In the 1990s, two international teams of astronomers formed to make use of this new technique of detecting and observing type Ia supernova to assess the amount of deceleration of the universe. One group was the High-Z Supernovae Search Team, headed by Brian Schmidt and Adam Riess. The other group was the Supernova Cosmology Project, led by Saul Perlmutter. The two teams hoped to accurately find the distances of enough high redshift galaxies to find the expected upturn in the Hubble relation and hence measure the amount of gravitational deceleration in the universe. To the astonishment of both teams, they discovered that rather than an upturn in the Hubble relation at great distance, there is a downturn. This result was so unexpected that it delayed publication while the two teams attempted to find what they had done wrong. Once they decided that their results were real, the implication was clear – just as an upturn in the Hubble relation would have indicated deceleration of the universe, a downturn in the Hubble relation indicates an acceleration of the universe. The teams published their findings in 1998-1999, and this result was so groundbreaking that the three leaders of the teams shared the 2011 Nobel Prize in Physics. After seven decades, it seemed the cosmological constant was back. However, rather than being a constant repulsion term in the universe as the cosmological constant was, cosmologists today entertain the possibility that the repulsion in the universe may change over time. Hence, cosmologists chose a new term to describe this repulsion, dark energy. Why choose those two words? For a long time, cosmologists have used fields to describe various effects in the universe, such as a field to drive cosmic inflation in the early universe. In physics, a field is associated with a force (the force is the negative of the gradient of the field, thus transforming a scalar field into a vector force). A field represents a potential energy, so when formulated this way, the accelerating force of the universe requires energy to drive it. The word “dark” was chosen in comparison to dark matter, though dark matter and dark energy have nothing in common. The similarity of the terms “dark matter” and “dark energy” is most unfortunate because it confuses many people who do not understand the difference. Quantum field theory (QFT) did not exist in the 1920s when modern cosmology took form. QFT offers a physical basis for λ. The cosmological constant appears as the expectation value of the quantum fields in their lowest energy state. One manifestation of the so-called “zero-point energy” is “vacuum polarization” that drives the Casimir effect. The energy in that state is non-zero and the expectation value of the fields will appear as a contribution to the stress-energy tensor. The contribution to stress-energy turns out theoretically to be equivalent to a “cosmological constant” as proposed originally by Einstein, but in this case it is not ad hoc. It is true that the present state of QFT does not provide a known method for producing a finite value of λ. A finite value can be obtained if a UV cutoff is introduced in momentum space for the vacuum energy. However, a theoretical basis for computing the cutoff is unknown at the present. Such cutoffs would depend on new unknown theoretical parameters, which could indicate new physics yet to be discovered. Both dark matter and dark energy are now incorporated into the standard cosmology, indicated as the λCDM model. The λ refers to the inclusion of dark energy. The CDM refers to “cold dark matter.” The term cold here does not refer to temperature but rather to the assumed speed of the particles comprising dark matter as compared to the speed of light. Models in which dark matter particles move slowly seem to fit other parameters of the big bang model than fast moving dark matter particles, hence the exclusion of fast moving (or “hot”) dark matter particles in the latest big bang models. As the perceived association of dark matter with the big bang model accounts for some of the opposition many recent creationists have to dark matter, so the close association of dark energy with the current big bang models probably explains why recent creationists generally resist dark energy (e.g., Coppedge 2008; Hartnett 2002; Hebert 2012; Sarfati 2018). Indeed, as Hill (2017) has shown, the evidence for dark energy, the downturn in the Hubble relation at great distances, has been interpreted entirely within the big bang model and hence, unlike the case for dark matter, the existence of dark energy does rely upon the big bang model. However, as Hill also pointed out, even if the big bang model is incorrect, the evidence from the Hubble relation remains. A different cosmology/cosmogony may result in an interpretation of that evidence that is different from the interpretation of dark energy. How might a biblical cosmology/cosmogony reinterpret the downturn in the Hubble relation at great distances? We don’t know, because no such detailed model exists yet. I encourage recent creationists to be more guarded in their comments about dark energy, making a distinction between the conclusion of dark energy and the data upon which that conclusion is based. We need to honestly and publicly admit that the downturn in the Hubble relation at great distances is real and awaits a different interpretation. V. CONCLUSION Many recent creationists reject both dark matter and dark energy, though their reasons are not always clear. I perceive that some of the motivation in resisting dark matter and dark energy is an attempt to refute the big bang model. However, as discussed in this paper, this is an ill-advised tactic. Much of the criticism of dark matter coming from recent creationists tends to focus on two fronts: 1. Treating dark matter as a rescuing device for the big bang and other evolutionary ideas 2. The negative results of the tests of different theories of the identity of dark matter particles However, these discussions do not properly handle the facts. There are three lines of evidence for dark matter. Two of those three lines of evidence preceded dark matter’s inclusion in the big bang model and modern ideas of galactic evolution by many decades. It wasn’t until after astronomers eventually became convinced of the reality of dark matter from the evidence that astronomers and cosmologists began to employ dark matter to solve problems with their models. Keep in mind that astronomers greatly resisted dark matter for decades – they hardly embraced dark matter as a rescuing device. Rather than denying the existence of dark matter, recent creationists must effectively engage with the immense amount of evidence for dark matter. Similarly, recent creationists tend to view dark energy as a rescuing device for the big bang model. The reality is that within the big bang model, dark energy is the best interpretation of the downward inflection of the Hubble relation at great distance. That is, dark energy is based upon real data that is interpreted in terms of an evolutionary model. Simply dismissing dark energy out of hand is tantamount to FAULKNER Dark matter and dark energy 2023 ICC 8
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