Wednesday, March 15, 2017

A Universe From Nothing?

Could the universe spontaneously come into existence from nothing as the astrophysicist Lawrence Krauss has proposed in his 2012 book, A Universe From Nothing: Why there is something rather than nothing? And what is this "nothing" that Lawrence Krauss has proposed? Is it actually no thing? Does Krauss's proposal eliminate the theists' claim that the Big Bang beginning of the universe requires a transcendent cause that is not bound by space and time? The publication of this book generated a significant dialogue that dealt with these questions. Although initial publication of the book was five years ago I still consistently get asked questions about its content and the scientific validity of its proposals. I think it is important and valuable to address these issues from both a scientific and Christian perspective.

Saturday, March 4, 2017

Looking for God in Nature


One of the biggest misconceptions in the discussion about science and faith has to do with our ability to explain natural phenomena and what those explanations imply about God's actions in the universe. This is a misconception that is explicitly held by many who don't believe in God and implicitly held by many who do believe in God. The result of believing this idea is a complete misunderstanding of God and biblical teaching, and leads to false conclusions about God's involvement in the natural world. The misconception is the idea that if science has developed a naturalistic explanation for some phenomena then that removes God's involvement from the process. A closely related corollary to this misconception is the idea that if there is a phenomena that we can't explain, then God must be the explanation. This latter corollary is called the "god of the gaps". We invoke God as an explanation for things we don't understand.  Both of these ideas, a god of the gaps argument or the idea that a scientific explanation removes God, are false, unbiblical, poorly reasoned, and lead to incorrect conclusions.

Saturday, February 25, 2017

A Small Big Universe

The universe is unfathomably large. Our galaxy, the Milky Way, is made of around 200,000,000,000 stars and there are about 200,000,000,000 galaxies in the visible universe. The Milky Way galaxy is about 100,000 light years across, which is  9.5 × 1017 km (6 × 1017 miles). (A light year is the distance light travels in a year which is 9,500,000,000,000 km or 6,000,000,000,000 miles.) We can see galaxies that are so far away it has taken about 13 billion years for their light to reach us.  Since the universe is expanding, those galaxies have continued to recede away from us during the time it took their light to reach us. So the present size of the known universe is approximately 93,000,000,000 light years across in all directions. That is, the universe we can see is now a sphere about 9 × 1023 km (6 × 1023 miles) in diameter. We talk about the "visible" or "known" universe because that is all of the universe we can see. We have no idea how large the universe is beyond that.

It is impossible to understand how big this is. Consider something much smaller, the distance to the nearest star which is about 4.3 light years away. If we could travel to that star at about the same speed as the Apollo astronauts traveled to the moon, it would take almost 1 million years to get there. That is just to the closest star in our galaxy! Even if we could travel at the fastest speed of any object ever created by humans it would take about 30,000 years to reach the nearest star.  You can do the math, but even at that extreme speed it would take 700,000,000 years to cross our galaxy.

Friday, February 17, 2017

The World at CERN



And now for something completely different...  The main focus of this blog is to discuss issues relating science and reason to Christianity and God.  However, I have spent the last week at CERN attending meetings, talking with people, trying to develop computer code to analyze data, and other such activities.  So I'm going to take this opportunity to talk about how experimental particle physics research is done within large collaborations like those at CERN.

I am a member of the ATLAS collaboration.  ATLAS is the name given to both the detector that we use to analyze data from proton-proton collisions at the Large Hadron Collider and the group of scientists who use the data from that detector to try to understand the fundamental particles and forces in the universe.  There are currently about 5000 scientists from about 180 institutions in 38 countries who are members of the ATLAS collaboration, with 1200 of those scientists being students working toward their Ph.D.  It takes that many people to operate the ATLAS detector and to analyze all of the data that we take with the detector.

Saturday, February 4, 2017

A Changing Arrow of Time?


This is one post I am not looking forward to writing.  Some of my readers have asked me to comment about alternative theories to the Big Bang which remove the necessity of our universe having a beginning.  I have been thinking for some time about how to write on this subject in a non-technical manner, which is the tone I strive for on this blog.  Because most of these ideas are quite theoretical, requiring complex mathematics and intricate nuances, it is quite a challenge for me to give an accurate and adequate description of most of these proposals, yet still be comprehensible.   Nevertheless, in this post I want to try to discuss the paper by Anthony Aguirre and Steven Gratton (AG) that describes a scenario which they claim requires no beginning.1   I also want to give some thoughts on how their idea fits into the whole discussion of evidence for or against a deity, particularly the Christian God.  My attempt may be an epic fail.

In the model proposed by Aguirre and Gratton, they claim to avoid a beginning by proposing a thermodynamic arrow of time that points in different directions depending on whether the universe is expanding or collapsing.  To understand what this means I need to first take a diversion to discuss what the thermodynamic arrow of time means.  Actually, no one really knows for sure why we experience time moving forward but we do know that a quantity called entropy must increase in any non-reversible process.  Entropy strictly has to do with the number of microstates available to a system. The concept of a microstate can be illustrated by considering two six-sided dice. There is only one microstate available for the dice to roll 2: both must show a one. However, there are six possible microstates available for the dice to roll a 7. The combinations are 1 and 6, 2 and 5, 3 and 4, 4 and 3, 5 and 2, or 6 and 1. Because there are more available microstates, the dice will more often roll a 7. A macroscopic system with more available microstates has a greater entropy than one with fewer microstates. The second law of thermodynamics states that an isolated system will evolve spontaneously to the state with maximum entropy.   This is a statistical idea.  In general, all processes move toward those that are more statistically probable.  That gives us the arrow of time.   Time moves in the direction where entropy increases.

Saturday, January 28, 2017

The Significance of the BGV Theorem

Let's continue to explore the question of whether or not our universe had an actual beginning.  In two previous posts I have said that (1) if our universe had a beginning, then the cause of the universe must be transcendent, a characteristic of the Christian God, and (2) we may never have any observational or theoretical evidence about what happened in the first 10-35 seconds of the universe.

However, there have still been a lot of ideas from theoretical physicists about what may have happened to bring the universe into being and what we can surmise from the equations and laws that we know describe our universe.  One of the most often discussed papers dealing with our past was published by Arvind Borde, Alan H. Guth, and Alexander Vilenkin in 20031 and called the BGV theorem after the three authors.  In this paper, the authors show that any universe which is on average expanding has a timeline that cannot be infinite into the past, it must have had a beginning when it started to expand.  Since our universe is known to be expanding this theorem seems to require that it had a beginning.  (There are some technicalities to this conclusion like, for instance, the difference between "expanding" and "on average expanding" but, in general, what is known about our universe corresponds with the requirements of the BGV theorem.)