the asinine cretin

Sorry about that. Here are some documents available on the internet that may be interesting. The third from the top is coauthored by Zubrin. A Model for Mars Ecosynthesis (PDF) The Terraformation of Worlds (PDF) Technological Requirements for Terraforming Mars Terraforming Mars: A Review of Research

Thank you. As a non-biologist that's kind of what I was wondering. Where does the hype meter register on this? I have to confess that at first hearing the use of "dark matter" made me cringe a bit. And I agree, the facts are extremely interesting. When I get some time I'd like to find resources that are more technical. P.S. Why did someone give juanrga's post a -1? Please explain. Thank you for the interesting remarks.

Zubrin's The Case for Mars talks about how Mars might be terraformed. It's a good read all around. There is also a Springer book that comes to mind called Terraforming. There are a lot of interesting ideas out there. Sad to say that while Venus is one of my favorite worlds, I've been forced to give up on the dream of terraforming it. There are some problems that I think are insurmountable. I still like the idea of aerostatic Venusian outposts and colonies though.

D H, Okay, well, your post is about 5% relevant to me. Mostly stating the painfully obvious and repeating things I've said or alluded to, which is obnoxious. Not an interesting convo. Moontanman, The more I look into them the more intrigued I am by stirling radioisotope generators. The tech exists and has demonstrated to be both significantly more efficient and lighter than RTGs; at least according to the stuff I've been reading. There is a big push to finish its development. Fission power back on NASA's agenda Using Nuclear Fuel for Future NASA Missions... Advanced Stirling Radioisotope Generator Flight Development The TiME mission is completely awesome and will likely use the tech. The NASA Space Technology Roadmaps and Priorities document, as of May 4th of this year, mentioned Advanced Stirling Radioisotope Generators 35 times. "NASA and DOE have been developing advanced RPSs that would use Stirling engines to replace thermoelectric converters. Because the energy conversion efficiency of the Stirling engine under development is about 5 times that of thermoelectric converters, Stirling engines require significantly smaller quantities of Pu-238 to achieve similar power levels." "The planetary science decadal survey committee cited its highest priority for near-term multimission technology investment was the completion and validation of the Advanced Stirling Radioisotope Generator. (NRC, 2011, p. 11-5)" "There were two technologies, Advanced Stirling Radioisotope Generators and On-Orbit Cryogenic Storage and Transfer, that the committee considered to be at a "tipping point," meaning a relatively small increase in the research effort could produce a large advance in its technology readiness." In other words, don't be surprised when we start seeing these on outer solar system spacecraft. Very cool.

In other words you don't know? Right. I was only talking about the fuel and not infrastructure. But I wouldn't call thermocouples "extremely massive infrastructure." There are things to consider beyond just the fuel? No kidding, everyone knows that. Perhaps you mistook this for a formal proposal. lol. Condescension isn't the reply I was hoping for. You evidently missed my comments about efficiency. Based on modern RTGs I suggested 7% as a reasonable efficiency but later mentioned a contemporary prototype device that is said to attain 30% efficiency. Since I'm freely speculating about what's possible, and not trying to be cynical, I think it's okay to imagine what could be done with a 7-30% efficient system. Moontanman's interpretation is correct. Obviously the radioisotope would be manufactured in situ on Mars. Clearly the killer problem with this Martian refill idea is that it assumes some serious infrastructure on Mars (for example, the neutrons required by the production process would probably require building and maintaining a large nuclear facility, as well as mining operations, refineries, and so on), but if we could already develop Mars on that scale it's hard to see why the VASIMR discussion would be relevant. In other words, it's a circular idea. There are ways to make it more worthwhile but I wouldn't actually say that I think it is workable. Just indulging in some stream of consciousness.

sammy, I'm on my way out the door but I've seen your post and will reply later. CharonY, Thank you very much. Good info.

It's definitely super lethal stuff. However, so is Pu-238 and we're still launching kilos of the stuff into space. The RTGs are pretty solid. An RTG from the aborted Apollo 13 mission is at the bottom of the sea some place. Actually dispersing the material in the atmosphere like you suggest isn't really going to happen even in the worst catastrophic failure. We've put Po-210 in orbit, and the Soviets certainly launched some good chunks of the stuff with their funny looking moon carts. But anyway, if your point is that it's dangerous stuff, I wholeheartedly agree. At least the majority of the Po-210 will decay into Pb-206 quite quickly. If Apollo 13 had used Po-210, a much smaller amount of dangerous material would have been needed and it would probably have been basically gone before I was born. "To minimize the risk of the radioactive material being released, the fuel is stored in individual modular units with their own heat shielding. They are surrounded by a layer of iridium metal and encased in high-strength graphite blocks. These two materials are corrosion- and heat-resistant. Surrounding the graphite blocks is an aeroshell, designed to protect the entire assembly against the heat of reentering the Earth's atmosphere. The plutonium fuel is also stored in a ceramic form that is heat-resistant, minimising the risk of vaporization and aerosolization. The ceramic is also highly insoluble." - Wikipedia: RTG Here's a bit of NASA's safety analysis for the Cassini-Huygens mission, which launched 3 RTGs and 129 radioisotope heaters. http://saturn.jpl.nasa.gov/spacecraft/safety/fseisd.pdf

Interesting. Has anything changed since 2010? As I mentioned in another thread, Ad Astra says that the VASIMR is to be tested on the ISS in the near future. I've not seen any substantial details. A two inch cube of polonium-210 would emit 140kW. That could definitively get you many kilowatts per kilogram; perhaps the two orders of magnitude you desire when compared with your numbers. The half-life is less than five months but I imagine a very compact and light weight RTG could power a VASIMR on a robotic spacecraft and ramp it up to extreme speeds for outer solar system recon and the like. (I haven't researched this or anything, just looked up some numbers of radioisotopes and talking out of my ass.) Just speculating here, but if polonium-210 production could be carried out on Mars you could make the trip to Mars in a few months or less and then obviously swap out the little power source for the return trip. Apparently it's been used in RTGs already so it's not that far-fetched. According to the VASIMR wikipedia page the 200kW engine is serious business. "Results presented to NASA and academia in January 2011 have confirmed that the design point for optimal efficiency on the VX-200 is 50 km/s exhaust velocity, or an Isp of 5000 s. Based on these data, thruster efficiency of 72 % has been achieved by Ad Astra, yielding an overall system efficiency (DC electricity to thruster power) of 60% (since the DC to RF power conversion efficiency exceeds 95%)." 1 kg of polonium-210 emits 140kW, and good RTG efficiency by today's standards is something like 7%. Therefore, 20 kg of radioisotope could create a worthy generator. No? Also, I tend to suppose that the 7% RTG efficiency could be improved upon in this day and age. The wiki article mentions something about a craft with a MW solar array and five of the 200 kW thrusters. Hmm.. It might look goofy, but if it works... And maybe with the expected innovations in photovoltaic tech that I often hear about such an array wouldn't be as ridiculous as I'm imagining. I'm thinking that the ISS arrays total to something like 150-200kW (I could be wrong); extrapolating from that to 1 MW results in a rather goofy spacecraft. It looks like there really isn't a Po-210 supply. Russia has one facility that produces less than 100 grams per year. That's really about it. It must have been produced in notable quantities in the past given its use for Russian lunar rovers and some U.S. experiments and things. Plutonium-238 seems to be tending toward the same fate at the moment. I wonder if Po-208 is viable for use in an RTG? The half-life of nearly 3 years seems more useful than the 5 months of Po-210. I wonder what the heat energy would be for a kg of the stuff. Oh well... P.S. The prototype ASRG power system attains 30% efficiency and a fourfold reduction in fuel. With plutonium-238 as the energy source it could power a spacecraft for >14 years. If the design could be effectively scaled up for the 200 kW demands of VASIMR... The prototype seems to get 175 watts per kilogram of Pu-238, or about 6 kg per kW. It's a good step I suppose. Or maybe the uber efficient design of the ASRG with a more concentrated fuel such as Po-210 or whatever. Yeah, no doubt 30 or 40 kW per kg could be worth something. A radioisotope in between Pu-238 and Po-210 would be ideal. Oh well.

Anyone know if the VASIMR is really legit? I hear they are supposed to put VASIMR thrusters on the ISS in the near future. On the other hand, I can remember Robert Zubrin vehemently trashing the VASIMR and basically saying it's a scam. I can recall a PBS show that spent ten minutes talking about the VASIMR and thought it was a load of crap. As if the only options are the VASIMR or a ridiculously long chemical rocket journey. If my impressions are correct it was very skewed pro-VASIMR propaganda with Neil deGrasse Tyson as the host. P.S. Here is the Zubrin screed I was thinking of. The VASIMR Hoax

New Scientist: Biology's 'dark matter' hints at fourth domain of life Comments?

Truth.

Again, I'm familiar with what ring species are. I was hoping for a summary description of macroevolution and an elucidation of why ring species are a particularly good example of this. The problem I have with ring species as an example of macroevolution is the possibility of gene flow and ambiguity. I do think that ring species are good for illustrating why categorical thinking about species is wrong. Where I'm coming from here is trying to communicate with a creationist. My concern is that the ring species example might complicate things.

I'm familiar with ring species but I don't know what you mean. How are you defining macroevolution and why are ring species a good example of this?

I'm hoping a biologist will happen upon this and be kind enough to reply. I've been trying to come up with a short summary of what I understand the distinction to be between micro and macro evolution. Is the following correct? If not, what would be correct? Thanks. Microevolution refers to evolution at the species level. Evolution as it occurs above the species level involves microevolution and speciation, which is sometimes referred to as macroevolution. Basically, the distinction comes down to evolution (so-called "microevolution") within populations that are exchanging genetic information vs. microevolution between gene pools that are separate and necessarily diverging. Thus, microevolution will not produce new species on its own (e.g., a dog will never bring forth a non-dog), but if speciation occurs microevolution may produce distinct lines of descent that can become highly divergent over time (e.g., the split at the common ancestor between hippos and cetaceans has lead to very distinct species). I would also welcome and appreciate book recommendations. Regards. P.S. If any creationists happen upon this I would be curious to hear what you understand "macroevolution" to mean. I encounter these terms in the context of creationist argumentation almost exclusively anyway.

Yes... Let the butthurt flow through you.

I speculate that's it's a rock.

What started and stopped happening in the past? Evolution? If so, what is the basis of this claim? If you invoke the shape of evolution, stasis, punctuated equilibrium, or any other such thing I will be forced to ironically remind you of your radical epistemology. But I should let you clarify and finish. So, the start and stop of evolution were both unobserved? Who didn't say it? Dawkins? I'm a bit confused. Thanks.

I've watched the video, sammy.

If (no offense) comments are allowed I've just got to say that your demonstrated level of expertise on the subject of evolutionary biology does not instill much confidence in your judgments about what is or isn't reliable science vs. propaganda. I'm sure an actual evolutionary biologist would be even more dazzled than I am. As far as I'm concerned, post on. I'm interested in your sources as well. The E. coli claims you were making before were somewhat interesting.

The video mentioned by sammy A related video for context A page of possible interest http://www.skeptics....tion-challenge/

I must introduce a distinction: 1. Evolution in the sense of common descent; 2. The mechanism of evolution, e.g., natural selection. By "macro-evolution" I'll take you to simply mean common descent - for the sake of unmuddled discussion. So, the question is, what reason is there to think that common descent is a fact? How conclusive is the evidence? Okay, so, your straw man is that immediate observation alone is what constitutes science and that anything else is mere "stories/speculations/belief systems/religions." First, you seem to be effectively admitting that religions are just stories and specious speculations. For an evidently religious person you seem to have little regard for faith. (I'm teasing btw.) Second, this is mere argument by definitions. Weak sauce. Evolutionary theory is more than mere observation of facts; it is an explanatory framework. An explanation that brings together independent lines of evidence and that makes testable predictions is a true scientific theory. What are the observations and how does evolutionary theory explain these data? The following pages contain a great deal of information along these lines. 1. Evidence of Common Descent 2. TalkOrigins Evidence Page One could literally go on all day elucidating the data behind evolution ("macroevolution" if you prefer) and the myriad of things that are explained by common descent as well as natural selection. The record of biological history that we possess is an observational fact. Life is extant and evolving and we have made mountains of observations regarding it. The successful scientific theory that explains these data is evolution. This is putting it mildly. So, do you not consider the data of DNA sequencing to be empirical? And if not evolution, what explains the many observations? Some of the innumerable things that common descent helps to explain: Why does the mammalian recurrent laryngeal nerve take such an extreme detour? Why do hoofed animals have an extra toe that doesn't even reach the ground? Why do chickens have the ability to grow alligator-like teeth? Why can humans grow tails? And snakes limbs? Why do flightless birds have wings? Why do whales have pelvic girdles? Why does the human eye have a blind spot? Why does the vas deferens take such a circuitous route? What explains what we see in the genome (e.g., endogenous retroviruses)? And of course there are innumerable features of the paleontological record that evolution (i.e., "macroevolution," common descent, and the like) explains. E.g., Horse fossil series, flatfish, cetaceans, hominini, bats, sirenia, et cetera. And more encompassing questions such as the branching of life that we see in the phylogenies yielded by various independent means. Why is this so? Et cetera. Ad nauseum... The icing on the cake? Testable predictions. I think the old "God did it; end of discussion" approach isn't so robust. What do you mean "a fish became a reptile.."? There is absolutely no reason, based on evolution, to suppose that we should ever observe a fish becoming a reptile, or any other such nonsense. When fish reproduce the offspring are more fish. Were a fish to bring forth a non-fish this would require an explanation that evolution cannot provide. Life forms descend with modification and diversify. As populations do their thing over time we end up with a branching bush of gene pools variously related by common ancestry. At no point along the way does one species suddenly "turn into" another species in some metamorphosis event that we could observe. Even the creationist's beloved Cambrian "explosion" was not something so dramatic but rather was a radiation that occurred over millions and tens of millions of years and there are fossils documenting the gradualism of this "event." And again, macroevolution is the sense of common descent is based on mountains of empirical evidence. Macroevolution as in speciation has been observed both in the lab and in the wild. See the links posted above for more information.

I. "macro-evolution = molecule to man, matter to human being , piece of bacteria to a human being." 1. Molecules to man: Again, the topic of abiogenesis is distinct from evolutionary theory. I must insist. 2. Bacteria to man: The origin of the eukaryotic cell is a fascinating discussion, as is the thread in the history of life that leads from primitive eukaryotes to Homo sapiens. Ironic that one of the few books I've read by Richard Dawkins is called The Ancestor's Tale, and I would recommend it if you hadn't just expressed your distaste for the man. 3. Macroevolution: While I don't really find myself using those terms, I think of macroevolution as having two senses (disclaimer: I'm not a scientist and have no training in this subject): a. The first sense being paleontological and referring to evolution as it occurs over large timescales. b. The second sense would be more in the context of something like population genetics; namely, evolutionary changes looked at between different populations. In both senses I simply understand macroevolution to be microevolution at a bigger scale. It is a quantitative term, not qualitative; and I don't think it's rigorously defined. It's a loose term. And in my layman's experience it is most often encountered on the lips of creationists. Hopefully if I'm wrong a biologist will notice this and correct me. II. "micro-evolution = speciation, variation within a kind, change in allele frequency over time, mutations etc etc.." 1. Speciation: If we must use the macro/micro prefixes I tend to see speciation as being on the side of macroevolution, but upon reflection I don't think this is necessarily so. I mean, a speciation event can occur on a short timescale and such events have been observed. Speciation is not the same as significant morphological change (what I suppose most creationists have in mind when they speak of "kinds" becoming other "kinds." No?) (As a non-biologist here ranting and sharing my armchair ideas about biology I feel like kind of an ass - hence the screen name, I suppose. But anyway...) 2. Variation within a kind: What is a kind? I'd rather not comment until I'm clear on what you mean. I have an idea of what Kent Hovind means by "kind," but I don't want to assume you agree. 3. Change in allele frequencies in a population over time: Yes. This is a part of microevolution as I understand it. But I think one might drop the "micro-" and simply say evolution. Changes in allele frequencies in a population as a function of differential survival and reproduction. It's kind of a dry description of evolution, but I guess it's a good one. The shorthand might be evolution by natural selection. III. "these [micro-evolution things] are standard things that we observe today and have absolutely nothing to do with the the MACRO-evolutionary theory." Based on the above I think that you basically accept biological evolution. You seem to object to the plausibility of abiogenesis (which isn't evolutionary theory), and have questions about the history of life (i.e., bacteria to man). The things that you accept as "micro-evolution" are essentially the basic ingredients of evolution. What do you think? I think what you're doing here is just evasive incredulity. I think if you apply your principles consistently you'll face a reductio ad absurdum. Rather than bicker with you I'd just presume to encourage you to think about this a little more deeply and honestly.

Okay, so you find abiogenesis (the chemical origins of life) and our common ancestry with modern bacteria to be unbelievable? I will grant that these are indeed big claims that go against common sense. I don't know very much about Richard Dawkins and don't think I have much to offer on that. I would like to point out that abiogenesis (e.g., prebiotic chemistry to metabolic networks & rudimentary biology capable of evolution) is distinct from evolutionary theory. I consider this to be an important distinction to make in a discussion of this kind. I would also mention that there is no theory of abiogenesis, only provisional hypotheses. They are very interesting and suggestive though. It kind of rubs me the wrong way how people often say "we don't know anything about the origins of life" and so on. Okay, sure, we've not explored it enough to have more than a vague idea about it, but I want to talk about how excellent and intriguing are the things that we do know. But that is a rant. Evolutionary theory, on the other hand, is a mature scientific theory that's been confirmed in many ways and that has a vast body of evidence related to it. I'm sure you can see why including abiogenesis in the definition of macroevolution is problematic to me. More later...

What is "the theory of macroevolution," exactly? Biodiversification across large time scales? Evolution on the scale of gene pools? Speciation? These are things based on strong physical evidence, observation, and fact. I genuinely do not understand what you're saying.