Perhaps the most famous sight of a dying star is the Ring Nebula, known since 1779.
At just over 2,000 light years away, it is the closest dying star to Earth.
Upon observing it, Charles Messier wrote: “it is very dull, but perfectly outlined; it is as large as Jupiter & resembles a planet which is fading.”
This is where the term planetary nebula comes from: where dying stars blow off their outer layers.
But despite looking very much like a ring to our eyes, the Ring Nebula is anything but.
A huge, diffuse set of hydrogen shells surround it, showcasing the material blown off as the star dies.
Along our line-of-sight, two lobes of low-density gas extend towards and away from us.
We are viewing this structure almost directly down one of its poles, which explains its ring-like appearance.
In 2013, astronomers used new Hubble data to map out the nebula’s 3D structure.
The reflective, high-density gas is all most telescopes can see.
But we now know it isn’t a ring at all, but also displays intricate structure, with an outer halo, inner turbulence, lobes and knots.
This may be exactly the fate awaiting our Sun in the future.