.
-as of [20 SEPTEMBER 2024]-
.
*NOTE* –>
*’ITU’* –> *”INTERNATIONAL TELECOMMUNICATIONS UNION”*
.
“extremely low frequency” (‘ELF’) is the ‘ITU designation’ for ‘electromagnetic radiation’ (aka ‘radio waves’) with…
*’frequencies’ from ‘3 Hz’ – ’30 Hz‘*
*corresponding ‘wavelengths’ from ‘100K kilometers’ – ’10K kilometers’*
.
(…although the definiton researchers in the field(s) of ‘atmospheric science’ prefer to multiply ‘Hz upper limit’ by 100,,,)
*from 3 Hz to 3 kHz.*
(or ‘3000 Hz’)
.
(in the related ‘magnetosphere science’, the ‘lower frequency electromagnetic oscillations’ (or ‘pulsations’ occurring below ~3 Hz) are considered to lie in the ‘ULF’ range, which is thus also defined differently from the ‘ITU radio bands’)
(‘ELF radio waves’ are generated by ‘lightning’ and ‘natural disturbances’ in earth’s ‘magnetic field’, so they are a ‘subject of research’ by ‘atmospheric scientists’)
(because of the difficulty of building ‘antennas’ that can ‘radiate’ such ‘long waves’, ‘ELF frequencies’ have been used in only a very few ‘human-made communication systems’)
(‘ELF waves’ can penetrate ‘seawater’, which makes them useful in ‘communication’ with ‘submarines’)
(‘USA’ / ‘RUSSIA’ / ‘INDIA’ are the only 3 ‘nations’ known to have constructed ‘ELF communication facilities’)
(the ‘USA facilities’ were used between ‘1985’ – ‘2004’ but are now ‘decommissioned’)
(‘ELF waves’ can also penetrate significant distances into ‘earth’ or ‘rock’, and “through-the-earth” ‘underground mine communication systems’ use ‘frequencies ‘of ‘300Hz’ to ‘3000 Hz’)
.
(the ‘frequency’ of ‘alternating current’ flowing in ‘electric power grids’ (~ 50 – 60 Hz), also falls within the ‘ELF band’, making ‘power grids’ an ‘unintentional source’ of ‘ELF radiation’)
.
.
*👨🔬🕵️♀️🙇♀️*SKETCHES*🙇♂️👩🔬🕵️♂️*
.
.
.
👈👈👈☜*“NON-IONIZING RADIATION”* ☞ 👉👉👉
.
.
💕💝💖💓🖤💙🖤💙🖤💙🖤❤️💚💛🧡❣️💞💔💘❣️🧡💛💚❤️🖤💜🖤💙🖤💙🖤💗💖💝💘
.
.
*🌈✨ *TABLE OF CONTENTS* ✨🌷*
.
.
🔥🔥🔥🔥🔥🔥*we won the war* 🔥🔥🔥🔥🔥🔥