Researchers uncovered a “dark impactor” that is punching holes in the Milky Way Galaxy. The lack of understanding about mysterious holes in the Milky Way galaxy comes because we can’t really see it, as it may be a result of dark matter that surrounds the visible universe. While our telescopes can’t directly observe it, researchers have evidence that the impactor exists.
Ana Bonaca, a researcher at the Harvard-Smithsonian Center for Astrophysics, who discovered evidence for the impactor presented her findings on April 15 at the conference of the American Physical Society in Denver. The dark impactor seems to be making holes in the galaxy’s longest stellar stream called GD-1. Stellar streams represent lines of stars that stretch across the galaxy. The stars located inside GD-1 are remains of a “globular cluster” that collided into the Milky Way galaxy and then stretched in a long line across the sky.
“We can’t map [the impactor] to any luminous object that we have observed,” Bonaca told Live Science. “It’s much more massive than a star… Something like a million times the mass of the sun. So there are just no stars of that mass. We can rule that out. And if it were a black hole, it would be a supermassive black hole of the kind we find at the center of our own galaxy.”
Bonaca has also not ruled out the possibility that there is another supermassive black hole which could answer to the mysterious holes in the Milky Way Galaxy. However, she noted that there would be evidence or sign of it before, such as flares of radiation that originate from its accretion disk. Moreover, the vast majority of large galaxies have a supermassive black hole at their hearts. With that in mind, the only possibility that is left to the scientists is that dark matter affects the holes from GD-1. However, that doesn’t mean that the entire object making mysterious holes in the Milky Way galaxy is from a black hole.
“It could be that it’s a luminous object that went away somewhere, and it’s hiding somewhere in the galaxy,” she said. “We know that it’s 10 to 20 parsecs [30 to 65 light-years] across,” she said. “About the size of a globular cluster.”
Still, the researchers suggest it could be a luminous object, as they don’t know how fast the object was moving when the impact happened. That said, perhaps it moved quite fast, but didn’t measure as heavy as expected. On the contrary it could be an extremely heavy object with slower movement. Until researchers have the answer, they can only propose different theories.
The possibility of dark matter punching holes in the Milky Way Galaxy is still fascinating, as researchers haven’t answered the question about dark matter’s definition yet. The visible universe consists of luminous matter but a great part of it remains invisible. Researchers only know about the dark matter as a result of its gravity acting on visible matter, as galaxies bind together exposing something heavy, yet invisible to our eyes.
According to Bonaca, the research will continue, with more mapping projects to com, that could expose the origin of the dark impactor.