My friend Gordon is an atheist and a reader of this blog. Recently in a comment on a previous post, he made the above comment.
It is still holiday time, I’m a nerd, and I enjoy a challenge, so I wondered whether I could analyse the science, and the belief. People with dedicated serious minds should turn away now!
What would stop the sun rising?
- The sun might cease via (a) natural processes, or (b) intervention by humans, aliens or God.
- The earth might also cease via (a) natural processes, or (b) intervention by humans, aliens or God.
Stopping the sun
Astrophysicists have classified our sun as a ‘normal’ star, one of about 90% whose physics and life cycle make it part of the ‘main sequence‘ of stars. They are therefore able to predict confidently that the sun will eventually (in about 6 billion years) expend its usable hydrogen, expand to become a red giant, then contract to become a white dwarf.
Scientists still debate the fate of the earth in this process, but it seems most likely that it will be destroyed as the sun expands – something more than 6 billion years into the future, and not before.
It should be noted that the sun is not of a size that it will explode, nor could a supernova close to our solar system destroy the earth.
So how probable is it that the sun will disappear by tomorrow morning? Because the main sequence contains the most common types of stars, its physics is well known, and can be described by equations and models that are well-supported by observations. The probability of these equations being wrong is very small.
Believe it or not, some scientists have seriously considered the possibility that the sun could be exploded by humans. Other scientists disagree it is possible, but regardless, it would take “centuries” to attain the capability.
The possibility that aliens or God could or would explode the sun is impossible to analyse (unless someone is more in the know than I am!). But a person who doesn’t believe in God should presumably also disbelieve in aliens capable of traversing deep space.
Is it possible to estimate a probability for the sun ceasing to exist by tomorrow morning? I have done it, though I don’t claim infallibility! If we assume that the probability of the sun not following the main sequence models has been constant over its life, we can say that if the daily probability of the sun not rising was 1 chance in ten billion, there was only 1 chance in ten million that the sun would have lasted this long.
We can conclude that it is extremely unlikely that the sun will cease to exist by tomorrow morning! I bet that’s a load off your mind! 🙂
Destroying the earth
Could the earth could be destroyed by a space object? NASA estimates that collisions that might put the earth’s population at risk occur several times every million years, but notes that “as best as we can tell, no large object is likely to strike the Earth any time in the next several hundred years”.
But even these massive collisions wouldn’t stop the sun rising, though they might stop anyone being here to see them.
As for aliens or God, the same applies here as for the sun. If you can’t believe in God, are you going to believe in aliens?
A similar calculation can be done as for the sun, giving slightly greater daily probability of the earth being destroyed (because it has been around slightly less time), but it is still true that the daily probability is minute. Don’t put off that visit to the dentist just yet!
The probability of God
What is the probability that God exists? There is no objective way (at present, at any rate) for us to assess this (as the man in black said: “anyone who says differently is selling something”). It’s all opinion.
The level of evidence required for anyone to believe or disbelieve must be proportioned to the strength of their belief or disbelief.
- If a person is agnostic, they have no opinion either way that God exists, and they thus imply a 50/50 probability.
- At the two extremes, a person who is certain that God exists, or doesn’t exist, would need to have absolute proof.
- But most of us have opinions but not certainty, and we can reasonably be asked to offer evidence and logical argument appropriate to our level of belief or disbelief.
My evidence and arguments
I don’t claim certainty about my belief in God – I claim that there is good evidence to justify my belief that God’s existence is probable. This website contains that evidence – see e.g. Why believe?
Greater certainty about God than the sun rising?
We have seen that the probability of the sun not rising tomorrow is of the order of one chance in billions – an extremely sure bet! To be more certain that God doesn’t exist than that would require amazing evidence and argument. I haven’t seen it. And I’m not holding my breath!
No brain cells were harmed in the making of this blog post!