The universe we inhabit comprises not only the visible matter we can see and touch but also a mysterious substance called dark matter. Despite its significant presence, dark matter remains an enigmatic entity, its true nature still shrouded in secrecy. Astronomers are determined to unravel this cosmic mystery, and one promising avenue lies in observing its gravitational impact on regular matter.
However, the complexity of galaxies, with their myriad interactions and events, poses challenges in isolating the influence of dark matter from the ordinary behavior of regular matter. Researchers at the University of Tartu in Estonia have identified a potential solution in ‘superbubbles,’ giant cavities carved out of interstellar space by colossal stellar explosions known as supernovas.
Superbubbles arise when multiple supernovas occur close together, their blast waves creating vast, high-density regions stretching thousands of light-years across. These cavities exhibit slightly lower density than their surroundings, resulting in subtle gravitational variations in their vicinity.
Through computer simulations of superbubbles and their environments, the researchers revealed that these gravitational differences influence both stars and dark matter passing through them. The superbubbles act as a source of friction, gradually slowing down the rotation rate of both types of matter.
Their findings indicate that the presence of superbubbles can reduce the overall rotation rate of stars and galaxies by approximately 4% per billion years. Over time, this can significantly deplete a galaxy’s rotational energy, impacting the orbits of both stars and dark matter.
Intriguingly, superbubbles affect dark matter and stars differently. Dark matter experiences a slower deceleration compared to stars, leading to a divergence in their respective evolution. The properties of dark matter within galaxies, including its rotational energy, also adapt to the frictional effects of superbubbles.
This adaptation, in turn, influences the gravitational connection between dark matter and normal matter, potentially offering a detectable signature. The researchers acknowledge that their results rely on simulations, but they anticipate that future studies will solidify the role of superbubbles in disentangling the enigmatic relationship between dark matter and normal matter.
By meticulously mapping the positions and velocities of stars near superbubbles, astronomers may uncover telltale signs of the underlying dark matter’s behavior, finally unlocking the secrets of this elusive cosmic entity.
