Thursday, April 18, 2013

Chronology of the Universe

Our universe is 13.7 billion years ago. It turns out that it is actually comparatively young in terms of the whole lifetime of the universe.

We can review this below by looking at what physics says about the lifetime of the universe and its various eras:

(1) Primordial Era (beginning to 1 million years after the Big Bang)
The Big Bang is thought of as the beginning of the universe, and time and space had a beginning that is conventionally understood to be the origin of matter and energy inside of the singularity that was the Big Bang. Before the Big Bang, no space, time, matter, or energy existed.

One hour after the Big Bang and the cosmic inflation, there was the emergence of quarks, hadrons, hydrogen nuclei, and the origin of gravity, the strong force, weak force, and electromagnetic forces.

For the next million years, continuing inflation occurred and stable atoms formed.

(2) Stelliferous Era (1 million to 100 trillion years after the Big Bang)
The present era we live in is called the “Stelliferous Era.” By 100 million years after the Big Bang, the first stars developed.

This Stelliferous Era is a time in which new stars are still forming and most energy comes from nuclear fusion in stars. This is the era in which organic life can evolve and live, and in which civilizations with organic sentient beings can exist. This era will end by about 100 trillion years from now.

Since it was been 13.7 billion years from the big bang, we are at 0.0137% of the total age of the Stelliferous Era. In other words, only 0.0137% of the total age of the Stelliferous era has passed. The universe is remarkably young.

(3) Degenerate Era (100 trillion to 10 trillion trillion trillion years)
In 100 trillion years, the “Degenerate Era” will begin. Stars will no longer form and all the stars will die. Civilizations at that time will need to find new ways of existing in the absence of stars. By 10 trillion trillion trillion years from now, all the stars will have collapsed into black holes, neutron stars, or white dwarfs.

(4) Black Hole Era (1038 to 10100 years)
During this era, black holes are the only star-like objects. In this era, they all evaporate.

(5) The Dark Era (10100 years to infinity)
In the Dark era, all the black holes have evaporated. Only photons, neutrinos, electrons, and positrons remain. The universe is dark and empty. This state of affairs will then continue to infinity. This era will begin in 10 000 trillion trillion trillion trillion trillion trillion trillion trillion years from now.
Finally, some examples of the types of numbers used above, so one can grasp the time scales:

10100 = 10 000 trillion trillion trillion trillion trillion trillion trillion trillion years

10 trillion trillion trillion = 10 000 000 000 000 000 000 000 000 000 000 000 000

1037 = 10 trillion trillion trillion years = 10 000000 000000 000000 000000 000000 000000

Wednesday, April 17, 2013

George Ellis on the Nature of Causality in Complex Systems

I post a video of the cosmologist George Ellis giving a talk called “On the Nature of Causality in Complex Systems,” given at the 16th Krak√≥w Methodological Conference “The Causal Universe,” from May 17-18, 2012.

It discusses the history of the universe and the nature of causality.


Sunday, April 14, 2013

The Block Universe, Entropy, Science and “Miracles”

The major point I am going to make below is simple: what science tells us about the universe suggests that it is scientifically possible for events that look like miracles to happen, but in realty if we ever observed such an event (an alleged “miracle”), it is highly unlikely it would be a “miracle” in the accepted sense of the term. It would still be explicable in terms of science, and entirely non-supernatural.

I also make some assorted comments on the nature of the universe and time.

In order to make my point, I am afraid you have to read and at least understand these terribly difficult articles about modern physics:
Andrew Thomas, “Time and the Block Universe,” 2009.

Andrew Thomas, “The Arrow of Time.”
I also recommend watching this documentary below, part of the “Fabric of the Cosmos” series by Brian Greene.




In short, mainstream science tells us this:
(1) all things and events in the future and past have an existence as real as all things and events in the present. We live in a block universe in the sense that all that has happened, is happening now, and will happen in the future exists simultaneously in a huge block of 4-dimensional space-time.

(2) We have an illusion of a moving “present”: a forward, irreversible direction of time. Why we experience this is unclear. It seems to be an unresolved question in science, perhaps one of the most important, profound problems! As Andrew Thomas (author of the articles above) says:
“The reason why we don’t see causality happening in the backward direction is purely because of a bias in our psychological systems: something about the complexity of our psychological system (our brains!) causes our thought processes to work only in the forward direction of time.”
It seems to have something to do with human consciousness.

If, for example, the future already exists and your own future in all states already exists, then why can’t you remember events from the future in the same way that you remember events from the past? I have never seen an adequate explanation of this, and it must be regarded as an unsolved problem, if the block universe view of mainstream science is correct.

(3) as the author of the articles above says, what is extremely interesting is that the arrow of time is “something of a mystery to physicists because, at the microscopic level, all fundamental physical processes appear to be time-reversible.”

What seems to explain the forward flow of time is entropy (or disorder). Entropy can be seen as an emergent property of relations and interactions between a group of particles, molecules, or aggregates of atoms or molecules. The big bang created the universe with a very low entropy state. The initial conditions of our universe are crucial for understanding its current state (from our perspective). The low entropy state at the big bang meant that disorder has increased since that time.

Any closed system moving forward in time and subject to randomness will see its state become more disordered over time. This is the second law of thermodynamics.

However, the process is to be understood from a probabilistic perspective: in any set of possible states a system could have, the number of possible disordered states is vastly greater than the possible ordered states. Our belief that the state of affairs we see in the universe is necessarily caused by the universal second law of thermodynamics is somewhat misleading:
“the second ‘law’ of thermodynamics is not really a ‘law’ at all, certainly not an unbreakable law on the same basis as other physical laws - it is a statistical principle. In fact, it might be possible for a room full of randomly-distributed particles to re-order itself quite by chance so that all the particles end up in one corner of the room - it would just be incredibly unlikely!”
In theory, then, there is no reason why a thing cannot move from a state of disorder to order. That is to say, an event that might look like a reversal of time such as a broken glass reassembling itself is not impossible, just mindbogglingly, highly improbable. It would require some way for energy to be imparted to the broken glass shards and move them in the right directions to converge, and then chemical bonds between atoms and molecules to be reassembled. An event like this would give the illusion of being a miracle, but it would not be: it would have some material, scientific explanation with matter and energy, but involve a set of events that is incredibly, extremely improbable.

With this in mind, it is not impossible for a human being who has been (correctly) pronounced clinically dead to come back to life. A sufficiently advanced human technology could do it, if you could repair all the damage to cells, molecules, and the brain, and restart all the chemical and other physical properties of a living organism. If you had a good record of the brain state of the person before he or she died, you could even restore memories and the mind, even if there was bad damage to the brain.

But I would contend that it is also not absolutely impossible that a dead man might come back to life by some some sheer accidental natural processes, just mindbogglingly, highly improbable. Of course, it is almost certainly true that such a thing has never happened, and never will, but the issue is simply that it is not absolutely impossible in theory.

How does this relate to miracles? I think it is obvious: think of the claims made by Christians about Jesus’s resurrection.

Of course, I do not for a second think that any of the evidence for Jesus’s bodily resurrection is remotely convincing, for reasons described here.

For one thing, the earliest conception of Jesus’s resurrection in 1 Corinthians 15.35–53 written by St Paul seems to show that Paul and the early Christians did not think of a bodily resurrection (of flesh and blood) for Jesus at all: they thought of Jesus being resurrected as a new spiritual being with a pneumatic body (soma pneumatikos in Koine Greek) without flesh or blood. This body was then exalted to heaven at the moment of the resurrection, and was only seen subsequently by human beings in visions or dreams. Paul even says that “what you sow is not the body that is to be” (1 Corinthians 15.37), which suggests that what is buried (a body of flesh and blood) is completely different from the “pneumatic body.” Paul says flesh and blood will not inherit the kingdom of god (1 Corinthians 15.50) - the “pneumatic body” will not be one of flesh and blood (but of some heavenly substance, like the bodies of angels). And 1 Corinthians 15:3–6 does not in any way require an empty tomb story, which was most probably the invention of the author of the gospel of Mark some 40 years after Jesus’s death for literary and theological purposes. The bodily resurrection is an invention of still later Christian writers like the author of the gospel of Luke.

It is even possible that Paul thought that Jesus’s dead body stayed in the grave and rotted, since (in his view) Jesus was re-created as a new spiritual being with a non-material body, possibly already part of the unseen heavenly realm.

But my main point is this: even if we saw a human being who was dead somehow come back to mortal life in 2013, and this was verified by science, it would still be theoretically explicable in terms of modern science; it would still most probably have some material explanation in terms of mater and energy, even if that explanation was not entirely clear at first. Such an event would not necessarily give us any proof of the supernatural or supernatural beings like gods. It would just be a mindbogglingly, extremely improbable event.

Even if you (for the sake of argument) make massive concessions to Christians in debate and concede that there is some convincing evidence that Jesus died and came back to life (although I do not think there is any such evidence), this does not necessarily prove this event was supernatural. It does not necessarily prove the existence of god. It does not necessarily prove the truth of Christian supernatural dogmas, and it certainly does not necessarily prove that Jesus ever did other alleged miracles or was anything but a mortal man after he came back to life.

The event would in theory be explicable in terms of, and consistent with, modern science, just an extremely mindbogglingly improbable event. Perhaps it is so improbable that it might only happen once in the whole 100 trillion year history of the entire universe. Or maybe twice or half a dozen times.

But such things would not necessarily prove the supernatural at all!