Tuesday 20 April 2021

Cat's Eye Nebula is a celebration of cat's eyes

There is a nebula in space, millions of light years away, which is called the Cat's Eye Nebula. It is a beautiful, gaseous object that was first discovered by William Herschel on February 15, 1786. Although it is difficult to measure its distance from Earth, it is believed to be 3300 light years away. This means it would take 3300 years to travel to the nebula when travelling at the speed of light which is 186,000 mi/s or 300,000 km/s. The photograph is a composite image of three different images taken at different wavelengths. The images were taken by the Wide Field Planetary Camera-2.

Cat's Eye Nebula. Photo: Wikipedia under CC license.

Surprisingly to me, it's estimated age is believed to be 1000 years ± 260 years.

Turning to cats! The domestic cat's eye is a beautiful object. There are two perhaps four things that come to mind, immediately. Firstly, we all know that there is a reflective layer behind the retina which directs light back onto the retina which in turn enhances the eye's ability to detect objects in low light conditions. The cat's eye also has a preponderance of rods over cones which are designed to detect light under difficult conditions and produce a black-and-white image. Thirdly, a kitten's eyes have no colour or pigmentation in the iris and are therefore blue due to the refraction of daylight through the eye. Fourthly, in the cat fancy, breed standards dictate the colour of the eyes of any one cat breed. They may be a wide selection to choose from but sometimes they have to be just one colour such as for the Russian Blue whose eyes have to be vivid green.

Russian Blue vivid green eye colour per breed standard. Pic: in public domain.

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