You exist on a rocky planet orbiting a yellow dwarf star of little importance that will get brighter, then expand, burning Earth to a crisp (in about 1-3 billion years), before exploding and spreading atoms—including yours—across the Milky Way.
The Sun fuses hydrogen atoms into helium atoms. This is nuclear fusion and it produces incredible energy. However, as its hydrogen reserves dwindle that process will speed-up, making the Sun shrink yet shine more brightly. Earth will be scolded and become bone-dry.
In about 5.5 billion years the Sun will run out of hydrogen and begin expanding as it burns helium. It will swap from being a yellow giant to a red giant, expanding beyond the orbit of Mars and vaporizing Earth—including the atoms that make-up you.
The Sun as a red giant will then… go supernova? Actually, no—it doesn’t have enough mass to explode.
Instead, it will lose its outer layers and condense into a white dwarf star about the same size as our planet is now.
It’s that cloud of dust expelled by our dying Sun as a white dwarf visible around our Sun as a white dwarf that will be our legacy—a spectacular planetary nebula.
A planetary nebula is the glowing gas around a dying, Sun-like star.
It will glow with the ultraviolet light from the Sun as a white dwarf.
A planetary nebula is the final—and fairly brief—stage in the life of a medium-sized star like our Sun.
There is, however, a kicker.
When the Sun leaves behind a nebulae it will no longer be in the Milky Way.
A billion years before the Sun explodes, the Milky Way will have collided and merged with the Andromeda Galaxy—currently the closest major galaxy to us at 2.5 million light-years—to create a new, massive galaxy called (perhaps) “Milkdromeda.”
Wishing you clear skies and wide eyes.