China has a plan to launch a new project an “Artificial Moon” that will light up the skies as far as 50 miles around. The…
This visible-light image that was taken by the high resolution channel of Hubble’s Advanced Camera for Surveys shows planetary nebula Hen 3-1333.
Planetary nebulae have nothing to do with planets, they actually represent the death throes of mid-sized stars like the sun. As they puff out their outer layers, large, irregular globes of glowing gas expand around them, which appeared planet-like through the small telescopes that were used by their first discoverers. The star at the heart of Hen 3-1333 is thought to have a mass of around 60% that of the sun, but unlike the sun, its apparent brightness varies substantially over time. Astronomers believe this variability is caused by a disc of dust which lies almost edge-on when viewed from Earth, which periodically obscures the star. It is a Wolf-Rayet type star, a late stage in the evolution of sun-sized stars. These are named after Wolf–Rayet stars, which are much larger. Both Wolf–Rayet and Wolf–Rayet type stars are hot and bright because their helium cores are exposed: the former because of the strong stellar winds characteristic of these stars, the latter because the outer layers of the stars have been puffed away as the star runs low on fuel.