Everyone believes things without strong evidence. What's dogmatic or irrational is believing things despite strong contrary evidence. For example, believing the creation dogma of fundamentalist Christianity, or believing that global climate change is a hoax or not supported by evidence (because it is; denying that is just denying what's in front of your nose).
But there are a lot of propositions, especially about likely future outcomes of trends, where rational extrapolation or inference is either wildly uncertain or really just impossible. Yet we all have beliefs about such things, whether we give them conscious thought or not, or whether we voice them or not.
Having said that, here's a belief of mine, which I share with Annalee Newitz (here): The human race will survive the current mass extinction. In fact, I'd go so far as to say, we will beat the odds on average lifetime of terrestrial species by at least several standard deviations,
and when our species does cease to exist, it will be because our
descendants have evolved into other species, not because we became
extinct without descendants.
Why do I believe this? Because I have a gut feeling. But it isn't just a
gut feeling, it's a feeling that our particular and peculiar favorable
adaptation, which is the ability to relatively accurately model reality and construct technology to modify the environment, is so blazingly superior to precursor adaptations in our ancestors and relatives, and so very adaptive, that I would not bet against our longterm survival and success. We will figure out how to survive, and thrive, and prevail. Even beyond the confines of "our time" and this Earth. Not all of us, but as a species.
If that's hominicentric (or whatever the word is), I plead guilty. Except I don't think it's wrong, I think it's just real.
02 May 2013
24 April 2013
Panspermia Hypothesis (with further reflection)
When I took a paleontology course, lo, these long seasons awent, the instructor was very dismissive of the so-called panspermia hypothesis. "This solves nothing," he said, "it just transfers the origin problem in time and space." (Paraphrasing; I suspect he said this a little less succinctly, but that was the gist).
But, look at it from a different perspective. I have read Christian DeDuve (Vital Dust, also Life Evolving) and some other writers on how organic chemists believe life might have originated and, well, let's just say the mechanism envisioned is a bit vague. On Earth, it seems to have occurred quite quickly. Very shortly after the crust cooled enough for oceans to form and the era of hourly impacts of bolides and other debris from the Solar System had quieted enough for stable environments to exist, life emerged. Something on the order of ~4 billion years ago, when the Earth had only existed in any form for about 500 million years. (Interestingly, Mars might have had a more benign environment a little earlier, which invites speculation that life could have originated there, and been transported here on ejecta thrown up by impacts to the Martian surface. Neat idea, but the failure so far to find evidence of life on Mars makes such a scenario highly speculative at best).
So, OK, life may emerge whenever the conditions are right, and relatively quickly. Or, Earth could have been lucky. Maybe even fantastically, phenomenally, once-in-a-thousand-galaxies lucky. We can't know without at least a second example of the phenomenon under discussion, i.e., life.
Or, it has to be acknowledged, life might emerge occasionally, given a soupcon of luck, and favorable conditions, and a fair amount of time. In which case, panspermia might well come in to play.
As I've argued before, the universe is much the same everywhere, and, as well, it has been more or less the same as it is now for something like a third to half of the time it's existed. The early universe was very different; we can actually see those early Galaxies, 10+ billion light years distant (and old; same thing). But galaxies of the universe of the time the Sun formed (4½ b.y. ago) (also visible, at that number of light years distance) look much like those of the current time. A lot of disk population stars not unlike the Sun, some already billions of years old, and no doubt many with planets, some not so different from the Earth. So, given the assumption that life is likely to originate given favorable conditions, life probably originated in many, many, many places much earlier than it did on Earth. But let's speculate that life actually doesn't form all that easily, and that, say, only 1% of the time, all by itself, from nonliving matter, even given favorable conditions, will it emerge. Still, 1% of untold billions of stars is a lot of stars, and life must have originated many, many times even within ordinary middling sized sprial galaxies like the Milky Way.
So here we have, the first "generation" of life-bearing worlds, existing before the Solar System even formed. What if a few times, or even only once, life evolved to the status of a highly technologically advanced civilization, that looked out at the somewhat younger universe that existed then, and said, Yea, behold, there are worlds in their millions and billions yet to form! Let us make it our mission to seed these worlds with life of our own kind, so that life will abide, and not perish in the universe!
We, puny humans, are almost at a technological level where we could build autonomous interstellar craft to travel the spaceways, enter into suitable target systems, and deposit canisters containing living organisms into environments where it stood some chance to survive, and subsequently to evolve. We may well even do this in the future ourselves.
So, then, who is to say that this did not happen in the distant past? It is easy to see, from the logic I’ve tried to follow above, that such an origin of life on Earth is plausible, and, given some quite possible parameters for the likelihood of origin of life in any given environment, might just possibly be more likely than the more usual, single unique origin of life from non-living matter in the earliest days of our world’s existence.
Perhaps someday, not too far in the future, information which will enable us to understand this issue better will be emerging.
FURTHER REFLECTION
When I wrote this several years ago on the whole topic of the Fermi Paradox I commented on the possible role of Von Neumann (self -replicating) machines in cosmic biological evolution. It still seems to me that there are implications of the mere fact that there doesn't seem to be any particular reason such technology could or would not be developed, for the whole issue being discussed here.
Returning to the idea that at the approximate time of the formation of the Solar System (4½ billion years ago), the universe was similar enough to its present state that there were already older, relatively metal rich disk population stars in existence that could have already had time and resources necessary for the evolution of complex life on the surfaces of planets (statistically). The proportion of such stars where this actually happens (one of the factors in the Drake Equation) is essentially unknowable at this point, but there are hints already from the Spitzer Space Telescope data and other exoplanetary search data that planetary systems are highly variable, and the presence of cozy Earth analogs may be somewhat rare, as opposed to very common. That's about all you can really say about that issue right now; the recent discovery of two planets in orbit around a dwarf star not radically different from the Sun (Kepler 62), both of which could have liquid water on their surface, is at least some confirmation that even if not necessarily very common, such planets exist in large numbers. So it's reasonable to posit that there was already a fairly large number of such planets in the Galaxy, including some which had already existed for several billion years, at the time of the formation of the Solar System.
Remember, too, that what was likely in our Galaxy was also likely in a virtually uncountable number of other similarly situated spiral galaxies in the Universe, even though that is not saying that it was likely in all galaxies, since galaxies are not all the same; the point being that we are talking about universal principles here, and even if life turns out to be really quite rare, there is an unbelievably huge sample size if you're talking about the whole universe.
So, could some civilization have arisen before life emerged on Earth, that, as I speculate above, sets as its goal, the propagation of life for its own sake? I see no reason why that could not have happened. But saying that begs a question. Would they have been likely to have developed Von Neumann technology to do it?
The answer to that question is vastly important for whether the panspermia hypothesis should be considered plausible. Because, if something is possible, in a large enough sample size, it's going to happen. As far as I'm aware, there is no reason intelligent beings could not build devices that act as "arks" for living organisms, probably only basic single cell forms, and which then use some form of interstellar propulsion (a difficult, time consuming but not impossible process, particularly suitable for long lived robots, which is what we're contemplating). These machines would scan the heavens for suitable stars where candidate worlds for "seeding" with life might exist, and go there. On arrival, they would deposit their "seeds," then proceed to make some number greater than one copies of themselves, replicating their payload of living organisms as well, and set out, again, this time to multiple new targets. Even allowing for the probability that some kind of error would creep in and cause such systems, no matter how well thought out their self-repair modalities, to eventually fail, it is easy to see that, Sorcerer's Apprentice style, such technology could eventually deposit life in all the suitable star systems in some appreciable chunk of a galaxy, or even possibly all of it. The numbers have been run by others, but suffice it to say that if a Von Neumann propagation was successful through a few hundred iterations, say, and that it could manage an average travel time between stars (including the time needed to replicate itself and start out again) that was measurable in centuries rather than millennia or longer, every star in a given galaxy could be visited in much less time than the age of the galaxy itself. On the order of a million or two years, in galaxies that are (were) several billion years old.
So what's the problem? Life could have originated, somewhere in the Galaxy, from nonliving matter (which after all, without panspermia we hypothesize for every living world); evolved to complexity and the emergence of intelligence (hey, it happened here, unless...); then started such a process, just because. How likely is this? Who can say, but it can't be ruled out. The point is, it's possible that all life in the galaxy at the approximate time of the apparent emergence of life on Earth could have come from such a process, and have had a common origin. (Or a small number of similar origins, it makes little difference).
But this raises another issue. What about since then? The Earth has existed a long, long time. During that time, no civilized creatures, as far as we can tell, have visited here; certainly none has come and stayed. If panspermia-by-Von Neumann process could have occurred 4½ billion years ago, it could have occurred again and again since then. It seems contrived to me to posit that any such device, on encountering worlds where life was already present, would just move on without interfering. Sure, that's a possible program for such machines, but would it always be, like some law of nature, and would it always work? Seems unlikely. So, could life, or variations of already existing life, have been injected into the Earth's biosphere from external sources more than once? Could biological evolution actually be a cosmic story, rather than a planetary one?
Again, as far as I know, there's nothing impossible about such a scenario. But it really, really does beg the Fermi question, all over again. Because you have to ask, even if it were to turn out that intelligent beings are often biophilic, i.e., they see value in propagating life for its own sake, wouldn't at least some of them be territorial, expansionistic, explorational, or otherwise interested in visiting the worlds of the Galaxy themselves, in the flesh? So why, if technological civilizations were, in our scenario, involved in propagating life, have the actual intelligent beings themselves not shown up here, and everywhere, in all that time? It's the Fermi paradox all over again, and all the usual objections apply. (Follow the link above for my thoughts on what that all means). Also, the likelihood that life has been "injected" into the biosphere of Earth multiple times has to be discounted. The generally accepted inference from available data is that all life on Earth shares a single origin and has one common ancestor. Not impossible, but inconsistent with observation, and so requiring extraordinary evidence.
The unspoken possibility here is that panspermia might occur without intelligence. Life might just ride on ejecta and stray comets, and spread through space that way. The problem with that, again, at a rough estimate, is that space is just too vast, such chance depositions probably so rare, that, while occasional transference of life from one star system to another probably can't be ruled out and may well have happened from time to time and place to place in the vast universe, it seems unlikely to have occurred in a general way or on a large scale. The main reason is the same factor as plays a big role in all discussions of the emergence of life and intelligence in the universe: on average, stars are really, really far away from each other. (Alpha Centauri is 40 trillion kilometers, and that's the nearest system). In other words, it takes a bit of consciously directed, deliberate effort, for stuff, like packages of micro-organisms, to get from one star system to another.
So, what, then?
We don't know. Seems to me panspermia is conceivable, but there are objections to it based on probable consequences that don't seem to have occurred. The default hypothesis, I suppose, needs to remain the null one. Which is to say, seems most likely life had a unique origin from nonliving matter on this planet, and most likely on others, in this Galaxy and vast numbers of others in the universe. But, already, it must be said that it looks like this series of events (origin and subsequent evolution of intelligent life) is not necessarily particularly common.
CONCLUSIONS
From all this thought, which, I hope, is based on consideration of real information, I draw the conclusion that the evolution of intelligent, technological living beings, and/or another of the Drake Equation factors, the average lifetime of such civilizations, seems likely to be sufficiently improbable that these factors serve as choke points, making the continuous or frequent-over-geological-time presence in this Galaxy (or any galaxy) of starfaring "peoples" unlikely. Still, the possibility that life has been artificially propagated, and that even life on Earth may have originated from such a process, cannot be ruled out, although to advocate that this may have happened requires a bit of special pleading, given the likely corollary events that do not seem to have occurred. And from these, I think another inference can reasonably be drawn:
The next (and, it has to be said, quite possibly first ever) biopropagative starfaring race to emerge in the Galaxy is likely to be our own.
But, look at it from a different perspective. I have read Christian DeDuve (Vital Dust, also Life Evolving) and some other writers on how organic chemists believe life might have originated and, well, let's just say the mechanism envisioned is a bit vague. On Earth, it seems to have occurred quite quickly. Very shortly after the crust cooled enough for oceans to form and the era of hourly impacts of bolides and other debris from the Solar System had quieted enough for stable environments to exist, life emerged. Something on the order of ~4 billion years ago, when the Earth had only existed in any form for about 500 million years. (Interestingly, Mars might have had a more benign environment a little earlier, which invites speculation that life could have originated there, and been transported here on ejecta thrown up by impacts to the Martian surface. Neat idea, but the failure so far to find evidence of life on Mars makes such a scenario highly speculative at best).
So, OK, life may emerge whenever the conditions are right, and relatively quickly. Or, Earth could have been lucky. Maybe even fantastically, phenomenally, once-in-a-thousand-galaxies lucky. We can't know without at least a second example of the phenomenon under discussion, i.e., life.
Or, it has to be acknowledged, life might emerge occasionally, given a soupcon of luck, and favorable conditions, and a fair amount of time. In which case, panspermia might well come in to play.
As I've argued before, the universe is much the same everywhere, and, as well, it has been more or less the same as it is now for something like a third to half of the time it's existed. The early universe was very different; we can actually see those early Galaxies, 10+ billion light years distant (and old; same thing). But galaxies of the universe of the time the Sun formed (4½ b.y. ago) (also visible, at that number of light years distance) look much like those of the current time. A lot of disk population stars not unlike the Sun, some already billions of years old, and no doubt many with planets, some not so different from the Earth. So, given the assumption that life is likely to originate given favorable conditions, life probably originated in many, many, many places much earlier than it did on Earth. But let's speculate that life actually doesn't form all that easily, and that, say, only 1% of the time, all by itself, from nonliving matter, even given favorable conditions, will it emerge. Still, 1% of untold billions of stars is a lot of stars, and life must have originated many, many times even within ordinary middling sized sprial galaxies like the Milky Way.
So here we have, the first "generation" of life-bearing worlds, existing before the Solar System even formed. What if a few times, or even only once, life evolved to the status of a highly technologically advanced civilization, that looked out at the somewhat younger universe that existed then, and said, Yea, behold, there are worlds in their millions and billions yet to form! Let us make it our mission to seed these worlds with life of our own kind, so that life will abide, and not perish in the universe!
We, puny humans, are almost at a technological level where we could build autonomous interstellar craft to travel the spaceways, enter into suitable target systems, and deposit canisters containing living organisms into environments where it stood some chance to survive, and subsequently to evolve. We may well even do this in the future ourselves.
So, then, who is to say that this did not happen in the distant past? It is easy to see, from the logic I’ve tried to follow above, that such an origin of life on Earth is plausible, and, given some quite possible parameters for the likelihood of origin of life in any given environment, might just possibly be more likely than the more usual, single unique origin of life from non-living matter in the earliest days of our world’s existence.
Perhaps someday, not too far in the future, information which will enable us to understand this issue better will be emerging.
FURTHER REFLECTION
When I wrote this several years ago on the whole topic of the Fermi Paradox I commented on the possible role of Von Neumann (self -replicating) machines in cosmic biological evolution. It still seems to me that there are implications of the mere fact that there doesn't seem to be any particular reason such technology could or would not be developed, for the whole issue being discussed here.
Returning to the idea that at the approximate time of the formation of the Solar System (4½ billion years ago), the universe was similar enough to its present state that there were already older, relatively metal rich disk population stars in existence that could have already had time and resources necessary for the evolution of complex life on the surfaces of planets (statistically). The proportion of such stars where this actually happens (one of the factors in the Drake Equation) is essentially unknowable at this point, but there are hints already from the Spitzer Space Telescope data and other exoplanetary search data that planetary systems are highly variable, and the presence of cozy Earth analogs may be somewhat rare, as opposed to very common. That's about all you can really say about that issue right now; the recent discovery of two planets in orbit around a dwarf star not radically different from the Sun (Kepler 62), both of which could have liquid water on their surface, is at least some confirmation that even if not necessarily very common, such planets exist in large numbers. So it's reasonable to posit that there was already a fairly large number of such planets in the Galaxy, including some which had already existed for several billion years, at the time of the formation of the Solar System.
Remember, too, that what was likely in our Galaxy was also likely in a virtually uncountable number of other similarly situated spiral galaxies in the Universe, even though that is not saying that it was likely in all galaxies, since galaxies are not all the same; the point being that we are talking about universal principles here, and even if life turns out to be really quite rare, there is an unbelievably huge sample size if you're talking about the whole universe.
So, could some civilization have arisen before life emerged on Earth, that, as I speculate above, sets as its goal, the propagation of life for its own sake? I see no reason why that could not have happened. But saying that begs a question. Would they have been likely to have developed Von Neumann technology to do it?
The answer to that question is vastly important for whether the panspermia hypothesis should be considered plausible. Because, if something is possible, in a large enough sample size, it's going to happen. As far as I'm aware, there is no reason intelligent beings could not build devices that act as "arks" for living organisms, probably only basic single cell forms, and which then use some form of interstellar propulsion (a difficult, time consuming but not impossible process, particularly suitable for long lived robots, which is what we're contemplating). These machines would scan the heavens for suitable stars where candidate worlds for "seeding" with life might exist, and go there. On arrival, they would deposit their "seeds," then proceed to make some number greater than one copies of themselves, replicating their payload of living organisms as well, and set out, again, this time to multiple new targets. Even allowing for the probability that some kind of error would creep in and cause such systems, no matter how well thought out their self-repair modalities, to eventually fail, it is easy to see that, Sorcerer's Apprentice style, such technology could eventually deposit life in all the suitable star systems in some appreciable chunk of a galaxy, or even possibly all of it. The numbers have been run by others, but suffice it to say that if a Von Neumann propagation was successful through a few hundred iterations, say, and that it could manage an average travel time between stars (including the time needed to replicate itself and start out again) that was measurable in centuries rather than millennia or longer, every star in a given galaxy could be visited in much less time than the age of the galaxy itself. On the order of a million or two years, in galaxies that are (were) several billion years old.
So what's the problem? Life could have originated, somewhere in the Galaxy, from nonliving matter (which after all, without panspermia we hypothesize for every living world); evolved to complexity and the emergence of intelligence (hey, it happened here, unless...); then started such a process, just because. How likely is this? Who can say, but it can't be ruled out. The point is, it's possible that all life in the galaxy at the approximate time of the apparent emergence of life on Earth could have come from such a process, and have had a common origin. (Or a small number of similar origins, it makes little difference).
But this raises another issue. What about since then? The Earth has existed a long, long time. During that time, no civilized creatures, as far as we can tell, have visited here; certainly none has come and stayed. If panspermia-by-Von Neumann process could have occurred 4½ billion years ago, it could have occurred again and again since then. It seems contrived to me to posit that any such device, on encountering worlds where life was already present, would just move on without interfering. Sure, that's a possible program for such machines, but would it always be, like some law of nature, and would it always work? Seems unlikely. So, could life, or variations of already existing life, have been injected into the Earth's biosphere from external sources more than once? Could biological evolution actually be a cosmic story, rather than a planetary one?
Again, as far as I know, there's nothing impossible about such a scenario. But it really, really does beg the Fermi question, all over again. Because you have to ask, even if it were to turn out that intelligent beings are often biophilic, i.e., they see value in propagating life for its own sake, wouldn't at least some of them be territorial, expansionistic, explorational, or otherwise interested in visiting the worlds of the Galaxy themselves, in the flesh? So why, if technological civilizations were, in our scenario, involved in propagating life, have the actual intelligent beings themselves not shown up here, and everywhere, in all that time? It's the Fermi paradox all over again, and all the usual objections apply. (Follow the link above for my thoughts on what that all means). Also, the likelihood that life has been "injected" into the biosphere of Earth multiple times has to be discounted. The generally accepted inference from available data is that all life on Earth shares a single origin and has one common ancestor. Not impossible, but inconsistent with observation, and so requiring extraordinary evidence.
The unspoken possibility here is that panspermia might occur without intelligence. Life might just ride on ejecta and stray comets, and spread through space that way. The problem with that, again, at a rough estimate, is that space is just too vast, such chance depositions probably so rare, that, while occasional transference of life from one star system to another probably can't be ruled out and may well have happened from time to time and place to place in the vast universe, it seems unlikely to have occurred in a general way or on a large scale. The main reason is the same factor as plays a big role in all discussions of the emergence of life and intelligence in the universe: on average, stars are really, really far away from each other. (Alpha Centauri is 40 trillion kilometers, and that's the nearest system). In other words, it takes a bit of consciously directed, deliberate effort, for stuff, like packages of micro-organisms, to get from one star system to another.
So, what, then?
We don't know. Seems to me panspermia is conceivable, but there are objections to it based on probable consequences that don't seem to have occurred. The default hypothesis, I suppose, needs to remain the null one. Which is to say, seems most likely life had a unique origin from nonliving matter on this planet, and most likely on others, in this Galaxy and vast numbers of others in the universe. But, already, it must be said that it looks like this series of events (origin and subsequent evolution of intelligent life) is not necessarily particularly common.
CONCLUSIONS
From all this thought, which, I hope, is based on consideration of real information, I draw the conclusion that the evolution of intelligent, technological living beings, and/or another of the Drake Equation factors, the average lifetime of such civilizations, seems likely to be sufficiently improbable that these factors serve as choke points, making the continuous or frequent-over-geological-time presence in this Galaxy (or any galaxy) of starfaring "peoples" unlikely. Still, the possibility that life has been artificially propagated, and that even life on Earth may have originated from such a process, cannot be ruled out, although to advocate that this may have happened requires a bit of special pleading, given the likely corollary events that do not seem to have occurred. And from these, I think another inference can reasonably be drawn:
The next (and, it has to be said, quite possibly first ever) biopropagative starfaring race to emerge in the Galaxy is likely to be our own.
08 April 2013
Miserable Foreign Policy Failure
I think it has to be said. The Obama administration is doing an absolutely miserable job of dealing with the North Korean diplomatic crisis. It's obvious to all Korea hands that this new leader is not crazy,* although he is inexperienced and is the hereditary monarch of a strange and difficult country that has to be dealt with carefully. The policy of "strategic patience" has obviously failed. It is now time to shift gears and talk to these people. Could anything be more obvious? The fact that Obama's national security advisers are all Iraq war hawks (and thus people proven to lack sound judgment, and I would include Hillary Clinton in that except she's not there anymore)... is far from reassuring.
North Korea is NOT a nuclear threat or a strategic threat to the US, apart from the dire consequences of escalation gotten out of control. The administration needs to get serious about a diplomatic offensive to reset this relationship now.
---
UPDATE
* To a friend who said this reminded him of Catch-22, in that all leaders are crazed (with power), I noted:
North Korea is NOT a nuclear threat or a strategic threat to the US, apart from the dire consequences of escalation gotten out of control. The administration needs to get serious about a diplomatic offensive to reset this relationship now.
---
UPDATE
* To a friend who said this reminded him of Catch-22, in that all leaders are crazed (with power), I noted:
...What I was trying to say was that saying the NKs are nuts is just a cop-out. It's more accurate to say that they are a ninth century medieval absolute monarchy cloaked in the mantle of a Stalinist early 20th century totalitarian state, trying to finagle some kind of ongoing existence in a 21st century world. That poses a challenge for smart people. But going around saying "We won't stand for a nuclear North Korea," (which Kerry did last week), and having your military leaders saying we'll be ready for war if it comes, and saying your policy is to sit on your ass and hope they go away, doesn't strike me as a smart strategy; hence my comment. I give the Obama people some credit for being on the whole less belligerent than the Neocon Bushites (although his policy seems hardly different from the second term of W. to me), but this is just bad policy badly executed, and there's no way around it.
19 March 2013
Profiles in Economic Stupidity of Breathtaking Proportions
Allow me to refer to two recent examples of unbridled stupidity in the field of public economics. The details are all over the internet tubes, so I will spare you.
1. The Ryan Budget, with its mendacious and clearly deliberate fictionalization of future revenue, its wanton and churlish disregard for the vital importance to the health of the economy of a functioning social safety net, and its absolutely disgusting pandering to the narrow (perceived) interests in preservation of the wealth and unearned privilege of the super-rich. (None of that is even slightly exaggerated, in my humble opinion).
2. The Finance ministers in Brussels, Berlin, and the ECB, who actually (apparently) thought it was a good idea, probably because it was a far corner that wasn't even really in Europe, to tax savings deposits of banks inside the Eurozone (Cyprus), thus making a mockery of deposit insurance (which they learned from Depression era America to begin with). This unbelievable stupidity now has the very real prospect of unraveling the Eurozone financial system entirely, just when the world markets had more or less concluded that they just might muddle through. This despite a whole host of previous stupid decisions (but this one really takes the cake!). Just pray that North America's economy is sufficiently integrated and independent of Europe's that it doesn't crash our economy too; or that they somehow manage to blunt or at least partly reverse this idiocy before the worst of the damage becomes irreversible.
--
Needless to point out, I suppose, is the fact that the second example is far worse than the first, if for no other reason than that the "Ryan Budget" is and always was a work of fiction, which will go nowhere and have little or no effect on policy, whereas the incredible recklessness of the Eurozone finance dictators has already caused enormous damage, and has a huge potential to wreak havoc worldwide. Stay tuned. I wish I could say they will probably fix this once they see what's happening, but if past is prelude, there's no reason to think that.
1. The Ryan Budget, with its mendacious and clearly deliberate fictionalization of future revenue, its wanton and churlish disregard for the vital importance to the health of the economy of a functioning social safety net, and its absolutely disgusting pandering to the narrow (perceived) interests in preservation of the wealth and unearned privilege of the super-rich. (None of that is even slightly exaggerated, in my humble opinion).
2. The Finance ministers in Brussels, Berlin, and the ECB, who actually (apparently) thought it was a good idea, probably because it was a far corner that wasn't even really in Europe, to tax savings deposits of banks inside the Eurozone (Cyprus), thus making a mockery of deposit insurance (which they learned from Depression era America to begin with). This unbelievable stupidity now has the very real prospect of unraveling the Eurozone financial system entirely, just when the world markets had more or less concluded that they just might muddle through. This despite a whole host of previous stupid decisions (but this one really takes the cake!). Just pray that North America's economy is sufficiently integrated and independent of Europe's that it doesn't crash our economy too; or that they somehow manage to blunt or at least partly reverse this idiocy before the worst of the damage becomes irreversible.
--
Needless to point out, I suppose, is the fact that the second example is far worse than the first, if for no other reason than that the "Ryan Budget" is and always was a work of fiction, which will go nowhere and have little or no effect on policy, whereas the incredible recklessness of the Eurozone finance dictators has already caused enormous damage, and has a huge potential to wreak havoc worldwide. Stay tuned. I wish I could say they will probably fix this once they see what's happening, but if past is prelude, there's no reason to think that.
06 March 2013
Planets: of itnerest to space enthusiast types
I can't cite anything to prove the following points, but from my reading and inferring from what I've read about research into these areas, I believe the following is accurate.
Planets are everywhere. Not only are brown dwarfs (and non-nucleosynthetic L dwarfs, which really should be classed with the brown dwarfs), ... neither planet nor star but intermediate... far more common than all stars put together, but actual planets are more common even than that.
1. Essentially all stars have Kuyper and Oort "clouds" containing lots of stuff. Comets, small icy planets, some rocky and metal asteroids. Human exploitation of space will eventually focus on these resources, if we accomplish real space travel. Starting with our own Solar System. And stars are, first and foremost, abundant energy sources.
2. Most stars have planets. The only ones that don't (among the normal so-called 'dwarf' stars, which in Astronomese includes stars like the Sun) are the ones which have had their orbits disrupted by binary capture or other disruptive events (typically stars early on when close together in formative cluster come too close, eject the lowest mass star and form new pairs; this is quite common and probably throws most of the planetary disk out into space as well). (See this month's Scientific American which has an article about galactic star clusters and how this process enables some of them to expand without dispersing). (It's also true that massive stars, which form differently from former T Tauri type stars like the Sun and smaller dwarf stars, may usually lack planetary systems, but massive stars are rare and mostly very far away so they can be disregarded).
3. That phenomenon, and less violent but even more common planetary ejection events, mostly in the early phases of star system development, mean that there are at least as many planets, both rocky and gas type, NOT associated with stars as that are. THESE are really everywhere.
Planets are everywhere. Not only are brown dwarfs (and non-nucleosynthetic L dwarfs, which really should be classed with the brown dwarfs), ... neither planet nor star but intermediate... far more common than all stars put together, but actual planets are more common even than that.
1. Essentially all stars have Kuyper and Oort "clouds" containing lots of stuff. Comets, small icy planets, some rocky and metal asteroids. Human exploitation of space will eventually focus on these resources, if we accomplish real space travel. Starting with our own Solar System. And stars are, first and foremost, abundant energy sources.
2. Most stars have planets. The only ones that don't (among the normal so-called 'dwarf' stars, which in Astronomese includes stars like the Sun) are the ones which have had their orbits disrupted by binary capture or other disruptive events (typically stars early on when close together in formative cluster come too close, eject the lowest mass star and form new pairs; this is quite common and probably throws most of the planetary disk out into space as well). (See this month's Scientific American which has an article about galactic star clusters and how this process enables some of them to expand without dispersing). (It's also true that massive stars, which form differently from former T Tauri type stars like the Sun and smaller dwarf stars, may usually lack planetary systems, but massive stars are rare and mostly very far away so they can be disregarded).
3. That phenomenon, and less violent but even more common planetary ejection events, mostly in the early phases of star system development, mean that there are at least as many planets, both rocky and gas type, NOT associated with stars as that are. THESE are really everywhere.
The 100 Stars within 20 light years
A sphere centered on the Sun with a radius of just under (actually almost exactly) 20 light years has 100 stars in it. (Source: RECONS (Research Consortium on Nearby Stars). ---Unfortunately, this data includes some brown dwarfs and Red subdwarfs, which complicates things, because these things are not stars, really, and, worse, there are probably lots more of them than this data shows, but the essential points are correct anyway).
Of the remaining 95 stars, there are no F dwarfs. (stars of the next brighter class relative to the Sun). (Only Procyon, see above). Stars in this class are also relatively common. We have two A dwarfs (Sirius and Altair) and one F dwarf (Procyon) in our actual Sun-centered population. Probably more typically it would be two or three F type in 100, probably on average there should only be one A dwarf. The very bright classes O and B are only found in star forming regions (because they don't live very long), and are exceedingly rare compared to these other classes. Which is why they're often referred to as giants and supergiants.
Among the remaining 95, then there are five more G dwarfs (same class as the Sun), all quite a bit dimmer than the Sun (in addition to Alpha Centauri A and the Sun, above, so 7 total, including the Sun). (Tau Ceti, Sigma Draconis, Eta Cassiopiae A, 82 Eridani, and Delta Pavonis).
There are 17 K dwarfs. (Next dimmer class). These include Alpha Centauri B, Epsilon Eridani, 61 Cygni A & B, Epsilon Indi A, AX Microscopii, Omicron-2 Eridani, 70 Ophiuchi A & B, Eta Cassiopiae B, and 36 Ophiuchi A, B & C, plus several stars that only have catalog numbers. When you get to 20 light years or so, the mid-to late-K dwarfs are very inconspicuous in the sky.
That leaves 78 stars. Of these 78, (skipping the most numerous category), seven are White Dwarfs, which are stars which were once bright G or brighter stars but which have ended their lives as burnt out little white stars, no longer undergoing nuclear fusion in their cores. These include Sirius-B and Procyon-B; and van Maanen's star. The rest just have catalog numbers. All white dwarfs are very inconspicuous. Sirius at 8+ ly is far and away the brightest star in Earth's sky, but its white dwarf companion, besides being drowned out by close proximity to Sirius, would not be a naked eye star in its own right even if Sirius A weren't there... despite being one of the six or seven nearest stars to the Sun.
That leaves 71. Of those, another 7 are T-dwarfs, or methane dwarfs, better known as brown dwarfs. These are failed stars that never did undergo nucleosynthesis. These stars, if they are stars at all, are practically invisible, almost no matter how close they are. The only ones with 'names' are Epsilon Indi B & C, and the only reason they have those designations is that they're in the Epsilon Indi system (although A is a relatively dim star in its own right; see above). [In fact, as noted, it's likely that there are even more of these, so if you count them as stars, the percentiles are off but the meaning is clear. There may well be over 100 more of these. If you don't count them as stars, you could extrapolate percentiles but just multiplying by ~108%].
So, disregarding the brown dwarf issue, we're left with 63. The majority. A landslide in a presidential election.
All 63 of the remaining stars are red dwarfs. Class M.* Red dwarfs are little stars that burn hydrogen to helium, slowly and steadily, produce on average just a percent to a few percent of the light of the Sun, and live up to a trillion years without evolving off the "main sequence" (so we're told... the Universe is only 13.7 billion years old, so you have to believe the theory).
Over half of the individual stars in this population are in multiple systems, which translates, if you think about it, to something less than half of the systems being multiple. (If you have two systems, one single and one binary, 2/3 of the stars are in the binary system).
There's every reason to believe in disk populations in typical spiral galaxies, these proportions ought not to be too far from the norm.
---
To me, the takeaway is confirmation of something I already knew, which is that most stars are red dwarfs, and the brighter stars become increasingly rarer, more or less in direct proportion to increase in their mass, which directly correlates to increasing brightness, with minor adjustments for age and composition.
The Sun is a relatively bright star, not a typical star.
But on the other hand, there is a selection effect when you look at the night sky. Very very bright stars are SO MUCH brighter than dimmer stars that they dominate the night sky in visible light. MOST of the naked eye stars are exceptionally bright and very rare stars. Whereas, in the actual population, most of the stars are very dim dwarfs. And if you count the bodies that never really started shining with thermonuclear energy, there are even more of them. They're everywhere.
For the future of humanity, the brown dwarfs are less interesting, because it's hard to imagine how future Homo stellaviator (Man the Starfarer) will be interested in systems that only contain them. These stars, if they even are stars, glow only with the heat of their own collapse and are so cool they don't really emit enough light to drive photosynthesis or solar power generation. It's hard to see how it would be worth the cost and time to travel to such systems.
The abundance and energetics of thermonuclear fusion core Red Dwarfs, though, may be another story. If we someday literally cross the great voids of space in person, these are what's out there in huge numbers, and they are engines of energy production, like the Sun but smaller and weaker, and their systems are already known to typically have planets and probably other material in abundance. I'm enough of a dreamer to think of all that as real estate.
----
*(One is Class L, a special class of even lower temperature Red Dwarfs, which may also be under-represented even in this population study of the very nearest stars because they're so dim some are being missed. But this particular star is probably in thermonuclear fusion. The dimmer L's should be classed with the Ts. Look up spectral class T and L on Wikipedia if interested in this subject).
- The brightest star, type A, is Sirius, Alpha Canis Majoris. 8.58 ly distant.
- The second brightest is Procyon, Alpha Canis Minoris. Type F-5, just edging off the main sequence. 11.4 ly distant.
- The third brightest is Altair, Alpha Aquilae. Type A7, 16.7 ly.
- The fourth brightest star is THE SUN. Type G main sequence star.
- The fifth brightest is Alpha Centauri A, 4.37 ly distant. Main sequence type G2, similar to the Sun but a bit older.
Of the remaining 95 stars, there are no F dwarfs. (stars of the next brighter class relative to the Sun). (Only Procyon, see above). Stars in this class are also relatively common. We have two A dwarfs (Sirius and Altair) and one F dwarf (Procyon) in our actual Sun-centered population. Probably more typically it would be two or three F type in 100, probably on average there should only be one A dwarf. The very bright classes O and B are only found in star forming regions (because they don't live very long), and are exceedingly rare compared to these other classes. Which is why they're often referred to as giants and supergiants.
Among the remaining 95, then there are five more G dwarfs (same class as the Sun), all quite a bit dimmer than the Sun (in addition to Alpha Centauri A and the Sun, above, so 7 total, including the Sun). (Tau Ceti, Sigma Draconis, Eta Cassiopiae A, 82 Eridani, and Delta Pavonis).
There are 17 K dwarfs. (Next dimmer class). These include Alpha Centauri B, Epsilon Eridani, 61 Cygni A & B, Epsilon Indi A, AX Microscopii, Omicron-2 Eridani, 70 Ophiuchi A & B, Eta Cassiopiae B, and 36 Ophiuchi A, B & C, plus several stars that only have catalog numbers. When you get to 20 light years or so, the mid-to late-K dwarfs are very inconspicuous in the sky.
That leaves 78 stars. Of these 78, (skipping the most numerous category), seven are White Dwarfs, which are stars which were once bright G or brighter stars but which have ended their lives as burnt out little white stars, no longer undergoing nuclear fusion in their cores. These include Sirius-B and Procyon-B; and van Maanen's star. The rest just have catalog numbers. All white dwarfs are very inconspicuous. Sirius at 8+ ly is far and away the brightest star in Earth's sky, but its white dwarf companion, besides being drowned out by close proximity to Sirius, would not be a naked eye star in its own right even if Sirius A weren't there... despite being one of the six or seven nearest stars to the Sun.
That leaves 71. Of those, another 7 are T-dwarfs, or methane dwarfs, better known as brown dwarfs. These are failed stars that never did undergo nucleosynthesis. These stars, if they are stars at all, are practically invisible, almost no matter how close they are. The only ones with 'names' are Epsilon Indi B & C, and the only reason they have those designations is that they're in the Epsilon Indi system (although A is a relatively dim star in its own right; see above). [In fact, as noted, it's likely that there are even more of these, so if you count them as stars, the percentiles are off but the meaning is clear. There may well be over 100 more of these. If you don't count them as stars, you could extrapolate percentiles but just multiplying by ~108%].
So, disregarding the brown dwarf issue, we're left with 63. The majority. A landslide in a presidential election.
All 63 of the remaining stars are red dwarfs. Class M.* Red dwarfs are little stars that burn hydrogen to helium, slowly and steadily, produce on average just a percent to a few percent of the light of the Sun, and live up to a trillion years without evolving off the "main sequence" (so we're told... the Universe is only 13.7 billion years old, so you have to believe the theory).
Over half of the individual stars in this population are in multiple systems, which translates, if you think about it, to something less than half of the systems being multiple. (If you have two systems, one single and one binary, 2/3 of the stars are in the binary system).
There's every reason to believe in disk populations in typical spiral galaxies, these proportions ought not to be too far from the norm.
---
To me, the takeaway is confirmation of something I already knew, which is that most stars are red dwarfs, and the brighter stars become increasingly rarer, more or less in direct proportion to increase in their mass, which directly correlates to increasing brightness, with minor adjustments for age and composition.
The Sun is a relatively bright star, not a typical star.
But on the other hand, there is a selection effect when you look at the night sky. Very very bright stars are SO MUCH brighter than dimmer stars that they dominate the night sky in visible light. MOST of the naked eye stars are exceptionally bright and very rare stars. Whereas, in the actual population, most of the stars are very dim dwarfs. And if you count the bodies that never really started shining with thermonuclear energy, there are even more of them. They're everywhere.
For the future of humanity, the brown dwarfs are less interesting, because it's hard to imagine how future Homo stellaviator (Man the Starfarer) will be interested in systems that only contain them. These stars, if they even are stars, glow only with the heat of their own collapse and are so cool they don't really emit enough light to drive photosynthesis or solar power generation. It's hard to see how it would be worth the cost and time to travel to such systems.
The abundance and energetics of thermonuclear fusion core Red Dwarfs, though, may be another story. If we someday literally cross the great voids of space in person, these are what's out there in huge numbers, and they are engines of energy production, like the Sun but smaller and weaker, and their systems are already known to typically have planets and probably other material in abundance. I'm enough of a dreamer to think of all that as real estate.
----
*(One is Class L, a special class of even lower temperature Red Dwarfs, which may also be under-represented even in this population study of the very nearest stars because they're so dim some are being missed. But this particular star is probably in thermonuclear fusion. The dimmer L's should be classed with the Ts. Look up spectral class T and L on Wikipedia if interested in this subject).
18 January 2013
Are we living in a Young Universe? Some further thoughts on the Fermi Paradox
[Updated]. This post is a follow up to a post I put on here almost three years ago to the day. Here.
What if the answer to the
Fermi Paradox is simply that, contrary to what we like to think, the Universe
is yet young, and no (or very few) Elder Races have yet appeared?
Here is a (perhaps)
plausible scenario. Items noted with ♠ are, to my understanding,
"generally accepted as true," although perhaps not widely
known.
♠ The Sun is more than one
third the age of the Universe, and is significantly (not to say greatly) anomalous,
in the direction of having a higher proportion of elements beyond Helium in the
Periodic table (higher metallicity) than is typical for stars of its age. (Some
stars older than the Sun have even higher metallicities, such as Alpha Centauri
(7 b.y. old, somewhat higher metallicity), but we're talking averages here).
Typical 5 billion year old stars in the Galactic Disk formed from the
moderately enriched Galactic medium of the time, and are consequently less
metal rich than typical stars forming today. (It's also true that star
formation has tapered well off, but it may be that of all the life bearing
worlds that ever form, a high proportion will be from the later-formed stars,
for this reason, and the point below). (How stars form plays a role here; there
are at least hints that the Sun formed in a cluster where a chain reaction of
supernovas had enriched the medium; this is not unusual, and was probably more
common in the past than now, but is not typical).
♠ Metallicity is thought to
be positively correlated with the likelihood of the evolution of life; in the
sense that planets forming in systems where the protostellar neblua was
initially metal-poor, (the ubiquitous and only gradually diminishing condition
of the general population of Stars in the early universe), would not yield the
materials necessary to form rocky watery worlds like Earth and the marvelously
complex chemical/energetic systems we refer to as "life."
♠ [New from original version of this post] It's perhaps worth noting that when these facts are generalized, i.e., we are talking about "stars of the Galactic Disk" as opposed to "the Sun," the basic facts will apply, more or less, with no great degree of variation, to all spiral galaxies everywhere in the Universe, since they're all more or less similarly formed, and all are roughly the same age, having resulted from an evolutionary process instigated by the Big Bang itself. Other types of galaxies may not have sunlike stars at all, for reasons I won't go into here, but there are such a vast number of galaxies essentially similar to the Milky Way in the wider universe that it really doesn't make any difference for purposes of this discussion. Also, the fact that the Milky Way is a "barred spiral" as opposed to other types of spiral galaxies doesn't appear to make any difference; the populations of disk stars in all galaxies with dust-containing disk regions are all essentially similar. Moreover, it's an accepted principle that all parts of the universe are much like all other parts, so it's generally accepted as true that this will be the case everywhere in the universe, even in regions beyond the "time horizon," i.e., beyond the border of where the universe is theoretically observable (the horizon's distance in light years equal to the age of the universe in years; adjusted for recessional velocities from the expansion of the universe itself. Most of the universe is beyond this horizon).
♠ [New from original version of this post] It's perhaps worth noting that when these facts are generalized, i.e., we are talking about "stars of the Galactic Disk" as opposed to "the Sun," the basic facts will apply, more or less, with no great degree of variation, to all spiral galaxies everywhere in the Universe, since they're all more or less similarly formed, and all are roughly the same age, having resulted from an evolutionary process instigated by the Big Bang itself. Other types of galaxies may not have sunlike stars at all, for reasons I won't go into here, but there are such a vast number of galaxies essentially similar to the Milky Way in the wider universe that it really doesn't make any difference for purposes of this discussion. Also, the fact that the Milky Way is a "barred spiral" as opposed to other types of spiral galaxies doesn't appear to make any difference; the populations of disk stars in all galaxies with dust-containing disk regions are all essentially similar. Moreover, it's an accepted principle that all parts of the universe are much like all other parts, so it's generally accepted as true that this will be the case everywhere in the universe, even in regions beyond the "time horizon," i.e., beyond the border of where the universe is theoretically observable (the horizon's distance in light years equal to the age of the universe in years; adjusted for recessional velocities from the expansion of the universe itself. Most of the universe is beyond this horizon).
From these generally
recognized facts, let's posit this: the Earth is a pioneer among worlds.
Having formed in an unusually metal rich system, in a typical spiral galaxy at
an early age, its complex biosphere is likely to be more typical of those found
in star systems that formed later (which will only later come to resemble
ours), or which are yet to form, than those that began the process of evolution
at approximately the same time as the Solar System.
Now, of course, in the
vastness of all of space, this same "pioneer world" phenomenon has
probably occurred innumerable times (and sometimes much earlier than here, no
doubt), but let's just posit that it is an explanation for something we might
begin to suspect, which is that advanced living worlds are currently rather,
or possibly even extremely, rare. This says nothing about their likely future prevalence,
which, by this reasoning, could be very much greater than it is now.
Now, another posit: the
evolution of intelligent life on Earth took 5 billion years or so from the
origin of the Solar System. Maybe this is typical. Maybe it's an extra-long
time. But, from information available to us, we don't know: maybe, on other
hand, it's remarkably fortuitous, and atypically efficient and quick. Maybe
life sometimes or even usually goes its merry way and does not evolve
into beings that use thought as a competitive adaptation to ensure their
survival; or that, on average, such evolution usuallytakes longer than it
did on Earth. These are not known; we have no real way to evaluate any of these
possibilities. Remember that it took complex (i.e., multicellular) life over 4
billion years to emerge on Earth, and it took a further 550 million years before
technologically adept creatures (us) evolved (please don't plead for the Whales
and Dolphins... they may be smarter than us but they're not building spaceships
or intergalactic radios anytime soon). So most of the history of Earth, which,
again, is over 1/3 the entire history of the universe, saw life but
no "intelligence." So the latter is not necessarily
implied, at all, by the former. (Stephen Jay Gould, in reasoning that I found
unconvincing, hypothesized in his book Wonderful Life that if you
could "play the tape" of evolution over again, given the same
starting conditions, it was spectacularly unlikely that intelligent
beings would evolve again. I thought, and still think, his rationale was
hopelessly parochial, and failed to take into account the power of convergence.
Nonetheless, the fact that for hundreds of millions of years there was no
intelligent life surely indicates that the chances of its evolution are not
100%).
So, here's what I think may
be happening. Supercivilizations are possible. They may already exist, in some
corners of the Vast Universe (although probably not real near here, since we
see no signs of their amazingly stupefying technology, which we would,
presumably, if they were mucking about on our doorstep). We may evolve into one
of these, ourselves, eventually. What that will look like, we can hardly guess.
But the Young Universe has yet to produce Supercivilized Elder Races in
abundance. Most living worlds, even those which have chanced to evolve
intelligent beings, are, in fact, isolates, like ours.
Someday, that may all
change, as the universe matures.
But in the meantime, this is
why, at least for now, we appear to be, and effectively are,
"alone."
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