Planetary nebulae have nothing to do with planets?

Infrared image of the Helix planetary nebula

The durations of the lives of stars compared to our timescales feel like ages, but even our Sun will come to a natural death. It can be appreciated that even in the darkness of this event, beauty can be found since they produce planetary nebulae – one of the most captivating and prettiest astronomical objects to observe.

Looking at the sun (metaphorically, don’t look straight at the sun) we can see how brightly it shines compared to any other earthly phenomena, may they be natural or man made. That is only possible since the Sun and similar stars experience extreme conditions in their cores, the temperature and pressure being so high that hydrogen can fuse together forming helium. Therefore the “burning” inside the Sun is emitting the light that makes our plants grow, giving us life.

However, as the star keeps shining it keeps using its fuel and since the amount of hydrogen in the star is finite it will run out at some point. Now, not being supported by an insanely energetic progress anymore, the star is compressed under the gravitational force, making this the beginning of the end. Compressing means increasing the temperature again, which incredibly allows the star one last breath by now burning the helium in its core, heating it up again. This makes almost a heart beat effect of the star expanding and compressing until at last it stops. Each time the star expands it flings out its material to its surroundings leaving only its hot core. The star has now transformed into a white dwarf.

There is now a lot of material just floating around, being heated by the white dwarf. This makes the material shine in different visible colours that can be seen by us. The first planetary nebulae were discovered in the 18th century and mistakingly named so because they reminded the observers of planets, due to their shapes and colours. Although, the phenomena has nothing to do with planets, it is still interesting to see this piece of history remain.

A similar fate will await the sun in about 5 billion years, changing our solar system irreversibly, leaving behind a beautiful masterpiece for other life to observe.