Astronomers now know that the observable universe contains about 200 billion medium and large-sized galaxies and about a hundred times more dwarf galaxies.1 It all adds up to about 50 billion trillion stars. That’s a lot of light bathing the cosmos! Yet all these—stars, galaxies, gas clouds, planets with their heat and light, and burnt out extinct stars—make up just 0.27 percent of the “stuff” in the universe.
Darkness comprises 99.73 percent of the universe. It comes in three forms: ordinary dark matter, exotic dark matter, and dark energy. Of these forms, dark energy is predominant; it also reveals the greatest level of fine-tuning design for life’s benefit.
Dark energy is best described as the self-stretching property of the cosmic surface, along which all matter, energy, space, and time is 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 either will never form or will form at the wrong times.
If the dark energy density level were changed by as little as one part in 10120, the universe would be unable to support life.2 Dark energy, in the words of Stephen Hawking and Leonard Mlodinow, delivers “the most impressive fine-tuning” evidence.3 Nowhere else in science do we see such a high level of measurable fine-tuning design. The best examples of human fine-tuning design fall short by much more than a factor of a quadrillion quadrillion quadrillion quadrillion quadrillion quadrillion times (greater than 1090 times).
This is an extraordinary example of fine-tuning design for the specific benefit of life. It comports well with the Bible, which stood alone for millennia in predicting that the universe expands continuously under constant laws of physics from an actual beginning of all matter, energy, space, and time.4 No wonder some atheistic physicists have insisted that dark energy cannot be real.5
Clearly, much is at stake theologically in the reality of dark energy. Astronomers have gone to great lengths to test both dark energy’s reality and cosmic dominance. The principle is that, given an adequate number of independent experiments and observations, if every possible method of testing produces results consistent with a particular hypothesis, then scientists (and the rest of humanity) can be assured the hypothesis is correct.
Because of this principle, I often refer to nine different lines of observational evidence that establish dark energy’s reality and dominance in my talks. These nine are:
- radial velocities of type Ia supernovae;
- WMAP of the cosmic microwave background radiation (CMBR);
- ground-based measures of the CMBR;
- Sloan Digital Sky Survey of galaxies and galaxy clusters;
- Two-Degree Field Survey of galaxies;
- gravitational lens measurements of distant galaxies and quasars;
- distributions of radio galaxies;
- galaxy velocity distributions; and
- x-ray emissions from galaxy clusters.
In the last several years, astronomers have added seven additional lines of observational evidence, bringing the total to sixteen. These seven are:
- Lyman-alpha forest measurements;
- polarization measures of the cosmic microwave background radiation;
- stellar ages;
- cosmic inhomogeneities;
- gamma-ray bursts;
- evolution of galaxy clustering; and
- galaxy cluster angular size measurements.
Over the years, the Reasons To Believe (RTB) scholar team has written numerous articles about discoveries relating to the first nine lines of evidence and some of the last seven. For ease of searching, I’ve pulled together a collection of RTB’s dark energy articles, which can be accessed at https://www.reasons.org/dark-energy-articles. The collection includes three sections:
- Articles written for Today’s New Reason to Believe (TNRTB) from 2007 to 2011 or published in Connections (RTB’s former newsletter). These are all available individually on our website, so I’ve simply provided links to these posts and citations of the papers they discuss.
- Articles written for TNRTB from 2003 to 2006. These articles are not yet available individually on our website. Therefore, I’ve included them here in their entirety.
- Citations to the most recent astronomical research literature documenting the best observational confirmations of dark energy and the remaining lines of evidences that RTB has not yet covered.
This compilation of evidence for dark energy provides yet one more example of how the more we learn about the universe the more evidence we accumulate for the existence of the God of the Bible. It also shows God’s exquisite design, care, and love for life, especially human beings. The reality and the dominance of dark energy testify of the reality and dominance of God in each of our individual lives.
- For a discussion of the complete inventory of the universe, see my book Why the Universe Is the Way It Is (Grand Rapids: Baker, 2008), 30–41.
- Stephen Hawking and Leonard Mlodinow, The Grand Design (New York: Bantam Books, 2010), 161–62.
- Ibid., 161.
- Hugh Ross, A Matter of Days (Colorado Springs: NavPress, 2004), 139–48.
- Lisa Dyson, Matthew Kleban, and Leonard Susskind, “Disturbing Implications of a Cosmological Constant,” Journal of High Energy Physics 10 (October 2002): 011. The last sentence in the free downloadable paper (page 17) states, “Perhaps, the only reasonable conclusion is that we do not live in a world [universe] with a true cosmological constant [dark energy].”