Ophiolite

Newton didn't believe these things, he accepted them because that is where observation, experiment and logic directed him. Provisional acceptance is the correct stance for a scientist to take. If the scientist starts believing things they have, temporarily at least, abandoned the scientific method.

Close to two hundred individual stones, derived from perhaps eighty meteors, are known to have come from the moon. Nevertheless a new lunar find would be exciting. The photographs are very blurry, so any serious identification is not possible. Nevertheless I doubted ACG52's suggestion that they were a conventional igneous rock. Those would be unlikely to weather in the way this specimen did. Some form of nodule as suggest by tamu (Texas A&M?) does seem most likely. It certainly looks nothing like a lunar rock.

I believe that is true.

In science there should be no beliefs. There are hypotheses that are confirmed, modified or rejected on the basis of verifiable observations and experiments. A scientist is obligated to provisionally accept such a hypothesis until evidence justifies its rejection. One is not entitled to any beliefs in the matter.

OK, you've heard of thermodynamics, but you don't understand it. Fair enough.

Your questions seems based on the understanding that early biochemistry was based on RNA, not DNA. You seem to be thinking in terms of what is called The RNA World. I don't subscribe to the notion that this existed, therefore my suspicion is that RNA did not self replicate. I appreciate that that is not very helpful for you. It is also a minority view, so perhaps a believer will provide the specific interpretation you are looking for.

So you are asking us to accept an assertion based on nothing better than anecdotes. That is hardly very convincing and certainly not scientific.

I echo EdEarl's observation. The picture you painted of our understanding of abiogenesis is a fairly accurate version of what is often publicly presented. The truth is we have many ingenious ideas as to the steps involved, but little or no confirmation of any of them. There is a strong tendency to gloss over weaknesses in hypotheses, or to treat provisional assumptions as if they were established fact. Let me illustrate these problems with an example. You are probably familiar with the experiments conducted by Stanley Milller under the direction of Harold Urey. Amino acids were produced when electric sparks were generated in a reducing atmosphere of ammonie, methane, water vapour, etc. This experiment was important, in my view, not for the results, but for the demonstration that perhaps the origin of life could be investigated experimentally. It has been repeated many times with many variations in the experiemental set up and the atmospheric composition. What is rarely mentioned and almost never emphasised is that most of these tests produce either nothing, or incredibly low yields and that they are remarkably sensitive to the physical structure of the apparatus. We still debate the nature of the primeval atmosphere and cannot even agree on whether or not it was reducing. Even those versions of the experiment generating amino acids do not produce ones that are handed, as is the case with all biological amino acids. Nor are the amino acids produced a decent reflection of the twenty or so found in terrestrial life. This level of ignorance may sound depressing, but it should be embraced as a magnificent field in which to investigate. Which is more exciting? Editing the works of a literary genius for small grammatical errors, or being a literary genius? I know where my money is placed.

Popcorn Sutton, it seems reasonable to suppose that you have an interest in science, since you post on a science forum and take a significant amount of time out of your day to construct and make posts on this forum. That interest in science should, you would think, unite all members here. It should give us a common ground to work on. So, I have some related questions: Do you understand the scientific method? Do you understand that that method does not require, or tolerate idle, unsubstantiated speculation that ignores current observations and explanations.? Do you understand that what you are posting here is not science in any shape, or form, or universe? If your interest in science is genuine, why do you post this - forgive my bluntness - drivel? Why do you not, instead, make a real effort to learn? Why do you not ask questions of knowledgeable members to broaden your knowledge? It seems to me that if you choose not to do so, but continue with these frivolous excursions of the imagination, then you are wasting your time and everyone elses time who chances across your posts.

Have you heard of thermodynamics?

All the gold ever mined in human history (and pre-history) would, it is estimated, occupy a cube 20.7 m on a side. A single mansion has more volume than this.

And every year we identify many new comets that have never been seen before and are never seen again. The problem is not the comets we know about, it is the comets we don't know about. The point is that the tail does not appear until the comet is relatively close to the sun. It is coming in from the Oort cloud, where its temperature is close to absolute zero. Have you considered what the temperature is out at, say, the orbit of Jupiter? So, by the time we can identify the comet it is already well into the inner reaches of the solar system and accelerating. How are you going to get a suitable missile into space, supplied with sufficient fuel, which you also have to get into space, and directed towards where the comet will be, and supplied with even more fuel to allow you make the necessary change of velocity to change orbit and accelerate so that it reaches its target soon enough to make a difference? Where is the technology coming from to produce such a missile. Check out how long it took us to get the Messenger probe into orbit around Mercury. It could have been done a lost faster, but only at the cost of massive fuel requirements. (And all the time I am saying fuel, you need to think fuel and oxidiser.) You need a rocket that will deploy the warhead. You need rockets that will serves to carry fuel into orbit. You need a system for transfering that fuel in orbit. That's not going to be robotic, so you need humans. Where is NASA's manned delivery system? And you have to do this not once, but many times. Seriously, calculate what mass of payload you have to deliver to the comet. Decide where it is going to be when we intercept it. Figure out how much fuel you need to attain the appropriate delta V to get there. (I really hope you are not one of those people who think it is easy to 'fall towards the sun'.) Now show me that you have rocket that we can place in space, with operable engines and a fuel tank capacity that will let us achieve the goal. DH knows way more about this than I, but I am pretty damn sure that we have nothing that would allow us to do this today, or on the horizon that could be reached in the time frame we would have. Feel free to prove me wrong with the math. Please calculate the mass of a typical comet and review whether you want to retain that opinion. This is a seriously flawed observation. The asteroids we are concerned with, those which are at some risk of impacting the Earth, are measured in tens, or at most, hundreds of metres. Comets are measured in kilomteres. You have created a false dichotomy: you suggest either the astronomers are telling the truth and there is a risk, or they are lying. You have not considered the possibility that you misunderstood their comments and explanations.

You stated that "The subject was fairly common in Darwin's time, and theorists from Lamarck to Darwin's uncle would have been known to him." Darwin's uncle was not a theorist in this field. Do you accept that?

Two points. 1. When one asks for a citation on a science forum one generally refers to a peer reviewed research paper, not a popular science treatment, even if it is from a paper as reputable as the Observer. Please provide such a citation from the 'many' you have available. 2. The link provides absolutely nothing to support your argument. Here, specifically, is what they say would happen during the reduction in magnetic field we could expect during a pole reversal. "The effects could be catastrophic. Powerful radiation bursts, which normally never touch the atmosphere, would heat up its upper layers, triggering climatic disruption. Navigation and communication satellites, Earth's eyes and ears, would be destroyed and migrating animals left unable to navigate." Did you get that? Climate disruption, satellites destroyed and migratory animals unable to navigate. Absolutely nothing about radiation damage to the biosphere. Let me adapt Captain Panic's question. Wouldn't it be easier to accept you are mistaken?

I've already provided an answer to that in post #5. "My understanding is that Darwin was impressed by the logical structure and flow of Paley's argument in the work Natural Theology. He mirrored this structure when he came to right On the Origin of Species." I'm British. We use understatement. When I say "my understanding is" I actually mean "this is pretty much as definitive as anything gets, and in this particular topic area I know my facts very thoroughly, but I'm too damned modest to assert it so definitely." Was that an acknowledgement that you were mistaken?

I have read his writings. I have followed his arguments. I have much more than a clue to their contents. And I stand by my observation that his approach is extremist and thus, in a scientific context, seriously unhelpful. I am not interested in the ramblings and ravings of anyone who has reached an uninformed opinion about him. Mine is informed and it stands.

Split Infinity, provide citations please to justify your unwarranted claim that the absence of a magnetic field would be disastrous for Earth life. Repeating popular mythology on this point is not convincing. Moontanman's points are, in my understanding valid. To change that understanding you need to come up with facts. Moontanman, I have seen estimates that an Earth type atmosphere would be eroded in around 50,000 years, rather than the possible millions you proposed. I cannot currently find a copy of the research paper I read that in. However, we might reasonably anticipate that the technological advances possible in, say, 10,000 years would provide us with a solution. (A neat trick would be to direct the comets to hit from a specific angle to reduce the rotational speed of the planet. I haven't done the calculations, but it might be possible to slow it down so the Martian day matched the Earth's precisely, rather than being half an hour longer. )

And you might want to check into DH's background. Here are some other points: 1. No one is denying that we are investigating ways of deflecting bolides. We are simply saying those technologies are all speculative at present and could not be implemented in the available time frame. 2. You blithely continue to ignore the difficulty of detecting comets until they are quite close in to the sun. While larger comets are easier to detect they are also much more difficult to deflect. 3. In terms of trajectory calculation you have completely ignored the fact that as a consequence of assymetric degassing comet's orbits change unpredicatably. (Now one day we may land robot craft on comets to induce selective degassing to effect the change in trajectory - but not today, and not in eighteen months. 4. You still seem to have zero grasp of the importance of delta-V in this problem. We would find it practically impossible to get 'a device' to the comet in the time frame required. Do the maths. Your ideas on this are ill informed. If you continue to ignore the detailed explanations other posters are giving you then your ideas become silly.

My understanding is that Darwin was impressed by the logical structure and flow of Paley's argument in the work Natural Theology. He mirrored this structure when he came to right On the Origin of Species. Darwin's uncle! If you mean Erasmus Darwin, that was his grandfather. The only uncle I know of who played a significant role in regard to Darwin and evolutionary theory was Josiah Wedgewood. He helped persuade Darwin's father to allow him to travel on The Beagle, but contributed nothing in terms of ideas to Darwin's research.

Your optimism is misplaced. NASA completely lacks the technology to do anything about such a comet were it on a collision course with the Earth. We are decades away from having such technology.

Effeminate implies an over-empahsis of female characteristics. Macho implies the same for male characteristics. I find weak handshakes as laughable as power grips.

I'm not sure what your point is here, The analagous terms leaps instantly to mind, requiring no more time than to respond to "what do you call the green stuff on a lawn". Obviously the word is macho. It may or may not be telling that you were unable to recognise that.

Comets have struck Earth in the past. This was, in the early days, beneficial, since they provided a proportion of our water and perhaps a lot of out prebiotic chemistry. Later impacts were less convenient. A cometary strike today would be a disaster for civilisation and humanity. However, with a tiny smidgeon of luck we shall have the technology to detect and deflect such threats in the near future. Therefore, Seven Seas, can you not find a more conviincing topic with which to troll the forum? This amateurish effort isn't even amusing.

What evidence do you have that the universe is all that exists? In the absence of such evidence - which many of us would be fascinated to see - then there is no automatic reason to prohibit the creation ex nihilo of the universe we inhabit. Secondly, what evidence do you have that the laws of thermodyanimcs must apply to all universes at all times? Again, I would be enchanted to see the evidence you have for that. You applaud the hypothetical four year old boy for working out that Santa Claus is a fiction. Don't you think it is time you abandoned the simplistic notion that all possible universes must follow the same rules, or do you wish to remain a child forever?

Thank you for your measured response. Please keep in mind that on an internet forum we have only the raw words to deal with. Intonation, pace, volume, emphasis are all absent. Body language is totally invisible. Almost any conversation has some degree of sub-text in it. Ignoring this sub-text can lead to one quite missing the point. Trying to interpret it can lead, as it did in this instance for me, to a gross misinterpretation. You asked me why would I think you had made a personal attack when you opened with the phrase "Thank you for your thoughts". Well, I can produce - and suspect you have seen - many examples of where a formal politeness is used to sarcastically attack. Without the voice and the body language distinguishing the two becomes difficult. I would likely have taken the thank you as genuine were it not for your following sentence: "I take it that you have read the whole thread (it is not very long) and can therefore find answers to the above in my previous responses." I'll translate that into what I understood you may have intended: "Well, if you've bothered to read the thread, which you shouldn't find all that difficult because it is short, then you wouldn't need to ask the damn question. I mean my intention is clear. You can see where I am going with it. Read the bloody thing and don't expect me to do all the work." So, I can be personally critical when a person's post is ambiguous and the balance of interpretation is negative. However, in this instance I was not personally critical - I criticised what I thought you may have said and meant - I did not criticise you. i notice at this point I have acquired two Likes for the post. I'm not sure what in particular those were for, but it suggests that my proposed interpretation resonated with at least two members sufficiently to cause them to press the green button. Now, just so we are clear - I'm pleased to hear that I misinterpreted your intent. I believe that means we can now move on, or rather back to topic. In that regard I think what could undermine your efforts here is the presumption that there is a single definition of evolution. Certainly the evolution I think of when wearing a miniature botantist's hat is quite different from the one I wore as a student palaeontologist. Would you accept that it is entirely possible to use differing definitions of evolution without this creating any logical errors?