NOT all galaxies grow up to be productive star-forming members of the universe. But just as delinquent youth can reveal a lot about the human condition, these delinquent galaxies could tell us about the conditions required for star formation.
Galaxies begin as clouds of hydrogen and dark matter that contract under their own gravity until they become dense enough to create stars. Usually that triggers a runaway reaction, with more and more stars forming until the ratio of star mass to gas mass is more than 2 to 1.
But certain galaxies appear to stop developing almost as soon as…
