Reasons to Believe

Another Dwarf Galaxy Test of Big Bang Cosmology

Recent astronomical research has accounted for a "missing galaxies problem" and thereby buttressed the notion of a cosmic creation event according to what the Bible has taught for centuries1. This big bang creation model is now well established by astronomers' observations of the universe.2 The evidence shows that the universe is predominantly comprised of dark energy (energy embedded in the space surface of the universe that causes the cosmic surface to expand faster and faster as the universe ages) and cold exotic dark matter (slow-moving particles that weakly interact with photons).

However, this cold exotic dark matter model (ΛCDM) of the universe predicts that thousands of cold exotic dark matter halos should accompany large galaxies. The gravitational pull of these haloes ought to attract enough ordinary matter (protons, neutrons, and electrons) to produce populations of stars, or dwarf galaxies, for astronomers to be able to detect them through their largest telescopes.

Astronomers do see lots of dwarf galaxies but not nearly enough to satisfy the prediction arising from the dark-energy-dominated ΛCDM model. It anticipates more than ten times as many exotic dark matter halos than the number of dwarf galaxies astronomers have actually detected. This shortfall is known as the "missing galaxies problem."

Recently, astronomers have more than doubled the number of known dwarf galaxies associated with the Andromeda and Milky Way Galaxies and they found one reason for the missing galaxies problem: most dwarf galaxies are not nearly as efficient in present-day star formation as once thought. Consequently, most of the expected dwarf galaxies are simply too faint for astronomers to ordinarily detect them with their telescopes. Unleashing extraordinary observing techniques yielded the harvest of newly discovered dwarf galaxies connected with the Milky Way and Andromeda Galaxies.

However, in order to test and refine cosmic creation models astronomers really need to study a specific group of galaxies. This group needs to be far enough away so that local obstructions will not hide many of the dwarf galaxies. Yet it should also be close enough so that very faint galaxies can be detected and their distances measured to prove whether or not they are members of the group. These requirements are crucial for establishing a complete census of dwarf galaxies for a galaxy group.

The M81 Group at a distance of 12 million light-years comes the closest of all galaxy groups to meeting the necessary qualifications. An American and two Russian astronomers recently completed a deep survey of a 65-square-degree region around M81.3 In that region they detected 22 new dwarf galaxy candidates. So far, their research reveals that 12 of the 22 are likely members of the M81 group. This brings the number of known dwarf galaxy members of the M81 Group up to 34, though it remains about a factor of ten below predictions arising from the simplest ΛCDM model.

In the conclusion of their research paper the three astronomers make a number of suggestions for resolving this discrepancy. First of all, they point out that the gap is closing. What was once a factor of a hundred has now been reduced to a factor of ten. They also mention the possibility that there are still faint dwarf galaxies remaining to be detected. However, they propose that the most likely resolution will arise from adopting a slightly more complex ΛCDM model. For example, analytical models show that including the effects of tidal disruption and photoionization from nearby large galaxies over the history of the universe brings the current number counts of discovered dwarf galaxies into satisfactory agreement with the ΛCDM model. Another successful route centers on positing that dark matter halos had much more mass when the universe was young but since have lost mass through dynamical friction. In all, the researchers propose five different ways the discrepancy can be resolved without abandoning the ΛCDM model.

Given what astronomers now know about the detected dwarf galaxies and their likely evolution over the history of the universe, there is no reason to presume that a missing galaxy problem plagues the ΛCDM big bang creation model. Consequently, this cosmic creation model, which is most consistent with what the Bible predicted thousands of years ago, remains even more securely established than what astronomers previously had concluded.

  1. Hugh Ross, The Creator and the Cosmos 3rd ed. (Colorado Springs: NavPress, 2001), 23-29.
  2. Ibid: 31-67, 99-199; Hugh Ross, Why the Universe Is the Way It Is (Grand Rapids: Baker, 2008), 27-106, 209-14.
  3. Kristin Chiboucas, Igor D. Karachentsev, and R. Brent Tully, "Discovery of New Dwarf Galaxies in the M81 Group," Astronomical Journal 137, 2 (February 2009): 3009-37.

Subjects: Big Bang, Origin of the Universe, Universe Design

Dr. Hugh Ross

Reasons to Believe emerged from my passion to research, develop, and proclaim the most powerful new reasons to believe in Christ as Creator, Lord, and Savior and to use those new reasons to reach people for Christ. Read more about Dr. Hugh Ross.