Honing in on Dark Energy Design

Honing in on Dark Energy Design

The Supernova Cosmology Project has achieved the most precise measurement of the universe’s dark energy density. The team’s measurements also yield the strongest evidence yet that a cosmological constant provides the best explanation for dark energy.

Increasingly accurate measurements of the quantity and character of dark energy provide an ever-stronger case for the supernatural design of the universe for the benefit of life and human beings in particular.

At one point during the science “quiz” put before Job and his friends, God asks:

What is the way to the abode of light? And where does darkness reside? Can you take them to their places? Do you know the paths to their dwellings?

While the ancients did not comprehend the nature of light or the means or velocity of its travel, they did recognize that the Sun, Moon, planets, and stars were “abodes of light.” Their failure to measure any parallax for the stars informed them that they had to lie at great distances. These distances led them to conclude that the stars had to be exceedingly bright. As for darkness, they presumed that darkness was merely the absence of light. But in this passage in Job, God implies that both dark stuff and stuff that emits light resides in specific locations of the universe.

Until the latter part of the twentieth century, the definition of darkness as the absence of light was textbook physics. Only in the past few decades have astronomers realized that the book of Job had it right in stating that darkness is a real substance with specific cosmic locations. Today, we know that darkness comprises 99.73 percent of the universe.1 It comes in three forms: ordinary dark matter, exotic dark matter, and dark energy. Of these forms, dark energy is predominant and reveals the greatest level of fine-tuning design for the benefit of life.

What Is Dark Energy?
Dark energy is best described as the self-stretching property of the cosmic surface, along which all matter, energy, space, and time are constrained. Dark energy is the most significant factor governing the rate at which the universe expands. If the universe expands either too rapidly or too slowly at different epochs throughout cosmic history, the stars and planets essential for life will either never form or form at the wrong times for life to exist. In fact, if dark energy were changed by as little as one part in 10120, the universe would be unable to support life.2 This level of fine-tuning design for life to be possible exceeds the best examples of human fine-tuning design by much more than a factor of a quadrillion quadrillion quadrillion quadrillion quadrillion quadrillion times.

The Latest Research
In all the sciences, the fine-tuning of dark energy required for physical life’s existence ranks as the most spectacular measured evidence for supernatural design. Thus, more accurate and more comprehensive measurements of dark energy by astronomers imply a stronger case for the existence and operation of a cosmic supernatural Designer. Now, a team of 65 astronomers who make up the Supernova Cosmology Project (SCP) have provided us with substantially more accurate and comprehensive measurements of dark energy.

In an Astrophysical Journal paper (February 10, 2012) the SCP reported on Advanced Camera for Surveys, Near Infrared Camera and Multi-Object Spectrometer (NICMOS), and Keck adaptive-optics-assisted photometry on 20 newly discovered Type Ia supernovae (see figure 1) in the redshift interval 0.623 < z < 1.415.3 The redshift interval corresponds to look back times (light travel times) ranging from 5.838 to 9.101 billon years. The SCP’s updated catalogue now includes measurements on 580 supernovae. The 20 new supernovae are the most distant ones for which astronomers possess accurate measures of supernova eruptions’ luminosity history (see figure 2).

Figure 1: SN 1572, Tycho’s Supernova
This multiwavelength X-ray/infrared image shows the remnant of the Type Ia supernova that erupted in our galaxy and was first observed by astronomers in 1572.
Image credit: NASA/ESA/Hubble (STScI/AURA)/CXC/JPL-Caltech/Calar

Type Ia supernovae are standard candles because they all begin with exactly the same mass (the Chandrasekhar limit of 1.38 solar masses), therefore they all manifest the same maximum brightness during their supernova eruption (see figure 2). Astronomers can use distance measurements to nearby Type Ia supernovae to infer distances to much more distant ones. Armed with both distance and redshift measurements of hundreds of Type Ia supernovae astronomers can gain a precise determination of the expansion history of the universe and reveal the clearest picture of the quantity and nature of dark energy.

Figure 2: Light Curve of Typical Type Ia Supernova Eruption
Image credit: NASA/Hubble Space Telescope/High-Supernova Search Team

For a flat geometry universe the SCP team determined that dark energy comprises 72.9 ± 1.4 percent of the total density of the universe.4 Mass makes up the other 27.1 percent. This is the first time the universe’s dark energy density has been measured to better than 2 percent precision, including accounting for systematic errors.

The team also measured the dark energy equation of state parameter, w, to be -1.013 ± 0.070. If the w parameter is greater than -1.0, then the dark energy density will decrease slowly as the universe expands. If it is less than -1.0, the dark energy density will increase slowly with cosmic expansion. If it is exactly -1.0, the dark energy density remains constant. That is, the percentage of all the universe’s dark energy stuff will never change. This latter scenario describes the situation where the cosmological constant defines the character of dark energy.

These conclusions from the SCP change only marginally if the universe’s geometry or curvature departs slightly from perfect flatness. Based on already-published results from the Wilkinson Microwave Anisotropy Probe (WMAP) satellite,5 the SCP and the rest of the astronomical community knew that the universe departed from perfect flatness by no more than 1.74 percent on the negative side and no more than 0.51 percent on the positive side (see figure 3). The SCP’s own determination of cosmic curvature based on their observations of Type Ia supernovae constrained the curvature (departure from perfect flatness) to about 0.7 percent in the case where the w parameter = -1.0. Where w is allowed to vary within permissible observational limits, their data show that cosmic curvature departs from flatness by no more than 2.0 percent.

Figure 3: Geometry of the Universe
The constraint on the universe’s geometry comes over seven years from the WMAP satellite’s observations of the cosmic microwave background radiation.
Image credits: NASA

Precision cosmology and the testing of competing cosmological models depend fundamentally on astronomers’ capacity to determine as accurately as possible how rapidly the universe is expanding at different epochs throughout its history. With their latest results, the SCP has taken precision cosmology to the next level. They close their paper by noting that this discipline should reach an even higher level, thanks to multi-passband photometry of several dozen Type Ia supernovae beyond redshift z = 1 (corresponding to a look back time of 7.74 billion years) by the Wide Field Camera 3 on board the Hubble Space Telescope.

Already, we can thank the SCP for providing (even unintentionally) a stronger body of evidence for the cosmic creation model. Thousands of years ago, the Bible uniquely predicted what astronomers have only recently discovered: that we live in a universe traceable back to a space-time beginning from which the whole cosmos expands continuously under constant laws of physics, including a pervasive law of decay, that results in the universe becoming colder and colder as it gets older and older.6 We can anticipate receiving still more evidence yet for the Bible’s cosmic creation model—and the biblical God.

  1. For a comprehensive description of cosmic darkness see my book, Why the Universe Is the Way It Is (Grand Rapids: Baker, 2008), 27–41, 90–93.
  2. Stephen Hawking and Leonard Mlodinow, The Grand Design (New York: Bantam Books, 2010), 161–62.
  3. N. Suzuki et al., “The Hubble Space Telescope Cluster Supernova Survey. V. Improving the Dark Energy Constraints Above z > 1 and Building an Early-Type-Hosted Supernova Sample,” Astrophysical Journal 746 (February 10, 2012): id. 85.
  4. Ibid.
  5. E. Komatsu et al., “Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation,” Astrophysical Journal Supplement 192 (February 2011): id. 18; N. Jarosik et al., “Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Sky Maps, Systematic Errors, and Basic Results,” Astrophysical Journal Supplement 192 (February 2011): id. 14; E. Komatsu et al., “Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation,” Astrophysical Journal Supplement 180 (February 2009): 330–76.
  6. Hugh Ross, The Creator and the Cosmos, 3rd edition (Colorado Springs: NavPress, 2001), 23–29.