Science
Related: About this forumBig Bang May Have Created a Mirror Universe Where Time Runs Backwards
Why does time seem to move forward? Its a riddle thats puzzled physicists for well over a century, and theyve come up with numerous theories to explain times arrow. The latest, though, suggests that while time moves forward in our universe, it may run backwards in another, mirror universe that was created on the other side of the Big Bang.
Two leading theories propose to explain the direction of time by way of the relatively uniform conditions of the Big Bang. At the very start, what is now the universe was homogeneously hot, so much so that matter didnt really exist. It was all just a superheated soup. But as the universe expanded and cooled, stars, galaxies, planets, and other celestial bodies formed, birthing the universes irregular structure and raising its entropy.
ne theory, proposed in 2004 by Sean Carroll, now a professor at Cal Tech, and Jennifer Chen, then his graduate student, says that time moves forward because of the contrast in entropy between then and now, with an emphasis on the fact that the future universe will so much more disordered than the past. That movement toward high entropy gives time its direction.
The new theory says a low entropy early universe is inevitable because of gravity, and ultimately thats what gives time its arrow. To test the idea, the theorys proponents assembled a simple model with nothing more than 1,000 particles and the physics of Newtonian gravity. Heres Lee Billings, reporting for Scientific American:
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http://www.pbs.org/wgbh/nova/next/physics/big-bang-may-created-mirror-universe-time-runs-backwards/
TerrapinFlyer
(277 posts)Some people are moving froward, and others are moving back - all on the same plane, at the same time.
The Democrats are moving forward... and the Republicans are going back in time.
TexasTowelie
(112,150 posts)after (before) tonight's drawing?
jakeXT
(10,575 posts)Last edited Sat Dec 13, 2014, 08:37 PM - Edit history (1)
ret5hd
(20,491 posts)looking at a wheel spin on an axle:
You look at it from one side and it is spinning clockwise
You look at it from the other side and it is spinning counter-clockwise.
It's all the same direction tho.
defacto7
(13,485 posts)and point of perspective. What's forward to us is forward to them. Are we talking mirrored time rather than forward and backward?
Orsino
(37,428 posts)AlbertCat
(17,505 posts)Well, I care, because I've got to get back to making Xmas presents before the Dec. 25th deadline!
But...really.... since time is a measure of how things changed from the last time you noticed.... wouldn't ANY change (even one that created a replica of something already past) be perceived as something different (or the same) as something gone before and so time would appear to go "forward" to any creature in any universe.... events not like (or just like) something before... if your definition of time is a measure of change.
Of course when you get into the math and stuff.....
WillyT
(72,631 posts)FiveGoodMen
(20,018 posts)As Mister Spock would say "That is not logical".