Reasons to Believe

Higher Dimensions

My favorite science fiction stories, next to those tales involving time-travel, include some aspect of extra-dimensionality...

Where the reader gets to explore the strange effects that could occur when moving beyond the three spatial dimensions in which we live. Unlike time travel, however, there is a possibility that higher dimensions actually exist. I refer to string theory, where as many as seven spatial dimensions beyond the normal three are posited to exist.

In the physics and engineering departments of the Virginia Institute of Technology, scientists are working together to explore the possibility of an extra dimension in the structure of our universe. As they note in a news release describing their research, “this extra dimension would be curled up, in a state similar to that of the entire universe at the time of the Big Bang.” They hope to find some type of evidence that would indicate the existence of higher dimensions.

The group is looking for small primordial black holes that, when they explode, may produce a radio frequency pulse of radiation that could be detected here on Earth. Scientists believe these black holes were created in the first fraction of a second after the Big Bang. Usually we think of black holes as objects that gain mass by gravitationally pulling in any material in their surroundings but also have gravitational fields so strong they will not let anything out, including light. However, theory says that black holes evaporate over time by a quantum tunneling process called Hawking Radiation, losing mass and thereby shrinking. This process can take a very long time, about 1067 years for a black hole the size of a solar mass. For smaller black holes the time can be much shorter, even as brief as one second for a black hole of mass equivalent to about 3 cubic meters of rock.

When the size of the black hole is larger than the curled-up extra dimension, it wraps around that dimension like a rubber band wrapped around a rolled-up hose. As the black hole shrinks down to the size of the extra dimension, it becomes stretched so thin that it snaps, causing an explosion and releasing a pulse of radio emission. The Virginia Tech team has built an Eight-meter-wavelength Transient Array (ETA) radio telescope to search the sky for these radio pulses. Its sensitivity should pick up this radiation from explosions as far away as 300 light-years. They have had a similar telescope in operation for several months. By requiring coincident pulses from both instruments, they can weed out false detections.

If these observers can detect this radiation, it will provide some of the first direct evidence for the extra dimensions required by string theory. Extra dimensions also play an important role, by analogy, in RTB’s argument for the transcendence of the Creator.

Subjects: String Theory

Dr. David Rogstad

Dr. Dave Rogstad received his PhD in physics from Caltech and worked over 30 years for NASA’s Jet Propulsion Laboratory. Though now retired, Dave continues to serve as an RTB board member and participates regularly in several RTB podcasts.