Every movement has its founding texts; for nanotechnology there’s general agreement that Richard Feynman’s lecture There’s plenty of room at the bottom is where the subject started, at least as a concept. The lecture is more than forty years old, but I sense that its perceived significance has been growing in recent years. Not least of the reasons for this is that, as the rift between the mainstream of academic and commercial nano- science and technology and the supporters of Drexler has been growing, both sides, for different reasons, find it convenient to emphasis the foundational role of Richard Feynman. Drexler himself often refers to his vision of nanotechnology as the “Feynman vision”, thus explicitly claiming the endorsement of someone many regard as the greatest native-born American scientist of all time. For mainstream nanoscientists, on the other hand, increasing the prominence given to Feynman has the welcome side-effect of diminishing the influence of Drexler.
Many such founding documents easily slip into the category of papers that are “much-cited, but seldom read”, particularly when they were published in obscure publications that aren’t archived on the web. Feynman’s lecture is easily available, so there’s no excuse for this fate befalling it now. Nonetheless, one doesn’t often read very much about what Feynman actually said. This is a pity, not because his predictions of the future were flawless, nor because he presented a coherent plan that nanotechnologists today should be trying to follow. Feynman was a brilliant theoretical physicist observing science and technology as it was in 1959. It’s fascinating, as we try to grope towards an understanding of where technology might lead us in the next forty years, to look back at these predictions and suggestions. Some of what he predicted has already happened, to an extent that probably would have astonished him at the time. In other cases, things haven’t turned out the way he thought they would. We’ve seen some spectacular breakthroughs that were completely unanticipated. Finally, Feynman suggested some directions that as yet have not happened, and whose feasibility isn’t yet established. In my next post in this series, I’ll use the luxury of hindsight to look in detail at Plenty of Room at the Bottom, to ask just how well Feynman’s predictions and hunches have stood the test of time.
RAIN CYCLE BEATS THE HEAT ENGINE LAW
Comment from: Adess Singh [Visitor] ¬? http://adess@sify.com
We all know that rain falls.
We all know that this is the vapour of water evaporated from the ocean surface as also from other large water bodies.
We all know that volume to volume wet air is lighter than dry air. So when dry air picks up moisture it becomes lighter and is thus moved by displacement action under the action of gravity, up high into the atmosphere, where it gets cold and the vapour condences and falls as rain.
If wet air is lighter obviously no thermodynamic work need to be done in moving it upwards as that is its natural diraction.
Now take a look at that rain cycle as a theoretical heat engine. The water absorbes an amount heat say ‘H’ at the ocean surface. As the water vapour moves up under the action of displacement by gravity it does no ‘work’ so when at an altitude the vapour condences back to water it must return to space exactly the same quantity of heat ‘H’.
In a thermodynamic heat engine if heat absorbed minus heat rejected is equal to the amount of work done, and if the two are equal then no work should have been done but in this case of the rain cycle, there are a billion tones of water at a height in a gravational field.
take a look at the heat budget of the earth in any science encyclopedia, it shows very clearly the heat absorbed by water at ocean surface is the same as heat radiated back to space at high altitude, only the heat absorbed at the ocean surface is at a higher frequency as compared to the heat returned to space which is at some what lower frequency but the amounts are the same.
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