A "Dense Bullet of Something" Blasted Holes in the Milky Way

Dan Robitzski in Off World
Scientists say that something mysterious punched gigantic, cosmic “bullet holes” in parts of the Milky Way.

There’s a string of holes in a long stream of stars called GD-1 that suggests that some yet-undiscovered thing blasted its way through, according to research presented to the American Physical Society last month and first reported by Live Science. Harvard-Smithsonian astrophysicist Ana Bonaca, the scientist who discovered the cosmic crime scene, suspects that the gigantic “bullet holes” may have been carved out by invisible dark matter.
Whodunnit

Unfortunately, the culprit of this celestial shooting seems to have gotten away with it — Bonaca told Live Science that there’s no evidence at the crime scene beyond the size of the gaps in the stellar stream.

“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.”

Dark Hammer

Because there’s no evidence of such a black hole, Bonaca suspects a ball of dark matter may have crashed through the stars. But it’s too early to definitively rule out any possibilities.

“It’s a dense bullet of something,” Bonaca said.

Editor’s note: this story has been updated to clarify that the research was first reported by Live Science.