Greg Boyles

I beg to differ. He is comparing the hideous fuel usage of the concorde to the hideous infrastructure requirements of solar thermal and voltaics etc. It is a reasonable comparison to make. On what basis are you arguing that the comparison is a logical fallacy? You would appear to be mainly attacking Graham Palmer's credibility rather than addressing his argument. I am sure that the advocates of the concorde would have argued similarly about its benefits and economic viability. But in the end they were proven wrong as the concorde is dead and no one has any plans to implement another regular (as opposed to novelty for the rich)supersonic airline service.

How do you know that Graham Palmer is a mouth piece of the fossil fuel lobby?

Graham Palmer, industrial engineer from Melbourne, Okhams Razor, ABC Radio 621

And is anyone prepared to comment on this assessment of renwable energy? Although more solar energy falls on each square metre of ground than is currently generated............... Is the EROEI of solar voltaics voltaics and wind energy etc considerably less than is assumed when you take into consideration the construction, maintenance and replacement of the infrastructure compared to oil refineries, rigs and power stations etc.

Graham Palmer, industrial engineer from Melbourne

Graham Palmer, industrial engineer from Melbourne

I did a graduate diploma in computer science and the I required nothing more than basic maths skills to learn the basics, although I did have a certain amount of natural appititude for logical sequential thinking. I programmed a very simple number guessing game in BASIC in form 4 in the 1980s and found it quite intuitive. Although what business area your end up in will determine the level of mathematics you will require, or more likely, the level of your mathematics education will determine what business programming areas you end up in. For example specialised programming areas, like insurance and games graphics will require a higher level of mathematics than the majority of run of the mill programming jobs where you design user interfaces etc. If I were in your situation I would get myself a "C++ for dummies" and "windows programming for dummies" type of books and start learning how to program. Also try and get yourself a copy of Microsoft Developer Studio, which comes with C++ and visual basic, and start learning how to use the development environment and the compiler. This software includes tutorials with sample projects already setup so you can quickly learn how to get a project up and running from scratch. When I was doing my course I got hold of a free copy of the UNIX gcc/make command line equivalent compiler that ran under windows. That also had a windows programming add on with a visual editor along the same lines of Microsoft Developer Studio. However Microsoft Developer Studio is still probably the environment that most IT businesses still use. Learn how to write a basic C++ program, using libraries etc. The learn how to use classes and objects under C++. Then once you get the hang of that start learning how to write a basic windows C++ program using the Microsoft Foundation Classes (MFC) The bigger the head start you get the easies you will find your course.

Some of the calcium will precipitate out as calcium hydroxide which is partially soluable in water - the solution will turn milky.

Perhaps if you wrote it like this 2(MgSO4*7H2O) it would be clearer.

Each skeletal muscle has a nerve which consists of a bundle of axons from more than one neurone. The end of the axons branch out from dendrons to dendrites that infiltrate all the individual muscle fibres which they activate when an action potential travels down the nerve. I would assume that the multiple axons in the nerve give the muscle contraction and anologue character where the amount of force applied can be varied. I.E. If an action potential flows down all the axons in the nerve then muscle contraction is strong where is if it only flows down some of the axons then the muscle contraction is weaker. Something like that any way.

There is the issue of the genetic viability of a population of any given species. In short a population requires a minimum number of individuals, and the genetic variability they possess, to avoid inbreeding as in pedigree dogs where fatal genetic flaws are unleashed through breeding between to closely related individuals. An inbred population is ultimately doomed to extinction. In fact it has been suggested that tasmanian devil facial tumour is a result of inbreeding within a population that has lost to much genetic diversity due to land clearing etc. So the asteroid impact need not have wiped out every dinosaur immediately, merely reduced the numbers of many species to levels where long term recovery was impossible. Removal of key species would then have caused an ecosystem collapse taking down many other species that were not necessarily badly effected by the aftermath of the impact.

Technically 'a best fit' rather than 'the best fit'. It is conceivable that some other pigment system, unknown to science, could have evolved. If modern plants did not evolve chlorophyll then would the chlorophyll molecule be known to modern science?

Clearly it is not only esbo's lack of biological knowledge that is a problem here. Clearly his/her lack of understanding of quantum mechanics, which is behind the conversion of sunlight to chemical energy, is also preventing him/her from understanding the explanations that have been provided. Also he/she obviously has little understanding of the constraints on evolution due to fixed genetic variability. The decendants of horses have no chance of sprouting wings and flying in the same way that the decendants of modern plants have no chance of developing a replacement for chlorophyll that converts more of the visible spectrum to chemical energy. There may be more chance of decendants of present autotrophic archae evolving into higher plants that are purple in colour.

Really! Black surfaces with the sole purpose of absorbing solar energy as opposed to providing camoflage! Then name them Esbo!

Even solar voltaics converts only about 30% of the incident electromagnetic radiation to electricity. Since biological systems, including chlorophyll, are reliant upon quantum transitions of electrons to harvest some of the energy in sunlight and since quantum transitions can't just occur with any old wave length perhaps 100% harvest of visible light is simply not biologically possible with out a multiple parallel pigment systems. And the chance of such a system evolving is remote.

I question your assumption that the fact that plants do not absorb the green and yellow proportion of the visible spectrum means that photosynthesis is inefficient. Clearly it is more efficient than the retinol system despite the fact that the cholorophyll system absorbs less of the visible spectrum than the retinol system.

That is not what the original poster is asking though. The debate has been about why plants didn't evolve a form of chlorophyll, or some other pigment, that absorbs light from across the spectrum rather than just from the red and blue end of it. For reasons of efficient use of solar energy. Although, as I found in Wikipedia a few posts back, red algae are using the red phycobilin as an add-on to chlorophyll so they are of limited relevance to the debate. Yes they abosrb a greater proportion of the spectrum but they never the less rely on and are evolved from chlorphyll only containing ancestors. Of more relevence is the suggestion that the early earth's oceans were dominated by autotrophic members of Archae that use the light absorbing pigment bacteriorhodopsin, related to retinol. This appears red-purple and absorbs mostly the green and yellow part of the spectrum. This left the chlorophyll containing ancestors of modern algae and plants to aborb the red and blue parts of the spectrum that the Archae did not absorb. This was at a time when there was little or no oxygen in the atmosphere. Under these conditions it has been suggested that bacteriorhodopsin was easy to synthesis but that the system was not as efficient as the chlorophyll system. So over time and as the oxygen built up in the atmosphere perhaps, the ancestors of modern algae and plants took over dominance from the autotrophic archae, which were relegated to extreme habitats - high salinity and high temperatures where bacteriorhodopsin and other unique features of archae are more stable. So, although chlorophyll absorbs only a small proportion of the visible spectrum, the energy conversion process of light to chemical energy is more efficient. So the original poster's starting assumption that chlorophyll is inefficient because it 'throws' away a large amount of energy from the visible spectrum, is flawed.

I remember seeing a report on a fellow who did not have legs, can't remember why, who got around using his arms and a skate board. After a decade or two of this his shoulders were breaking down due to the fact that they are not biologically engineered to be weight bearing in the same way as our legs. Actually I think it was a woman rather than a man.

Also from wikipedia..... Phycobilins, the red pigment in red algae, are not independant of chlorophyll. So chlorophyll came still first and phycobilin is an add-on. So where does that leave us? Autotrophs are fundamentally green? It is biochemically possible for phycobilins, or other light absorbing biomolecules, to be directly copuled to the photosynthetic machinery without any requirement for chorophyll? Or is it the case that the genes/proteins that could make this possible simply never evolved? http://www.livescien...y-suggests.html So it is a false assumption from the start that a hole in the absorption spectrum of chlorophyll represents an inefficient sunlight harvesting mechanism.

Here is a more detail possible explanation for you esbo, from another forum.... And another explanation from Wikipedia..... And let's not forget red marine algae Limitations on evolution So from the limitations on evolution...... It may indeed be theoretically possible to come up with a biological pigment that absorbs all or most wavelengths of light and that can be coupled to the cellular energy producing machinery. But there may simply not be the genetic capacity with the current stock of green plants to synthesize such a pigment or the means to synthesize any intermediary molecules that couple that pigment to the cellular machinery. Perhaps, if any such primitive plants with other than chlorophyll did exist, they lost the evolutionary race hundreds of millions of year ago and the genes required for it lost forever. Or until they arise again through random mutation. As I have poreviously said, there have been billions of evolutionary steps between the first autotrophs and modern plants. To try and figure out why chlorophyll containing macroscopic autotrophs are now dominant on Earth is akin to trying to figure out why a particular rain drop came to fall on your nose. The pathway that led to current reality is just to long and complex to compute.

That is nothing more than unstoppable momentum. The weight and momentum of the collapsing part of the building simple exceeded the engineering limits if the hooks that held the floor trusses in place. The more the building that collapsed the greater the weight and momentum impinging on the next set of hooks below.

OK then a sloth does not have grasping hands but is none the less exceptionally profficient at climbing. Each species of bat use very specific frequencies that its sonar operates at. So in effect they do have great unexplained wopping holes in their sonar systems. Think of all the additional information it could theoretically discern from its surroundings if it used multiple frequency sonar. Obviously, despite the fact that logically to us it might seem beneficial, there is no evolutionary value to multiple frequency sonar in bats or it is not bilogically possible for some reason. Same with principal with photosynthesis.

That is not an answer esbo. The golden mole, that has no functional eyes, is also equally profficient at avoiding predators. And bats hunt at night using sonar rather than sight. A possum, that does not have grasping hands, is equally proficiant, if not better, at climbing trees. The point is that eyes and grasping hands are not the superior solutions to survival problems. They are just one of many and varied, and equally valuable, solutions.

Who knows. At the dawn of life on earth maybe there where cyanobacteria with energy absorbing pigments in them other than chlorophyll. Perhaps there were purple, black and orange cyanobacteria. But since none exist today we can assume that such alternative pigments were of little survival value in the evolutionary race. Perhaps the chemical processes associated them were even less efficient than chlorophyll. Perhaps by chance these other pigments were not stable in the presence of large amounts of oxygen. Who the hell knows? There is no way we can know, at least at present. You could ask a million similar questions. Why did fish evovle eyes? Why did primates evolve grasping hands? We can only ask questions about the possible merrits of what we observe, but we can never really answer questions as to why what we observe came to be. There have been far to many evolutionary steps between now and when those features first started arising. You may as well ask why a particular rain drop came to fall on your nose.

I think it would be considerably more than just difficult. The tower was hit by a plane and was on fire. People streaming down the stairs and elevators below the impacts. Fire crews every where and trying to get up. How would the fake maintenance crews get up in time through the throng of people? Wouldn't it look massively suspicious with a maintenace crew going up under such conditions? How would the fake maintenace crew get past the impacted part of the building to the weaked part of the structure? Remote control plains and pre-positioned charges? Where did all the airline passengers go who disappeared that day? How did an jet airliner manage to take off via remote control at an international airport loaded with passenegers? Who was the control tower talking to when directing the air craft? It is all just totally inconceivable.