It’s not just paleontologists who are eager to study fossils. Astronomers are also fascinated by them—fossils of a different sort, that is. Their quest is to understand the remains of primordial galaxies, the very first galaxies to form. Why? The “fossils” of such galaxies hold key details about the cosmic creation event and the emergence of a universe fit for life.
These details hold theological significance, as well as scientific. Evidence for the biblically predicted (anticipated) big bang creation model1 has been overwhelming for some time now (though the model has yet to be universally embraced). In fact, so much scientific evidence for it exists that astronomers have been able to identify one specific version of the model that simultaneously explains the origin, the history, and the design of the universe. That model is the LCDM (Lambda-Cold Dark Matter) inflationary hot big bang model. It describes a big bang universe dominated primarily by dark energy, L, and secondarily by exotic dark matter, DM (matter that interacts poorly or not at all with photons––basic units of light), and wherein most of the exotic dark matter particles are “cold,” that is, moving at low speeds relative to the speed of light. While this model is well-established scientifically, its theological implications rouse strong opposition, particularly among atheists/naturalists, Hindus, New Age proponents, and young-earth creationists. So subjecting this model to still more stringent tests carries significance beyond the interest of astronomers.
One prolific testing arena for the LCDM cosmological model is made possible by computer simulation studies. Researchers can compare the properties of primordial galaxies (provided by the simulations) with direct observations of ultra-faint dwarf galaxies, thought to be the pristine survivors of the primordial cosmic era. In this way they can gain insight into natural systems where such knowledge may not be otherwise attainable. According to the LCDM model, the first galaxies formed prior to the reionization event, in which the first supergiant stars went supernova. Galaxies that formed before reionization would be tiny, with stars comprising only a small portion of the galaxy’s mass. Although many of these primordial galaxies would have merged to form large galaxies, the LCDM model predicts that a significant number survived to the present era. To discover exactly how many still remain, where they reside, and what characteristics they manifest requires a careful determination of the conditions at the time of initial formation.
Two University of Maryland astronomers, Mia Bovill and Massimo Ricotti, recently performed tests that yielded such a determination.2 Their simulation took into account feedback mechanisms critical for star formation and included three-dimensional radiative transfer (equations that describe energy transfer in three dimensions).
Figure: Fornax Dwarf Galaxy
This photo of a dwarf galaxy illustrates one of the challenges researchers face. As faint as it is, Fornax is very much larger and brighter than a true fossil of a primordial galaxy.
credit: ESO/Digitized Sky Survey 2
Their LCDM simulation showed that the maximum luminosity (brightness) of true remains of primordial galaxies should be no greater than a million times that of the Sun and but no less than a thousand times that of the Sun. Furthermore, their simulation predicted that true fossils within 160,000 light years of the Milky Way Galaxy (MWG) would be tidally stripped (many of their stars pulled in toward the MWG), leaving them even less luminous. True fossils at greater distances would have their stars spread apart from one another by as much as 10,000 light years. The greater distances and the diffuse nature of the galaxies mean that currently they are beyond the detection capability of our most powerful telescopes.
Bovill and Ricotti were able to compare the LCDM model’s predictions of detectable primordial galaxy fossils with actual observations of ultra-dwarf galaxies in the MWG’s immediate vicinity. (At the same time they projected how many true fossils next-generation telescopes will detect between 1 and 3 million light years away.) They discovered that both the number of detected dwarf galaxies in the MWG’s vicinity and their brightness are consistent with predictions based on the LCDM model.
Additionally, this research anticipates that the soon-to-be-operational James Webb Space Telescope and the ground-based Extremely Large Telescope should detect a total of about 300 ultra-faint dwarf galaxies orbiting the MWG, of which 150–210 will prove to be wellpreserved true fossils of primordial galaxies. The model simulation also forecasts the masses, diameters, and heavy element abundances that will be manifested in the 300 galaxies.
Thanks to Bovill and Ricotti’s research, the biblical statements about cosmology have passed yet another stringent test. The details that emerge from the team’s study buttress scientists’ understanding of the universe’s early history, allowing human observers to appreciate the processes that ultimately led to a habitat for advanced life. And, the opportunity for even more in-depth testing is at hand. The duo’s work provides another example of how advancing knowledge of the universe unveils more reasons to believe in the complete trustworthiness of what the Bible reveals about God and His creative work.