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STARS FORM
FROM THE
INSIDE OUT
NSIDE GIANT MOLECULAR CLOUDSI
S
tars form inside dark globules
of dust and gas that are
called giant molecular clouds
(GMCs). However, the process by
which a cloud of gas transforms
into an embryonic star, or protostar,
has never been observed, partly
because the process must take
millions of years, and partly because
even the most advanced telescopes
find it difficult to penetrate the dark
density of the cloud.
Without observational evidence,
astrophysicists must construct
mathematical models for what they
think is happening inside those
dark globules. The most consistent
model of star formation was derived
by US mathematician Frank Shu.IN CONTEXT
KEY ASTRONOMER
Frank Shu (1943–)BEFORE
1947 Bart Bok observes dark
nebulae and suggests that
they are sites of star formation.1966 Frank Shu and
Chia-Chiao Lin develop
the density wave theory
to explain spiral arms in
the Milky Way.AFTER
2003 The Spitzer Space
Telescope, an infrared
observatory, is launched.
It produces the best view
yet of stellar nurseries.2018 First light on the
James Webb Space Telescope
will allow astronomers
to study protostars inside
dark Bok globules.