Picture of the month

This brand new image of NGC 2440 adds to the already very impressive collection of planetary nebulae observed by the Hubble Space Telescope. It shows the last colourful display of a star like our Sun in the act of dying. The star is ending its life by casting off its outer layers of gas. The core of the dying star – visible as a white dot at the centre – is called a white dwarf. Although no bigger than the Earth, it is very hot and thus radiating ultraviolet light, making the ejected material glow. Image: ESA/K Noll/STScI.