Astronomers say they’ve finally spotted something they’ve only talked about in theory: a “failed galaxy” made mostly of dark matter and gas, with not a single star in sight. NASA has nicknamed the object “Cloud-9,” describing it as a starless, hydrogen-rich cloud dominated by dark matter about 14 million light-years away. Researchers have long suspected such structures existed — essentially dark matter clumps that never gathered enough gas to ignite stars — but this is the first confirmed example, according to NASA. The team says Cloud-9, described in Astrophysical Journal Letters, offers a fresh look at how galaxies might have formed, or fizzled, in the early universe, per CBS News.
First flagged three years ago, Cloud-9 was recently scrutinized with the Hubble Space Telescope, which found no stars inside. That absence is exactly the point, says lead investigator Alejandro Benitez-Llambay of the University of Milano-Bicocca, who calls it “the tale of a failed galaxy,” adding that “in science, we usually learn more from the failures than from the successes.” The cloud’s core is made of neutral hydrogen spanning roughly 4,900 light-years, with hydrogen alone totaling around a million times the mass of the sun. The dark matter component is far larger — about 5 billion solar masses — prompting team member Andrew Fox to describe Cloud-9 as a “window into the dark universe.”
Cloud-9 is one of nine gas clouds on the outskirts of the nearby spiral galaxy Messier 94, but it stands out as smaller, denser, and more spherical than its neighbors and appears physically linked to that galaxy, NASA says. Its existence suggests there may be many more small, dark-matter-heavy structures lurking unnoticed, usually drowned out by the light of nearby stars and galaxies. Astronomers plan additional surveys to hunt for similar objects and to test ideas about dark matter, galaxy formation, and the conditions of the early cosmos. As for Cloud-9 itself, NASA notes it may not be finished evolving: if it keeps accumulating gas, this failed galaxy could one day turn into a real one.
