SkepticLance

In lots of ways, all this discussion, and discussion by those who actually have political power, is lacking potence. As the science of genetic modification grows, it is inevitable that someone, somewhere, will produce a genetically modified human. Just as a first human clone is inevitable. Once the technology develops sufficiently, a demand for these services will grow, and a new industry develop. What parent would not like his/her child to be of high IQ, athletic, good looking etc. All this will eventually be possible, and will be achieved and paid for. I do not really see any problem with this. The world of the future will be populated by smart, good looking, healthy and athletic people. Hey, what's the problem? No doubt, this new industry will be regulated, and we will have laws preventing someone being modified to, for example, have an elephant's trunk growing out of his/her neck (shades of Monty Python). However, we can guarantee it will happen. I believe that the net result will be good.

If we are to have extended duration of humans in space, they will be exposed to terrible radiation. A 6 month trip to Mars will seriously increase long term risk of cancer. However, there are plenty of organisms able to withstand much more radiation than humans. In theory, we can make a few small genetic modifications, and create humans able to live under this radiation indefinitely.

KNO3 when heated releases oxygen and becomes KNO2. It is the oxygen that causes rapid combustion of the sugar. This works for a range of other combustible materials. Mix KNO3 in, and they burn much more quickly, even explosively. This is the basis of old fashioned gunpowder. I believe that originally KNO3 was extracted from under manure piles. Not a pleasant task!

Just a note to Sunspot. the idea of fingernails growing long after death is an urban myth. Mistake because skin draws back from fingertips giving the illusion of growing nails.

There is an excellent article on synthetic biology in the latest New Scientist (20 May 2006). It is a kind of engineering. You make things, but made up of biological bits and pieces, such as lengths of DNA. The researchers are building up 'tool kits' made up of special sequences of proteins / nucleic acids etc. It is different to genetic engineering in that it starts from scratch, instead of 'stealing' genes from living organisms. Like engineering, start with simple things, and build up slowly to the complex. So far, there is only a bunch of biological tools. However, they aim to create complex items, such as the equivalent of synthetic bacteria.

"Exactly. If you exploded one piece of Uranium onto the other using military grade explosive, the uranium would indeed go supercritical for under a microsecond, cause the uranium to deform into a sausage shape because the engineering has small defects you were not aware of, and the nuclear reaction would stop." Actually my recipe for a bomb will work. This is not a secret. It was published in Scientific American. The big problem is getting hold of 40% U235, which is almost impossible unless you have enormous resources. The WWII bombs used against Japan were enormous because of the lack of purity in the Uranium. 50kg U235 + 50 kg U235 = Big Bang! However, the big bang will still be a lot less than, say, Hiroshima, since this is a pretty unsophisticated bomb. It would still take out a number of city blocks.

Hey, think you can teach us an atomic bomb next? Really easy if you have the ingredients. The most important are : 1. Two 50 kg blocks of 40% Uranium 235 2. Someone happy to commit suicide. Put a square cross section tube on top of your car. Fix one U235 block at the front. Insert the second at the rear, but well oiled so it can slide. Get your suicide to ram the car at speed into your target. The sudden stop will drive the rear block into the front one. Thats all folks!

Frog said : I'm still wondering if my organism can escape the black hole? It doesn't have to be perfect, but it has to make SOME kind of sense. Can quantum tunnelling work? Sorry Frog. As said before, cain't be done!!! if you are in a black hole (below the event horizon), you are there forever.

Go to a zoology museum. Take a look at a chimpanzee skull. The canines are big. Why? Because chimps are hunters, and kill animals, and eat their meat. Humans are also hunters. Guess what? Our canines are small - indeed, puny. Why? Best guess is that we have ben using fire and cooking for long enough to affect our evolution. Big canines are not needed when food is prepared by cooking.

As mentioned, the problem is obtaining enriched Uranium. As mined, Uranium metal is over 99% of the 238 isotope, which is essentially inert. Only the 235 isotope can explode in a bomb. You can make a bomb if you have, say 40% 235 in a block of uranium metal. If you can get it, it is real easy. Just make two 50 kg cubes of Uranium metal, 40% 235. Drop one block onto the other. Boooomb!!!! The problem is getting enough 235. Good luck!

Cthulhu quote : it is a lot easier to predict what the global climate will likely be in the year 2080 This statement is still unproven in the scientific sense. Only when there is proper empirical evidence to back up a climate model or models can we say that.

herpguy. Feel free to reject slogans. They are not helpful. Let's look for the science, instead.

I don't like these ads either. I believe this debate should be based on science, not slogans. However, to do a knee jerk reaction against the ad message without thought is equally culpable. Increases in carbon dioxide in the atmosphere do actually increase plant growth. Not only is this significant, but there is also another factor. With more carbon dioxide, plant stomata do not have to open as wide to obtain this raw material for photosynthesis. They lose less water that way. This makes crop plants more drought resistant. I am not supporting the ads. Just telling you guys to use a little thought before attacking them.

How does one move in space? As others have said, by throwing something in the opposite direction - the principle of the rocket. The force from this is equal to mass times velocity squared. Mass. the more you throw, the more you move. Velocity. the faster you throw, the faster, squared, you move. What this means, is that the best means of moving in vacuum is to fire mass in the opposite direction at enormous speed. Current Earth to orbit spacecraft tend to work the wrong way. They depend on lots of mass rather than lots of velocity in their exhaust (what is thrown away). A really efficient space craft will fire lots of mass, but at enormous velocity. The fastest speed achievable, for the matter thrown away, is close to the speed of light. Thus, the best rocket for the vacuum of space is a linear accelerator, that fires heavy atoms such as Xenon at close to the speed of light. Over a period of time, this will permit the rocket to accelerate in the opposite direction to very high speed. How does one escape a black hole. As the very first reply said, it is impossible. To be in a black hole, by definition, means being inside the event horizon. Once you are there, you are gone. In fact, you will be torn apart by tidal forces as you spiral down into the singularity.

Genecks. If the technology of the Matrix time is that far advanced, so are other methods of developing energy. There is more energy in the deuterium in a human body for fusion energy than could be obtained by chemical processes throughout that humans life. And there is a whole ocean containing deuterium... As someone said, the concept in the Matrix is just unbelievably stupid. After watching Matrix I, I had a thought that might 'save' the series. At least make it logical. If the human/AI wars were actually won by humans (though this fact is kept secret), and one single human rises to power and controls the matrix, then having all other humans tied to a computer link controlled by him would create the ultimate dictatorship. Then Neo could end up fighting a real (but evil) human, making the series much more rational. Sadly the producers had other ideas.

One of the most useful tools in scientific thinking is the principle of Occams Razer. "If you have various explanations for a particular phenomenon, the most likely to be correct is the simplest, with the fewest novel and unproven assumptions." Here we have a phenomenon regarding water : Two possible explanations. 1. there is a brand new, staggering different effect, of a nature to turn all our scientific knowledge on its head, discovered by people who are scientific ignoramuses. Or... 2. A bunch of TV guys are pulling our leg. Which do you think meets the principle of Occam's Razer?

Whether viruses are alive or not is purely a matter of semantics - the meaning of words. In other words, decide on your definition of 'life', and then see if viruses measure up. It is not a purely scientific question. My definition of life is something that includes the following three attributes. 1. It is based on organic chemistry. 2. It reproduces. 3. It evolves. This is not too dissimilar to the nucleic acid definition postulated in a previous post. Just, perhaps, a little more precise. Attribute 1 above is included purely to exclude some computer programs that reproduce and evolve. Some people would debate that the programs might be alive, but I suspect most biologists would dispute that point. Attribute 3 is essential, since fire reproduces, and may be based on organic chemistry as fuel, but does not evolve. Thus, these 3 attributes are the minimum required for a realistic definition of life. My own view is that, based on this definition, viruses are alive. They are only just alive, but still living.

Those who have read my previous posts know that I am SERIOUSLY skeptical of catastrophism. And energy resource depletion is another catastrophist notion. We are not going to run out of oil for a few decades yet. And people are already working on alternatives. Hydrogen can be made by electrolysis of water, plus a number of other techniques. There are even people researching GM algae to directly make hydrogen with sunlight. Vege oils can be used as biodiesel. Methanol can be made direct from carbon dioxide and water, with enough electrical input. Ethanol from fermentation. Even, as an interim, diesel from coal. Bjorn Lomborg (the Skeptical Environmentalist) quoted an oil baron who said : "The Stone Age ended. But not because we ran out of stone. The Oil Age will end. But not because we run out of oil." I agree. Society will move on, and the energy economy will use a greater variety of sources.

I am wondering what this course is you are doing? Is it science? Obviously not. Sounds like fantasy to me. Reminds me of the preface to Larry Niven's book; Flight of the Horse. He states that he realised time travel was impossible. Thus any story about time travel had to be fantasy. This permitted him to include elements of pure fantasy and mythology into his time travel stories. Any project about life in a white dwarf or a black hole is also clearly fantasy. Such life could not exist, except by calling on some hypothetical science that we might as well call magic. The answer to your problem is the same as the answer to the white dwarf one. Life could not exist within, therefore it must exist without. There is nothing to prevent life existing in orbit around a black hole, clear of the event horizon. Black holes suck in matter - particles or gas - and radiation is emitted from the accelerating matter. This could be your life form's energy source.

Ultralord. Impress your tutor with the quality of your research. Show that it is not theoretically possible for a life form to exist on the star itself. Create a whole ecosystem in orbit about the star, in the liquid water zone. For energy, remeber that there are ways that humans obtain power from heat. eg. a thermocouple. There is no reason why a molecule could not exist that acts like chlorophyll, except using heat to generate the current that drives organic synthesis.

Because of the way the question was worded, I had to answer "never". A switch to ethanol will only ever be partial. Eventually, petroleum based fuels will give way to alternatives. However, there are so many possibilities, and it is so difficult for one (eg ethanol) to cope with all needs, that it is much more likely that a mixture of solutions will be used.

Mars has two ice caps. North and south. Interestingly, they are currently shrinking. Global warming on Mars. The 'green' colour of the sun would appear to be an artifact of the method of photography. The sun is not green.

Building a cell from scratch in a laboratory. No, it cannot be done, at least not yet. What we need to remember is that the eucaryote cell (from all 'higher' forms of life) did not evolve till about 2 billion years ago. Plus or minus some hundreds of millions. For the purposes of this discussion, I am not counting the much smaller procaryote cell, which may have existed a billion years earlier. Life, however, is 3.5 to 4 billion years old. In other words, almost 2 billion years of evolution had already occurred before the first true cell with a nucleus came into being. That's a lot of evolving, and represents enormous complexity in that cell. It is hardly surprising that no-one has yet been able to do it. From one view point, a simple eucaryote cell is half as complex as the human body. It is the result of 2 billion years evolution, while the human body is the result of 4 billion. (OK, you can attack me on exact dates. However, that will not change the point I am making.)

If you ignore speculation of currently unknown sciences, there is no way even in theory that a life form can live on any star, much less a very hot one. The one factor that seems to be essential for life is liquid water. Any speculation of life without that is way out in neverneverland. May I suggest that you set up your life form on a planet (or even in a nebula) in orbit about the star, just far out enough to permit liquid water.

I have thought long and hard about this simple question. I have dealt a lot with those who push pseudo-science, and have wanted a simple definition to provide a distinction. My conclusion is that there is no simple definition for science in its entirety. It is just too big. We could say something like : "Science is the study of the universe using the scientific method." Then we would have to define the scientific method. That would take a book - a very big book! However, I see no reason why we cannot define the 'core' of science. The central principle that the rest must revolve around. Following such luminaries as Carl Sagan, Carl Popper etc. Let me try. This is defining the core of science only. I believe that centres on testing. We must test data, hypotheses, methods etc. Science is testing everything. "The core of science is the process of collecting and testing data in an objective and empirical way, formulating hypotheses, and testing these many times with predictions, followed by novel experiments or observations to check those predictions, with the aim of falsifying incorrect ideas, and testing in the same objective manner all test methods used." Perhaps a bit clumsy. Anyone think they can polish it?