It’s often been said in cosmology circles that data should never get in the way of a good model.
I have written about the discrepancy between measurements of the Hubble constant, the parameter that is interpreted as the rate of the expansion of the universe. One approach has been direct, measuring the redshifts and distances of galaxies. The other method is cleverer, but far from direct. It involves measuring properties of the cosmic microwave background (CMB), a radiation field that fills the universe and presumably comes from a period very early in the big bang universe. If the big bang model correctly describes the origin of both the universe and the CMB, then it ought to be possible to extract a measure of the Hubble constant from the CMB. It was expected that these two diverse measurements of the Hubble constant would be consistent, thus giving confidence that the big bang model is correct.
Alas, that was not to be, because the two approaches have consistently produced different results. The direct, observational approach has yielded a Hubble constant of 73–74 km/s/Mpc (Mpc = megaparsec, a unit of distance used in extragalactic astronomy and cosmology). On the other hand, the indirect, model-dependent result is 67 km/s/Mpc. The difference is much greater than the errors of the measurements, indicating that they both cannot be right (though they both could be wrong). There is such great confidence in either method that this discrepancy has shaped up as a major crisis in cosmology. There have been several proposed solutions, mostly involving new physics. New physics is physics that we don’t yet know about, so it must not affect the world around us much but would have a profound effect on the structure of the universe. As you might expect, such solutions are radical and highly speculative.
Now a new study has weighed in with a simpler solution: we live inside a vast bubble in space, a bubble with lower than average density. The bubble’s lower density would alter the rate of local expansion (the expansion that we can directly measure), but it wouldn’t alter the CMB and the measure of the Hubble constant from it. How big must this bubble be to do this, and how much lower than average is its density? The bubble must be about 250 million light years across and contain about half the density that the universe has on average. The authors of the study argue that the irregularities in initial density required in the big bang model would allow for this sort of large-scale structure to exist today.
Notice what is going on here. The data disagree with the model, so the data must be wrong. This is the reverse of the way that science is supposed to work.
Notice what is going on here. The data disagree with the model, so the data must be wrong. This is the reverse of the way that science is supposed to work. But it is an example of an all-too-common attitude that has been rampant in cosmology for decades. It’s often been said in cosmology circles that data should never get in the way of a good model. Also notice that there is no evidence for this bubble. Far too many people apparently think that the necessity of the bubble to salvage the model is evidence for its existence. Again, this is not how science is supposed to work. Such rescuing devices have been par for the course in cosmology for decades. As problems have arisen, cosmologists have invoked all sorts of hypothetical things, such as inflation, to fix the problems. Though there is no evidence for these rescuing devices, cosmologists are convinced that these rescuing devices must be true, or else the big bang model would be wrong. The reasoning is that since the big bang model must be true, then it follows that anything the big bang model requires must also be true. It never occurs to most scientists that the big bang model may not be true. There is a word for this attitude. That word is dogmatism.
We at Answers in Genesis know that the big bang model is wrong, because it contradicts what the Bible says about the origin of the world. It is great that there is mounting scientific evidence that this conclusion based upon Scripture is correct. The question is, will the scientific community ever come to realize that their emperor has no clothes?