The Puffy Ring Nebula:
A SPHERICAL WIND BLOWN BUBBLE
A cosmic  smoke ring? No this nebula (also known as NGC 6369) is the gravestone of a dying sun-like star more than 1000 light years (a trillion trillion trillion miles) away. The glowing ring shown in this Hubble Space Telescope image is actually a spherical shell of gas produced 5,000 years ago.  The star at the center is just like the sun only 5 billion years older. As it the star ages it drives a sequence of powerful winds into space.  The older the star gets the faster the wind becomes.  The fast winds overtake the slower ones sweeping them up into the bright glowing shell you see in this picture. There are other examples of spherical wind blown bubbles around dying stars. Click on the images below to see some more.