Every element used in the chemistry of life was originally synthesized in stars that exhausted their hydrogen fuel and began fusing the heavens.
I think as ancient stars died, they would cast off large clouds of heavy elements.
That they ultimately formed into the gas and dust clouds forming the next generation of solar systems.
All of the nitrogen, carbon, oxygen and iron used by life was present in primordial clouds that formed the solar system.
Carl Sagan’s quote was a poetic way of expressing the chemical connection between living things on Earth and the stars above them.
All this still remains; is it the same sky everywhere; maybe the cosmos is within us.
Maybe that’s it’s just a part of the mystery of the universe. I wonder.