Monday, May 16, 2016

Ask Ethan: How Does Dark Matter Interact With Black Holes?

Ask Ethan: How Does Dark Matter Interact With Black Holes? (Synopsis):

“A single day is enough to make us a little larger or, another time, a little smaller.” –Paul Klee
When it comes to normal matter, dark matter is a bit of a puzzle. Other than through the gravitational force, there’s no way we’ve yet figured out to make it interact. Try and collide it with matter and it passes right through; try and bombard it with energetic particles or radiation and it’s completely transparent. But the story is quite different when it comes to dark matter and black holes.



A black hole feeding off of an accretion disk. Image credit: Mark Garlick (University of Warwick).


A black hole feeding off of an accretion disk. Image credit: Mark Garlick (University of Warwick).
While it won’t make an accretion disk or “funnel” into the black hole, once it crosses the event horizon, it inevitably hurls towards the singularity, adding to the mass and angular momentum of the black hole. But beyond that, there’s no way to know what went into your black hole, as what comes back out in the form of Hawking radiation will have no memory of how much dark matter vs. how much normal matter went into your black hole to begin with.



Image credit: Concept art by NASA; Jörn Wilms (Tübingen) et al.; ESA.


Image credit: Concept art by NASA; Jörn Wilms (Tübingen) et al.; ESA.
Come get the answers to even more questions about dark matter and black holes on this edition of Ask Ethan!