July 1, 2002
By Dr. Hugh Ross
As physicians use scanning devices to view the hidden structures and activities of the brain, astronomers can now use distant supernovae and high-resolution cosmic background radiation maps to scan the structures and properties of “branes.” This new capability allows them to examine the most remarkably fine-tuned feature of the universe: space energy density, or the self-stretching property of space.1
Branes are space surfaces having any number of dimensions. The most familiar brane is the 3-brane (three-dimensional surface) on which the galaxies, stars, and solar system reside. (This 3-brane is the surface of the four-dimensional, space-plus-time universe.) Since the 1998 discovery that the cosmic expansion transitioned, roughly 7 billion years ago, from slowing down to speeding up,2 theoreticians have attempted to explain the turnaround and acceleration by some means other than the currently accepted space energy density feature, or cosmological constant.
Some researchers have speculated that gravity operates on a higher brane than does the light from stars and galaxies. Among the brane models closest to matching established data for the universe are those in which the familiar 3-brane is embedded in a 5-brane, a five-dimensional surface—length, width, height, and time, plus one extra space dimension.3 According to this scenario, bodies having mass (galaxies, stars, planets, protons, and electrons) reside within the length, width, and height dimensions while gravity operates in these three plus two. With gravity thus “spread out” over five dimensions, its force would be sufficiently weakened by the expansion process to account for the turnaround and for the accelerating expansion rate without invoking a cosmological constant.
A recent Astrophysical Journal article, however, argues against this possibility. Astronomers from Portugal and England used new astronomical instruments to test the validity of the 5-brane model.4 Combining several improved measurements of the geometry of the universe, the acceleration rate of the universe’s expansion, and the date at which the deceleration turned to acceleration, these astronomers demonstrated that the mass density of the universe is at least 75% greater than that which the 5-brane model allows.5 In their words, 5-brane models are “strongly disfavored by existing cosmological data sets.”They go on to say that “currently available cosmological observations are already powerful enough to impose tight constraints on a wide range of possible models. . . . The era of precision cosmology has indeed started.”6
This arrival of “precision cosmology” means that ongoing research holds great hope for refining human understanding of the origin and development of the cosmos. Both Christians and skeptics will have more data with which to test biblical claims that God “stretches out the heavens like a canopy, and spreads them out like a tent to live in” (Isaiah 40:22).7 Scientific confirmation becomes all the more significant when one recognizes that for 3,400 years Bible authors stood alone in describing this characteristic of the universe.
Lawrence M. Krauss, “The End of the Age Problem and the Case for a Cosmological Constant Revisited,” Astrophysical Journal 501 (1998): 461; Hugh Ross, “Flat-Out Confirmed,” Facts for Faith 2 (Q2 2000), 26-31.
P. P. Avelino, J. P. M. DeCarvalho, and C. J. A. P. Martins, “Supernova Constraints on Spatial Variations of the Vacuum Energy Density,” Physical Review D 64 (2001): 063505; A. G. Reiss et al., astro-ph/0104455 preprint (2001); M. S. Turner and A. G. Reiss, astro-ph/0012011 preprint (2001).
G. Dvali, G. Gabadadze, and M. Porrati, “4D Gravity on a Brane in 5D Minkowski Space,” Physical Letters B 502 (2001): 199-208; C. Deffayet, G. Dvali, and G. Gabadadze, “Accelerated Universe from Gravity Linking to Extra Dimensions,” Physical Review D 65 (2002), 044023.
P. P. Avelino and C. J. A. P. Martins, “A Supernova Brane Scan,” Astrophysical Journal 565 (2002): 661-67.