One of the first planetary nebulae to be discovered, the Cat's Eye nebula has a very complex structure for its type. Planetary nebulae are formed when stars expel gas from their outer layers, creating spectacular shapes like the rings, knots and jets of a cat's eye.

In this image from NASA's Hubble Space Telescope, each visible "ring" is the outer boundary of a spherical dust bubble. This nebula has eleven visible shells, each formed by the mass ejection of its stars at 1,500-year intervals, forming onion-like rings from our perspective. The mass of each dust sphere is equal to the sum of all the planets in our solar system.

Image Description:

The Cat's Eye Nebula stands out with its light orange and blue colours against black space. Eleven rings can be seen, changing colour from blue to orange as they reach the knotted gas bubbles in the centre. An orange fountain of gas cuts diagonally across the centre.