Today’s New Reason To Believe

by Jeffrey Zweerink

A team of particle physicists hope to soon being operation of the most powerful man-made particle accelerator, the Large Hadron Collider (LHC). Although much press has focused on scientists who claim that LHC might produce objects that will eventually destroy Earth, I thought it useful to discuss one potential discovery it might make, namely the existence of extra dimensions.

The advances in string theory research over the past two decades indicate the existence of dimensions beyond the four space-time dimensions we experience. Precision tests of gravity constrain the size of any proposed extra dimensions at less than the average width of human hair. However, particle colliders like the LHC provide more powerful probes of the size of extra dimensions and also their shape.

Almost every currently available model that attempts to unify all four fundamental forces under one theoretical umbrella requires the existence of these extra dimensions. One might wonder how these extra dimensions fit within RTB’s creation model because life depends on the universe having exactly three large spatial dimensions and one large time dimension (referred to as 3+1 dimensions).

While life requires a universe 3+1 dimensionality (for the large dimensions), the extra dimensions in unified theories are small and highly curved or compactified. No experimental evidence supports the existence of these extra dimensions, but LHC scientists hope to find such evidence as data accumulates from the abundant particle collisions. In particular, certain particles can be formed only if the compactified dimensions are highly curved. Detection of these particles would verify the existence of the extra dimensions required in unified models. (For a more technical description of the particles, see this article in the Physical Review Letters.)

Only time will tell what the experimental data will reveal, but I believe the LHC will probably detect evidence of these dimensions. Furthermore, I expect future investigations of the dimensions to provide further support for the idea that a supernatural Creator fashioned this universe to support humanity.

If you would like to see a question about the multiverse addressed in this forum, send it to multiverse@reasons.org.

by Dr. Jeffrey Zweerink

“Test everything. Hold on to the good.” This biblical passage underscores a central principle of the scientific enterprise. Any successful model must undergo testing that will either affirm or falsify its validity. Many scientists work diligently to provide such tests for a popular (though virtually untested experimentally) model known as string theory.

Astrophysicists Rishi Khatri and Benjamin D. Wandelt of the University of Illinois at Urbana-Champaign seek to develop an observational test for the cosmic strings (not to be confused with the strings of string theory) that result from incorporating a popular form of inflation—brane inflation—into string theory. They outline the test in a recent Physical Review article (a more lay-accessible description appears in Science Daily).

The abundant neutral hydrogen that fills the universe emits electromagnetic radiation with a specific wavelength: 21 cm. Astronomers have mapped this radiation as a function of position in the sky as shown below (see the description at the Astronomy Picture of the Day). All the structure in the image arises from material within the Milky Way Galaxy.

The hydrogen in the early universe would have produced evenly distributed 21-cm radiation (similar to the cosmic microwave background radiation). According to the research of Khatri and Wandelt, the cosmic web of strings produced during inflation will leave a signature in the 21 cm wavelength radiation which would be detectable with future instruments. However, the expansion of the universe will have redshifted the radiation roughly one hundred times to a wavelength around 21 meters. To make measurements precise enough to detect the cosmic string signature would take a square array of radio telescopes more than 100 kilometers on a side!

This daunting technical challenge demonstrates the difficulty in testing string theory. However, the rewards are worth the effort because the detection of cosmic strings would reveal to scientists the energy where gravity and quantum mechanics unify. While these tests may lie far in the future, RTB anticipates that the outcome of such tests will further demonstrate the fine-tuning (necessary for life) in the fundamental laws of physics that govern our universe.

by Jeff Zweerink

Richard Feynman

Level III multiverse

Kip Thorne

Wormholes

Hugh Everett

Black holes

The man representing the common thread linking these influential scientists and important scientific concepts, John Archibald Wheeler, passed away on April 13th, 2008, at the age of 96. During his scientific career, John Wheeler worked on topics ranging from nuclear explosions to quantum mechanics to black holes and the nature of space-time. He collaborated with Albert Einstein, Neils Bohr, and many other influential scientists. Additionally, he supervised the graduate research of many (Feynman, Thorne, and Everett) who would become leaders in their fields.

Wheeler’s scientific legacy demonstrates his willingness to address hard questions—even ones that he found philosophically uncomfortable. His encouragement of Everett’s work in quantum mechanics provides a great example.

Unlike the everyday “classical” world which we experience, the quantum mechanical world operates in a bizarre fashion. A thought experiment by Erwin Schrödinger, among the earliest to study quantum mechanics, demonstrates the strangeness. Imagine a cat confined to a box. A scientist puts one undecayed atom of a radioactive material inside the box. This material has sufficient power to kill the cat when the atom decays. At any given time, there is some probability that the atom has decayed and some probability that it has not. All this makes sense in a classical picture.

However, according to quantum mechanics, the atom exists in a state described as a combination of its original state and its decayed state. While that may make sense for the atom, the condition of the cat depends on the state of the atom. The cat also exists in a combination of a live state and a dead state! Yet when someone observes the cat, it will either be dead or alive. How the quantum world gives the observations of our “classical” world has been debated for nearly one hundred years.

The argument advanced by Hugh Everett forms the basis of the Level III multiverse. Briefly, observers will see the cat in one of two possible states—dead or alive—with some probability associated with each outcome. Everett argued that whenever a quantum event has multiple possible outcomes, each outcome actually occurs, resulting in new universes that never again interact!

Many arguments exist for and against this “many worlds interpretation” (MWI) of quantum mechanics. The MWI does present challenges to RTB’s model. However, like Wheeler, RTB scholars hope to address challenges head-on. Research into this difficult issue provides avenues to better understand how God created the universe and as well as additional tests to validate and refine RTB’s cosmic creation model. Based on its track record, we expect our creation model to pass these quantum challenges with flying colors.