RE: Galactic Effect On Biodiversity
-Original Message- From: brin-l-boun...@mccmedia.com [mailto:brin-l-boun...@mccmedia.com] On Behalf Of Doug Pensinger Sent: Friday, January 23, 2009 10:36 PM To: Killer Bs (David Brin et al) Discussion Subject: Re: Galactic Effect On Biodiversity Dan wrote: Even really revolutionary data, like the data that suggests dark energy, are written up in such a way that it implies that the big bang is now in question. That drives me crazy in the same way. Yea, god forbid scientists that are skeptical about the big bang! I was flip and trying to be humorous in my reply, but was then thinking that you might be referring to questions that exist about the initial big bang theory that are being looked at. For the general outline of the big bang and the evidence for it, UCLA has a nice site: http://www.astro.ucla.edu/~wright/cosmology_faq.html#bestfit But, the very start of the big bang, without modification from the original idea, is known to be problematic. I found a good site for discussing those difficulties: which are mainly the non-existence of relic exotic particles, (e.g. magnetic monopoles) that would have been expected to have been produced at ultra-high densities. http://www4.ncsu.edu/unity/lockers/users/f/felder/public/kenny/papers/inflat ion.html Well, I should say those are the problems that place a limit on how far back we can extrapolate. Things are clearly problematic at the Planck density, about 10^93 g/cc. On the other end, the big bang theory describes conditions very well back to nuclearsynthesis. For the time in between the theory of inflation has been developed. quote from the last article As I said before, it is almost certain that the big bang model gives an accurate description of the universe back at least as far as the time of nucleosynthesis. The earliest it could possibly be applied would be the Planck era. If we were to consider it valid all the way back to the Planck era we would have to suppose that all the very fine-tuned initial conditions we observe such as homogeneity and flatness were present from the beginning, presumably as a result of some unknown quantum gravity effects. Even given this assumption, however, it is unclear how the theory could avoid the production of relic particles that would destroy the successful description it has made of the later universe. It would be wonderful if a theory existed that with a minimum of assumptions could explain the initial conditions such as flatness and homogeneity, eliminate all high energy relic particles, and then segue into the big bang model itself by the time of nucleosynthesis. In 1980 Alan Guth proposed such a theory, known as inflation, end quote The actual process of nucleosynthesis is though to have stopped 20 minutes after the big bang. We know that the inflationary period had to end after densities were below those sufficient to produce magnetic monopoles. So, if you are arguing that the big bang did not survive without modifications, and that some tweaking may still be needed, then that's not problematic. The common nomenclature for this is that the big bang needed to be modified to handle these problems, not that it is false. False would be, for example, finding the steady state universe to be correct. So, I think you had been arguing more towards something of the latter, but if it is the former, than our differences are mainly semantic. Dan M. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Space folk on Twitter
I guess it is not that unusual to come across well-known people on Twitter, but here's one that stopped me in my tracks: http://twitter.com/worden Particularly when he tweeted About to visit Jerusalem and meet with Israel President Shimon Peres plus meetings with Israeli Space Industry. And a bit later, Just finished a wonderful reception with Israeli President Peres and US Astronaut Reisman. The President is quite a space enthusiast Nick ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Galactic Effect On Biodiversity
Dan M wrote: Which scientists? Are they the same ones who are skeptical about evolution? :-) I don't believe that The Big Bang Theory is on as sound a footing as evolution do you? Doug ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Galactic Effect On Biodiversity
Dan wrote: Sorry, I made my last post prior to reading this one. The actual process of nucleosynthesis is though to have stopped 20 minutes after the big bang. We know that the inflationary period had to end after densities were below those sufficient to produce magnetic monopoles. So, if you are arguing that the big bang did not survive without modifications, and that some tweaking may still be needed, then that's not problematic. The common nomenclature for this is that the big bang needed to be modified to handle these problems, not that it is false. False would be, for example, finding the steady state universe to be correct. So, I think you had been arguing more towards something of the latter, but if it is the former, than our differences are mainly semantic. I didn't read about it before last night but this summary of the problem of induction from the Wikipedia article on the Cosmological Principal describes my feelings rather well: Empirical observations of patterns occurring within a limited scope can shed no light on the state of things outside that scope. So what I believe is that any theory that attempts to describe the origin of the universe from our extremely limited perspective is flawed. Put it this way; If I could shrink an observer to the size of a virus, and place that observer under a thousand feet of water in the middle of the Pacific Ocean, how well do you think that that observer could describe the Earth? Doug ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Galactic Effect On Biodiversity
I didn't read about it before last night but this summary of the problem of induction from the Wikipedia article on the Cosmological Principal describes my feelings rather well: Empirical observations of patterns occurring within a limited scope can shed no light on the state of things outside that scope. If you really believe that, then you would throw most of evolutionary theory out, beause we've only been making good scientific measurements over a very limited scope of time, say the last 150-200 years. But, in evolution, we make inferences concerning time by all sorts of different methods. I consider them valid measurements. Just as I consider orbiting telescope measurements valid measurements of distant, past events. But, there is no scientific arguement that can possibly counter Last Thursdayism. But, if we limit ourselves to science modeling what we observe, then having both the universe and life on earth evolve over billions of years makes sense. The next assumption that I would make is that the earth is not in a phenomenally unique position in the universe. I think entropy is a good model to see what I mean. Take for example, a glass full of milk delecately balance on the edge of a counter. A draft of air hits it; it falls, and hits the carpet. The glass is broken an the milk is spilled, soaking the carpet. At a microscopic level, each process involved is reversible. There is an extrodinarily samll but very real chance that macroscopic phenomenon would reverse, and the milk would unsoak, regather; the glass would reattach itself and the glass of milk would find its way back on the counter. The arguement against this is entropy, but that's statistical. The chance of this happening is 1 in 10 to the zillinth power, but not zero. Positing that our galaxie is not in a unique place in the universe is akin to this. It would be arguing that we happen to be at the very center of the universe, and the highly isotropic nature of the observed universe in all directions is merely a result of this. You can't disprove this assumption, but we know no reason to accept it. So, models assume that our galaxy is not singular in its position. Finally, I assume that modern physics (say from SR on) is correct, and we do not live in a Newtonian/Maxwellian universe. If you give me that much, I can show why the principal alternatives to the big bang have far bigger problems in matching data than does the big bang (especially as modified by inflation). It will take some work to walk through the physics. I don't mind doing it, but don't want to do this if the real difference in our viewpoints are with the basic assumptions each of us are making. Not to accuse you of anything, but it feels to me that you are tacitly assuming that QM is inherently wrong.becasue if I am allowed to assume QM, SR, and GR, the arguement becomes pretty straightforward. From past discussions, I think you differ with physicists in that you want science to describe reality instead of merely modeling observations. But, I will stand to be corrected, I just don't want to write long posts that are not germaine to your main arguement. Dan M. Dan M. mail2web - Check your email from the web at http://link.mail2web.com/mail2web ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Galactic Effect On Biodiversity
- Original Message - From: dsummersmi...@comcast.net To: brin-l@mccmedia.com Sent: Monday, January 26, 2009 6:38 AM Subject: Re: Galactic Effect On Biodiversity Finally, I assume that modern physics (say from SR on) is correct, and we do not live in a Newtonian/Maxwellian universe. If you give me that much, I can show why the principal alternatives to the big bang have far bigger problems in matching data than does the big bang (especially as modified by inflation). What are the principal alternatives? Do they include a matrix like we are all living in a simulation scenario? I don't disbelieve the big bang theory, but the theory of evolution seems much more elegant and obvious by comparison. Also the big bang theory might model things very well, but to me it seems somewhat unfullfilling. The interesting question is, What caused the big bang? That's the real Brane Teaser. Regards, Wayne Eddy ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Galactic Effect On Biodiversity
Dan wrote: If you really believe that, then you would throw most of evolutionary theory out, beause we've only been making good scientific measurements over a very limited scope of time, say the last 150-200 years. The difference in limits of scope between evolution on earth and universal evolution, if you will, are vast. We have data points from near the beginning of life on earth to the present, but in UE we have comparatively few data points. Beyond that, where in EE we can observe and experiment upon the entire real time scope, in UE we must make our observations from a minuscule point within the system. I return to my analogy about the tiny observer 1000 feet beneath the sea. How much of earths evolution could that observer deduce? But, in evolution, we make inferences concerning time by all sorts of different methods. I consider them valid measurements. Just as I consider orbiting telescope measurements valid measurements of distant, past events. But, there is no scientific arguement that can possibly counter Last Thursdayism. But, if we limit ourselves to science modeling what we observe, then having both the universe and life on earth evolve over billions of years makes sense. The next assumption that I would make is that the earth is not in a phenomenally unique position in the universe. I think entropy is a good model to see what I mean. Take for example, a glass full of milk delecately balance on the edge of a counter. A draft of air hits it; it falls, and hits the carpet. The glass is broken an the milk is spilled, soaking the carpet. At a microscopic level, each process involved is reversible. There is an extrodinarily samll but very real chance that macroscopic phenomenon would reverse, and the milk would unsoak, regather; the glass would reattach itself and the glass of milk would find its way back on the counter. The arguement against this is entropy, but that's statistical. The chance of this happening is 1 in 10 to the zillinth power, but not zero. Isn't this kind of a straw man? A fair coin will come up heads half the time, but an unfair coin is far from inconceivable. Positing that our galaxie is not in a unique place in the universe is akin to this. It would be arguing that we happen to be at the very center of the universe, and the highly isotropic nature of the observed universe in all directions is merely a result of this. You can't disprove this assumption, but we know no reason to accept it. So, models assume that our galaxy is not singular in its position. Ah, but if you read the article on the cosmological principal you would have found in the last section (sorry about the font): Standard assumption that the observed high-degree of isotropy of the cosmic microwave background radiationhttp://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation (CMB), combined with the Copernican principlehttp://en.wikipedia.org/wiki/Copernican_principle, necessarily forces the universe to be homogeneous (i.e., the *cosmological principle*), is seriously undermined by some recent investigations.[2]http://en.wikipedia.org/wiki/Cosmological_Principle#cite_note-Undermining_the_cosmological_principle:_almost_isotropic_observations_in_inhomogeneous_cosmologies-1 In 2008, researchers studying fluctuations in the cosmic microwave background caused by the scattering of its microwave photons by hot X-ray-emitting gas inside clusters of galaxies found that the 700 clusters reaching out up to 6 billion light-years are all moving nearly 3.2 million km/h toward a 20-degree region in the sky between the constellations of Centaurus and Vela. This flow is difficult to explain by gravitation and may be indicative of a tilt exerted across the visible universe by far-away pre-inflationary inhomogeneities.[3]http://en.wikipedia.org/wiki/Cosmological_Principle#cite_note-2 [edithttp://en.wikipedia.org/w/index.php?title=Cosmological_principleaction=editsection=4 ] Finally, I assume that modern physics (say from SR on) is correct, and we do not live in a Newtonian/Maxwellian universe. If you give me that much, I can show why the principal alternatives to the big bang have far bigger problems in matching data than does the big bang (especially as modified by inflation). You don't have to show me, I'll take your word for it. That merely makes the Big Bang the most correct of all the _proposed_ possibilities and says nothing about the possibilities we can't even imagine because our powers of observation and our ability to conduct experiments is so abysmally limited. What you could help me understand is how well the Big Bang works if the universe is not homogeneous and isotropic? Doug ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Galactic Effect On Biodiversity
On 26/01/2009, at 7:38 AM, dsummersmi...@comcast.net wrote: Empirical observations of patterns occurring within a limited scope can shed no light on the state of things outside that scope. If you really believe that, then you would throw most of evolutionary theory out, beause we've only been making good scientific measurements over a very limited scope of time, say the last 150-200 years. Given that it's the 150th anniversary of the publication of The Origin this year, and that built on a couple of decades of research by Darwin... Most of evolutionary theory was built in the last 100 years, once the mechanism of heredity was worked out and the statistical tools were developed to actually test Darwin's ideas. You would not throw out most of evolutionary theory at all, by your criterion. Really, it's amazing how much of what most people think they know about biological science, particularly evolutionary biology, is completely wrong. Fossil record, for example. It's nice that the fossil record is there and is so detailed, but it's entirely superfluous to evolutionary theory. There are nice overlaps, but evolutionary theory explains the fossil record, not the other way round. (Most of the great discoveries of dinosaurs, marine reptiles etc were in the late 1800s, again after the publication of Origin). If we had no fossil record at all, it would have made virtually no difference to the development of evolutionary theory, and yet evolution by natural selection is one of the best supported scientific theories - if it was going to have serious weaknesses it would have failed long before now. Evolution underpins the whole of biology. Nothing makes sense without it, and every single time we ask what would this looks like if evolution were true, that's what we find. And Natural Selection is the one of the most elegant ideas in science, right up there with elliptical orbits and laws of motion. But despite that, it's viewed as a soft science, or worse, a trivially easy one. Being able to recite the soundbyte survival of the fittest and mumble something about variation of hereditary characters doesn't mean that one understands the implications. That's why it's a degree level subject, it's why I spent 4 years doing very little else (British degrees being much more focused than US ones, f'rex). One simply can't get to the same level of understanding if you're not living and breathing it. This is why I tend to stay out of physics discussions, 'cause I know how little I know, and reading A Brief History Of Time doesn't make me an expert. Charlie. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Galactic Effect On Biodiversity
On 26 Jan 2009, at 00:20, Charlie Bell wrote: On 26/01/2009, at 7:38 AM, dsummersmi...@comcast.net wrote: Empirical observations of patterns occurring within a limited scope can shed no light on the state of things outside that scope. If you really believe that, then you would throw most of evolutionary theory out, beause we've only been making good scientific measurements over a very limited scope of time, say the last 150-200 years. Given that it's the 150th anniversary of the publication of The Origin this year, and that built on a couple of decades of research by Darwin... Most of evolutionary theory was built in the last 100 years, once the mechanism of heredity was worked out and the statistical tools were developed to actually test Darwin's ideas. You would not throw out most of evolutionary theory at all, by your criterion. Really, it's amazing how much of what most people think they know about biological science, particularly evolutionary biology, is completely wrong. Dan's Kantian views about epistemology lead him to this position I suspect. Evolutionary theory is much more firmly established than cosmology and at least as well established as classical physics. Evolution underpins the whole of biology. Nothing makes sense without it, and every single time we ask what would this looks like if evolution were true, that's what we find. And Natural Selection is the one of the most elegant ideas in science, right up there with elliptical orbits and laws of motion. But despite that, it's viewed as a soft science, or worse, a trivially easy one. Being able to recite the soundbyte survival of the fittest and mumble something about variation of hereditary characters doesn't mean that one understands the implications. That's why it's a degree level subject, it's why I spent 4 years doing very little else (British degrees being much more focused than US ones, f'rex). One simply can't get to the same level of understanding if you're not living and breathing it. My BSc computer science degree was *five* years :-) This is why I tend to stay out of physics discussions, 'cause I know how little I know, and reading A Brief History Of Time doesn't make me an expert. Knowledge in every field is now so specialised and abstruse that we have to rely on the opinions of experts. Experts have to explain their views in simplified or analogical ways which are always open to misunderstanding. Polymath Maru -- William T Goodall Mail : w...@wtgab.demon.co.uk Web : http://www.wtgab.demon.co.uk Blog : http://radio.weblogs.com/0111221/ I embraced OS X as soon as it was available and have never looked back. - Neal Stephenson ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Galactic Effect On Biodiversity
On 26/01/2009, at 7:38 AM, dsummersmi...@comcast.net wrote: Empirical observations of patterns occurring within a limited scope can shed no light on the state of things outside that scope. If you really believe that, then you would throw most of evolutionary theory out, beause we've only been making good scientific measurements over a very limited scope of time, say the last 150-200 years. Given that it's the 150th anniversary of the publication of The Origin this year, and that built on a couple of decades of research by Darwin... Most of evolutionary theory was built in the last 100 years, once the mechanism of heredity was worked out and the statistical tools were developed to actually test Darwin's ideas. You would not throw out most of evolutionary theory at all, by your criterion. Really, it's amazing how much of what most people think they know about biological science, particularly evolutionary biology, is completely wrong. I think that I didn't clearly communicate my point. I read the paragraph you wrote above and there is nothing that contradicts the understanding I had when I wrote my post. I was getting at another point entirely. For evolution to make sense, you have to have millions of years of time over which it occured. If the observations we have made since, say, 50 years before Darwin, shed no light at all over what happened before that time, how do we understand evolution? If, for example, fusion wasn't found, we'd be scratching our heads because we couldn't reconcile the maximum length of time that the sun could possibly shine with the intensity it does (I think about 6,000 years without nuclear physics) and the length of time needed for what we see now to evolve from the most primitive form of life. All evolutionary models that I've seen have 1 billion years between the time that life first existed and now. There are no young earth evolutionary models that are real scientific theories (well maybe there is a falsified theory that I don't know about, but you know what I mean). The model extends over a time frame that is many orders of magnitude than do the observations. That's all I was saying. I understand that evolution is the best means we have to understand biology, and it's not just a means to understand fossils, and that fossils are in no way essential to the theory. Fossil record, for example. It's nice that the fossil record is there and is so detailed, but it's entirely superfluous to evolutionary theory. There are nice overlaps, but evolutionary theory explains the fossil record, not the other way round. Yea, models are verified by observations of all kinds. If they don't match observations, they aren't good models. The more data to check the theory against the better. The smaller the difference that falsifies the model, the better. (BTW, like most physicists, I see scientific theories as models of observations) But, my point is that our understanding of life as it exists now is an evolutionary theory that describes a process that took far longer than the time scale over which scientific observations were made. Thus, if this is verbotten, then evolution wouldn't be accepted by the person who wouldn't accept that process. To summerize the arguement I was trying to make: Evolution is accepted as a well verified scientific theory (I knew Doug accepted this). Evolution is a theory that describes a process that requires far more time than the time frame over which observations were made. Therefore, if one rejects theories that require time scales that are greater than the time range of observations, then one must reject valid scientific theories, like evolution. None of the other stuff you were argueing against has anything to do with the point I was making. Dan M. mail2web LIVE Free email based on Microsoft® Exchange technology - http://link.mail2web.com/LIVE ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: Galactic Effect On Biodiversity
Original Message: - From: Doug Pensinger brig...@zo.com Date: Sun, 25 Jan 2009 15:15:44 -0800 To: brin-l@mccmedia.com Subject: Re: Galactic Effect On Biodiversity Dan wrote: If you really believe that, then you would throw most of evolutionary theory out, beause we've only been making good scientific measurements over a very limited scope of time, say the last 150-200 years. The difference in limits of scope between evolution on earth and universal evolution, if you will, are vast. Not that vast. Now, as Charlie pointed out, I'm no expert in biology, but everything I've read indicates the timescale of the universe and the timescale of life on earth are best estimated to be within a factor of 10 of each other. Wikipedia (not the best source I know but probably good for an estimate) has single cell life existing on the earth for 3 billion years. We have data points from near the beginning of life on earth to the present, but in UE we have comparatively few data points. A couple of things. First, I've long understood that fossil records are not critical to the theory of evolution (just to reinforce the point that I've long in _agreement_ with Charlie's point on this). Second, fossil records are not measurements made in the past, but measurements made in the present that fit a model that extends far into the past. Similar things can be done with cosmology. I'd be happy to show why other models, that assume that the age of what is observed is vastly shorter than is assumed by the astrophysics community, have been fasified by the array of available data. Beyond that, where in EE we can observe and experiment upon the entire real time scope, in UE we must make our observations from a minuscule point within the system. I return to my analogy about the tiny observer 1000 feet beneath the sea. How much of earths evolution could that observer deduce? Well, that observer can't see very far. How far can we see with our orbiting telescopes (tuned to various wavelengths)? The arguement against this is entropy, but that's statistical. The chance of this happening is 1 in 10 to the zillinth power, but not zero. Isn't this kind of a straw man? A fair coin will come up heads half the time, but an unfair coin is far from inconceivable. No, but if we observe billions upon billions of fair coins(galaxies), why would we live on one of the few unfair coins? In the sense I was talking about, we know that galaxies are receding from us at the same distance/pace rate (to within 1 part in 10,000) in every direction. The simplest assumption is that this is true for an observer in any given galaxy. Now you could assume that the earth just happens to be in the middle of the universe, or in another extremely rare spot, but then I think you need to explain why. Now, if you were arguing that there is variation in the universe and things like the speed of light varies, then that is a different story. People have made up models with variable fine structure constants, etc. Those have testable results, and up to now, they have provided results that do not match observations. Ah, but if you read the article on the cosmological principal you would have found in the last section (sorry about the font): I read that. But, maybe the implications are not clear. Inflation is genrally thought to occure in the 10-34 sec to 10-32 seconds after the big bang. http://aether.lbl.gov/www/science/inflation-history.html from the Lawarance Berkley Lab is my source for these numbers. I'm guessing that we don't have these numbers down cold, and the length and time of inflation might vary a good fraction of an order of magnitude here. The paper that's being discussed indicates that the data might point to events happening before 10^-34 seconds. It presupposes the big bang, in other words. It is fair to say that inflation has explained a lot. As one of my references pointed out, there were quantitative predictions made by the inflationary model that have later been varified by experimentation. So, while we still have a lot of uncertainty concerning the first small fraction of a second after the big bang, we've done a nice job matching the observed universe down to a universe that existed, say, 1 second after the big bang. It has been stated that aspects of the inflationary universe and anything before inflation involve guesswork. But, assuming that the general framework is wrong and we have to start over would take a lot more. You don't have to show me, I'll take your word for it. That merely makes the Big Bang the most correct of all the _proposed_ possibilities and says nothing about the possibilities we can't even imagine because our powers of observation and our ability to conduct experiments is so abysmally limited. But, all science does is model observations. Rich and I have very different metaphysical viewpoints, but we agree (as does virtually every physicists I have talked to
Re: Galactic Effect On Biodiversity
Original Message: - From: Wayne Eddy we...@bigpond.net.au Date: Mon, 26 Jan 2009 08:10:41 +1000 To: brin-l@mccmedia.com Subject: Re: Galactic Effect On Biodiversity - Original Message - From: dsummersmi...@comcast.net To: brin-l@mccmedia.com Sent: Monday, January 26, 2009 6:38 AM Subject: Re: Galactic Effect On Biodiversity Finally, I assume that modern physics (say from SR on) is correct, and we do not live in a Newtonian/Maxwellian universe. If you give me that much, I can show why the principal alternatives to the big bang have far bigger problems in matching data than does the big bang (especially as modified by inflation). What are the principal alternatives? The main ones I know of are the steady state universe and the various young universe theories that creationists come up with. The former was a real scientific theory, the latter aren't. Do they include a matrix like we are all living in a simulation scenario? No, that's metaphysics. I don't disbelieve the big bang theory, but the theory of evolution seems much more elegant and obvious by comparison. Well, elegance is a YMMV kinda thing. Although I do agree that there is something inelegant about renormalization, it works very very well, and nothing has taken its place yet, after almost 60 years. Also the big bang theory might model things very well, but to me it seems somewhat unfullfilling. The interesting question is, What caused the big bang? That's the real Brane Teaser. The best explaination I've seen is the freezing of the vacume. But, at some point, theories just start with axioms. Dan M. mail2web.com What can On Demand Business Solutions do for you? http://link.mail2web.com/Business/SharePoint ___ http://www.mccmedia.com/mailman/listinfo/brin-l
