"Could Time Flow Backwards in Other Universes?" Rising Star Rocks Einstein With New Theory of Time

A rising star in theoretical physics offers his awesome vision of our universe and beyond, all beginning with a simple question: Why does time move forward? In January, Caltech physicist Sean Carroll will release his much-anticipated debut book, From Eternity to Here: The Quest for the Ultimate Theory of Time. SciFi buffs will grok out on his thesis that our perception of time is informed by entropy — the level of disorder in a system. The basic laws of physics work equally well forward or backward in time, yet we perceive time to move in one direction only—toward the future and that the movement from low to high entropy as the universe expands establishes the direction in which time flows. To account for it, we have to delve into the prehistory of the universe, to a time before the big bang.  Our universe may be part of a much larger multiverse, which as a whole is time-symmetric. 

Time may run backward in other universes. Some universes, he argues, don’t experience time at all; once a universe cools off and reaches maximum entropy, there is no past or present.

Here's how Carroll describes his thesis: "Microscopic laws of physics are essentially time-reversal invariant, but macroscopic thermodynamics exhibits a profound time-asymmetry; entropy typically increases in closed systems. This intriguing feature of the real world has a cosmological origin: the entropy of the early universe was fantastically small. After a century of effort, it has been difficult to explain this arrow of time without assuming time-asymmetric boundary conditions. Jennifer Chen and I have suggested a simple scenario in which increasing entropy is natural, based on the idea that the entropy can increase without bound (there is no equilibrium state) and that the way entropy increases is by creating universes like our own. In our picture, any generic state first evolves to an empty de Sitter phase; the small temperature of de Sitter allows for fluctuations into a proto-inflationary configuration, which grows and reheats into a conventional Big-Bang spacetime. The same thing happens in the far past, but with a reversed arrow of time. On ultra-large scales, therefore, entropy is growing without bound in the asymptotic future and past."

Casey Kazan

http://www.scientificamerican.com/article.cfm?id=the-cosmic-origins-of-times-arrow
http://preposterousuniverse.com/research/#arrow
http://www.wired.com/magazine/2009/12/pl_print_carroll/

Comments

[Zirkman]

I don't agree. Once the Universe reaches a state of maximum entropy there is no way any fluctuations would create entropy-small regions and start new Big Bangs. The only way high entropy states can be converted into small-entropy ones is compression of energy to a point it is forced to create its own spacetime i.e. through various variations of black holes.

[john]

This idea isn't new. In the mid 80s Hawking said virtually the same thing of the potential effects on the arrow of time by fluctuating states of entropy, be it in black holes, or in an alternate universe.

[dmarx]

Not a scientist ( points at himself )

If i were experiencing this...backward flow of time, wouldn't "I" still perceive time as flowing forward?

[ShadowDS]

@ dmarx

Yes, backwards would be forwards for you unless you can percieve both directions of time (or more). Only then could you tell the difference.

[TheTopDoc]

I know this isn't exactly the point here but see the Red Dwarf episode "Backwards" for one interpretation. Of course this episode is a Sci-fi interpretation and a comedic one at that. In any case the shows depicts a 'time hole' which I believe was a special type of black hole.

[DelGastro]

so... in a backward-timed universe, enthalpy become entropy, gravity and strong interaction become repulsive forces?

SOUNDS EXCITING!!

[Keith]

Up is down, black is white, cats and dogs living together, total chaos!

[Narendra Nath]

Time is a concept that is unique and its combination with space provides Physics the frame work to describe our universe. Thus, questioning these two concepts are bound to result in drastic changes in Physics as developed thus far. Time has a funny origin that is tied to the birth of this universe. For space, we need to fix an origin in a frame of reference we choose to work with. Then the space coordinates can show both +ve and -ve values in reference. Thus Sean Carroll ideas can have impacts through questioning the linearity of time. Yes, entropy does provide a direction to time but if entropy in some universe changes the other way or shows discontinuous behavior, the picture will change in a manner we have yet to evaluate.

[Mark Henkel]

"Some universes, he argues, don’t experience time at all"
As long as that universe is a singularity.

[Rajnish]

Time, in absolute sense, is non-existent. It is just an experiential reality that is assumed by an experiencer. If there is no experiencer, there is nothing like time. The brain tends to link up two points of actions (motions or processes) with its memory function. This associative experience is called time. The universe is perpetuity of motions or processes, chemical or otherwise.
Or else: imagine the beginning or end of so-called time billions and trillions of years before or after, but still the question remains: what was before or will be after that? Saying that time started with big bang and ends with the end of the universe, is partial explanation. Big bang was rather a beginning of a series of processes/motions that would stop one day.
Time is an illusion, but a persistent one for any life form as such.
Rajnish
http://rewiringthebrain.net/

[Ben]

Time is not an 'illusion'. Time is a CONCEPT, residing within a CONCEPTUAL VESSEL, which is your (somewhat dim) Intellect.

Time is perception perceived. It is purely an intellectual function.

Hence...

[Daniel Foster]

I found this incredible article written in response to Sean's Discover magazine cover story for the March Discover magazine still on the stands now. You can read it yourself online even at this link - http://discovermagazine.com/2010/mar/02-the-real-rules-for-time-travelers . It's about time travel and paradoxes BUT the article that I found that really got me was this one at Scientific Blogging - http://www.scientificblogging.com/temporal_mechanic/blog/“new_rules_time_travel_”_and_sean_carroll’s_gate_2 . Just go to www.scientificblogging.com and do a word search for "sean's gate" if the link I've left doesn't work (it's real long so it might not). It's by a writer named Marshall Barnes, some kind of R&D geek, but it was one of the most detailed things that I've seen on the topic of time travel. Excellent. Especially if you have a real interest in time and time travel and find most of the current fare wanting...

[Salih Kırcalar]

Dear Dr...,

Very small free roaming particles lifetime very short.[free photons, free notron, free proton,free
electron ,vs].And their lifetime is its energy Mc2. Protons are observed to be stable and their theoretical minimum half-life is 1x10'36 years.Grand unified theories generally predict. That proton
decay should take place, although experiments so far have only resulted in a lower limit 10'35 years for proton's lifetime. I see that. The earth lifetime is its Mc'2 energy. When this is calculated
the lifetime of earth.

Earth Mass= 5.97x10'24 kg. the lifetime 1 kg of mass in space is 2851927903,26 years.

Earth Lifetime is 1.7x10'34 years. I think that, this is a very interesting result.

Best regarts
Salih Kırcalar

[Salih Kırcalar]

Dear Dr...,

In your opinion, discovery of a planet is more exciting. Or, as I've presented in the attached article,
whether observing 'A very tiniest mass in the space, having completed its life, have been turning
into energy' would be more exciting or not ? It is my belief that, this observation will be the proof
of the General and the Special Theory of Relativity. This observation can be made only by NASA or
ESA. I hope that I will be able to see this consequence while I'm still alive. For further information,
please visit my web site www.timeflow.org . I will be indebted for your interest.

Sincerely

Salih KIRCALAR

[finger skate]

Finger skate are used by a range of people from those utilizing them as toys to skateboarding and related sports professionals envisioning not only their own skating maneuvers but for others as well and can include the use for planning out competition courses as skating boarding develops into an international sport.

Skate with your fingers, another feeling

[Dov Henis]

Essence And Mechanisms
Lucidity And Confusion

Law & Disorder
Physicists keep trying to explain why time flows one way
http://www.sciencenews.org/view/feature/id/59896/title/Law_%2B_Disorder

Time is a human artifact. We are in space-distance, not in space-time. It's the ever increasing distance that consumes cosmic energy in its mass format.

The universe is simpler than their minds conjure. Don't be ensnared in mechanisms. Stick to the essence.

Dov Henis
(Comments From The 22nd Century)
03.2010 Updated Life Manifest
http://www.the-scientist.com/community/posts/list/54.page#5065
Cosmic Evolution Simplified
http://www.the-scientist.com/community/posts/list/240/122.page#4427
"Gravity Is The Monotheism Of The Cosmos"
http://www.the-scientist.com/community/posts/list/260/122.page#4887