From the August 2010 issue

Billions of years from now, what will be the fate of our Sun? Would it be a hard surface we could walk on?

Rich Livitski, Norwalk, California
By | Published: August 23, 2010 | Last updated on May 18, 2023
October 2010 sun-like star
A Sun-like star ends up as a carbon-oxygen white dwarf (center), the leftover core of its former self. In the late stages, the star pulsates and loses its atmosphere, usually in brilliant fashion, forming a planetary nebula. The Cat’s Eye Nebula, shown here, is one of the most complex planetary nebula structures.
NASA/ESA/HEIC/and The Hubble Heritage Team (STScI/AURA)

When all that is left is the carbon-oxygen core — which is extremely small and dense (a teaspoonful would weigh a ton) — we would call the Sun, ultimately, a white dwarf. I wouldn’t recommend trying to walk on one of these objects, however.