No, it's not the next soft-drink campaign. "Dark
gulping" is a new hypothesis about how giant black holes might have formed
from collapsing dark matter.
Supermassive black holes are a
mystery. These behemoths can pack the mass of billions of suns, and often
lurk in the centers of big galaxies like
the Milky Way. But scientists don't know how they got started nor how they
grew so massive.
A new computer model suggests dark gulping is one possible
route to forming these monsters. The idea involves invisible dark matter, which
is stuff of unknown nature that astronomers know exists because they see its
gravitational effects on galaxies.
In this scenario, a large cloud of dark matter could
interact with gas to form a dense central mass. Depending on how the dark
matter stores heat, this mass could be unstable. A small disturbance might
prompt the dark matter to collapse quickly, gulping itself down to create a
black hole. Though it would originally
be invisible, soon it would gobble down regular matter and gas and, with
all that material swirling in and being superheated and luminous, become
visible.
This hypothesis seems plausible, but there is no proof yet
that it ever happened, said Kinwah Wu, an astrophysicist at University College
London's Mullard Space Science Laboratory, who built the model with colleague Curtis
Saxton.
"It's a viable, possible scenario," Wu told SPACE.com.
"The model works, but it doesn't mean that nature behaves like that. We
need more observational proof or disproof of this."
Saxton will present the findings this week at the European
Week of Astronomy and Space Science at the University of Hertfordshire in
Hatfield, England.
Black holes can't be seen because once light and matter get
inside one, they are trapped. But on the way in, all the material creates a
chaotic mess of radiation that does escape into space. From observations of far-away
quasars — bright objects thought to be anchored by black holes and
surrounded by intense star formation — scientists think that supermassive black
holes existed when the universe was less than a billion years old. Yet most
theories about these gigantors can't explain how they formed so early.
For example, many experts have suggested that supermassive
black holes are the result of smaller black holes merging. But that process
would likely have taken too long to account for their appearance when the
universe was so young.
Dark gulping is appealing because it would happen very
quickly, Wu said. Black holes born this way would simply be born huge, and
wouldn't have to accrete the matter slowly over time.
Ongoing studies attempting to figure out what dark matter is
made of and how it is spread around the universe could help prove or disprove
dark gulping.
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