Aurora Borealis – arise when the charged particles from the Sun (the so-called solar wind) hit the Earth’s magnetic field. Along its lines are directed to the poles, where they collide with molecules of air. There was a belief that between fairy tales you should put in the history that polar lights sometimes made sounds, even “whispered” – until the case was investigated by scientists from the University of Aalto in Finland. The truth is that when the nights are cold and silent, auroras create rustlings and cracks. Audible for hundreds of kilometers. The reason is the so-called inversion layer. It arises when it is colder near the surface of the planet than at higher levels of the atmosphere. It causes that negatively charged particles from the Sun are trapped in the cold zone. If their accumulation exceeds the critical point. By reacting with positive ions in the atmosphere and causing discharges, rustling and crackling.
Birds made sounds
Birds made sounds – Birds make sounds using a special organ called the lower larynx. Situated at the end of the trachea, it has no vocal cords, such as mammals. Their function is performed membrane located in the trachea and bronchi major. A loud sound is made possible by strengthening it in the air sac – special tabs lungs. In addition, organ voice bird consists of two parts which can work independently of each other, and some species are able to sing at the same time two different melodies. Many species of birds there is no organ voice, and the sound from such dates. Clatter of the bow (storks) or hitting with various hard objects (woodpeckers).
Rat hearing border – Squeaky sounds
Rat hearing border – Rats communicate squeaky sounds over the boundary of human hearing – to hear sounds in the frequency range of 250 Hz to 80 kHz. Their hearing is most sensitive to the range of 8-38 kHz. For comparison – the human ear responding to sound between 16 Hz and 20 kHz. And most sensitive to a range of 2-5 kHz.
Drunk zebra finch
Drunk zebra finch – Christopher Olson of the Oregon Health and Science University, conducted an experiment on the zebra finch (Taeniopygia guttata), to learn and make sounds in a manner similar to humans. Males were divided into two groups. The first group was treated fruit juice for 4 days and the other was added to the juice 6.5% alcohol. Birds that consumed alcohol, singing slower, quieter and less clearly.
Dogs barking volume – Most dogs is 80-90 dB
Dogs barking volume – Volume barking most dogs is 80-90 dB, which is maintained at the level of the human scream. However, the record in the field of barking is the golden retriever Charlie from Australia, which in 2013. Was in the Guinness World Records, with his voice the strength of 113.1 decibels.
Brain prediction – Recognize problem 0.1 s before it
Brain prediction – Researchers from the Max Planck Institute for Neurological Research, discovered that the brain can predict events that may have unpleasant consequences for us. They found that if the pianists when playing commit falsehood, a record electroencephalograph (EEG) jumped before the musicians touched the wrong button and heard a bad sound. Brain recognize the problem 0.1 seconds before it.