HomeScience and Nature 5 sounds not meant for the human ear

5 sounds not meant for the human ear

by admin

HUMAN HEARING has its limits. Frequencies as high as 20,000 hertz (think of an anti-loitering alarm) can cause a pair of young ears to perk up. Any vibes above that fall into the range of ultrasound, meaning they don’t register to us at all. But gadgets like full-spectrum recorders and radio scanners have upped our auditory sensitivity and let us explore new worlds of information. Here are five shrill and mysterious noises that we’ve harnessed in some form.

A singer’s impossible peak

You might imagine Mariah Carey or Maria Callas would top the scales, but Brazilian soprano Georgia Brown set the bar by hitting a G in the high 10th octave. Musical experts later confirmed the note, which translates to about 25,000 hertz, earning Brown a Guinness World Record in 2004.

A medical device’s dramatic whine

Ultrasound machines create energy waves so fast and furious that they can pass through bone, fat, tissue, and other masses. The intensity of the transmissions depends on the medical application: Prenatal checks are usually set at 2.5 million hertz, breast scans at 5 million hertz, and skin-inflammation screenings at 100 million hertz. In some cases, extreme frequencies heal too: Pulses at 1 million to 3 million hertz have proven therapeutic for knee injuries like MCL sprains.

The cosmos’s cryptic message

In general, the universe operates in low frequencies (NASA recently recorded a black hole “screaming” at 57 octaves below the average adult voice). A mysterious radio signal from an unknown extraterrestrial location, though, screeches at such a high pitch that astronomers haven’t been able to precisely measure it. Nicknamed the “space roar,” this intense but diffuse energy wave could top out at 3 billion hertz.

A bat’s remarkable song

A diverse collection of creatures communicate in ultrasound, including katydids and hummingbirds. One species, however, takes it to a whole other level. The clear-winged woolly bat of Southeast Asia has one of the widest vocal ranges ever measured. Its echolocating buzzes can reach 250,000 hertz—more than 10 times higher than a human’s top shriek. Biologists hypothesize that the night flyers are locked in an evolutionary war with tasty moths: The higher the mammals raise their voices, the lower the chance their prey will hear them coming.

The body’s telling thrum

Heart murmurs can be a benign quirk or the sign of a deadly health condition. Family doctors might listen for them with a stethoscope, but a test called a Doppler ultrasound shows these irregular blood flows can whoosh around at up to 410 hertz, which is more than double the usual pitch. As a murmur courses through the arteries in the chest at varying speeds, the frequency of its sound changes, giving cardiologists a clue to the source’s severity.

This story originally appeared in the High Issue of Popular Science. Read more PopSci+ stories.

Source : Popular Science

Related Articles

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish.AcceptRead More

5 sounds not meant for the human ear  
Le petit soldat de plomb: Les plus beaux contes pour enfants * JO de Paris 2024 : pas de sportifs russes « tant qu'il y aura la guerre – Le Parisien * The Hill’s Morning Report — Biden to GOP: ‘Let’s finish the job’ *  *Salem High coach Mark McGinn credits family and hockey with helping him battling melanoma – Eagle-Tribune * Gordon S Gin Crisp concombre Gin (1 x 0,7 L) *  *-*25 pièces Décor de l’habitat Reptiles, PietyPet Dragon barbu Hamac, 2 naturel Hamac reptile avec Artificielle Vignes d’escalade et Lierre Plante pour Lézard escalade, Caméléon, Gecko, Serpents, Tortue * Scott Casque de Ski Bleu Taille M * Télévision : Michel Drucker hospitalisé pour des tests, son émission hebdomadaire passe en rediffusions *  * Erreur : SQLSTATE[HY000] [1203] User jpc_theglobe already has more than 'max_user_connections' active connections5 sounds not meant for the human ear*5 sounds not meant for the human ear 5 sounds not meant for the human ear