Sounds that are lower pitched are less studied than other types. Some say it’s a health hazard. Others have doubts. By Lourdes Medrano/Undark Published Apr 17, 2024 8:00 AM EDT This article was ...

Mechanical antennas represent a disruptive approach to low-frequency communication by exploiting the mechanical oscillation of electric charges or magnetic dipoles to generate electromagnetic ...

Quasiperiodic (QP) very low frequency (VLF) emissions are intermittent bursts of electromagnetic energy, observed in the frequency range of approximately 3–30 kHz, that recur at quasi-regular ...

For decades, seismologists have known that Earth is never completely still, even when no earthquakes are happening and no volcanoes are erupting. Sensitive instruments worldwide record a continuous ...

Non-ionizing radiation includes the spectrum of ultraviolet (UV), visible light, infrared (IR), microwave (MW), radio frequency (RF) and extremely low frequency (ELF). Lasers commonly operate in the ...

A head-mounted device generates an ultra-low frequency ultralow magnetic field, known as an Extremely Low Frequency Magnetic Environment (ELF-ELME). A head-mounted device that generates an ultra-low ...

Visit NAP.edu/10766 to get more information about this book, to buy it in print, or to download it as a free PDF.

In the global game of nuclear brinksmanship, secrets are the coin of the realm. This was especially true during the Cold War, when each side fielded armies of spies to ferret out what the other guy ...