NASA Hubble Image: Planetary Nebula NGC 5189

This object is an expanding cloud of gas rushing away from a dying star. Right in the very center you can see the star itself, a tiny blue dot whose appearance belies its power.

Once a star like the Sun, the central star of NGC 5189 is now a dense, extremely hot cinder called a white dwarf.

It’s probably only the size of the Earth but is 100,000 times denser than our planet.

A few thousand years ago this star was dying.

It had swollen into a red giant, a huge, bloated thing that was expelling a strong, thick wind of gas into space.

Over time the star shrank and heated up, turning bluish and starting to blow a thinner but much faster wind.

The fast wind caught up with and slammed into the older, slower, thicker wind, carving out a cavity in it.

We call these kinds of clouds planetary nebulae, becasue through small telescopes some of them look round and green, like planets.