Scientists have long known that most of the matter in the universe is invisible. This hidden material, called dark matter, makes up about 85% of all matter.
Even though we cannot see it, we know it exists because of its strong gravitational pull on stars and galaxies.
Now, a new study suggests that a special type of dark matter may help explain several puzzling observations in space.
The research, led by physicist Hai-Bo Yu at the University of California, Riverside, proposes that dark matter may not be as simple as scientists once thought.
The traditional view describes dark matter as “cold” and collisionless, meaning its particles do not interact with each other and simply pass through one another.
While this idea works well in many cases, it struggles to explain some unusually dense structures that astronomers have observed.
Yu and his team explored a different idea called self-interacting dark matter, or SIDM.
In this model, dark matter particles can bump into each other and exchange energy, much like people moving through a crowded space.
Over time, these interactions can cause the dark matter to clump together and form very dense regions. This process is known as gravothermal collapse.
The researchers found that these dense clumps could be incredibly massive, each containing about a million times the mass of our sun.
Despite their size, they would remain invisible because they do not emit light. However, their gravitational effects could still be detected.
What makes this idea especially interesting is that it may explain three very different cosmic mysteries at once.
One example comes from a distant system known as JVAS B1938+666, where astronomers have observed an extremely dense object through its ability to bend and magnify light from galaxies behind it.
This effect, called gravitational lensing, suggests the presence of something massive but unseen.
Closer to home, in our own galaxy, there is a long stream of stars called GD-1. This stream shows a strange gap and a spur-like feature, as if something invisible passed through it and disrupted the stars. The new study suggests that a dense clump of self-interacting dark matter could have caused this disturbance.
A third mystery involves a compact group of stars known as Fornax 6, located in a small galaxy that orbits the Milky Way. Scientists have struggled to explain how such a tight cluster formed. According to the new model, a dense clump of dark matter could act like a gravitational trap, pulling in nearby stars and holding them together.
What is striking about this research is that one simple idea may explain all three phenomena, even though they occur in very different parts of the universe. From distant galaxies to our own cosmic neighborhood, these invisible clumps could be shaping the structure of the universe in ways we are only beginning to understand.
While more evidence is needed, this study opens a new path for exploring the true nature of dark matter and how it influences the cosmos.
