Planetary nebulae have been the subjects of some of Hubble's most stunning images. Despite their name, these picturesque objects have nothing to do with planets. The earlier astronomers observing them knew they weren't planets. They didn't move across the sky. But they were given the name as they resembled distant planets in the telescopes of the day. When better telescopes came along, astronomers were able to see their more intricate structure and reveal their true nature. They are huge shells of gas, formed when sun-like stars run out of fuel and throw off their outer layers. These shells are then heated up, ionized and illuminated by the fierce ultraviolet radiation from the star's hot core, which remains at the nebula's heart, resulting in spectacular light shows like the ones seen here. These nebulae glow in all manner of beautiful colors, due to the presence of different gases. The famous ring nebula, for example, glows in vibrant blue greens, reds and oranges, caused by regions of glowing oxygen, hydrogen and nitrogen. The twinge-et nebula has a rather different appearance from the ring nebula, with two iridescent lobes of material stretching outwards from the nebula's centre. The reason for this odd structure is hidden at the nebula's core. The twinge-et nebula is a bipolar nebula, and the characteristic shape is thought to be caused by there being not one, but two stars at its heart. The ring nebula is a bipolar nebula, which is thought to be caused by there being not one, but two stars at its heart. Within the lobes, starting from the star system and extending horizontally outwards like veins, two faint blue-hued patches are visible. These are intense twinge-ets of gas, streaming out into space. The jets are hurtling away from the star system, at speeds in excess of 1 million kilometres per hour. As they travel, they slowly change their orientation over time, twisting slowly through space like water from a garden lawn sprinkler. This phenomenon is again thought to be attributable to the duo of stars orbiting at the nebula's centre. Despite the clarity of this image, binary star systems and the nebulae are still mysterious. Hubble has much to explore, but for now, we can continue to enjoy their beauty from afar.