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Conversation with my Six Year Old: Infrasound

(While putting him to bed, after looking at a book about fossils.)

6 yr. old:  I wonder if the dinosaurs knew the meteor was coming.

Me:  How would they know it was coming?  They weren’t that intelligent.  

6 yr. old:  Infrasound.

Me:  Infrasound? 

6 yr. old:  All natural disasters make a noise before they hit.  Every time the space shuttle launches in Florida the alligators grumble.

Me:  What does that have to do with natural disasters?

6 yr. old:  They hear the noise and think one is coming.  If a tsunami is about to hit the safest place to be is on top of an elephant.

Me:   Because it is high up?

6 yr. old:  Because he will hear the infrasound and run away.

Me:  Are you making this up?  I have never heard of it.

6 yr. old:  Scientists just recently discovered it.  

Me:  Alright, time for bed.  (To my husband, sitting at the computer when I got downstairs)  Can you Google infrasound and find out if it is a real thing? 

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The human eye detects a limited amount of light.  Light waves continually travel through our atmosphere by stealth.  Gama-rays, microwaves, ultraviolet light, they all get by (and through) us unseen.  Of all the light in the electromagnetic spectrum – a scale of available light in the universe ranked in order of energy – we humans can visually detect about a millionth of a percent.   Our ears are no different; they have a detection limit too.   

Infrared radiation is the name for light with shorter frequencies (longer wavelengths) than our eyes can detect.   Similarly, infrasound comes from sound vibrations with shorter frequencies than our ears can detect.  The human ear can pick up a range of sounds between 20 to 20,000 Hertz.  Infrasound is anything below that range.  It is produced by both human induced processes – like atomic explosions – and by geophysical events, such as earthquakes, volcanic activity or severe weather.  

Up until the 1970’s infrasound detection was hampered by instrumentation that lacked sufficient sensitivity to distinguish these low frequency sounds from background noise.   Higher quality electronics and improved software have lead to advances in infrasonic detection in the past few decades, but significant limitations still exist.  For example, utilizing infrasound in early warning systems is hampered by the fact that sound bends and shifts with temperature, making it difficult to pin-point its source.  The National Oceanic & Atmospheric Administration (NOAA) has an Infrasonics Program working to overcome this problem and put infrasound to work as a natural disaster detector.  The main drive of the program is the development and installation of instruments to measure low-frequency sounds.  

While humans struggle to measure infrasound, animals are getting the message loud and clear.  Many large animals are known to communicate over long distances using infrasound.  The infrasonic communications of elephants have been studied most intently, but rhinoceroses, hippopotami, alligators, and buffalo have also been identified users.  It is believed that the size of the animals allows them to receive infrasound wavelengths which are tens to hundreds of meters long.

Although these wavelengths are a stretch for human ears, there is evidence we can sense infrasound.  Studies which expose participants to infrasound laced music without their knowledge reveal a wide range of effects on the body.  Some participants felt that music containing low frequency sounds made them tired, uncomfortable or depressed.  Many described pressure in their ears and vibration of internal organs.   

There are even studies that suggest infrasound explains the paranormal.  British researcher, Vic Tandy, discovered that infrasound can pulse at the resonance frequency of the human eye.  The sound induces a vibration which distorts the eye and creates a hazy figure.  Couple this vision with a feeling of awe or fear – as reported by some experiencing infrasound – and, according to Tandy – who published a 1998 paper on the subject – you have a scientific explanation for believing in ghosts.  

Infrasound is not a recent discovery, but technological advances are allowing scientists to determine its significance in our world.  In the world of a six year old boy, it ranks way up there at Super Cool.  Thankfully I have him around to teach me these things.  Maybe he should be the science writer. 

Flickr Photo: Infrasound array 

Bruises and Brutality

In the latest episode of This Chaotic Life, our heroine, Rebecca Guenard, receives a blow to the head from her dog.  With Marsha Brady insightfulness, she is immediately aware that the impact has broken her nose (on the distal third of the nasal bone – according to the radiology report).  As a crimson geyser erupts from her right nostril, she is stricken by the thought that she is the only adult in the house and it is too late to call a neighbor for help.  So she does what any other emotionally resilient woman would do, she goes to bed, crying like a baby over eminent raccoon eyes  

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A bruise occurs when blunt trauma ruptures capillaries and blood spills into surrounding tissue.  Hemoglobin in the pooled blood breaks down and results in the familiar sequence of a bruise’s appearance.  A bruise is initially red, it turns green by day six and as the tissue enters the final stages of healing the bruise becomes yellow (8-9 days).  Hemoglobin is a protein in blood that transports oxygen throughout the body.  A contributor to hemoglobin’s red color, iron, is caged in a ring structure known as a porphyrin.  As a bruise heals the porphyrin cracks open, freeing iron and producing biliverdin; a compound that emits a green hue.  The cracked cage of biliverdin is then bent completely open into the compound bilirubin.  Bilirubin, the same compound responsible for jaundice, gives a bruise its final yellow color before skin coloration returns to normal.    

This physiological kaleidoscope was demystified in the late fifties and early sixties by a scientist at Ohio State University name Mostafa K. Hamdy.  The research is simple, precise, regularly cited by a number of fields and, for a time, set the guidelines for the forensic determination a bruise’s age.  Decades later his research (along with others) was found to be overly generalized, especially as it pertained to bruised children and whether they had suffered parental abuse.     

The experiments are brutal.  A frequently cited paper titled, Bruised Tissues III. Some Factors Affecting Experimental Bruises describes repeatedly inflicting bruises on 40 rabbits to observe the effects of consecutive bruising.  It is determined that subsequent bruising reduces healing time - by nearly a day and a half on the third bruise.  And they found that a blood transfusion from triply abused bunnies into first time abusees also shortened their healing time.  Fascinating research, but does relevance justify the means?

There were sections of the article that were impossible for me to read.  One section began:  Relationship of forces applied to extent of bruising.  Both cattle and rabbits were bruised by various techniques.”  Beyond that my eyes flashed upon the words “hammers” and “wooden sticks” and I couldn’t read any further. This is the section of the article that most citations refer to, which states the chronological color change of a bruise is the same regardless of force.

In the past few days people look away quickly after initial eye contact.  Do they assume that the coloring under my eyes is a result of abuse?  Or are they grimacing in empathy to my pain?  Would they be interested to know that our physiological understanding of my bruised face is a result of the pain inflicted in the course of animal cruelty?