Dark matter is an invisible, hypothetical form of matter in the universe. It does not emit light, nor does it reflect or absorb light. Scientists estimate that 26.8 percent of the universe is composed of dark matter. However, a new discovery this year has, for the first time, confirmed the existence of a dark matter celestial object.
According to a statement released by the National Aeronautics and Space Administration (NASA), a research team has discovered a new type of celestial body named “Cloud-9.” It is described as a dark matter hydrogen cloud rich in gas but containing no stars. Reports indicate that Cloud-9 is located 14 million light-years from Earth and is believed to be a remnant formed during the early stages of the universe. NASA noted that scientists had previously theorized the existence of objects like Cloud-9, but this discovery marks the first confirmation. It is considered a dark matter cloud because it failed to accumulate enough gas to form stars.
About three years ago, the galaxy associated with Cloud-9 was identified, but only recently did observations from the Hubble Space Telescope confirm that there are no stars within it. Alejandro Benítez-Llambay, an assistant professor at the University of Milano-Bicocca in Italy and the lead researcher of the Hubble team, stated that Cloud-9 is essentially a failed galaxy. However, he noted that failed cases often teach us more than successful ones. The absence of stars in the observations confirms theoretical predictions. Alejandro added that this represents the discovery of primordial building blocks of galaxies that have yet to form in our nearby universe.
Despite not having formed into a galaxy, Cloud-9 is still substantial in scale. According to NASA, its core is composed of neutral hydrogen with a mass one million times that of the Sun and a diameter of 4,900 light-years. In addition, Cloud-9 contains a large amount of dark matter—estimated to be equivalent to five billion solar masses. Because of this, research team member Andrew Fox has referred to it as “a window into the dark universe.”
Andrew explained that previous theories suggest most of the universe’s mass consists of dark matter, but since it does not emit light, it is extremely difficult to detect. The appearance of Cloud-9 provides a rare opportunity to observe a cloud primarily composed of dark matter. Its discovery suggests that there may be other small celestial objects in the universe also dominated by dark matter. However, their presence may be concealed by nearby galaxies or stars, which draw scientists’ attention due to their brightness. Cloud-9 offers a different perspective.
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So far, Cloud-9 is the ninth gas cloud discovered in the outer region of the spiral galaxy M94. Compared with other cases, it is more compact, smaller in size, and nearly spherical in shape. Scholars believe it may have some physical connection with the spiral galaxy M94. Just as air is invisible to the naked eye yet truly exists, objects like Cloud-9 are the kind astronomers seek. They may lead to new discoveries about dark matter and the early universe. Researcher Rachel Beaton commented that among the Milky Way’s neighbors, there may be some “abandoned houses.”
As for Cloud-9’s future, NASA believes it may continue to evolve. If it keeps expanding, it is not impossible that it could eventually form into a galaxy.
This article is based on NASA’s report titled “NASA’s Hubble Observes Cloud-9, the First Newly Discovered Object of Its Kind.”
