Hints of 'time before Big Bang'

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A team of physicists has claimed that our view of the early Universe may contain the signature of a time before the Big Bang.

The discovery comes from studying the cosmic microwave background (CMB), light emitted when the Universe was just 400,000 years old.

Their model may help explain why we experience time moving in a straight line from yesterday into tomorrow.
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The laws that govern physics on a microscopic scale are completely reversible, and yet, as Professor Carroll commented, "no one gets confused about which is yesterday and which is tomorrow".

Physicists have long blamed this one-way movement, known as the "arrow of time" on a physical rule known as the second law of thermodynamics, which insists that systems move over time from order to disorder.
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In his presentation, the Caltech astronomer explained that by creating a Big Bang from the cold space of a previous universe, the new universe begins its life in just such an ordered state.

The apparent direction of time - and the fact that it's hard to put a broken egg back together - is the consequence.
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http://news.bbc.co.uk/2/hi/science/nature/7440217.stm

Makes sense, since the only way to measure time on a cosmic scale is through motion.

would be moving backward in time. A bit simplistic, IMO.

Not to mention that any definition of "order" is fraught with anthropomorphic biases.

couldn't the same thing be said of time too? Or is that question just leading us down the rabbit hole of never discovering something for lack of ability to define terms.

Difficult stuff to wrap my brain around.

The order imposed by man comes at the cost of greater disorder elsewhere. To build a car requires that a great deal of heat energy is dissipated in the process, increasing entropy of the total system.

Even as we build cities we need to destroy some part of the environment to do so.

Planet Earth, however, is not a closed system. We get constant energy input from the sun. Given that, it is possible to create more and more order on the planet, but the sun itself must eventually be used up (dis-ordered) to make it possible for order to be created here.

Another way to look at the arrow of time is to look at all possible arrangements of all the atoms in a system. The VAST majority of those arrangements are what we would call disordered. Only a very, very few of them are what we would call ordered. Therefore, if we pick an arrangement at random the odds vastly favor a disordered arrangement. In other words, order is highly improbable, so the "arrow of time" simply means that if we start with an ordered arrangement and started shuffling it around, it is almost certain to become a disordered (i.e. more probable) arrangement.

A broken glass will not reassemble itself not because it is impossible. It is, in fact, completely possible. It's just that of all the trillions and trillions of ways to arrange the atoms of glass, only one of them is what we would call the original unbroken glass. The rest are what we call a broken glass. So the probability that random shuffling will ever find the the correct arrangement is virtually zero.

In other words, there is no "force" that pushes the world toward disorder. There is, instead, a huge numerical preponderance of disordered states, making the ordered states extremely rare.

...moving back and forth depending whether your surroundings were experiencing more of an increase or decrease in local entropy.

Apart from gravity wells and very fast motion, clocks seem to work the same everywhere.

I think time is a little more solid and reliable than just a net accumulation of disorder on the universal scale.

There is nothing inherently less "ordered" about a neutron star than a red giant.

You make reference to "what we would call disordered". But with great care, limitless technology, and too much time on my hands, I can reassemble a glass bottle to it's unfractured state -- within any chosen degree of accuracy. Thus there is no way to conclusively tell which state came "first", and the arrow of time is entirely indpendent of the physical structure of matter.

Maybe time is too. Who knows. Does the universe care that there's a difference between past and future? Maybe not. The laws of physics work in either direction. But humans certainly care, because humans define "order" to suit their own purposes.

(as far as we know), and define the cause-and-effect relationship we call time.

Taking two snapshots of the current physical state of the universe at two different times, however, provides us with no definitive proof of which came first.

Physical processes at the microscopic level are believed to be either entirely or mostly time symmetric, meaning that the theoretical statements that describe them remain true if the direction of time is reversed; yet when we describe things at the macroscopic level it often appears that this is not the case: there is an obvious direction (or flow) of time. An arrow of time is anything that exhibits such time-asymmetry.

http://en.wikipedia.org/wiki/Arrow_of_time

In fact it is only by reference to human definition of "order" that the direction of time can be distinguished. At the atom level cause-effect runs both ways.

See also "Feynman Diagram" http://en.wikipedia.org/wiki/Feynman_diagram Every sub-atomic particle interaction is not only time-reversible, but can be observed in nature to run either way.

if the direction of time is reversed, doesn't imply that time is reversible.

Entropy is insufficient to provide even a conceptual direction of time, one way or the other. As the planets of the solar system merged from the gravitational pull on interstellar dust, for example, the entropy of the system decreased, contradicting Eddington's view that the arrow of time inexorably leads to more randomness.

microbes still experience time in one direction.

And it's not at the atomic level but at the sub-atomic level.

The result being that for all practical purposes, time runs one way, but there is the hint that given the right conditions (quantum level) time has no omnidirectional arrow.

Experiments have shown that the laws of physics do not work the same backwards as forwards, the effects can be seen in how some subatomic particles, e.g. the kaon, decay.

http://physicsworld.com/cws/article/print/1327

There does seem to be a symmetry that is preseved however. It is a combination of charge, parity, and time reversal. Which is to say that if you took a movie of any physical process, ran the film backwards (reversed time), showed a mirror image (reversed parity), and changed all the matter to antimatter (reversed charge), then the resulting movie would seem to obey all the laws of physics as we know them.

Individually, the result of each of these transformations would not obey the laws of physics as we've seen them, but combined they all do.

The way it is defined in thermodynamics is related to how much information you need to specify in order to completely define a system.

For example, lets compare a large pile of silicon atoms with a single large silicon crystal.

In order to define the large pile of atoms, we'd need to give the position of every single atom of silicon, so that's three coordinates for every atom in the pile. Knowing where one atom is would tell us nothing about where the other atoms are.

In the much more ordered single crystal, we need only specifiy three coordinates to locate 1 atom, three coordinates to identify the orientation of the crystal, and a little information to describe how the crystal is arranged. Once we know how the crystal is built, and the location of one atom, we can figure out where all the rest must be.

In a very real sense, thermodynamics on the statistical level is much the same as information theory. It's kind of neat to see the same equations used to describe physical systems as are used in cryptology research...

The Universe can turn parts of itself inside out, can twist into a Mobius Strip, can blow things up, or compress them into black holes, can keep expanding or start crunching, or do both simultaneously, can send particles in and our of existence, and can contain phenomena within, or outside of, itself that we haven't even dreamt of, but that arrow never changes direction, so far as we know. We are born. We die.

That's what time IS.

Granted, we are like an amoeba on the back of an ant, trying to figure out Planet Earth--and Planet Earth itself is an amoeba on the back of ant lost among jillions and jillions and jillions of other bits of rock and flotsam, in an E N O R M O U S U N I V E R S E. Our perspective is EXTREMELY limited.

But our rather short lives, amidst these immensities, dominates our consciousness, and literally creates the arrow of time.

Time is irrelevant to the Universe, which is a Big Bubble bending back on itself, with jillions and jillions of big and little swirls and bubbles, and un-bubbles, churning within it, and around it. Maybe the dot that is "I" gets connected somewhere (end of the arrow curves back to the birth). Some think that. Some swear by it. Psychics and Buddhist monks say they feel it and know it. But most of us amoebae want proof. Cuz we seem to stuck here, in the Time we are creating.