Probing a super-giant shell of gas and stars In one of the
largest known star formation regions in the Large Magellanic
Cloud (LMC), a small satellite galaxy of the Milky Way, lie
young and bright stellar groupings known as OB associations. One
of these associations, called LH 72, was captured in this
dramatic NASA/ESA Hubble Space Telescope image. It consists of a
few high-mass, young stars embedded in a beautiful and dense
nebula of hydrogen gas. Much of the star formation in the LMC
occurs in super-giant shells. These regions of interstellar gas
are thought to have formed due to strong stellar winds and
supernova explosions that cleared away much of the material
around the stars creating wind-blown shells. The swept-up gas
eventually cools down and fragments into smaller clouds that dot
the edges of these regions and eventually collapse to form new
stars. The biggest of these shells, home to LH 72, is designated
LMC4. With a diameter of about 6000 light-years, it is the
largest in the Local Group of galaxi