|
|
|
|
|
Miniature Black Holes May Open Window to Other Dimension
By GAIL BROWN
|
|
|
UCSB physicist Steven Giddings plans to
use particle accelerators to try to create miniature black holes.
|
The possibility of scientists
identifying traces of miniature black holes created in an accelerator is
being explored by Steven B. Giddings, UCSB professor of physics and his
colaborator, Scott Thomas, an assistant professor of physics at Stanford
University.
"If certain theories of nature are correct, then black holes would be produced
in high-energy collisions of particles in particle accelerators," said
Giddings. These theories go by the generic name of "TeV-scale gravity.
"TeV-scale gravity is expected to be tested in the next generation of particle
accelerators, with the Large Hadron Collider near Geneva, Switzerland being
the first of these," he added.Giddings explained that the only scenarios
we know that allow black holes to be produced at energies around a TeV
are those with extra dimensions of space-time. There may, however, be other
scenarios not yet discovered. And if miniature black holes are produced
in accelerators, their properties will depend on properties of the extra
dimensions. In fact, the creation of bigger and bigger black holes may
allow exploration of the geography of any extra dimensions. "If nature
allows us to create black holes in accelerators, then that also means that
they should be created when cosmic rays strike the atmosphere," Giddings
said. Why create even small black holes? Wouldn't they gobble up everything
in sight?Giddings answered that one of British physicist Stephen Hawking's
greatest discoveries is that black holes evaporate. Small ones evaporate
exceedingly quickly, in around 10 to the minus 17 seconds. "They simply
don't have time to absorb an appreciable amount of matter before they explode,"
he said. When they explode they are expected to send out a tiny amount
of radiation, which scientists will be able to detect. Hawking has also
shown that black holes behave as if they have a temperature--which decreases
as the black holes get bigger. The little ones are quite hot, and therefore
radiate their energy away very quickly.Giddings expects miniature black
holes to increase understanding about the relationship between quantum
mechanics and gravity. Black hole evaporation is a quantum-mechanical phenomenon.
Big black holes, like those in the center of galaxies, evaporate so slowly
that scientists do not expect to be able to see this phenomenon there.
However, for small black holes, quantum-mechanical effects are very important,
indeed crucial, in determining their behavior and evolution. So, once scientists
can study small black holes, they can start learning about the relationship
between quantum mechanics and gravity.Studying miniature black holes will
reveal a wealth of information about the very fabric of the universe, explained
Giddings. "Black holes are perhaps the most profound and mysterious objects
we've imagined. Being able to create and study them should teach us a lot.
In particular, it can teach us about how quantum mechanics can be reconciled
with gravity; it could allow us to explore extra dimensions of space and
time; and it may tell us something about an ultimate unified theory of
physics." |
|