You should see the BIG solar tower.

I remember seeing one of these super solar ovens in a book about 15 years ago. It was in France if I remember right.

One version uses mirrors to melt sodium that is stored in a vacuum, which is then flooded with water which creates steam to turn turbines. It uses no feul, so all the costs are in building an maintaining it and current estimates of operating costs are very very low compare to coal or petrolium.

It has its disadvantages, such as requiring very large acreage, but apparently a relatively small portion of the the southern California desert (wasteland) could be used to create enough power for the entire US and Canada.

I'm sure it's nowhere near perfect, but if this video is any indication we have barely begun to harness the power of the sun for use in our civilization.

there was a British show for the open university presented by Adam hart davis, possibly 'what the ancients did for us' (or one of his other shows) that demonstrated that in ancient times it was possible to have done this using available resources. whether or not it was successfully achieved is another story, but they showed that it was entirely possible. they even went to Greece to prove it.

400 deg. would be enough to make steam for the powerturbine

This last comment reminded me of that 007 movie "die another day" where some guy built an archimedean death ray" with a satellite.. i think it was called Icarus.

I could easily imagine a company solely dedicated to do this type of thing placing such devices around the globe and using the suns rays to power cities.

You can of it like the solar version of Shell. We're still watching the infant steps to full realization of this power producing method. It's exciting to think about.

And still stand by the fantastical idea of solar based weapons. If anything we maybe able to BBQ food from them!

The "hot spot" is at the focal point, where all the reflected rays of sunlight converge. Outside of that focal point, the temperature is significantly lower. Therefore, the device would make a poor "death ray". I suppose if the curvature were adjusted so the focal point could be moved, it might be effective --- but I imagine the temperature would become exponentially less hot the farther that focal point was moved from the mirror.

What I thought was neat was there was no rapid oxidation like you would get from a cutting torch so you got to see the steel flow.

They revisited the myth later and used a parabolic mirror which was able to ignite a piece of wood in only a second.