Hubble Discovers Starless Dark Matter Cloud Near Messier 94

NASA’s Hubble Space Telescope has identified a rare and unusual astronomical object nicknamed Cloud-9, offering new insights into early galaxy formation. Located about 14 million light-years from Earth near the spiral galaxy Messier 94, the object appears to be a massive cloud of gas dominated by dark matter, with no stars formed within it. Scientists consider it a relic from the early universe, preserved in a largely unchanged state.

What Is Cloud-9?

Cloud-9 is classified as a Reionization-Limited H I Cloud (RELHIC). The term “H I” refers to neutral hydrogen, indicating that the cloud is composed primarily of non-ionised hydrogen gas. The structure spans roughly 4,900 light-years and contains hydrogen with a mass nearly one million times that of the Sun. Remarkably, calculations suggest that the surrounding dark matter halo has a mass of about five billion solar masses, making Cloud-9 overwhelmingly dark-matter dominated.

A Fossil from the Early Universe

According to NASA, RELHICs are natal hydrogen clouds left over from the universe’s earliest epochs that failed to ignite star formation. Alejandro Benitez-Llambay of the University of Milano-Bicocca, the principal investigator of the study, described Cloud-9 as “a failed galaxy.” He noted that the absence of stars is crucial evidence supporting theoretical models of galaxy formation, as it confirms the existence of primordial building blocks that never evolved into full galaxies.

Why the Discovery Matters

Cloud-9 provides astronomers with a rare opportunity to study dark matter in a relatively isolated environment. Since dark matter does not emit or absorb light, it is usually detected only through its gravitational influence. Observing a cloud where dark matter dominates but stars are absent allows scientists to test long-standing theories about how galaxies form and why some never succeed.

Imporatnt Facts for Exams

• “H I” denotes neutral hydrogen in astronomical terminology.
• Dark matter constitutes most of the universe’s total mass.
• RELHICs are relic gas clouds from the early universe.
• Hubble Space Telescope is jointly operated by NASA and ESA.

Scientific Publication and Global Significance

The findings were published in “The Astrophysical Journal Letters” and presented at a press conference in Phoenix. Andrew Fox of the Association of Universities for Research in Astronomy at the Space Telescope Science Institute, working with the European Space Agency, described Cloud-9 as “a window into the dark universe.” The discovery strengthens evidence that many dark-matter-dominated structures may exist nearby, offering crucial clues to the universe’s hidden mass and its earliest evolutionary stages.