Teen build R5800 death ray that can boil concrete

[Mustrum_Ridcully]

The Russians constructing nukes on the far side of the Moon disagree with you.

Yeah, it's only sunny half the time of the lunar day...

 

[Pbartender]

After yesterday, I just realized another great practical use for an R5800 Death Ray... Driveway snow removal.

 

[Joker]

After yesterday, I just realized another great practical use for an R5800 Death Ray... Driveway snow removal.

Very very slow driveway snow removal.

 

[Pbartender]

Very very slow driveway snow removal.

Perhaps, but how awesome would it be to clear your driveway of snow using an industrial heat ray out of your living room window, while everyone else is slogging around behind snowblowers or slinging shovels around?

"Maybe I can't kill super-spies or destroy the world with it, but at least I can save myself some back pain."

 

[Scott DeWar]

if you focus on one spot on the drive way it should heat up and melt large swaths.

 

[Umbran]

well, my theory was, if you had the mirrors that could pivot, they'd always be angled to bounce the sun onto the target.

Distance still matters, in a few different ways.

Set aside exactly what you use as a mirror for a moment - once that light comes off the mirror, it continues to travel through atmosphere, getting scattered and absorbed by air and dust. Even on a clear day, the light from the sun has lost about 20% of its power getting from the top of the atmosphere to your mirror this way.

As light that concentrated passes through air, it heats up the air. Heated air refracts light differently than the cool air (think mirages), so your beam will tend to lose focus that way - and the longer the path, the greater the distortion.

From there, we also have to talk about the mirror itself. The film had little mirrors, looks like they were the size of your pinky nail or so. Why, then, was the point of smallest focus a couple inches across? Part of that would be imperfection in mounting, but another part is that those are little flat mirrors - while in collection these things focus light, individually, they are still flat. The smaller you make the individual mirrors, the less you'll see the effect of flatness, but the more difficult it is to make your optics adapt.

the fixed mirrors on a fixed parabola is what gives it a fixed range, which is why distance matters for it.

That is not the *only* reason distance matters. Yes, with movable mirrors, you can change the focal point somewhat. You can only do so within some range, though, defined by the base curve you're modifying, and you don't suddenly get the ability to hit things 2 inches away and two miles away with equal power; and there are other effects that make distance matter.

one random idea:
get a sturdy ring and stretch cloth over it. Then mount the mirrors on that.

Then pull the center of the cloth back, which would cause a curve to form in the material.

If you pull the center of the cloth back, you'll get a straight-sided cone, not a parabolic curve. The curve required is pretty specific.

Perhaps, but how awesome would it be to clear your driveway of snow using an industrial heat ray out of your living room window, while everyone else is slogging around behind snowblowers or slinging shovels around?

About as awesome as being outside slogging behind your snowblower or slinging a snowshovel around and watching your smugly snug and warm neighbor ignite his own car...

(...says the guy who strained back muscles a week ago...)

 

[Pbartender]

...says the guy who strained back muscles a week ago...

...I was speaking as the guy who strained back muscles yesterday...