SkepticLance

Sayonara There is a serious lack of evidence in the suggestion that lots of people are killed by sharks. The evidence that the number is few comes from official statistics, and the fact that most people who go into the water do it in company. This makes an unwitnessed attack likely to be rare. Since most people are in the water in company, then most shark attacks should be witnessed. Simple logic.

Just another city commuter electric car noted today. http://www.stuff.co.nz/4431234a28.html This one is small - golf cart size - with the ability to fold up for easy parking. MIT hope to have the first prototype built in a year.

This simply illustrates that the only part of the christian faith that makes sense is the Golden Rule.

The US Army Field Manual specifically states that torture 'elicits unreliable information.' The simple fact is that torture does not work, and the military knows it. All the statements about it being needed to obtain information for national security etc is so much bushwa. I do not know why the US military uses torture. It is not to gain information, since they know perfectly well that any information so gathered is useless. I would suspect it is used as a punishment for prisoners who misbehave, or some such. The cynic might say it is because people who become military prison guards are sadists. It is definitely not to obtain information.

The idea of lots of people killed by sharks and the deed undetected does not make much sense to me. That requires that two things happen : 1. The attack is not witnessed 2. The body is never found. For both to happen would seem to be a rarity. A person who fell off a boat way out at sea might suffer such a fate. However, there are not many people in that position, and for those few it seems rather more likely that they simply drown. This statement is based on the fact that there are a number of cases like that every year where two or more people are drifting together at sea and one or more drowns. The survivors report drownings - not shark attacks. I have read the news items. Lethal shark attacks do happen, but they average about 4 per year world wide. There will be more, since some peoples do not report deaths to authorities. But to suggest more than, say, 10 per year would be a stretch.

To Sayonara While it is probable that a few people get killed by sharks, and their bodies never found, I think that the number would be small. I appreciate that your number 36 was just a f'rinstance, but that would be a major exaggeration. As I said earlier, people are gregarious, and most people who enter the water do so in company. It makes it more fun! I am not sure that lethal shark attacks are under-reported. Sharks are a very convenient scapegoat to blame other deaths on. I am aware of two case. One where a murder took place, and one where a person ran over the victim in a power boat by accident. In both cases the culprit tried to blame the death on a shark attack. In fact, I believe that police are actually made MORE suspicious when a death is called a shark attack. I sometimes wonder how many so called shark attacks are actually murders that the perpetrator got away with! In fact, if you look at official shark attack statistics, the great majority are non lethal. The place in the world where more shark attacks happen than anywhere else is apparently Florida. Partly this is due to the larger numbers of people in the water, but also due to the fact that Florida is a shark breeding area, and very large numbers of immature sharks (mainly lemon sharks, I think - but I am going by memory, so I could be wrong) are present. Those miniature sharks encounter humans in shallow water, and will bite if accidentally provoked. However, it is a bit like being bitten by a chihuahua. I suspect that there are a lot of shark bites that go unreported, since any really minor bite will not result in hospitalisation. The big thing that stands out to me, is the number of attacks - the vast majority - that are not followed up. In spite of the masses of blood in the water, and the reputation that sharks have for going into a feeding frenzy where blood is present, it just does not seem to happen. Perhaps human blood is not exciting.

Jerry You are asking some very difficult questions. I would have to do quite a bit of research to answer those questions for modern day cyanobacteria. Certainly, I could not for the first photosynthesizers. I doubt anyone could, since the fossil record does not include soft tissues, and anything else is speculation.

To jerry The oxygen content of the atmosphere has varied over time. The cyanobacteria seem to have taken about a billion years to create an atmosphere with large amounts of oxygen, but not what we have today. That happens in its entirety much later, with a world including green plants. Cyanobacteria are not, of course, plants. They are photosynthetic bacteria. Dates are a bit uncertain. The first organic traces come from Canadian rocks dated to 3.8 billion years ago. That is not proof of life, since the organic molecules present in those rocks might have come from a different source. Personally, I think it makes sense that this is a trace of early life. The Earth came into being about 4 to 4.5 billion years ago, and after a turbulent start (lots of collisions) was geologically reasonably stable at 4 billion years ago. Life probably began 3.5 to 4 billion years ago. The Australian stromatolite fossils are a bit controversial, and some people say they are not true fossils. However, as far as I can make out, those people are a minority. If the stromatolites are true fossils, then we have a clear indication that cyanobacteria were living 3.5 billion years ago. Iron oxides are very rich in strata formed over the next billion years or so, and this is taken as an indication that those chemicals were absorbing oxygen. This probably prevented the air having much oxygen. Younger strata are, by comparison, iron oxide deficient, suggesting that all the available iron had been oxidised. True green plants appear to have arisen about a billion years ago, or perhaps a bit earlier. The first ones would not have left fossil imprints, so the exact date is unsure.

The oldest probable fossils of cyanobacteria were stromatolites from Western Australia dated to about 3.6 billion years ago - way before the Cambrian. http://www.fossilmall.com/Science/About_Stromatolite.htm However, the geological record shows that it took about a billion years for the world to convert from an anaerobic atmosphere to a fully aerobic one. It appears that iron compounds absorbed the iron for most of that billion years. This means oxygen was a major part of the Earth's atmosphere for something close to 2 billion years. What was the evolutionary advantage? In short - zero. In fact, it was a major disaster. Most of the organisms living at the time were obligate anaerobes, which meant that oxygen was a toxic polllutant to them. The carnage must have been dreadful. However, there is always a silver lining. In time, new organisms came into being that were able to use oxygen as an energy source, by oxidising organic compounds. This released far more energy per gram of fuel than anaerobic processes, which opened the way for the evolution of high energy organisms. In time, multicellular organisms capable of vigorous movement developed, and the eventual outcome was warm blooded birds and mammals. Humans and our close relatives require a massive energy source, which is not possible without an oxygen atmosphere.

It has been said that the 20th Century was the physics century, and the 21st will be the century of biology. This is based on the practical benefits from those studies. From physics we got various forms of energy and work, electronics and computers, communications etc. Biology will give us medicines, agricultural productivity, biosynthesis of novel materials, longer life, and more human abilities. Of course, this difference is an over-simplification. Biology at higher levels is very complex. It involves increasingly the use of complex mathematics, and complex chemistry. We are moving from the world of simple description to a world of complex genetics, which is ultimately mathematical. At its simplest level, biology may still be descriptive, meaning that some memorisation is needed. However, that difference from physics and chemistry is rapidly disappearing at higher levels.

The Tesla Electric Roadster is a state of the art sports vehicle, making it expensive. It is not the first electric car by far. Smaller, cheaper, and lower performance cars have been available for a while. For example : the Reva Electric Car, made and sold in Bangalore, India, has been going for 7 years now. It is slow, short range, and small, but very cheap to run. An excellent commuter car. http://www.articles2u.com/vehicles/reva-electric-car/ As far as electric generation keeping up - well, when has it ever? The whole world has been struggling with under capacity for the past 50 years. The widespread use of electric cars will be a stimulus to new capacity. It is bloody time that the western world woke up to the need for a whole lot more large scale and non greenhouse gas polluting power plants. My bet lies with nuclear reactors. France runs over 70 such plants, selling electricity into much of the rest of Europe, and has never had a significant accident.

To Peak Oil Man No-one denies that oil will run out, and become commercially non viable. However, the timing is highly debatable. Lots of predictions have already been made, only to see the deadline pass with no crisis. Believe it or not, there is still a lot of the world yet unexplored for oil. My home is a classic example. New Zealand has an enormous continental shelf - larger than the total of all the Middle East oil countries put together. Only the tiniest fraction has been drilled, and from that tiny fraction, substantial oil and gas has been discovered. Several drills have discovered substantial oil fields which have been capped, since at the time, it was uneconomic to extract that oil. The whole of Antarctica remains unexplored, and geological surveys (without the drilling) have shown enormous potential for oil. Now, you might disapprove of such exploration, but you cannot deny the potential. There is little doubt that very big oil fields remain to be discovered. I am half way through reading the latest New Scientist. (Australian printed edition ; 1 March 2008) It has a couple of items that are of relevence. Section on electric vehicles. I quote : "The new roadster by Tesla Motors of San Carlos, California, is an all-electric sports car with a chassis based on the Lotus Elise. It boasts a 185 kilowatt engine powered by nearly 7000 finger sized lithium ion batteries packed into its trunk. This takes it from 0 to 100 kms per hour (63 mph) in about 5 seconds, and gives a top speed of 200 kms per hour. The range is a much more modest 350 kms - and then only if conservatively driven. Tesla hopes to sell 600 of the two seaters by the end of this year. Unfortunately, the performance figures are not the only spectacular numbers associated with the Roadster. It costs a cool $100,000 and the battery pack is expected to need replacing after 3 to 5 years at a cost of $20,000." This gives an idea of the technology level for electric cars. The cost will come down, and especially for lower performance runabouts. The article goes on to describe a new lithium battery technology that will extend the life of the batteries ten-fold. Thus battery life will no longer be a significant limiting factor, or battery replacement a major added cost. The other item is an article with the title "Let's Hear it for CO2." It describes several methods under development for converting CO2 to CO using concentrated sunlight. The CO can then be reacted with H2 to form hydrocarbons - synthetic fuel with no net greenhouse impact. The suggestion is that these techniques are quite suitable for very large scale synthesis of fuel. Maybe I won't have to trade in my car for a bicycle any time soon.

To MrSkeptic That's the old shepherd's sling. Once when I was stranded on an island by a storm, a bunch of us who had to fill in time made a shepherd's sling. We used a small pouch of leather, and two strings. We had a beach full of rounded pebbles to throw. Man that thing was powerful! When you hear about it, it sounds too simple. But those stones would have broken someone's skull if connected. The only real problem was accuracy. We sent those stones out with an error factor of plus or minus 30 degrees! Everyone else stood well behind the slinger. You wanna throw an egg a mere 30 ft? We could have sent an egg hundreds of metres.

klinka Am I permitted to disagree? If I take a big dose of heroine, I will be VERY happy. Is that meaningful?

To Paralith I don't want to pretend to be an expert on lions and their behaviour. I have only seen them in zoos and on TV. Sharks, on the other hand, I can speak about with the authority of first hand experience. However, a couple of thoughts. You said that :"If humans really were a prime menu option for lions, then I think my truck and many others like it or even more open than it would be highly unsafe" When the first Spanish appeared in America, riding horses, the local natives thought that the horse/man combination was a single new creature. If a creature as smart as a human can be so easily fooled, why should a lion see a human on a truck as a small animal? Your second point. I don't know any more about that incident than I told you. I could only guess why she didn't run back to the bus. Your third point is, of course, valid. However, I am talking of killing AND eating. Or killing for food. There is no doubt that lions do this. Not being an expert on African wild-life, I have to rely on what I have seen. However, what I have seen makes it look as though each land predator is able and willing to kill and eat an almost infinite range of prey animals. Reptiles, birds, mammals etc. Sharks are more restricted. Your fourth point, about acclimation changing behaviour definite does also apply to sharks. There are lots of places in the world where tourists chase the same sharks day after day all year long. Places where sharks are attracted each day by underwater tour guides handing out food. eg. Bahamas. Other places where sharks come regularly to cleaning stations, and where tourists are there each day by the dozen. eg. Red Sea. In spite of the acclimation, it does not seem to make the sharks more prone to attacking people.

To iNow Reaper/Lockheed has made no new points. We are back to the same tired old arguments, and we are not going to agree. I have pointed out at length that the irradiance measures used by the IPCC do not relate to the total changes caused by sunspot activity - ie. magnetic effects, and solar wind effects, and indirect effects due the fact that the irradiance is skewed to the ultraviolet during times of strong sunspot activity. Yet he returns to the same assumption that the total effect of changes in solar activity comes from changes in total electro-magnetic radiation - called irradiance. Why should I try to debate with him? We just go in circles.

Iceland is already trialling hydrogen fuel cells in buses. http://ec.europa.eu/research/energy/pdf/efchp_hydrogen16.pdf Electric vehicles are old technology, and will take little to introduce. Hybrids are becoming more common. I struggle to see why POM is so reluctant to accept that alternative personal motor vehicles will become part of society.

To Paralith Welcome to the discussion. Your input is welcome. In relation to land predators, I remember talking to a guy who was an African safari guide for some years. He stated unambiguously that a lion would kill and eat a person, without hesitation if given a chance. He said that his bus would often stop close to sleeping lions so that the tourists could take photos. If he opened the door, the lions would get up and start walking towards the bus. Apparently, on one occasion, a stupid tourist actually got out of the bus to take a better photo before the guide could stop her. A lion promptly took her down and killed her. The lion was in the process of dragging away the corpse, presumably to eat it, when shot. It is the lack of such behaviour I note in sharks. As I said, I have personal experience with lots of sharks. I do not know exactly how many sharks I have encountered underwater at various times, but it must be many hundreds. I counted, from memory, encounters with 18 different species. I have only twice experienced aggression. The Oceanic White Tip lowers its very long pectoral fins, and arches its back as a sign of aggression. It then swims at the target of its aggression. The two times I saw this, the shark abruptly stopped, turned very rapidly and swam off into invisibility. For most the other hundreds of sharks, I experienced the frustration of wanting to photograph them, and being totally unable to get close enough. They just would not approach close enough. My first Bull Shark encounter was actually quite humorous. This shark (known as the Zambesi Shark in Africa) is considered by many to be the most dangerous of the 'man eaters'. I encountered one in Fiji. I was snorkelling along a channel in the reef, and saw this large shape beneath me, at least my size (I am six foot tall). It was ascending, and our two paths, if continued, would have ensured coincidence in space-time! I was more than a wee bit nervous. I remembered in the old Hans Hass books, the author said you could scare sharks away with an underwater shout. So I took my snorkel out of my mouth and screamed - not too difficult under the circumstances. The shark had clearly not read the same books! It did not even flinch, but slowly started to rotate. I saw a big eye moving up the side of the rotating head, till it encountered my gaze. After a moment that took a million years, it shot off at enormous acceleration and disappeared. It also left a cloud of white stuff in the water. So scared that it s^@t itself! To Sayonara I have to say I agree with CDarwin. Most people do not enter the water alone, whether swimming or snorkelling, surfing or scuba diving. People like company, and do these things in company. If, occasionally, a solo person gets killed and eaten, then we would expect much larger numbers of people with company to get killed and eaten, and that does not happen.

Reaper Please tone down your language. I have no interest in debating with people who cannot moderate their emotional outbursts.

To POM I live in a small seaside community, with only one shop, no supermarkets etc. It is a 30 minute drive to the nearest town. Do you have a non car system for me?

iNow Why do you have to take it personally? My post was not aimed at you.

I know some people disagree with me, but in my own very humble opinion, understanding causes and mechanisms, while important, is secondary in science. Science first must start with obtaining clear cut and reliable data. That data often points to phenomena that are not understood. The lack of understanding of the phenomena do not in any way make those phenomena go away. Science works towards understanding the causes and mechanisms behind those phenomena. However, it is still scientific to work with phenomena that remain unexplained. A good example is quantum randomness. No-one REALLY understands quantum actions, though they can be described mathematically. Science can work with them, though, and make predictions based on what we know of them, and even design new gadgets of great value based on the quantum effects we do not truly understand. Alpha decay is the result of a quantum effect - the uncertainty of position. This means that a change in position due to a low probability action can lead to a nucleus decaying. This effect is essentially random. Thus, to the best of our knowledge, having no specific cause for that particular nucleus decaying.

I have a firm proposition to put. Human beings NEVER commit murder. My evidence is that I know a couple of hundred people quite well, and none of them have ever murdered anyone. Anyone see the flaw in that logic? Pit bulls are gentle and friendly, and are not dangerous. My evidence is that I know a few pit bulls and they are all friendly and tame. Anyone see the flaw in that logic?

Mr Skeptic Fear not. There are lots of scientists looking for an underlying reality which will bring quantum physics into the everyday world of cause and effect. It just does not look much like they are succeeding.

Here is what wikipedia says. http://en.wikipedia.org/wiki/Pit_bull "[edit] Pit Bulls and dog bite related human fatalities A study published in the Journal of the American Veterinary Medicine Association in September, 2000 reports that in the 20 years studied (1979 to 1998) "Pit-bull type dogs" and Rottweilers were involved in one half of approximately 300 dog bite related fatalities in the US[3]. Another study of American and Canadian dog bite-related fatalities from September 1982 to November 2006 by Merritt Clifton titled Dog attack deaths and maimings, U.S. & Canada, reported much higher numbers of human deaths and maulings by Pit Bulls (1,110). That report cited that Pit Bulls were responsible for 65% of fatal dog attacks. [4] This study also noted: "Of the breeds most often involved in incidents of sufficient severity to be listed, Pit Bull terriers are noteworthy for attacking adults almost as frequently as they attacked children."" I don't care too much about the politics of this issue. As has been regularly pointed out, lots of things kill more people than pit bulls. For this reason, I really do not care whether they get banned or not. However, I get annoyed at verbal crap. People who try to bend or ignore statistics because they don't like the data, really bug me. I feel the evangelical need to force them into recognising that good data is good data. If you don't like it, you still gotta swallow it. So the term 'pit bull' referes to a TYPE of dog rather than a specific BREED??? So what? That TYPE kills more people than any other. Pit bulls, whether type or breed, kill more people than any other breed, in lots of countries, including here in NZ. The exception is Britain, where they were banned in the 1990's.