“Emoclew dna olleh,” Columbia University string theorist Brian Greene said as he opened a conference at the New York Academy of Sciences last October. “If you understood that as ‘Hello and welcome’ in time reverse,” he clarified, “you probably don’t need to be here.”
No one left. Many of the world’s top theoretical physicists and cosmologists gathered at the conference to grapple with the mystery of how time works. New telescope observations and novel thinking about quantum gravity have convinced them that it is time to reexamine time. “We’ve answered classic questions about time by replacing them with other hard questions,” says cosmologist Max Tegmark of the Massachusetts Institute of Technology.
On the face of it, time seems pretty simple, like a one-way street: eggs don’t unscramble, laugh lines don’t vanish (not without Botox, anyway), and your grandparents will never be younger than you. But the universe’s basic laws appear to be time-symmetrical, meaning they are unaffected by the direction of time. From the point of view of physics, the past, present and future exist simultaneously.
For more than a century, physicists have proposed any number of explanations for this apparent contradiction, from the psychological (the flow of time is an illusion) to the physical (some unknown property of quantum mechanics reconciles the contradiction). None has proved satisfactory. In 1927 astrophysicist Sir Arthur Eddington coined the term “time’s arrow” for the phenomenon and linked it to entropy: as the universe gets older, it becomes more disordered, following the second law of thermodynamics.
But scientists cannot explain why order lies in the past and disorder in the future. A solution has appeared so elusive that at times it has been regarded as a distraction from more “respectable” research. Physicist Richard Feynman even refused to have comments about time’s arrow attributed to him at a conference in 1963, insisting on being identified as “Mr. X.”
“The problem is at the borderline between science and philosophy, and a lot of people don’t feel comfortable in that area,” says Laura Mersini-Houghton, a physicist at the University of North Carolina at Chapel Hill and co-organizer of the conference. “It’s been very difficult to make progress over the past 20 years, because there hasn’t been much new to say.”
That is all changing thanks to stronger instruments for probing the heavens. The cosmic microwave background radiation, a remnant of the big bang, shows that 380,000 years after its birth, the universe was filled with hot gas, all evenly distributed and highly ordered. Eventually the early cosmos underwent inflation and began to coalesce into the disordered universe of stars and atoms we know today.
What remains puzzling, though, is why the early universe was so orderly—a condition that physicists consider highly improbable—and what caused it to swell so rapidly. “The arrow-of-time problem, once you get down to the nitty-gritty of it, is, Why was the early universe the way it was?” says Sean Carroll, a cosmologist at the California Institute of Technology. What is more, the cosmos is now going through another period of expansion, with galaxies flying apart at an increasing rate because of a mysterious dark energy. “The fact that it appears that the universe is just going to expand forever and get colder and colder makes [the different conditions] even more striking,” Carroll adds.
Mersini-Houghton and her colleagues brought together some of the best minds in the field for the conference because, as she puts it, “we can’t just brush this problem under the rug anymore and hope it will be solved by something else.” Prominent physicists such as Greene, Tegmark, Lee Smolin of the Perimeter Institute for Theoretical Physics in Ontario, Paul Davies of Arizona State University and Andreas Albrecht of the University of California, Davis, invoked string theory, black hole equations and the idea that we live in one of many parallel universes as possible explanations.
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6 Comments
Add Comment"In a Gravimetrical Quantum Sense"
Reply | Report Abuse | Link to thisThis article really picked the pig up by the rear, as to say. I did however, have the clear notion of raving winged swine with snouts the size of houses pop clearly into my imagination. On a more particular note, though, it seems the focus of the article to be at least slightly in jest of our 'Ill at ease' attitude toward the subject. Lacking proper propulsion, this topic is not, but innuendo. I laughed, I cried, I decided to define 'evert' as 'random oscillation of,' and pretended that shape is affected by physical attributes only in zero gravity.
This set of early order is perhaps attributed to "shape"?
Reply | Report Abuse | Link to thisone, two , three, four.
Reply | Report Abuse | Link to thislook, read, think, react.
time is development.
development needs space.
space has identity.
all identities contain structures.
some structures develop because of the DNA .
human structures have apart from this the "will" to develop.
Time is a place holder.
Reply | Report Abuse | Link to thisDo articles like this bring out people like these?...
Reply | Report Abuse | Link to thisOr were they here all along?
Essence And Mechanisms
Reply | Report Abuse | Link to thisLucidity 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 draws 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