Outer space...is a vast slow cooker. The densest interstellar gas may contain 10,000 hydrogen atoms in a cubic centimeter, and three or four carbon atoms. This is a thousand trillionth of the density of the air we breathe. An atom in deep space may travel 100,000 kilometers before bumping into a partner.
But... a long underappreciated bevy of three protons and two electrons called protonated molecular hydrogen, or H3+, catalyzes a great network of reactions as elements collide, or stick to the surface of star-produced microscopic silicate and carbon dust grains. Over many millions of years, compounds as complex as polycyclic aromatic hydrocarbons are manufactured, with dozens of carbon atoms in arrays of benzene rings. Other structures are precursors to amino acids...Goodbye Copernicus, Hello Universe by Caleb Scharf.
See also Deep Space, Branching Molecules, and Life’s Origins?
Image: Ben McCall