There is a "dark object" in our galaxy that is creating gigantic holes.
It is invisible, and it may not be composed of conventional matter. It may be something that astronomers have never before identified. And despite the fact that we cannot see the enormous thing, astronomers have recently discovered its effects, while not having seen the object itself.
Astronomer at Harvard-Smithsonian Center for Astrophysics researcher Ana Bonaca described the mysterious object as "a dense bullet of something." Bonaca presented proof of the existence of the object at a convention of the American Physical Society in Denver.
In our galaxy's longest star stream, GD-1, evidence of the object that is creating holes was identified.
A stellar stream is a collection of stars that orbits a galaxy that was originally a globular cluster or dwarf galaxy but has been ripped apart and stretched along its orbit by tidal forces.
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| The top image shows us what the G-1 looks like. The bottom image shows what it should look like. Image Credit: New Astrophysical Probes of Dark Matter, Ana Bonaca/GAIA. |
Bonaca noted to Live Science that star streams are often consistent and should resemble a single line that has been elongated by the galaxy's immense gravity.
Now, this stellar stream may have up to one gap, which corresponds to the initial globular cluster before its stars began migrating in two directions.
What is odd, though, is that GD-1 has a second gap with a very jagged edge.
This area has been dubbed the "spur" of GD-1. It seems that something quite enormous exploded into the star stream not too long ago.
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| An image from Bonaca’s presentations shows a detailed map of GD-1, revealing a second gap and spur. Image Credit: New Astrophysical Probes of Dark Matter, Ana Bonaca/GAIA. |
Whatever hit the stellar stream with such force tugged the stars with its gravity.
In other words, the star stream seems to have been "hit" by an "unseen" bullet, as Bonaca described it.
What this bullet is, we are unclear.
But it is large. It is powerful. We cannot perceive it. Did I mention it is massive?
“We can’t map [the impactor] to any luminous object that we have observed,” Bonaca explained to 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. So 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 centre of our galaxy.”
Several hypotheses exist as to what the strange item may be. One theory suggests that we should blame a secondary supermassive black hole in our galaxy.
Obviously, we have no proof that another black hole exists in our galaxy, so we cannot be certain.
In addition to the hypothesis that GD-1 was affected by a Black Hole, Bonaca thinks that a large mass of dark matter may have collided with the star stream. Bonaca clarified that this does not imply that the object is composed completely of dark matter.
“It could be that it’s a luminous object that went away somewhere, and it’s hiding somewhere in the galaxy,” she added.
We are aware that whatever the thing is, its scale is enormous.
“We know that it’s 10 to 20 parsecs [30 to 65 light-years] across,” Bonaca revealed. “About the size of a globular cluster.”
Reference(s): APS Physics, LiveScience