The mysterious properties of black holes can be recreated on a tabletop, scientists now reveal.
Solving mysteries concerning black holes could yield key clues toward a "theory of everything" that unites how we conceive of all the natural forces.
Black holes rank among the greatest enigmas of the universe. Scientists
theorize black holes have gravitational pulls so powerful that nothing,
including light, can escape after falling past a border known as the
event horizon.
Direct experiments with black holes are unlikely, due at the very least
to how far any are from Eearth, not to mention how difficult these
warps in space and time would be to work with. Instead, researchers are
searching for ways to create lab models of event horizons.
Now scientists have created an artificial event horizon on a tabletop using fiber optics.
The researchers started by firing a stream of intense, brief laser
pulses inside an optical fiber. These pulses acted like a current of
flowing light.
Such intense, brief pulses "make physical effects visible that would
also occur for much longer and weaker pulses, but are hard to detect
there," explained researcher Ulf Leonhardt, a theoretical physicist at
the University of St. Andrews in Scotland. "High intensity and short
pulses are needed for seeing subtle effects and discriminating them
from noise."
At the same time, the researchers fired a continuous beam of infrared
light down the optical fiber. This beam created waves that got
overtaken by the laser flow, resembling how light waves are overcome by
the gravitational pull just past an event horizon.
"The most surprising aspect for me is how simple it actually is to
create artificial event horizons," Leonhardt told LiveScience. He and
his colleagues detailed their findings in the March 7 issue of the
journal Science.
Scientists had proposed other systems to mimic aspects of black holes.
All those, however, needed moving parts — specifically, very fragile,
ultra-cold blobs of matter — and none of them have yet successfully
displayed phenomena resembling event horizons.
The artificial event horizons Leonhardt and his colleagues have devised
could help researchers explore bizarre aspects of black holes, such as
radiation they are supposed to emit. Black holes are not entirely black
— instead, physicist Stephen Hawking discovered that all black holes
should evaporate at least a bit, leaking energy dubbed "Hawking
radiation."
Scientists have not yet seen this mysterious energy — Hawking radiation from normal black holes is completely obscured by the cosmic microwave background,
radiation left over from the Big Bang that pervades the entire
universe. However, Leonhardt suggests that with their new lab model,
"we can create artificial event horizons that would generate enough
Hawking radiation to be detectable."
A greater understanding of Hawking radiation could help unite our
currently disparate theories of physics into one "theory of
everything." that could conceive of all the natural forces.
So far scientists have not successfully united the field of general relativity,
which explains how matter and energy behaves at large scales and
predicts the existence of black holes, with that of quantum mechanics,
which helps explain how matter and energy behaveact at the atomic level
(and at smaller levels)below and predicts the existence of Hawking
radiation.
A better understanding of Hawking radiation could help bridge general
rel
ativity with quantum mechanics to understand how these "worlds are
connected," Leonhardt explained.
Copyright: Space.com
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