Abstract: The first galaxies form stars out of initially pristine gas. After a
few million years the gas is enriched with heavy elements formed by
the first generation of stars. Dust starts to appear in small
amounts, and H2 formation by catalysis on dust grains begins.
JWST Spectroscopy of I Zw 18, a very metal-poor star-forming galaxy in
the nearby universe, provides an opportunity to study these
beginnings. The composition of the first dust is found to be very
different from dust in a mature galaxy such as the Milky Way. The
molecular hydrogen emission spectrum allows the ortho/para ratio to be
determined, with the ortho/para ratio found to exceed 3 in some regions.
Implications will be discussed.