Worlds Energy requirements ' May be ' within our technological Grasp !

[Strange]

It is not that easy. The Sun doe not emit a lot in the radio spectrum and much of that is reflected by the atmosphere.

 

Several attempts were made to detect radio emission from the Sun including an experiment by German astrophysicists Johannes Wilsing and Julius Scheiner in 1896 and a centimeter wave radiation apparatus set up by Oliver Lodge between 1897-1900. These attempts were unable to detect any emission due to technical limitations of the instruments and the discovery of the radio reflecting ionosphere in 1902 led physicists to conclude that the layer would bounce any astronomical radio transmission back into space, making them undetectable.^[1]

https://en.wikipedia.org/wiki/Radio_astronomy

[Mike Smith Cosmos]

It is not that easy. The Sun doe not emit a lot in the radio spectrum and much of that is reflected by the atmosphere.

 

https://en.wikipedia.org/wiki/Radio_astronomy

That is some interesting information . I will digest .

 

Ps my other memorable occasion this time 14/15 years a dubious man swapped a radio that I had with a magic eye tuning device for some UHF / VHF ex naval fixed frequency Xtal receiver. I connected it to my long wire . I was disappointed , all I heard was a lot of ' hushssss!

 

Of course what I was probably listening to was the background radiation . Not realising , I took the receiver to bits , with its attractive UHF glass valve diode detector and it's 1 and a half turn copper coil . Looked very pretty .

 

Before , I went away to university in London on my motor bike in 1960 , I had gathered so much radio junk , I left my parents , in despair , with a room full of , transmitters , oscilloscopes, receivers , morse code keys , aerials hanging from trees , and vast piles of radio components .

 

Mike

 

Ps my father born in 1901 said radio came in to being , at the beginning of his life. Approx 1900. It progressed to a complete communication system world wide , space wide , satellite wide through to fibre optics . A LL in his life time . He tried to make 100 years year 2000 ( nearly he lived to 95 ) . All in one generation . Now we move on , into whatever !

 

A poet once said " children are like arrows. We fire( shoot ) them into the future. A future where they go, but we cannot go. " my father shot me into the future where I am , but he is not. I have shot my children into the future. , into the future where I can not go . ( maybe I should not have had that beer ! )

Edited July 11, 2015 by Mike Smith Cosmos

[swansont]

 

The spread out energy source , is intended to be low intensity . As I said only 10-100 watts per square meter. As sunlight is 1000 watts( 1kw/ sq m). And long wave is less aggressive than sunlight , this makes it very safe.

 

 

Low intensity means it's not useful. My iPad charger is 2 amps at 5V, or 10W. I'd need a 1m x 1m antenna to charge it like that using this wireless. And that's a fairly low-power device.

 

Sunlight is around a kW/m^2, true, and solar panels are around 20% efficient, so these are functionally equivalent. Laptops draw a few hundred watts. More if you want to charge while using.

 

As far as safety goes, you still have failed to cite any studies at all. Just an insistence that long wave is safer. Sunlight's on a human body is a kW, and so is a microwave oven. Do you cook things with (unfocused) sunlight? No. Why is that? (hint: one reason is because microwaves penetrate)

[Mike Smith Cosmos]

Low intensity means it's not useful. My iPad charger is 2 amps at 5V, or 10W. I'd need a 1m x 1m antenna to charge it like that using this wireless. And that's a fairly low-power device.

 

Sunlight is around a kW/m^2, true, and solar panels are around 20% efficient, so these are functionally equivalent. Laptops draw a few hundred watts. More if you want to charge while using.

 

As far as safety goes, you still have failed to cite any studies at all. Just an insistence that long wave is safer. Sunlight's on a human body is a kW, and so is a microwave oven. Do you cook things with (unfocused) sunlight? No. Why is that? (hint: one reason is because microwaves penetrate)

I think all E M waves penetrate to some extent , and related to the frequency . However , as I understand it , ' if the thing that is being penetrated or the object contained within the thing being penetrated has a natural resonance ,in some way or other ( exact multiple of wavelength , or simple fraction of wavelength, or order of magnitude similar to the penetrating wave ' , then energy can and will be adsorbed . This may be fine , warming , or stimulating in an acceptable way. But if this is too large , in any way , then damage may result.

 

This I believe , is what happens with microwave ovens , exciting things like water or metallic rings.

 

My stating " long waves are harmless " is in respect to 1500 meters seems very large with respect to anything human size . Yet would make a 750 meter cable get Hot . So as long as you don't go grabbing any 750 meter cables , metal bars , or the like , you should be o.k.

 

I will try and find a citation in this respect.

 

I think if you could set up a ambient zone as I describe , there would be no need for hard charging . As the energy could be used directly . Yes with a certain amount of local storage , much as happens with a smoothing capacitor in an electrical power supply . Trickle charge could also tick away gently in case of interruption of service .

 

 

I think a clever design of antenna could overcome your worry of walking around with a 1 meter x 1 meter metal plate over your head .

 

Up until quite recently power supplies for devices of all sorts , were always the heavy aspect of equipment . With metal core transformers , etc in recent times these have been replaced with other component power converters for I pads , mobile phones , with the USB type power supplies. etc . With this new venture I am talking about , you would plug into the " zone , EM. long wave field " perhaps a USB with a 750 meter dipole on top ?

 

No I think we can do better than that . We need to find something that resonates at 200khz .

( now there's a thing ) ? ( quartz crystals ) ?

 

 

Mike

Edited July 11, 2015 by Mike Smith Cosmos

[Mike Smith Cosmos]

.

Citations as I find them :-

 

A)

-----------------------

World health organisation .

The World Health Organisation, which has examined the topic in depth, says: "In the area of biological effects and medical applications of non-ionizing radiation approximately 25,000 articles have been published over the past 30 years. Despite the feeling of some people that more research needs to be done, scientific knowledge in this area is now more extensive than for most chemicals. Based on a recent in-depth review of the scientific literature, the WHO concluded that current evidence does not confirm the existence of any health consequences from exposure to low-level electromagnetic fields. However, some gaps in knowledge about biological effects exist and need further research."

 

B)

----------------------------

.wikipedia :-

https://en.m.wikipedia.org/wiki/Electromagnetic_radiation_and_health

 

Quote " Radio frequency fieldsEdit

See also: Mobile phone radiation and health

Apart from some suspicion that the electromagnetic fields emitted by mobile phones may be responsible for an increased risk of glioma and acoustic neuroma, the fields otherwise pose no risk to human health.[26][27] This designation of mobile phone signals as "possibly carcinogenic" by the World Health Organization has often been misinterpreted as indicating that of some measure of risk has been observed however the designation indicates that the possibility could not be conclusively ruled out using the available data.[28] "

 

. C)

-----------------------------

.Vexen Crabtree 2009

3.2. Radio Waves Cannot Cause Cancer

In order to have any chance of causing cancer, electromagnetic radiation has to be of a high enough frequency so that it can ionize atoms, as I have explained above. Even if such a photon is absorbed, the chances of it causing cancer are miniscule, but, it still does happen. The frequencies used by human technological gadgets are well below the frequency at which ionization occurs. The frequencies used by mobile phones are one million times too low to have enough energy to cause ionization. If you stood next to the world's most powerful mobile phone or mast, you would merely be exposed to a larger dose of non-ionizing radiation. The risk does not come from the power levels of the signal. To make a mobile phone's radiation ionizing, you need to increase its frequency by a million times, not just boost its power (which leaves the frequency the same). Obviously, no mobile phone is powerful enough to do this (and it would no longer be using radio waves). In fact, no gadgets use frequencies that are ionizing.

 

-

D)

--------------------------------------------

..this one is by a ' mike smith ' not me another one !

Link :- http://www.mds975.co.uk/Content/radtech.html

We will concentrate on the relatively harmless end of the electromagnetic spectrum - Radio Waves - which include Radio, Television and mobile phones.

 

THE RADIO PORTION OF THE ELECTROMAGNETIC SPECTRUM:

 

 

Classification:

ELF

VLF

Very Low Frequency

LF

Low Frequency

MF

Medium Frequency

HF

High Frequency

VHF

Very High Frequency

UHF

Ultra High Frequency

SHF -

EHF

 

Longest

Waves

-------------------------

 

 

I think in view of some of these citations.

 

The critical thing to do with possible human harm :- is not the power , but is the frequency .

The frequency needs to be sufficiently high as to cause " ionisation " . And it is this ionisation , that is viewed as doing damage to a human .

 

As one of the citations says " if you stood next to a very powerful radio transmitting station . It would do you no harm ' unless it was of sufficiently high frequency to cause ionisation ' , or something to that effect .

So I think this does rather endorse my points that a Low Frequency Long Wave system would be pretty harmless to humans .

 

What may cause problems with equipment , is something MORDRED brought up . That is electrical interference . As low frequency , could develop harmonics at higher frequencies, and if these were quite powerful , they might cause problems . A pure sinusoidal signal at low frequency will not cause harmonics , but an impure sinusoidal signal will cause harmonics at some multiples of the fundamental signal .

 

Mike

 

Ps I do hope That , I have not shot myself in the foot. ( or been shot in the foot by MORDRED )

Edited July 12, 2015 by Mike Smith Cosmos

[swansont]

.

Citations as I find them :-

 

A)

-----------------------

World health organisation .

The World Health Organisation, which has examined the topic in depth, says: "In the area of biological effects and medical applications of non-ionizing radiation approximately 25,000 articles have been published over the past 30 years. Despite the feeling of some people that more research needs to be done, scientific knowledge in this area is now more extensive than for most chemicals. Based on a recent in-depth review of the scientific literature, the WHO concluded that current evidence does not confirm the existence of any health consequences from exposure to low-level electromagnetic fields. However, some gaps in knowledge about biological effects exist and need further research."

 

 

(emphasis added)

 

We aren't talking about low-level fields, though. In the US, the maximum allowed radiated wi-fi power from a router is 1 Watt. The be exposed to that you'd have to be hugging the device, totally enclosing it. At 1 meter, you would be getting <80 mW/m^2. At 2 meters away, it's <7 mW/m^2. That is low-level.

 

You are talking about levels more than a thousand times higher.

 

I think in view of some of these citations.

 

The critical thing to do with possible human harm :- is not the power , but is the frequency .

The frequency needs to be sufficiently high as to cause " ionisation " . And it is this ionisation , that is viewed as doing damage to a human .

 

 

It's only going to be the power, because the frequency is not nearly large enough to ionize. Cancer isn't the concern. It's baking critters from the inside, and other possible thermal health effects. Those are the studies you have to find, or otherwise address with some science.

[Mike Smith Cosmos]

(emphasis added)

 

We aren't talking about low-level fields, though. In the US, the maximum allowed radiated wi-fi power from a router is 1 Watt. The be exposed to that you'd have to be hugging the device, totally enclosing it. At 1 meter, you would be getting <80 mW/m^2. At 2 meters away, it's <7 mW/m^2. That is low-level.

 

You are talking about levels more than a thousand times higher.

 

 

It's only going to be the power, because the frequency is not nearly large enough to ionize. Cancer isn't the concern. It's baking critters from the inside, and other possible thermal health effects. Those are the studies you have to find, or otherwise address with some science.

I could build a rather large coil and capacitor in a pi network with a long wire , and give it a big pulse . Or find some research that has already been done . The world Heath organisation seems to have done a lot of research .

 

However I do need to do a test , to see if it actually works , namely transfer energy as opposed to signals/ messages.

 

 

Mike

 

Ps . In fact I know this works at close range . As , if you just hold a fluorescent tube with no connections near a transmitter , it will ignite , like a Star Wars OB1 Kinoby light saber I need to get into the far field ( not farmers field , electro magnetic field )

Edited July 12, 2015 by Mike Smith Cosmos

[Mike Smith Cosmos]

On second thoughts a rhombic aerial array would be more directional , and probably more like the space antennas ,in a circular array . But for my test in the park ( maybe this time no woman pram baby and two Jack Russell , and a lead filled lizard in a cardboard tube ) .

If driven from one end , I recall it has four or more forward pointing lobes :-

 

 

Don't worry I have a licence for this sort of experimenting !

 

Mike

This is just a prototype model . But in the real test kit :- I recon we need 800 turns of copper wire for the main resonant coil . To be in the long wave band .

 

This should cause a one off click of energy transmitting from the switch , through a step function to the coil capacitor tuned circuit. A single ring with three or four decaying oscillations should arise . The antenna should translate the flow of cycles in the antenna at long wave , to be transmitted , complete with modest photon packet of energy , to a detector some meters away , beyond the near field . I hope ! A micro ammeter should measure a small fluctuation of current .

 

Edited July 12, 2015 by Mike Smith Cosmos

[Mordred]

Your better off with a radio watt meter. For diectivity look at Yagi antennae.

 

https://en.m.wikipedia.org/wiki/Yagi-Uda_antenna

 

I assume you have amateur radio licensing

[Mike Smith Cosmos]

Your better off with a radio watt meter. For diectivity look at Yagi antennae.

https://en.m.wikipedia.org/wiki/Yagi-Uda_antenna

I assume you have amateur radio licensing

Yes. You are correct , as usual on all counts .

 

One . the signal strength meter . Watt meter .

Two . The yagi for very tight direction, though I was wanting a bit of spread.

Three . Yes I am a licenced Radio Amateur . But have been an electronic engineer . Totally retired now , where technology has overtaken me , and left me for dead . So am trying to pick up the pieces of my addled brain , in my dotage . Go out thinking , and painting a lot ! With the Jack Russell. Dog ! While my wife runs a Cafe . Family spread to ' the four winds '

 

 

Mike

Edited July 13, 2015 by Mike Smith Cosmos

[dimreepr]

It is interesting that Sunlight, which is a composite group of high frequency electro magnetic waves are themselves falling to earth, say on a human body at 1000 watts ( 1 kilowatt ) of energy over each square meter , which is approximately a human flattened out . This is of course at very very high frequency , which is penetrating .

 

So compared to my long waves ( comparatively low frequency - much less penetrating ) of 100 watts ( 0.1 kilowatt ) per square meter .

I think we could accept this showering of energy from above a good thing ?

 

Mike

 

 

What you seem to be proposing is a high cost uncertain technology to send ten times less energy to earth than the sun already provides and that we can already collect; so my question is why?

[Mike Smith Cosmos]

What you seem to be proposing is a high cost uncertain technology to send ten times less energy to earth than the sun already provides and that we can already collect; so my question is why?

Perfectly reasonable question !

 

Sunlight isn't where you want it and when you want it .

 

it is not in a readily usable form . DC not AC .

 

Not continuous

 

May be plentiful in the middle of the Sahara desert , but distribution to where you want it is very very difficult .

 

Being in direct sunlight can be not where you want to be .

 

Mike

Edited July 13, 2015 by Mike Smith Cosmos

[dimreepr]

A potentially attainable technology is, perhaps, a photovoltaic cell that could be printed onto, something like, vinyl and so could be applied to the entire house/building rather than just the roof.

 

"May be plentiful in the middle of the Sahara desert , but distribution to where you want it is very very difficult ."

 

The point is your idea has exactly the same issues but with no immediate method to solve them whereas at least my idea builds on working tech; meaning it works now, can be applied now and at no, excessive, cost .

Edited July 13, 2015 by dimreepr

[swansont]

it is not in a readily usable form . DC not AC .

 

Plenty of things use DC. And it's not like your signal is immediately usable; it's not at 50 or 60 Hz. You still have to convert.

[Mike Smith Cosmos]

Plenty of things use DC. And it's not like your signal is immediately usable; it's not at 50 or 60 Hz. You still have to convert.

Well I was thinking of modulation the long wave with 50 hz , as opposed or in addition ,to modulating light waves with long wave .

I am not certain this latter is possible .

 

After I have proved it possible to send energy across a short distance using a rhombic antenna ( long waves , modulated with 50 hz ) . Then I need to address the issue of modulating some part of light wave ( say infra red with long waves ) to see if it is possible to receive long wave energy from originating infra red light .

 

Mike

A potentially attainable technology is, perhaps, a photovoltaic cell that could be printed onto, something like, vinyl and so could be applied to the entire house/building rather than just the roof.

 

"May be plentiful in the middle of the Sahara desert , but distribution to where you want it is very very difficult ."

 

The point is your idea has exactly the same issues but with no immediate method to solve them whereas at least my idea builds on working tech; meaning it works now, can be applied now and at no, excessive, cost .

I do agree with everything you say . I have been waiting for these promised tiles,( photovoltaic ) to appear , cheap on the market .so that every roof was an electric supply . They do not seem to have appeared. Rather fields upon fields are appearing all over the place .

 

The distribution benefit that I see with a space based platform or disc , is it can be directed to a requirement , as well as general distribution of "" harmless "" ( yet to be proved) . Energy.

 

The more I investigate, the more I see the advantage of long wave . The issue , as far as I can see is NOT penetration . But rather does it engage so as to do damage. If you shake me one cycle per second , I might get annoyed but not hurt. If you shake me 10times a second , my eyes will pop out and organs will probably damage . Again at relevant energies.

 

I thought this ' resonance issue ' is what is at the root of this whole exercise .

 

Resonant frequency - communicates - energy .

 

If there is nothing in the human body that will resonate at long waves , then ,surely, they are safe for humans . OR have I got it all wrong ?

 

I think if someone said " you can only take one word with you in life" , for me , it would be RESONANCE

 

Mike

Edited July 13, 2015 by Mike Smith Cosmos

[Mike Smith Cosmos]

.

RESONANCE

 

 

Notice below ( the diagram from Wikipedia ) , the sharp rise and fall to the resonance curve. This frequency spectrum can select out a desired safe frequency and exclude other dangerous frequencies. I am not sure of any resonant frequencies of the human body and brain . But provided these are outside of this curve ( the curve of resonance being the long wave frequency chosen , in this project ) . Then the human body should be quite safe , if not an alternative , suitable , permissible frequency in the long wave spectrum can be chosen .

 

 

 

Link :- https://en.m.wikipedia.org/wiki/Resonance

 

Mike

Edited July 14, 2015 by Mike Smith Cosmos

[swansont]

.

RESONANCE

 

 

Notice below ( the diagram from Wikipedia ) , the sharp rise and fall to the resonance curve. This frequency spectrum can select out a desired safe frequency and exclude other dangerous frequencies. I am not sure of any resonant frequencies of the human body and brain . But provided these are outside of this curve ( the curve of resonance being the long wave frequency chosen , in this project ) . Then the human body should be quite safe , if not an alternative , suitable , permissible frequency in the long wave spectrum can be chosen .

 

image.jpg

 

 

Link :- https://en.m.wikipedia.org/wiki/Resonance

 

Mike

 

The issue has little to do with resonance; it's not a matter of whether we're at the peak of a resonance curve or not. The response is incredibly broad at these frequencies. Microwave ovens, for example, are not tuned to a resonance in water, but they still cook things.

 

Here's the absorption curve for liquid water. Unfortunately it stops at 1cm, but the curve beyond that is featureless.

https://en.wikipedia.org/wiki/File:Absorption_spectrum_of_liquid_water.png

 

Notice how the attenuation curve is much larger even at 1 cm than for visible light, and the IR resonances don't have a huge dynamic range to them — being off-resonance only drops the attenuation coefficient by a fact of 10 or so from a very large number. At a wavelength of 1 m, the absorption coefficient is still 100x larger than for visible light's best behavior. An attenuation coefficient of 10 means that effectively all of the energy is deposited in a meter of water. With a value of 1, about 63% of the energy is deposited in a meter of water. And that's fresh water. I think salt water is about 100x better at attenuating EM radiation. The human body is mostly salt water.

 

Meaning that even at long wavelengths, you still have energy deposition.

[Mike Smith Cosmos]

The issue has little to do with resonance; it's not a matter of whether we're at the peak of a resonance curve or not. The response is incredibly broad at these frequencies. Microwave ovens, for example, are not tuned to a resonance in water, but they still cook things.

 

Here's the absorption curve for liquid water. Unfortunately it stops at 1cm, but the curve beyond that is featureless.

https://en.wikipedia.org/wiki/File:Absorption_spectrum_of_liquid_water.png

 

Notice how the attenuation curve is much larger even at 1 cm than for visible light, and the IR resonances don't have a huge dynamic range to them being off-resonance only drops the attenuation coefficient by a fact of 10 or so from a very large number. At a wavelength of 1 m, the absorption coefficient is still 100x larger than for visible light's best behavior. An attenuation coefficient of 10 means that effectively all of the energy is deposited in a meter of water. With a value of 1, about 63% of the energy is deposited in a meter of water. And that's fresh water. I think salt water is about 100x better at attenuating EM radiation. The human body is mostly salt water.

 

Meaning that even at long wavelengths, you still have energy deposition.

 

What you are in effect saying . " are the sort of long waves I am envisaging capable of being absorbed , anywhere near the level that it would cook human organs " . Surely as they are many orders of magnitude less than light waves , and sunlight does not cook us . At least as long as we don't lay in the sun for too many hours , then long waves should be a lot safer than sun light?

 

Mike

Edited July 14, 2015 by Mike Smith Cosmos

[Mordred]

Is human organs the only thing at risk? The SAR values I've come across are developed for human risk.

What about insects, plants and birds. I have encountered any surveys on this. Might bear looking into. The main risk is although your talking low frequency. You have a continuous stream. This alters the safe threshold limits on exposure times.

 

When I worked radio towers, all transmitters had to be shutdown. Regardless of transmission power and frequency. The only exception was when you were aligning microwave links. (Directional) even then we made sure to be behind the transmitter.

 

The effects of Radio wave pollution is still largely under study. We simply do not know for sure which frequencies and radiative power is considered 100% safe.

As such most sites state low frequency non thermal effects are still under debate.

although sunlight on Earth is on a daily schedule, this can be countered via battery storage. Far safer as your not introducing added radiwaves.

 

Plants, insects and wildlife have already adapted to the sunlight itself.

Edited July 14, 2015 by Mordred

[dimreepr]

Not to mention how you position a satellite to deliver the transmission on demand.

[Mike Smith Cosmos]

Is human organs the only thing at risk? The SAR values I've come across are developed for human risk.

What about insects, plants and birds. I have encountered any surveys on this. Might bear looking into. The main risk is although your talking low frequency. You have a continuous stream. This alters the safe threshold limits on exposure times.

When I worked radio towers, all transmitters had to be shutdown. Regardless of transmission power and frequency. The only exception was when you were aligning microwave links. (Directional) even then we made sure to be behind the transmitter.

The effects of Radio wave pollution is still largely under study. We simply do not know for sure which frequencies and radiative power is considered 100% safe.

As such most sites state low frequency non thermal effects are still under debate.

although sunlight on Earth is on a daily schedule, this can be countered via battery storage. Far safer as your not introducing added radiwaves.

Plants, insects and wildlife have already adapted to the sunlight itself.

I think I better do some feasibility testing first at almost non existent energies. Then if it does look feasible I can go more into safe or not , defining usable energies.

 

Also I will have to devise a way to go from sunlight to long waves with a mains hum on it ( as an energy chain ).

 

 

MIKE

[Mordred]

Here Is some possible side effects currently under research.

 

http://www.nature.com/news/electronics-noise-disorients-migratory-birds-1.15176

http://www.jstor.org/stable/1941976?seq=1#page_scan_tab_contents

[Mike Smith Cosmos]

Not to mention how you position a satellite to deliver the transmission on demand.

 

Surely we are already doing this sort of thing ? Are there not satellites buzzing about up there in all sorts of orbits . Covering the earth for monitoring tide, weather, earthquakes, sea temperature, global positioning , telecoms , etc .

 

Mike

Here Is some possible side effects currently under research.

http://www.nature.com/news/electronics-noise-disorients-migratory-birds-1.15176

http://www.jstor.org/stable/1941976?seq=1#page_scan_tab_contents

Yes I see what you mean . There must be some radio waves that are harmless , surely ?

 

Mike

[Mordred]

Possibly, like I stated there is still studies underway. As to feasability. That too is a yes. NASA has already been exploring this option.

 

https://www.google.ca/url?sa=t&source=web&cd=2&ved=0CCcQFjABahUKEwjukeDdz9vGAhWLOT4KHcpsAPg&url=http%3A%2F%2Fntrs.nasa.gov%2Farchive%2Fnasa%2Fcasi.ntrs.nasa.gov%2F20080036588.pdf&rct=j&q=nasa%20wireless%20power%20transmission&ei=xYalVa6bMovz-AHK2YHADw&usg=AFQjCNHdEETW3wGazwsevEaMQlGqXMZTCg&sig2=bC7iK4T20ozPMLL79ylL5g

[swansont]

What you are in effect saying . " are the sort of long waves I am envisaging capable of being absorbed , anywhere near the level that it would cook human organs " . Surely as they are many orders of magnitude less than light waves , and sunlight does not cook us . At least as long as we don't lay in the sun for too many hours , then long waves should be a lot safer than sun light?

 

Mike

 

The problem here is that you keep quoting two specifications that are mutually exclusive. You cannot simultaneously have low power for safety and enough power to be useful for powering things.

 

Light that gets absorbed at the surface can quickly be radiated away with a small increase in temperature. Waves that penetrate before depositing energy require the core temperature to increase, to conduct heat to the skin, so it can radiate away (and have evaporative cooling, etc.)