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Physics/directed energy


I am a completely unscientific person who would like to understand something about  directed energy. I see many complicated explanations on Google, from commercial  operations,involving lasers etc., but I think that I now understand that the simplest form of directed energy would be a handheld torch.Am I on the right track?

Since you freely admit to being an "unscientific person," forgive me if I attempt to make a few clear before I answer your (seemingly) simple question. It is apparent that your English is quite good (my knowledge of Portuguese is non-existent - sorry), so I will presume to explain scientific terminology in the English language only.

FIRST thing to understand about scientific talk is that scientists often use words that can mean many things in everyday language, but mean ONE THING ONLY in scientific terminology. Words like energy, power, force, strength, momentum, etc; may, in common talk, be used almost interchangeably. However, to scientists and engineers, each of these words mean ONE THING, and each is DIFFERENT from the other words. For example, a scientist might say that a device operates at an extremely high power but gives almost no energy -- a perfectly sensible statement to other scientists but possibly confusing to others.

The word "energy" is, to scientists, a catch-all term for various phenomena. Over the centuries, but particularly in the late 1800s, scientists found that a lot of things they thought were completely disconnected from each other - heat, motion, light, sound, magnetic fields, electricity, chemical bonds, etc, etc -- were actually simply FORMS of energy. What they found was that, although the FORM of energy might change (sunlight becoming heat when striking a solid object), the total energy remained the same.

"Directed energy" is another catch-all phrase. In its broadest meaning, it means transferring energy from one point (the user) to a specific, chosen point away from the user, WITHOUT the use of any mass or matter. Thus, a radio transmitter is NOT directed energy, simply the radio waves travel in all directions, not to any specific point. Likewise, a bullet from a gun is not directed energy, simply because the energy (kinetic, in this case) is carried by a projectile -- ie, an object with mass.

Lasers and microwave beams, however, ARE directed energy by this definition. The energy that leaves the user ends up at a specific point that can be chosen by the user, and that energy is carried by something other than an object with mass (specifically, electro-magnetic radiation in both cases).

I was almost completely done with this when I remembered that the word you used -- "torch" -- means two different things, depending on which side of the Atlantic you are on. In the U.K., this is a torch
Note, however, that here in the U.S.A., this object is called a "flashlight."
This is what we in the U.S.A. call a "torch":
and this is somebody using a "hand-held torch" (at least here):

I'm going to presume you're asking about a "torch" in the sense of what someone in the U.K. would mean. In that case, such an object is most definitely a directed energy device.


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I can help with understanding physics that does not involve eggs. I will NOT help with academic or professional questions, which are NOT limited only to homework. Please do not waste your time by asking a question that comes out of ANY kind of academic, professional, or business matters.


Have been fascinated by physical laws ever since I learned, at age seven, that magnets work under water. My study continued through college and has not ceased even after I retired.

B.A. in Physics (with honors) from University of California at Berkeley.M.A. in Physics (with honors) from University of Texas Austin.

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