Astronomy is experiencing an era of fundamental discoveries. An international team of scientists has confirmed the existence of a third dwarf galaxy that contains no dark matter. The discovery of object NGC 1052-DF9, located 67 million light-years from Earth, not only expands the catalog of celestial bodies but also challenges established theories about how stars are born and structures form in the Universe.
From Black Hole to Ghost Galaxy
The story of the discovery of NGC 1052-DF9 is full of surprises. Initially, astronomers mistakenly classified this object as a supermassive black hole. The turning point came when Yale University graduate student Michael Kaim put forward a bold hypothesis: what the scientists were facing was not a black hole, but a diffuse galaxy.
To test the theory, a detailed study was initiated using the Cosmic Web Imager optical instrument at the Keck Observatory in Hawaii. The observation results confirmed Kaim's assumption but revealed even more astonishing details.
The Mathematics of the Invisible
The key evidence for the absence of dark matter was the precise mass of the galaxy. By measuring the velocity of stars within DF9, researchers calculated its weight. It turned out to be equivalent to 100 million solar masses.
This figure fully corresponds to the volume of visible, ordinary matter for an object of this size. In the standard cosmological model, the situation would be different: if the galaxy possessed a normal amount of dark matter, its total mass would exceed 10 billion solar masses. In fact, DF9 is an object consisting exclusively of what we can see.
Witnesses of a Cosmic Catastrophe
The location of the new find is of particular interest. The galaxy NGC 1052-DF9 formed on a single straight line along with nine other galaxies. Two of them, DF2 and DF4, were discovered earlier by astronomers—they are also devoid of invisible matter.
The fact that three galaxies without dark matter are lined up in a narrow chain points to their common origin. According to the authors of the study, a high-speed collision of giant galaxies occurred in the past. During the powerful impact, ordinary gaseous matter separated from the heavy invisible dark matter. Subsequently, from this residual gas along the line of motion, a new trail of dwarf galaxies was formed.
Rewriting Physics Textbooks
This discovery changes fundamental views on the evolution of space. Until now, it was believed that stars could be born exclusively within a halo of dark matter, which serves as a gravitational framework. New data proves that under extreme conditions, this process is possible without its participation.
Furthermore, the discovery confirms that dark matter is a real physical substance capable of acting independently of gas. This deals a serious blow to alternative theories of modified gravity, which attempted to explain anomalies in stellar motion without introducing hypothetical dark matter.
Currently, astronomers continue observations using new telescopes, attempting to detect remnants of gas after the initial collision to finally reconstruct the picture of what happened billions of years ago.