Humans can smell 1 trillion odors

A study by scientists from the United States (U.S.) found that the human nose can smell at least a trillion different smells, exceeding previous estimates.

For many years, scientists believed the human nose can detect only about 10,000 smells, a lower level of ability than that of sight and hearing.

Director of Neurogenetics Laboratory at Rockefeller University, Leslie Vosshall said, 'The study conducted recently found that the ability of human smell is more intense than previous expectations.

Previously, in the 1920s, scientists estimated that the human nose can detect smells with the help of about 400 sensory olfactory nerves.

However, the ability of the nose is considered lower than that of the human eye, which has only three sensory nerves yet can differentiate millions of colors, and the ear can also differentiate 340,000 sounds.

"The latest research shows that the human sense of smell is greater compared to that of the eye and ear. The nose had an important social function in ancient times."

"People in the past relied on their sense of smell to differentiate an object or food, but the invention of the refrigerator and the level of hygiene has increased in modern times, limiting the ability of the nose to function."

Mystery of Zebra Stripes Revealed

The black and white stripes on zebras' bodies help protect these animals from predators. The colors that not mixed with the background skin of the body are used to outwit predators.

Scientists used a computer model to emphasize the lines until they can created an optical illusion when zebras moved. Line formation is apparently quite confusing that can protect it from predators. Dr. Martin How who is the studying leader said, "Stripe lines on Zebra body has long make's ​​evolutionary biologists confused"

The first theory of this line is like a signal of social communications, camouflage while grazing at dusk and dawn, and protect themselves from predators by creating a dazzling effect. The research was done by scientists from the University of Queensland, Australia, which and was published in the Journal of Zoology.

To test this new theory, Dr. How analyzes photographs and video footage of zebras. Computer models that track the collection of line pattern show the optical illusion lines that cause misleading information.

Scientists say that this includes the phenomenon of "Motion Detection Mechanism (MDM)," is, the neural circuitry that processes the motion of an object based on how the contours of the object appears. One example of the most confusing illusion mechanism is a barber pole effect. Red and blue spiral stripes on the barber pole seem to move up when the pole is spinning.