Large galaxies, like our own Milky Way, are thought to arise when lesser galaxies smash together and merge. But galaxy NGC 3621, shown here in an
optical image released today by the European Southern Observatory in Chile, seems to have missed
the drama. Located 22 million light-years away in the constellation Hydra, NGC 3621 is a spiral galaxy but lacks a central bulge of stars. Such bulges
reside in most spiral galaxies and often resemble the yolk of an egg. They typically form after a galactic collision, when the smaller galaxy dumps
stars into the central region of the larger one. Somehow, though, NGC 3621 has managed to remain bulgeless, suggesting it never experienced a major
galactic merger and thereby contradicting the idea that spirals grow by gobbling their lesser neighbors. The galaxy is part of a growing list of bulgeless spirals that challenge current models of galaxy formation.
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