How long do planetary nebulae last on average? What are some of the controlling factors? Doug KaupaCouncil Bluffs, Iowa To understand how long a planetary nebula remains visible, we first need to ...

In the cold dark of the constellation Ophiuchus, a faint, wraithlike shell of gas is quietly advertising the fate that awaits our own Sun. Astronomers call it the Little Ghost Nebula, a planetary ...