Saturday, March 9, 2019

Some "Problems" with the Big Bang

In 1936 Albert Einstein wrote, "One may say 'the eternal mystery of the world is its comprehensibility.' ...The fact that it is comprehensible is a miracle."1 This remark is often paraphrased as, "The most incomprehensible thing about the universe is that it is comprehensible." Of course I agree with this statement made by one of the smartest human beings who ever lived. Like Einstein, I find it quite remarkable that our universe is comprehensible and that we can discover and explain how it works and then precisely describe its workings using the language of mathematics. One of the most amazing facts that has been discovered by observing the universe has to do with its very origin and subsequent development. It is unlikely that any scientist who lived when Einstein was born in 1879 would have predicted that our universe would provide unambiguous insight about its history almost all the way back to its very beginning. Yet that is exactly what has occurred. From Edwin Hubble's 1929 discovery that all galaxies are moving apart from each other with a relative speed that is linearly dependent on their separation distance, to Arno Penzias' and Robert Wilson's 1964 discovery of the cosmic microwave background (CMB) radiation which is the residual heat from the infancy of our universe, to the accurate measurements of the CMB spectrum made by the Planck satellite in 2010, the universe has provided an amazing, accurate, and remarkable story of its beginning. All of the observational evidence and theoretical calculations tell a consistent story about the big bang origin of our universe: that all of space, time, matter, and energy came into existence nearly 14 billion years ago.

Over the decades starting in the early twentieth century, the scientific evidence that supports the big bang origin has become stronger and stronger. As described in a previous post, scientists were reluctant to accept the big bang partially because of its philosophical implications. If our universe had a beginning then it may have had a beginner. But because of the overwhelming evidence, scientists now agree about the origin of the universe and its development from about a trillionth of a second after its origin until now, although there is much discussion about what may have happened before that time since we have little observational evidence concerning the first trillionth of a second of our universe.

As the observational and theoretical evidence for the big bang increased, scientists noticed that certain properties of the universe were hard to explain. Some of these problems are referenced in a comment made by a reader of this blog who wrote, "In your book, I noticed that you did not respond to the supposed problems with the Big Bang. And these problems are acknowledged by many non-Christians as well. Problems include: the Horizon Problem, Missing Antimatter, Missing Magnetic Monopoles, the Flatness Problem, Population III Stars, and the starting and stopping of supposed Inflation." As stated in previous posts here and here, it appears the reader has brought up these problems in an attempt to discredit the big bang and instead try to support the idea that the universe is only a few thousand years old.

I'll address four of these apparent problems that are all related to each other in this blog post (the horizon problem, the missing magnetic monopoles, the flatness problem, and the inflation problem) and then address the remaining two in my next post. However, it should be noted that even if none of these apparent problems were solved, the overall evidence for the big bang would remain viable, and the big bang would still be the best explanation for what we observe in the universe. These problems only deal with the details of what exactly happened at the big bang and how to best explain what we currently observe in the universe.

The Horizon Problem: When we look throughout the whole universe at the Cosmic Microwave Background radiation, which shows us what the universe was like about 380,000 years after the big bang, we notice that the whole universe is nearly the same temperature, from horizon to horizon. The "problem" with this is that the parts of the universe that are farthest from each other are so far apart that light could not have traveled from one part to another, and consequently the different parts of the universe could not have had any contact with each other. Therefore, it seems surprising that the whole universe has nearly the same temperature since the different parts could have never been in contact with each other to allow their temperatures to equilibrate.

The Flatness Problem: The geometry of the universe is nearly flat. It could be highly curved rather than flat. (A two-dimensional analogy of curved space would be something curved either like the surface of the earth or a horse saddle. A two-dimensional analogy of a flat universe is a piece of paper.) The "problem" with this is simply that such a flat universe is highly unlikely.

The Monopole Problem: Any theory that unifies three of the four fundamental forces in the universe, the strong force, the weak force, and the electromagnetic force, should have created very massive monopole particles. A monopole is a particle that has just a magnetic north pole or just a magnetic south pole. All magnets we have every observed have both a north and south pole.

It should first be stated that these "problems" are not problems at all if one believes in God. These are only problems if one doesn't believe in God because they are highly improbable in a purely naturalistic scenario and they seem to be fine-tuned. So anyone who believes in God should never point to these problems as an indication that the big bang didn't occur. A God who created the universe through the big bang could easily fine-tune the universe so that it works without any other explanation. If a young earth creationist Christian is pointing to these problems in order to cast doubt on the big bang that person is actually implying that God couldn't fine tune the beginning of the universe if God used the big bang as his method of creation. So any theist pointing to these issues is not really repudiating the big bang itself but repudiating God's ability to make a finely tuned universe. Only non-theists should have a "problem" with these because they require design and are highly improbable within a purely naturalistic world view.

The most popular scientific explanation that solves these problems is called cosmic inflation, which proposes that during the first billionth of a trillionth of a trillionth of a second the universe expanded exponentially so that the universe doubled in size at least 90 times and expanded to over a trillion trillion times its initial size in less than that amount of time. With inflation all the universe we see now was at one time causally connected so the horizon problem is solved. Inflation forces the geometry of the universe to be nearly flat so the flatness problem is solved and it spreads monopoles so far apart that we may never find one near us so the monopole problem is solved. Inflation solves the three problems listed but it does present a new problem in that we don't yet know what caused inflation to start or to stop. We don't know why the universe expanded exponentially and why it ceased to expand so rapidly but continues to expand at a much slower rate. Does our lack of knowledge about the mechanism that drives inflation mean it didn't happen? Of course not. As discussed in my last post, there are many things in the universe that we don't know. There are things we definitely see evidence for their existence, we see their effects, but we don't yet know what causes those effects. Physicists are actively trying to discover the cause of inflation.

Those who want to criticize inflation as a desperate attempt to salvage the big bang should be aware that inflation itself must be finely tuned to create the universe we have. The period of inflation must stop at just the right moment and not continue on. Not all inflationary models work and those that do also look like they are finely tuned and are precisely designed to produce a flat universe. Inflation itself is a finely-tuned mechanism that performs an essential task in nature to produce a habitable universe and thus gives evidence for an intelligent designer.

Finally, let me provide one more word of caution to my young earth creationists brothers and sisters. If you do insist that the big bang did not occur because of a few unsolved problems despite the abundant evidence for the big bang, what will you do if those problems are ever solved? Since inflation solves the horizon problem, the flatness problem, and the monopole problem, if the mechanism of inflation is ever discovered those who have claimed that these problems concerning the details of the big bang somehow repudiate the whole idea will be further examples of Christians who have criticized good science and had to backtrack when that science is confirmed. From the time of Galileo and continuing until now Christians have rejected good science based on a dogmatic misinterpretation of Scripture and then those Christians look foolish when the science is confirmed. Unfortunately, those past mistakes plague the credibility of Christians today. It is time that Christians embrace the truth of good science, particularly science like the big bang that gives clear evidence for God and is clearly compatible with the biblical story of creation. It is exactly that consistent story of creation told in the Bible and in nature through the big bang that proclaims God's invisible attributes, his eternal power and divine nature, as Romans 1:20 says it will.

1Franklin Institute Journal, March 1936 'Physics and Reality'

3 comments:

  1. Bravo, BRAVO! The only BIG MIND, and you must also have a big brain that works well, that makes so much sense to me. I enjoyed your post and have nothing to say but BRAVO!!!!

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  2. "As stated in previous posts here and here, it appears the reader has brought up these problems in an attempt to discredit the big bang and instead try to support the idea that the universe is only a few thousand years old."

    This is one of the(many many many) things I've never understood. If this is true, how come I can take an inexpensive telescope and see stars much older than the 6-10 thousand year number I see spoken of?

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    1. The young earth creationist will argue that either (1) God created the light from those stars already in transit, or (2) light went much faster from distant stars for one reason or another so they really aren't farther than 6-10 thousand light years away. In case (1) God is creating a false history for us to observe so he is a lying god, and in case (2) there is no evidence for that and lots of evidence that the speed of light has always been the same and should have an isotropic speed.

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