Can causality exist without time?

[arthwollipot]

Welcome, Rev! Heh heh heh. I did warn you that it would be like this.

 

[The Man]

I was just reading the October 2008 issue of Scientific American, specifically the article “Following the Bouncing Universe” by Martin Bojowald, describing the Big Bounce application of Loop Quantum Gravity that I had mentioned before. It seems form those calculations, as one might figure, the only possible remnants of a pervious universe might be the least interacting particles, neutrinos and gravitational waves (or gravitons as theoretical particles). I recommend reading the article as it is interesting and relevant to this discussion.


Here is the link for that article

http://www.sciam.com/article.cfm?id=big-bang-or-big-bounce

ETA: I keep most of my unread magazines in the can, so I might be behind in my reading (if you’ll pardon the pun).

 

[Perpetual Student]

Here is an interesting article What Happened Before the Big Bang?
by Paul Davies, a theoretical physicist. http://www.fortunecity.com/emachines/e11/86/big-bang.html
He discusses the origin of the universe and questions of time and causality. Much of what he says relates to discussions on this thread. It is worth reading.

He says, "Gravitational theory predicts that under the extreme conditions that prevailed in the early universe, space and time may have been so distorted that there existed a boundary, or "singularity," at which the distortion of space-time was infinite, and therefore through which space and time cannot have continued. ... It did not stretch back for all eternity."

and,

"The lesson of quantum physics is this: Something that "just happens" need not actually violate the laws of physics. The abrupt and uncaused appearance of something can occur within the scope of scientific law, once quantum laws have been taken into account. Nature apparently has the capacity for genuine spontaneity.
It is, of course, a big step from the spontaneous and uncaused appearance of a subatomic particle-something that is routinely observed in particle accelerators-to the spontaneous and uncaused appearance of the universe. But the loophole is there. If, as astronomers believe, the primeval universe was compressed to a very small size, then quantum effects must have once been important on a cosmic scale. Even if we don't have a precise idea of exactly what took place at the beginning, we can at least see that the origin of the universe from nothing need not be unlawful or unnatural or unscientific. ..."

and,


"In spite of the space-time linkage, however, space is space and time is time under almost all circumstances. Whatever space-time distortions gravitation may produce, they never turn space into time or time into space. An exception arises, though, when quantum effects are taken into account. That all-important intrinsic uncertainty that afflicts quantum systems can be applied to space-time, too. In this case, the uncertainty can, under special circumstances, affect the identities of space and time. For a very, very brief duration, it is possible for time and space to merge in identity, for time to become, so to speak, spacelike-just another dimension of space. ...


The spatialization of time is not something abrupt; it is a continuous process. Viewed in reverse as the temporalization of (one dimension of) space, it implies that time can emerge out of space in a continuous process. (By continuous, I mean that the timelike quality of a dimension, as opposed to its spacelike quality, is not an all-or-nothing affair; there are shades in between. This vague statement can be made quite precise mathematically.)...


The essence of the Hartle-Hawking idea is that the big bang was not the abrupt switching on of time at some singular first moment, but the emergence of time from space in an ultrarapid but nevertheless continuous manner. On a human time scale, the big bang was very much a sudden, explosive origin of space, time, and matter. But look very, very closely at that first tiny fraction of a second and you find that there was no precise and sudden beginning at all. So here we have a theory of the origin of the universe that seems to say two contradictory things: First, time did not always exist; and second, there was no first moment of time. Such are the oddities of quantum physics."

 

[sol invictus]

The essence of the Hartle-Hawking idea is that the big bang was not the abrupt switching on of time at some singular first moment, but the emergence of time from space in an ultrarapid but nevertheless continuous manner. On a human time scale, the big bang was very much a sudden, explosive origin of space, time, and matter. But look very, very closely at that first tiny fraction of a second and you find that there was no precise and sudden beginning at all. So here we have a theory of the origin of the universe that seems to say two contradictory things: First, time did not always exist; and second, there was no first moment of time. Such are the oddities of quantum physics."

That doesn't require quantum physics at all - just the set of positive reals is good enough, as we've discussed ad nauseum.

The way time emerges in the Hartle-Hawking instanton is closer to the way north and south emerge when you move away from the north or south pole, which is why I used that as an example earlier. In fact the instanton actually is a sphere, albeit a 4D one.

 

[Perpetual Student]

That doesn't require quantum physics at all - just the set of positive reals is good enough, as we've discussed ad nauseum.

The way time emerges in the Hartle-Hawking instanton is closer to the way north and south emerge when you move away from the north or south pole, which is why I used that as an example earlier. In fact the instanton actually is a sphere, albeit a 4D one.

Yes. The analogy is now clear, thanks.