SkepticLance

To swansont I read an article in New Scientist that claimed that the dinosaur killer 60 million years ago would have flicked lots of debris into space, so it is still possible. If the bacteria express happens to be fine dust, rather than large rocks, then there is the added factor of the solar wind that will drive the dust outwards, permitting some to reach Mars. I doubt that the sun's gravity would help much in getting Mars debris to Earth. Anything in Mars orbit has to be decelerated to fall towards the sun, and that requires energy input. Some rocks DID reach the Earth, as I said before, but that would have been against the odds.

OK. My apologies to all sociologists who might have been offended by the comparison. I have changed the reference to post modernists, and I have no problem with insulting them. However, I repeat that denial of data is NOT the act of a good scientist.

One of the really bad flaws in the creationist argument is based on their idea of a perfect creator. Evolution is imperfect by its very nature - too many random variables. The results of evolution are very often seriously imperfect. If life had been created in finished form by a perfect creator, that life would, ipso facto, be perfect. Why would a perfect creator indulge in crappy workmanship? Some of the imperfections I see as a result of evolution's stuff ups are ; The human appendix The fact that our breathing tube (trachea) and our swallowing tube (esophagus) open in our throats side by side, resulting in thousands of choking deaths each year. Menstrual pains. Inability to make Vitamin C inside the human body in spite of most of the required genetic mechanism being present. Any comments, or other examples ?

There are two isotopes (well, actually 3, but 234 is rare). The Uranium 235 isotope is what is used in nuclear reactors and bombs. There is about 50 million tonnes of Uranium 235 dissolved in the oceans of planet Earth. The Japanese Atomic Energy Research Instititute has worked out a method of extracting Uranium from solution in the sea, and claim that the final cost will be about 5 times that of currently mined Uranium. The cost of Uranium in a nuclear power station is only 5% to 10% of the cost of the electricity produced. This means the Uranium from sea water will raise the cost of electricity by only 25% to 50%. The amount in sea water is sufficient to provide humankind with energy for thousands of years.

iNow You are being unreasonable. John has said that a dog that does not exist cannot kill people. I find that logic unassailable. The UK had a 'problem' with pit bulls of sufficient intensity to induce politicians to ban them. That is simple truth. The fact that the actual numbers on deaths before and after the ban are not readily available does not change this. Nor does it change the obvious conclusion that a pit bull that does not exist cannot kill someone. We can conclude with 100% certainty that an effective ban on pit bulls will reduce or stop most human deaths due to pit bull attacks. A ban that was 100% effective would stop 100% of those attacks. I have watched a similar debate in the newspapers here in NZ. Because we have a small population, we have not had a lot of deaths from dog attack, but from the very few, it is clear that pit bulls are disproportionately represented. As far as I know, no-one has collated the figures, so don't ask me for them. However, the 'problem' has got bad enough for it to be debated in parliament. I also know that something similar applies in Australia, since I have read of that debate in Australian newspapers when I was in Australia. I suspect you probably have also. So I have a clear indication that a 'pit bull problem' exists in the USA with 66 deaths in 20 years, a big enough problem DID exist in the UK to induce a ban, and enough serious attacks by pit bulls happen in NZ and Australia to induce a debate on desirable action. You are in denial. The data is incomplete, but is sufficient to show that pit bulls as a type, are more savagely aggressive than any other type of dog. If you refuse to accept this simple point, you are behaving like a post modernist rather than a scientist, and denying data. We are not talking about minor attacks. The most aggressive dog in numbers of attacks is probably the chihuahua. However, its bite is insufficient to even break skin most of the time. We are talking about serious attacks, with humans maimed or killed. And in this, the pit bull is king. Here is a nice Australian reference. http://www.edba.org.au/courier.html I quote : "You can have savage Labradors and savage Chihuahuas, but none of them has the potential to maim & kill that a pit bull does. 42% of all dog related deaths in the US are from Pit Bulls - & they constitute 1% of all dogs. 70% of those deaths were children."

If we were dealing with purely written or spoken language, foofighter would be correct. There is no way to decipher these without external clues. However, it is very likely that the signals would be the equivalent of television - carrying pictures. We could at least see the pictures. If the alien group was deliberately sending messages to unknown species, they would use a pictorial method which could be deciphered. Anyway, we are at a stage well before the need for any deciphering. We are just trying to see if any signals exist. SETI has run a rough study of most of the galaxy and a more detailed study of some thousands of stars, and not seen any sign of a signal yet. There are lots of ways we can interpret this finding. In my very humble opinion, this result combined with the Fermi Paradox indicates that the simplest explanation is that intelligent, advanced alien species are very, very rare.

To Jeff As I recall it, the results were considered to be explainable more reasonably by a purely chemical reaction, which would, of course, be much faster than simple microbial activity. There is a lot of radiant energy hitting the Martian surface, which could result in unstable and reactive chemicals forming there, ready to react with our culture media. However, even if the results are due to very quickly responsive bacteria, they may still be of Earth origin. If Earth bacteria reached Mars, it may have happened a hell of a long time ago, leaving plenty of time to evolve into substantially different forms. Adaptation to the nutrient deficient Mars environment may have resulted in bugs that respond really quickly to new opportunities.

You should also be careful about the causes of disease. There are, in fact, four main categories of disease causes, plus a few minor causes. Infectious, geriatric, nutritional, genetic. To suggest one cause for too many diseases, unless it is one of the big four just listed is to stick your head on the chopping block, metaphorically. Inflammation is both a good thing and a bad thing. It is part of the immune response and is essential to fighting infection. When it happens in the wrong circumstances, as with auto-immune illness, it may be bad. It is also implicated in cardio-vacular disease along with atherosclerosis. However, it is certainly not a major cause of a wide range of ills. It is a natural part of the body's functioning, and is mostly an action that improves health long run.

To Jeff Mars may not be a good example. There is now plenty of evidence that certain bacterial spores are tough enough to survive months in space, and even to survive serious impacts. Thus, Earth bacteria might travel inside rocks to Mars and colonise. There is no need for life to actually arise on Mars. It might have got there from Earth. We know that some asteroid impacts on Earth, like the dinosaur killer, can kick Earth rocks into space, and beyond. If one had bacterial spores inside it, and the rock made its way to Mars, it might introduce Earth life to Mars. Since we have rocks picked up in Antarctica which are identified as having come from Mars, the reverse seems very likely. I predict, that if we find life on Mars, a nucleic acid sequencing analysis will show it is related to Earth bacteria.

My own feeling is that the reason tobacco is so bad is simply dose. When the cigarette smoker sucks on the fag, it sends a massive amount of smoke, all concentrated into the smoker's lungs. A cooking fire sends most of its smoke into the atmosphere rather than into lungs, so causes less harm. Do you think this sounds about right? Marijuana is usually smoked with fewer joints than tobacco cigarettes. A nicotine addict will inhale the smoke from 20 to 40 fags a day, which the number of joints smoked is way less. Thus less cancer from joints. It is not that joints are safer - just fewer smoked.

To agentchange I have not personally described arachidonic acid as essential. Others may have, but I have seen no such data. I think this theory is a bit like vitalism - the theory that says life has a special vital life energy (sometimes called chi) which keeps creatures alive and healthy. When mooted, the theory seemed OK. However, today, after 100 years of proper scientific study, there is still no sign of that energy. The theory has been dumped in light of lack of evidence and lack of need for the theory. I suspect your inflammatory factors is in the same situation. It is someone's pet theory, but is simply not needed. Everything it seeks to explain has already been explained using more conventional medical science.

Agentchange The alkaline diet is a good example of faulty logic. A lot of the foods that are listed are simply fruits and vegetables. We all know that the recommendation for good health is five or more servings of fruit and vege each day. It appears that some food faddists mistook this for alkaline diets. There are also those who exploit this kind of fad to make money. For example : selling 'black box' gadgets that are supposed to make drinking water alkaline. Needless to say, these gadgets have no therapeutic value whatever, except to the wallet of the vendor. In fact, a number of fruits are acidic and contribute to lowering pH in the gut. However, the human body has a natural pH buffering system for the blood. Eating 'acidic' foods does not make one acidic. Nor does eating alkaline foods raise pH inside our bodies, except in the gut, where it is probably undesirable anyway, since the first part of the gut is supposed to be acidic. Not that the effect is sufficient to be of consequence.

We all know that smoking tobacco has serious health hazards, including increased risk of lung cancer, strokes, and heart attack. People are not quite so aware that other forms of smoke also carry health risks. For example : incense http://news.bbc.co.uk/2/hi/health/1467409.stm "Burning incense, popular in places of worship and in people's homes, could be a cancer risk. Researchers in Taiwan found that the smoke produced by burning incense is laden with cancer-causing chemicals." Example two : cancer of the stomach and smoked meat http://www.purlife.com/Stomach.htm "The people in Iceland eat a lot of smoked fish and smoked meat. Investigating 1,600 deaths caused by stomach cancer, the highest incidence correlated with the consumption of smoked meat. The carcinogen in smoked meat is called 3-4 benzopyrine. The amount of this carcinogen in 1 lb of smoked mutton equals that in 250 cigarettes." Example three : marijuana http://www.coolnurse.com/marijuana.htm "One thing to keep in mind, is that marijuana smokers tend to inhale more deeply and keep the smoke in their lungs for a longer period of time than tobacco smokers do. And if you smoke both -- obviously, more chemicals are being inhaled. Burning marijuana when smoking releases many other substances than THC. THC does not appear to be carcinogenic (cancer-causing), but some of the other chemicals released by smoking are poisonous. These include tar, carbon monoxide, and cyanide. One known carcinogen, benzopyrene, found in both types of smoke, seems to be greater in marijuana smoke. Another problem with marijuana is that it is almost always smoked without a filter. Using one would cut down on the amount of these chemicals. Consuming pot through a water pipe -- or bong -- would eliminate some of the byproducts of smoking. Currently, it does appear that pot smokers may run an increased risk of cancer, as well as other health problems listed above. " Example four : Eye and lung disease in third world countries from indoor cooking fires. http://burningissues.org/pdfs/cr-2003-10-smoketestresults.pdf "Pollutants found in smoke from indoor cooking fires are a major contributing factor to eye and lung diseases in developing countries, causing an estimated 2 million deaths every year." Would I be correct to generalise that tobacco smoke is only one case in a wider general health hazard - smoke from all sources - and that, when it enters lungs or the digestive tract, the degree of harm is probably more a question of dose than which type of smoke?

The formulation of a new theory should roughly follow as below. New data Formulation of hypothesis Testable prediction from hypothesis Novel experiment or observation to check prediction Further predictive testing Hypothesis passes tests and becomes a theory.

Humans evolved as omnivores. That means our bodies adapted to a wide range of foods. We developed the ability to thrive on a wide range. Only foods that are very different to that which we evolved to exploit are likely to harm us in any significant way. Thus, saturated fat can be harmful in large amounts, because the wild game our ancestors killed and ate had very low fat levels. Only domesticated animals are highly fatty, and humans are not adapted to a high saturated fat intake (with the possible exception of Inuits). Sucrose can be harmful in quantity, as our ancestors ate very little of it, and have no adaptation to large amounts. Salt in anything other than small amounts is very harmful to many people of African descent, since their ancestors lived far from the sea or other salt sources, and evolved a gene that prevents salt excretion. Cows milk is OK for most people of European descent, since it has been consumed by them for many thousands of years, and they have a gene to permit lactose utilisation. Some natural foods are toxic, such as nightshade berries which contain an alkaloid that is very poisonous to mammals, but not birds. However, foods such as chicken (or bird meat in general) are fine, since our ancestors ate it a lot and adapted to it. Most food faddists with their ideas of what things cause harm even in small quantities are simply wrong, since the human body is adapted to such a wide range of foods.

SH3RLOCK If we are talking about a few alien species, it is possible that the resources would be enough to keep them from expanding. However, if there are many such species in our galaxy, then at least one will have a rapidly expanding population that will force them to expand throughout the galaxy. This is where a heap of the explanations for why we have not seen any trace of ET fall down. Each explanation may suit for one species, but not for the wide range if alien species are common.

To CDarwin I understand what you are saying. However, it is new data that shows the need for a new theory. You are suggesting that human nature, being imperfect, means that scientists will not dump an old theory just on the basis of new data. There will be truth in this, sadly. However, that reflects the flaws in human decision making, rather than a part of good science.

Agentchange You need to be very careful of diet fad information. I have just left a discussion with a food faddist on another forum who believes that only alkaline food is healthy. Making all citrus fruit unhealthy. Yeah, riiight! Chicken really has only two health problems. 1. Fat levels. Removing skin makes it low fat and a good healthy food. 2. Micro-organisms contamination, and especially Campylobacter. This means that it MUST be cooked well. When preparing chicken, remove the skin and cook it thoroughly, and then just go ahead and enjoy eating the chicken, with no further health fears. I have had an interest in food and health for a long time. I have been inundated with all kinds of weird food fad beliefs, and the internet is loaded with them. When proper science is applied, pretty much all of them disappear.

To psynapse Exactly the same thing happens in the human body, where most of the cells, including the brain, are simply support structures for the gonads, to allow those specific cells to pass on their genes. Which makes no difference since all the cells share exactly the same genes. Which is what happens with slime moulds. The same genes are passed. To Mr. Skeptic Allow me to challenge one of your earlier statements, that a theory can only be destroyed by another theory. Not so. Theories are not wrecked by new theories. They are wrecked by new data. In science, data is king. If you want to test, and maybe destroy, an old theory, you make a prediction and then test the prediction. The results (new data) may support or oppose the old theory. If the old theory is destroyed, it may be replaced by a new theory, but not necessarily. To vexer. I think your point has been addressed very thoroughly. Evolution by natural selection has been attacked many times scientifically, and continues to be so. The fact that it continues is strong evidence that it is the best model of reality in this sphere. Today there are several creationist organisations who hire Ph. D. biologists to do work to try to destroy the principle of evolution. To date, they have consistently failed.

The fear here comes from the lack of empirical experience. In theory, a mini black hole will evaporate almost instantly and be seen no more. However, that is theory. Since no-one has actually made and studied a mini black hole, there will be a little bit of doubt. Maybe the theory is wrong and it will sit in the centre of the Earth and grow ....... And then there's that strangelet......

John Cuthber was right in saying this thread is going nowhere. Nor is an interminably long thread like this one of any likely educational value to others, assuming anyone else has the patience to keep reading. We are not going to agree. I suggest we close.

To thedarkshade As D H pointed out, the obvious shelter is space itself. Why become bound to a gravity hole? Living in space cities leaves civilisation mobile, and there are heaps of resources to tap - asteroids, mooms, Saturn's rings, - even the Oort Cloud.

To noz. Inside a galaxy, distance is not a problem. It is just a matter of time. Lots of people, including me, have calculated how long galactic colonisation would take. All agree it would be less than 10 million years. A space vessel able to travel at 0.1 c is theoretically very possible. That is quite sufficient to colonise the entire damn Milky Way inside 10 million years. My own view is that the future will include planet bound people, and people living in space habitats or cities. The latter will be those who colonise the galaxy. Easy to move a space habitat since there is no need to fight a gravity well from a planet. Such people will be genetically altered to be immune to high radiation and to harm from zero gravity. They may well live very long lives so that a journey of 50 to 100 years holds no fears. An alien species that reached that stage more than 10 million years ago would already have occupied the entire galaxy. Their space cities would be very visible, and probably radiate on all sorts of frequencies. Where are they?

I did a google under 'cern+strangelet' and got 34,000 hits. Plenty of data out there. For example ; http://www.theregister.co.uk/2008/03/28/lhc_cern_hawaiian_botanist_lawsuit/ I quote : "A lawsuit has been filed in Hawaii in an attempt to hold up the start of operations by the Large Hadron Collider (LHC) atom-smasher on the French-Swiss border. A colourful American botanist, teacher, former biologist and sometime physicist says (in outline) that the LHC may rip a hole in the fabric of the space-time continuum and so destroy the Earth. He wants the US government to act now and delay the LHC's startup while a new safety review is carried out. Walter L Wagner and his fellow Hawaiian Luis Sancho, according to a report on MSNBC, filed suit in the Hawaii federal court last Friday. The men are worried about one of several planet-busting physicists' nightmares being unleashed in the LHC's bowels deep beneath the Franco-Swiss countryside." While this all seems very light hearted, and the result of a couple of pseudo-scientific idiots, we should remember that the reassurances stem from theory, not empirical data. Who knows ......

To iNow I don't think I have said I have no position. My position is that 66 people in 20 years is too many. People are important, and human lives, even a small number, are important. Compared to most other causes of human death, this is trivial - but trivial is a relative term. 66 deaths is still too many. I would rather, of course, the government put effort into stopping smoking than an equivalent amount of effort into stopping pit bulls, since that would save more lives. However, an effort that saves a few is still better than no effort. However, as I said, the real reason I continue to argue is simly a distaste for silly 'logic', and there has been a hell of a lot of it from the pro-pit bull camp. For example : the argument that the numbers are wrong due to breed misidentification. As I said before, this may change the figures a bit, but not change the overall picture. If the number of pit bull generated deaths is plus or minus 15 (an extreme case) due to some breed misidentification, that means 51 to 81 human deaths over 20 years. Pit bulls are still the worst, and I get a bit annoyed with those who try to deny the numbers to make their case. Denial of data is most unscientific. I do not have a problem with other people having their own subjective opinion. Just a problem with them arguing in an irrational and non scientific way on the science forum. We should be better than that.