One idea around black holes is that they
connect to a dimension-spanning cosmic
wormhole. But what if instead of feeding
into a raging white hole on the other side
(see “C”, left), the universe’s plumbing is a
lot less spectacular?
Leonard Susskind of Stanford
University in California and Juan
Maldacena at Princeton University
have imagined a kind of wormhole that
branches away from a black hole in many
directions like the root network of a tree.
Each tiny pipe is only big enough for
individual photons of Hawking radiation
to emerge, allowing the black hole to
evaporate, while skirting the paradoxes
of the firewall and information loss. The
information is conserved as it exits the
black hole down one of these roots, and
no firewall is created because nothing
crosses back over the event horizon.
What’s more, because we have done away
with partner particles, the monogamy
of entanglement never needs to be
broken. Win-win!
Unfortunately, there is a problem.
According to Aidan Chatwin-Davies at KU
Leuven in Belgium, this process violates
the core principle of quantum physics
that information cannot be destroyed
(see “A”, page 31). If you toss a quantum
entity into a black hole, and what comes
out is thermal radiation, the information
it contained has vanished from our
universe. And that is a big cosmic no-no.
Y
You tried to violate information conservation –
and that never goes well. Maybe try ∞ (right)?
Take a space-time leak
What if our universe isn’t the only
one? It is a radical idea, but one that
proponents of the many-worlds view
of quantum mechanics take seriously.
Every time a quantum process takes
place, they say, the universe splits,
creating a different parallel world for
every conceivable future.
That means that when you jump into
a black hole, every conceivable outcome
is taking place somewhere in some
parallel plane of existence. That means
that you can appear to violate the
fundamental principle of information
conservation (see “A”, page 31), so long as
the way you do that is compensated for
in another cosmos.
The different branches of the many-
worlds multiverse are all correlated, says
Aidan Chatwin-Davies at KU Leuven in
Belgium, and that means your fate has
now been spread across multiple versions
of the multiverse. So pick your poison!
You could be burning up in firewalls,
falling through white holes, leaking into
the fabric of space-time or possibly never
falling in at all. The laws of physics may
break down in the universe that we can
see and interact with, but across the
billions of potential realities, sanity
is restored.Z
Split the universe
Congratulations (maybe) – one of you
(probably) survivedThere is a get-out-of-jail-free card for all these
unpalatable black hole scenarios: to simply
reimagine what a black hole is. In classical
physics, there is no way to stop matter from
collecting, turning into a star and then collapsing
into a black hole. Gravity just won’t stop.
Enter string theory. It starts with the idea
that matter isn’t made of fundamental particles,
but instead is composed of tiny strings. In the
crushing gravity where a normal black hole
would be, these strings would get tangled
together. “The more energy you put into a
system, the bigger the ball of strings becomes,”
says Samir Mathur at Ohio State University. “It
never really makes a black hole. It’s a planet-like
object made out of strings, and a planet doesn’t
create the information-loss problem.”
You would still die a pretty terrible death if
you fell onto a fuzzball like this, but instead of
becoming part of nothing, you would become
something. First, you would get warm as you
approached it. As you passed the event horizon
and continued towards the massive string ball,
you would be torn apart and your body would
turn into a bundle of strings just as you reach
the surface.
After you get absorbed into the ball of
strings, you would start spreading out across
the surface of the black hole, mixing in with the
other strings there. “At that point, you would
be pulled apart and you wouldn’t be living any
more. But your strings would be vibrating,” says
Mathur. Your thoughts and memories would be
long gone, but the stuff that made you would
be part of one of the most bizarre places in
the universe. Not a bad way to go.THE END – until some theorist dreams up
something better. ■Chelsea Whyte is a news reporter for New
Scientist based in Boston, Massachusetts∞
It wasn’t a
black hole
after all
20 April 2019 | NewScientist | 33