More than three dozen heavy thinkers will meet this month in Tucson to probe and test gravity, from the subatomic level to the scale of the universe.
Much of the discussion will center on Einstein's theory of gravity, which is considered incompatible with quantum field theories. Scientists have failed to come up with a workable quantum theory of gravity.
The word quantum means a discrete amount of energy, often referred to as a packet of energy, said Peter A. Wehinger, an astronomer at the University of Arizona's Steward Observatory. "On an atomic scale, when light (or energy) is absorbed by matter, light is absorbed in discrete amounts or packets.
"While these packets are tiny, they have large-scale effects that influence large objects such as the sun and planets," Wehinger added. "We can predict the influence of gravity on large objects, including planets orbiting the sun, but such predictions fall apart at the subatomic level."
Conference planners predict a lively exchange of ideas.
"Our quest has become intensely exciting," said UA physicist Dimitrios Psaltis, a conference organizer.
New ideas are challenging previous proposals of how the gravitational force works, Psaltis said.
One of those ideas is that the universe contains extra dimensions that can be detected only by gravitational force, Psaltis said. Other new ideas aim to explain the existence of a mysterious energy field that permeates the entire universe and accounts for three-quarters of all its energy, called "dark energy."
"This conference is in part about the tension between gravitational theory and quantum mechanics, which has been a long-standing problem for physics," said Daniel Eisenstein, another conference organizer. "Part of the reason why the problem has been so hard to solve is that the results seem to only matter on energy and length scales vastly different from what we can access on Earth."
The Jan. 22-25 conference, at Tucson Marriott University Park, is funded by the University of Arizona's Theoretical Astrophysics Program. Attendance is by invitation only.
http://www.tucsoncitizen.com/ss/local/38909.php
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