Our ears make sounds

The cilia of the inner ear - downloaded long ago, no source
The cilia of the inner ear - downloaded long ago, no source

According to this interesting article in New Scientist, our ears make sounds.  Called otoacoustic emissions or OAE’s, the tiny hairs in the ears (above) make very quiet sounds that are unique to an individual.

That’s because “hearing is an active process – the ear actually puts energy into the incoming sound waves to replace energy lost as sound is absorbed by the ear’s structure”, says Stephen Beeby, an engineer at the University of Southampton, UK, who is leading the research. “This process helps us hear things we otherwise would not, but as a result some of the energy added by the hair cells escapes as OAEs.”

Jacob Kirkegaard recording "Labyrithitis"

These sounds are between 0-5kHz and are thought to maybe be a kind of biometric password to be used over the phone.  A quick search found no recordings of OAE’s but did turn up the work “Labyrinthitis” by Jacob Kirkegaard.  The work is complicated, but Kirkegaard essentially recorded the frequencies his ear produced, synthesized and arranged a composition with them, and output them in a large performance/installation at the Medical Museion in Copenhagen.  The description of this work goes into more detail of how the piece was constructed and well worth the read.  An excerpt of a recording is below:

Images of molecules

Using a specially-designed microscope under extreme vacuum and low temperature, and a measuring tip smaller than the size of an atom, scientists were able to get very clear images of molecules.  This technique, known as non-contact atomic force microscopy (I think I often strive for the titles of my pieces to be as clear as the names of scientific processes, but that’s another post altogether) is covered in this article on the Royal Society of Chemistry site.  The above image is a pentacene molecule on a copper surface.

The technique works without touching the molecule – instead (as I understand it) there is an overlap of the electrons between the sensing tip and the molecule itself.  Energy is exchanged and recorded, that data is then translated into an image.  In a way, this is a lot like traditional photography, where the camera doesn’t touch the object but records light bouncing off of it.  Maybe we need consumer-level imaging devices that aren’t light-based, but record other types of energy.

Via: Make blog

Sound of the first million years

If you can ignore the initial ultra-cheesy graphic (not the one above, which is the Cosmic Microwave Background), Mark Whittle’s article on the unpacking of the sound of the universe after the Big Bang is fascinating.  It turns out that in space, people can hear you scream… at least, during the first million years you can.  A few interesting quotes (emphasis Whittle’s), and a simulation of the sound:

… the Big Bang started out utterly silent! The initial expansion was absolutely pure and “radial” – no parts were catching up any other parts, and hence there were no pressure waves, and hence no sound. All was quiet.

… [at the time of the Big Bang] the Universe was much smaller (by at least a factor of 1000), and all the matter we now find in stars and galaxies was spread out uniformly. Add to this the fact that the young Universe was also much hotter, and we learn that over the first million years, all of space was filled with a hot thin uniform glowing gas, a billion times denser than the current cosmic density. Not only did the Universe have an atmosphere – in a sense, it was an atmosphere. It was within this atmosphere that sound waves could form and move in the young Universe.

… How do we measure the pressure variations in the primordial atmosphere? Simple: we look at the brightness variations on the CMB. These variations tell us the strength of the pressure waves were between one ten-thousandth (10-4) and one hundred thousandth (10-5). So these correspond to around 110 decibels. This is neither inaudibly quiet nor lethally loud: it is powerfully loud — it is about as loud as a rock concert!

This is what the universe sounded like, shifted up 50 octaves (to be audible) and compressed into 10 seconds.

Via: Mark Whittle