extinctions.


Of course. But once we are immortal, the timescale changes.


Fair enough :)

But on that scale, why would we be limited to flesh? I'm reminded of Sobornost practices in Hannu Rajaniemi's Jean le Flambeur trilogy. Basically, make numerous copies of a mind, introducing more-or-less random changes, and select on some set of criteria. I mean, why is natural selection limited to biological systems?


It's not. We could in the end create our own pool for it. Would we be wise enough to do it?


Well, if a few billion people were doing it, at least some of them would get useful results. We might get lots of [insert name of "famous" person] variants, however.


> - beginners minds. Without it, systems will be stuck in what we assume are the best fit.

Couldn't we solve this by having an individual go through a mind erasing procedure every 100 years or so?


Death is the word you are looking for.


Death isn't the problem; aging is. Death without aging seems like a good solution.


It could be a partial erase.


> Imagine a world with essentially no children.

Thanks, but I don't want to get lost in fantasy while at work.


I get it--humans don't make progress except through culling of the elderly, people such as John McCain and Nancy Pelosi--won't be sad to see them go, lol! But seriously, if we're ever to be come a true spacefaring species, the aging thing has to get solved. Humans would then have a far better chance of ranging out. Right now we're just ants.


If death is so good, why should people live to 90? Why not 60? or 40?


Exactly. Life extension is the apex of selfishness, and also extremely inefficient. My death is a little annoying for me, but oh so great for everyone else!


>Life extension is the apex of selfishness, and also extremely inefficient.

Inefficient? It takes an enormous amount of resources to raise an infant to adulthood, namely with education, and many years of not only complete non-productivity, but distracting adults from being productive by having to spend time changing their diapers and such. There's a reason people aren't having many (or frequently any) kids these days. Industrialized nations are in negative population growth mode now.

>My death is a little annoying for me, but oh so great for everyone else!

If you really feel that way, you can off yourself at any time.


> My death is a little annoying for me, but oh so great for everyone else!

If that is true, then you are the problem.

Consider working on your character and/or your ability to contribute to other peoples' well-being (if possible).


It doesn't seem you got my point.


Could you elaborate on your point, then?


It reads like sarcasm (to me).


Yet it isn't.


> Imagine a world with essentially no children. No generation of young adults growing up and spurring change in the world. I think it would not just take away a crucial part of the human experience, but our entire economic system would collapse. There's just too much of it tied into the constant churn of people.

Basically "Children of Men", but without the cool camera work.


I know what you're saying, natural death from aging could be seen as a solution just as easily as it can be viewed as a problem.

If anything we should get better at it, for example, educate people more about aging and talk more about death and the benefits of caring for yourself in your youth so to age well, it doesn't really have to be sad.


The Great Common Task :)

> Fedorov stated that the struggle against death can become the most natural cause uniting all people of Earth, regardless of their nationality, race, citizenship or wealth (he called this the Common Cause).

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


It is kind of silly to talk about life extension, when we have cardiovascular diseases as the number 1 death cause which are around 90% preventable:

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


You got it upside down. It's silly to "talk" (talk as in communication in the medical research community) about deaths due to preventable diseases, which should be left to social scientists, politicians, celebrities, advocacy groups etc.

If science and medicine has given you a solution and you don't apply it in your life, it's your problem not of the scientific community.


Oh right, that's going to make fixing climate change nearly impossible isn't it? It would make the population boom of the last century and associated wide-spread destruction of the natural environment look like a picnic.

I guess if your able to upload your consciousness into a computer or some other some Transhuman fantasy like that it would probably be a much better outcome for the natural world and everyone left in the realm of mortals.


On the other hand, knowing that you will live to see the effects of climate change might be a great motivator to solve the problem, especially if it has the potential to cut short your infinite life. Eternal life may make us incredibly risk averse.

> It would make the population boom of the last century and associated wide-spread destruction of the natural environment look like a picnic.

How much of the population growth is caused by our mortality and the desire to "live" forever? A lot of it was almost certainly because children were the retirement plan before the aged pension became a thing.


> Oh right, that's going to make fixing climate change nearly impossible isn't it?

I would say we're going to need all the human ingenuity and hard work to tackle the issues we're facing. Yes, these are very difficult problems, but the reward would be well worth the effort!

> I guess if your able to upload your consciousness into a computer or some other some Transhuman fantasy like that it would probably be a much better outcome for the natural world and everyone left in the realm of mortals.

I'm all for that technology to be developed in parallel.


Ingenuity is one part of it, large scale behavioural and societal changes are what's really in-order though, the less individualistic view.

Rich countries sharing the wealth with the poor, investing your money in banks which don't fund exploitative and harmful projects, changing how you travel etc. This is the work that also has to be done by each of us.

We always seem to lean on developing new technology to solve our problems and technological development is wonderfully successful, it's a good thing, a fine thing, but we don't use it very well. For example everyone on earth could be fed, but that's not how we operate. It's all common sense though really.


>For example everyone on earth could be fed, but that's not how we operate.

It can't be done really. We've been trying to for decades, but famine isn't caused by a lack of resources, it's caused by political problems. Western nations have been sending food and supplies to impoverished African countries for ages, and it just gets stolen by their leaders and doesn't make it to the people who need it. The only way to fix this is to militarily invade and occupy these countries so we can run them properly, but we can't do that because it's imperialistic.

The fundamental problem as I see it is that there's a huge amount of undiagnosed sociopathy in human societies, and most of them are run by people with at least some degree of sociopathy, because they're uniquely skilled at working their way into those positions. The only way I see to fix this is to genetically engineer humans to remove this problem and make them more empathetic. This fix would then have to be forced on everyone somehow, perhaps with a virus.


It's funny I seem to have expressed my thoughts on this very recently [1]. Also a FAQ that you might be interested in [2].

[1] https://news.ycombinator.com/item?id=14205938

[2] https://carcinisation.com/2014/07/13/an-anti-deathist-f-a-q/


Ingenuity MAY solve it in the FUTURE. It's a potential.

Limiting our consumption WILL solve it NOW. It's a certainty. We have the power to do it. Just not the will. We loves our steaks and cars.


If resources are limited and human brains can live forever in an artificial substrate, I see three possible futures:

1) Send of these brains to other planets.

2) Time-sharing bodies.

3) Destruction of old brains.

I would not be surprised if the last option will be considered the most inhumane.


Ask me in two thousand years


From Wikipedia entry on milky way, "These oscillations were until recently thought to coincide with mass lifeform extinction periods on Earth.[148] However, a reanalysis of the effects of the Sun's transit through the spiral structure based on CO data has failed to find a correlation.[149]".

Those papers are from 2008 and 2009. Is this paper proposing something different?


Neat coincidence to see this on the front page today. On the train this morning I was re-reading David Brin's "The Deadly Thing at 2.4 Kiloparsecs". His 1984 article examining Earth's fairly regular mass extinctions and what might be causing them.

As a new forward to the story, Brin mentions the OP-linked theory.

Imho, the article still holds up well and you can read it here: http://davidbrin.blogspot.jp/2015/07/the-deadly-thing-at-24-...


"significant reductions in diversity at 415, 322, 300, 145 and 33 Myr ago" - it seems that periods between extinctions events are so large that you can easily fit there hundreds and even thousands of civilizations like ours. So not much to worry about, we will have plenty of opportunities to kill ourselves before a comet does us in.


I'm not a math wizard but going by that pattern it seems the periods are getting shorter.

I tried to find a sequence https://www.wolframalpha.com/input/?i=415,+322,+300,+145,+33....


The periods (intervals between events) there would be [93, 22, 155, 112] My. That doesn't look like they're getting shorter.


But they are getting closer! :)


My bet is that is because of observation biases. We don't know a lot about distant past, and may have lost some events that we'd call great extinctions if they were recent.


Hmmm. If this hypothesis held up, you'd want to factor it into the Drake Equation. Number of systems that didn't cross some threshold of intensity or frequency of arm crossing events that could cause mass extinctions often enough to make intelligent life impossible to develop.

Or something like that.


I suppose it's possible that just the right amount of mass extinction events are necessary for intelligent life to emerge.

Too many and evolution doesn't build up any momentum, too little and there isn't enough change to make intelligence (i.e. adaptability) worth having. So the Drake equation would need to be looking for that Goldilocks zone of mass extinctions.


Isn't the reverse just as likely, that many potential paths to intelligence were snuffed out by extinction events. The currently accepted theory is that it the evolutionary pressure of climate change was enough for us to evolve intelligence.


I think that humans as a species are more likely to survive a mass extinction event (even if 99% of the population is killed) through manipulation of their environment, stored food, eating rodents, insects and fish, and the cooperation of communities for having babies and raising children. Therefore, mass extinctions might serve as a winnowing out of dominant species that can't adapt to major changes. Of course the adaptability of humans has not yet been tested in that way (unless you count the recent ice age.)

Also there is the whole "multi-planetary species" option.


This is eerily similar to the plot of The Three-Body Problem[1], specifically the cyclical development of intelligent life and its race to avoid mass extinction caused by intersecting one of three suns in its stellar system.

[1]https://en.wikipedia.org/wiki/The_Three-Body_Problem


I heard this is a great book but could not get into this book. I was listening to an audio book. Maybe I should try a physical book next time.


Highly recommend (I read the physical book). It picks up after the first 100 pages or so.


The audiobook worked for me but I do admit it's written in a very different style than most western sci-fi novels.


I'm a bit puzzled here. I thought the arms themselves were moving around the galactic core. What does the Sun pass then? Little hint?


Originally, astronomers had the idea that the arms of a spiral galaxy were material. However, if this were the case, then the arms would become more and more tightly wound, since the matter nearer to the center of the galaxy rotates faster than the matter at the edge of the galaxy. The arms would become indistinguishable from the rest of the galaxy after only a few orbits. This is called the winding problem.

Lin and Shu proposed in 1964 that the arms were not material in nature, but instead made up of areas of greater density, similar to a traffic jam on a highway.[3] The cars move through the traffic jam: the density of cars increases in the middle of it. The traffic jam itself, however, does not move (or not a great deal, in comparison to the cars). In the galaxy, stars, gas, dust, and other components move through the density waves, are compressed, and then move out of them.


Apparently they're rather static: https://en.wikipedia.org/wiki/Density_wave_theory


Spiral arms are density waves. They move at different velocity than stars that make up the arm.

http://i.imgur.com/dtb8WrD.gifv


So how long till next arm?


There are two danger periods: passing through the galactic plane (duration 100k years every 35Myr) and passing through the galactic arms (duration 10Myr every 120Myr). The article only discusses passage through the arms.

We're currently moving away from the galactic plane, which our solar system last crossed 3Myr ago.

According to the article there are 11 extinction events spread across the last 500Myr, which corresponds to two orbits of our solar system around the galaxy but one traversal through the arms and spur (they're also orbiting, more slowly). Right now we're in the Orion Spur; the authors seem to attribute an extinction phase near the last exit from this spur; the spur is 1 kly across, so I estimate our solar system takes 3 Myr to transit the width of the spur.

I think our next destination is the Perseus Arm, 6.5 kly away, so we should reach it in about 20 Myr.


I don't know where we stand now, but there are two arms and a galactic year is ~250 million terrestrial years, so I'd say a priori on average ~250/2/2 = ~60 million years from now.


There are two thick arms, and two thin ones in the picture, as well as a spur (the Orion Spur in which our Sun presently dwells). The article postulates the existence of a second spur on the far side of the galaxy where we can't see, based on the history of extinction events in the past 250 million years and the observed symmetry of many other spiral galaxies.


Probably better to take the average of the last known extinction events and extrapolate from there.

Average time between events: 96 Myr.

Time since last event: 33 Myr.

Time to next event: 63 Myr.

Wow, surprisingly close to your method. Pack up your bags boys, we're gonna get extincted in 60 million years.


Full text: https://arxiv.org/pdf/1309.4838.pdf

With what reasoning or evidence do they propose their new model of the galaxy?

Is it:

- extinction events, therefore new model

or

- astronomical data, therefor new model, and look how nicely it correlates with known extinction events


A bit of both.

They say that with the model depicted in Fig 1, based on Spitzer/GLIMPSE surveys [1], nine of eleven extinction events which they identify (the six "canonical" ones plus five other significant drops in marine biodiversity, Section 2.2) occurred while the solar system was passing through a spiral arm (Section 3).

They then point out that it's easy enough to modify the model to fit all eleven events: we can't see what's on the other side of the galaxy, so we can hypothesize a "spur" there, similar to the Orion spur on our side, with some support for that idea coming from the symmetry of other galaxies.

But even without such modifications, nine out of eleven is not bad. Spiral arms need not necessarily explain every single one of them.

[1] http://inspirehep.net/record/817646?ln=en


Great summary. Thank you.


Here's an excellent interview of Jonti Horner by John Batchelor on this topic (free podcast):

https://audioboom.com/posts/4827661-mass-extinction-and-the-...


Interested parties should also look at the work of Dr. Adrian Melott[0].

[0] https://scholar.google.com/citations?user=GWB114EAAAAJ&hl=en...


I wonder when we're due for another crossing?


We're in the middle of the (minor) Orion Arm right now: https://en.wikipedia.org/wiki/Orion_Arm


That's the first question I asked. Or are we crossing one now? or about to cross?


This isn't new. I remember reading about this years ago. I suppose the new contribution is offering an actual model to do this.


One of the reasons why we need to find a way to get to Mars and other places where humans can thrive. If we were the only wonder in the world, imagine the travesty of getting wiped out.


How would Mars help? Mars, like Earth, is on a tight (1.6 AU) gravitational leash of the Sun. When the Sun dives into one of the galactic arms, so do Mars and Earth.

That said, interplanetary travel is probably something we need to get good at before we try the interstellar kind, so in a way, Mars settlement brings us a tiny bit closer to galactic safety.


If I'm reading that paper correctly, then we need more than interstellar capability, we need near-intergalactic capabilities. We would have to be solidly past a Kardashev Type II and almost attaining a Type III classification, to either move our own solar system, or establish habitats in safer galactic zones outside the arms (like outside the galactic poles or positioned above the arms). Perhaps these transitions is the Fermi Paradox's Great Filter: might it be exceedingly difficult for a civilization to hit the Kardashev Type II-III level and implement the necessary avoidance/mitigation sufficiently fast enough?


Wasn't this theory part of the inspiration of the story arc for the Mass Effect games?


Not so goldilocksie after all


Abstract: "We use the most up to date Milky Way model and solar orbit data in order to test the hypothesis that the Sun's galactic spiral arm crossings cause mass extinction events on Earth. To do this, we created a new model of the Milky Way's spiral arms by combining a large quantity of data from several surveys. We then combined this model with a recently derived solution for the solar orbit to determine the timing of the Sun's historical passages through the Galaxy's spiral arms. Our new model was designed with a symmetrical appearance, with the major alteration being the addition of a spur at the far side of the Galaxy. A correlation was found between the times at which the Sun crosses the spiral arms and six known mass extinction events. Furthermore, we identify five additional historical mass extinction events that might be explained by the motion of the Sun around our Galaxy. These five additional significant drops in marine genera that we find include significant reductions in diversity at 415, 322, 300, 145 and 33 Myr ago. Our simulations indicate that the Sun has spent ~60% of its time passing through our Galaxy's various spiral arms. Also, we briefly discuss and combine previous work on the Galactic Habitable Zone with the new Milky Way model."

TL;DR: our Sun's bumpy orbit through the spiral arms of out galaxy means periodic increases of comets and other bodies being jarred loose and later hitting Earth, resulting in mass extinctions.

The full paper is a free download from this page.


...Huh. I always assumed that most stars kept approximately the same position relative to the rest of the galaxy. (Barring "up/down" oscillation if the orbital plane isn't perfectly aligned with the galaxy's.) There must be some kind of overall structure to maintain distinct spiral arms, right?

Does the Solar System actually make a complete circuit of the bulk of the Milky Way? Is that unusual?


The spiral arms are not fixed masses. If they were, they would quickly wind themselves up tighter and tighter, as the inner areas are orbiting faster than the outer parts. Within a short time the spiral arms would be dispersed.

Instead, you can think of the spiral arms as being like the highest-density part of a traffic jam. In a traffic jam, cars are slowing down and bunching onto the back of the queue, while other cars are finally trickling off the front of the queue and speeding back up. In this way the traffic jam itself stays in a stable position, while individual cars constantly move through it.

In other words, it isn't the same stars that make up the spiral arms over time. As stars orbit the galactic center, they move in and out of the spiral arms.


Put a different way, a galaxy's spiral arms are like waves.


A good explanation. I think one detail may be corrected: a traffic jam typically goes backwards, with respect to the direction of the cars forming the jam, at a speed much slower than the speed of the traffic. Perhaps a similar behavior is observed with the galactic arms?


The author explains it pretty well in the Batchelor interview:

https://audioboom.com/posts/4827661-mass-extinction-and-the-...


Mind == blown


>I always assumed that most stars kept approximately the same position relative to the rest of the galaxy.

That was the original assumption. However, basic [0] orbital mechanics says that objects with smaller orbits orbit faster. If this were applied to the galaxies spiral arms, then as they continue to orbit, the inside ones would orbit faster than the outside ones, and the galaxy would become increasingly spirally. By this point, the galaxy would be so tightly wound that we would not even be able to see the spiral any more.

A more modern hypothesis is that the arms are more like waves of high density. Individual stars move through the the arm.

Since this high density region exerts gravity, stars that are moving out of it are slowed down, and stars that are moving into it are sped up. The end result is that orbiting stars tend to spend a little bit more time in the arm region then they would under a pure orbit. In doing so, they contribute to the mass of the arm, causing other stars to also spend more time in the arm then they otherwise would. The end result is a stable wave as all the individual stars move into and out of it throughout their orbits.

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

[0] As in, just applying Newtonian gravity.


a visualization of the current model orbital path http://m.imgur.com/Eup0Yoa


It's hard to be sure. But observing both the Wiki animation and this GIF, it appears that stars don't orbit at a constant radius from the galactic center. Rather, they appear to move significantly closer and further.

Does that seem right? If so, that's much different than planets orbiting our solar system. To a first approximation our orbits appear circular. Yes I know there's a certain eccentricity but for most planets it's not much.

I don't like the idea of our solar system getting too close to the galactic center. It gives me a vague sense of dread, like "bad things can happen there".


That's an exaggerated, simple model of spiral density waves; it's not a model for the Sun's orbit, which probably only varies in radius by about 10-15%.


The orbit in the model are supposedly eccentric, but the period for a complete prbit is quite long, allegedly around 220milliom years, and yes the paper is all about bad things happening periodically as we change our local neighboors. But not something we'll have to worry about in quite a while


I think that's just a side effect of the compressed scales used by the animation. If they didn't do that then you would not be able to see the wave effect as clearly.


> If this were applied to the galaxies spiral arms, then as they continue to orbit, the inside ones would orbit faster than the outside ones, and the galaxy would become increasingly spirally. By this point, the galaxy would be so tightly wound that we would not even be able to see the spiral any more.

I thought that problem was the same as the galaxy rotation curve problem? If we solve (erm) that issue by adding in some dark matter - can't we then also accept a spiral structure to rotate with the galaxy without "winding up" the spiral?


Right, density waves. But as rtkwe and the Wikipedia article note, there's also increased star formation in the higher-density arms. So more stuff hitting Earth also seems plausible.


The Spiral arms aren't really cohesive bunches of stars but just bunches of relatively new stars that burn brighter than the older stars outside the spiral arms.

http://www.space.com/24642-spiral-galaxies-milky-way-shape-e...


No, in many spiral galaxies the spiral arms are present in older stars as well; that's why they're considered density waves in the stars. The contrast is stronger for younger stars, but it's there in old stars, too.


> TL;DR: our Sun's bumpy orbit through the spiral arms of out galaxy means periodic increases of comets and other bodies being jarred loose and later hitting Earth, resulting in mass extinctions.

Isn't only one of the mass extinctions (the dinosaur ending one) somewhat tightly linked to a comet impact? It seems as though it's finding a pattern that does no fit the data.


Are the causes of other mass extinctions known? I can imagine comet impacts can be hard to trace over billions of years. Especially when it's not just a single big one, but a period of increased impacts.

Also, I believe the dinosaur extinction was not just a comet impact, but a combination of an impact and a period of increased volcanic activity. Could the volcanic activity be triggered by comets?

I think the jury is still out, but it's an interesting field of study across many different fields (astronomy, biology, geology and probably more), and it has obvious implications for humanity's future on Earth, in space, and the chances of finding other life out there.


I live not too far from the Danish location Stevn Klint, a chalk cliff formation where the Alvarez'es found one very neat exhibit for their case. Utterly fascinating: You can climb to the foot of the cliffs, and there, unmistakable and obvious, is the dark, horizontal line in the massive wall of white - you can see it, you can touch it, and you can ponder the very different nature of fossil below and above the line.

There is a local museum rigth next to the cliffs. A few years ago, I spoke to the leader there, a woman with a ph.d. in history, who more or less supplied the final death blow to any lingering respect I might have held for any kind of humanities: Her only take on Walter and Louis Alvarez and their world famous work in her own backyard was how of course they were so arrogant, they had raised hostility among scientists and everybody else the world over.


what's that to do with anything in the thread


Arrogant about what?


I took it to be a humanities view of being out of whack with concensus.


> Could the volcanic activity be triggered by comets?

That's an interesting question. My completely unqualified opinion would be no, an comet couldn't trigger the massive and ongoing volcanic activity that a mass extinction requires. I'd like to hear from someone more informed though.


Could a big enough comet impact cause the Earth behave like a liquid and therefore a wave destabilize the crust and increase volcanic events?


I believe a few of the mass extinctions are thought to have been caused by gamma ray bursts (GRBs) that were close enough to earth to either affect the atmosphere or the orgamisms on the surface.


Maybe update the title to say (2013)?


There's interesting parallels with the Hindu Yugas here. https://www.thoughtco.com/the-four-yugas-or-epochs-1770051


It might be interesting if the people who invented the Yugas could have had any awareness of mass extinctions and the structure and behavior of the galaxy. Since they surely didn't, there's obviously no connection at all and it's not interesting - just made up myths.


Oh shut up.

The number of people that keep living in denial and rationalization of their sub-optimal circumstance astounds me.

Just face it and be honest. There is nothing noble in being a 50 year old for an infinity given the option to be youthful and mentally/physically fit instead.

Vanity, superficiality, shallowness... All these buzzwords that criticize something that is perfectly natural to desire, in an effort to signal some higher moral ground.

Come on.


Whoa! we ban accounts for posting this uncivilly. Please (re)-read the site guidelines and don't do this again.

https://news.ycombinator.com/newsguidelines.html

https://news.ycombinator.com/newswelcome.html

We detached this subthread from https://news.ycombinator.com/item?id=14291715 and marked it off-topic.


Yea I am signalling the moral high ground because HN is full of fucking sociopaths who want to live forever so they can execute their dumb ass startup until the heat death of the universe or learn new languages - at the expense of completely fucking up the world and our place in it. It helps to take a look in the mirror sometime.

Life extension technology is going to ruin humanity and the earth. Look up this comment in fifty years and tell me I'm wrong.


Make that 500 years, and you might get some takers to seal the deal ....


Fair point. I will extend my offer even up to a thousand years.


Is this supposed to be some sort of academic joke? Reminds me of http://tylervigen.com/old-version.html Maybe this isn't, sometimes science do work in strange ways.




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