Martin Bojowald is a theoretical physicist at the Institute for Gravitational Physics and Geometry, Pennsylvania State University, in University Park. He has time on his mind and he is often seen looking curiously into our past—even to before the Big Bang—the theoretical beginning of our universe.

Bojowald uses loop quantum gravity (LQG), the theoretical study of gravity at very minute scales, to look back at the first moments of the universe. Bojojwald tries to reconcile the theories of general relativity and quantum mechanics by quantizing Albert Einstein’s equations within general relativity.

Bojowald works in an area where the physical laws break down—at the point when the universe began: the Big Bang. Physicists call this point the Big Bang singularity. In his studies, Bojowald divides the universe into cubes that are 10^-99 cubic centimeters in volume. Even though this is an extremely small volume, within each cube is matter, space, and time—all within tiny interconnected loops.

These intersecting loops are objects that are even more fundamental than strings (the fundamental structure of String theory). Space-time, itself, could be constructed of these fundamental particles, which are predicted to behave very closely to particles of matter. LQG predicts ten or eleven dimensions of the universe rather than the multitude of dimensions with one-dimensional strings of String theory and the four dimensions (three in space and one in time) with zero-dimensional particles of the Standard Model.

At these extremely small sizes, gravity (its called quantum gravitation) is repulsive, rather than attractive like in our normal world. In this state, quantum gravity (theoretically) prevents the collapse of space and time (space-time) into a singularity.

Bojowald has run mathematical equations through computers to show that the singularity can be eliminated as the end of a Big Bang cycle flows into the start of a Big Crunch cycle and, similarly, as the end of a Big Crunch cycle goes into the start of a Big Bang cycle.

However, when these points are reached, almost all the information from the previous universe is lost to the new universe, which is different from the old one. Thus, all universes are slightly different from each other. The old universe forgets most of what it knew at the end of its life, but does retain some of it for use in the new universe. Bojowald calls this loss of information: Cosmic Forgetfulness.

Most cosmologists have not supported LQG theory in the past. However, Bojowald is helping to make it a serious contender in a theory to explain the universe. Future experiments could help resolve whether Bojowald is correct or not—whether particles exist as points, strings, or loops. Are there other possibilities?

The Large Hadron Collider (LHC), built near Geneva, Switzerland, by CERN (The European Centre for Nuclear Research) is a particle accelerator that could produce such experimental evidence. It is scheduled to begin operations in May 2008. When it becomes fully operational it will be the world’s largest and highest energy particle accelerator. The 17-mile (27-kilometer) ring-shaped tunnel will collide two beams of protons head-on at speeds so great that conditions will be created similar to the first moments after the Big Bang.

In addition, the European Space Agency's (ESA’s) Planck Surveyor mission should also provide indirect support for Bojowald’s ideas. This satellite, scheduled to lift off in 2008, will test theories of the early universe by looking at the radiation left over from the Big Bang, what is called cosmic microwave background (CMB).

Sometime after the year 2015, data from NASA's and ESA’s Laser Interferometer Space Antenna (LISA) could reveal a quantum gravity effect from the early universe in its observations of ripples in space-time. It is an experiment that is designed to use three spacecraft arranged in an equilateral triangle to form a Michelson interferometer with sides that are about five million kilometers in length. When gravitational waves cross its field, the differences in the relative lengths of the sides can be measured.

Bojojwald’s theory is one of a number of theories that are trying to explain the structure of the universe. His latest paper, titled “What happened before the Big Bang?”, appears in the July 1, 2007 issue of the journal Nature.

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