I first came across Stephen Hawking’s “teacup” analogy in his book. It bugged me for months, but I finally put it aside, Then, while watching a PBS program, there it was again. In living color, no less. Another couple months of thought, and I again forgot about it. Now I’m reading Hannibal , and there’s good old Dr. Lecter fantasizing about the same thing. Great.
Here’s the idea. If the universe reaches maximum expansion and begins to contract, time runs backward with it. So a teacup, broken in the past, reassembles itself.
Nor willing to leave that alone, I have to take it to extremes.
Take a cheeseburger for example;
Sewage unflows from the sea, through the pipes, unbreaks down back to a turd, into the toilet, undown to a person, and eventually uneats itself as a cheeseburger. I’ve went a lot farther in my mind, ending up with grass.
Try this with a man, starting with worms and going back to a sperm and an egg, puking cheeseburgers, etc, all the way.
Anyway, I don’t have any real trouble with this concept. What I do have trouble with is the idea of awareness. Would we be aware of anything during this undoing? Awareness follows occurrence, does it not? And wouldn’t we think backwards, sort of? TYou know, unthink everything everything we ever thought?
This is a hypothethetical question at best, but I’m seeking solace in sharing it with the members of the SDMB.
Please, pardon the length.
Peace,
mangeorge (Don’t laugh.)
I’m going to have to ponder the unthinking part a bit more, but, should this come to pass we’ll finally have straightened out the ambiguity in the phrase “taking a dump.”
Eew! That was bad! Sorry all.
Finally, a thread that can fire up some cognitive abilities. I’m going to assume that people involved in the reversed time wouldn’t notice the effects, as they would have to be going forward in time for simple cause and effect to be registered by brains. Since there wouldn’t be any empirical evidence, people would be clueless. History would be played in reverse, as if shown on a high quality DVD. There was clearly no reason to notice the shrinking universe before it happened, so, as a playback, there would be no realization of a the shrinking.
You might be able to find more info on this topic by searching around…maybe Carl Sagan described it.
If you want to see what all this will look like, check the show Red Dwarf episode “Backwards”. Especially when Cat takes a dump in the woods!
What’s the deal with you guys and taking dumps? Is there really son wild fecal fun that I’m missing?
Heck, how do we know it’s not happening now? (The time thing, that is, not the dump.)
we should all take time now to play some good movies and songs backwards, so that the reverse us have something to entertain them when it’s their turn.
I thought the Beatles already did that, after Paul died. Or before he will have had dying, depending on which direction we’re going. 
Don’t worry, manhattan, we’re progressing in time. The universe is expanding, not contracting…funny little astronomers in white suits prove this by checking the curvature of space. I think they tested it by checking background radiation. Not that you’re really suppose to be interested in this, I’m just trying to remember my astronomy classes.
Up until now, the universe has been expanding. This has taken, so they say, billions of years. So if it stopped and started retracting at the same speed, it would be billions of years more before the turd hits the butt, as it were. I don’t think we have to worry about it in the very near future. :D:D
Lister: “It’s not a brawl, it’s a barroom tidy! C’mon, everyone, UNRUMBLE!!”
You didn’t think I’d let a Red Dwarf reference pass by me, did you?
As regards the OP, didn’t Hawking also say somewhere that the only difference between the past and the future is which one we remember? That is, if we define time to be backwards to what we experience, the universe is indeed contracting. We only remember the less expanded side of “now,” whatever that may be.
The other argument you hear a lot to get around this is entropy. By the 2nd Law of Thermodynamics, the future is defined as the direction in which entropy (of the universe as a whole) increases. Of course, if we lived in the opposite direction, we’d have “discovered” the opposite law.
So can someone explain why entropy will start to decrease as the universe starts contracting? I presume that’s what the “teacup fixing itself” example is supposed to illustrate.
In any case, the last time I checked, all evidence suggests that the universe is flat. So it will expand forever, though the expansion speed will approach zero.
I am somewhat familiar with the tea cup theory (having read about it a few times) but have not really studied up on it. I’m just going to throw some things out:
Okay, the Theory of Relativity basically states, along with a lot more, that the faster you go the slower time goes. But as I understand it, the person that is going very fast, and hence whose time is slowed down, doesn’t really feel different. This kind of makes me think that we are only aware of our personal time. Even if time was slowing down, stopping, and going in reverse, we wouldn’t notice. Again, I’m only partially familiar with Relativity, so I’m probably wrong.
Okay, here’s something else, would everything be running in reverse, like a VCR? This would make me assume that everything would just be going in reverse without us having any awareness. If everything has already been played out is just being erased, then you’re not really doing it over again, and have no consciousness. Ex: If you make a move in a game (say chess) and time goes backwards, you’re not taking the move back. You’re not going from point A to B and then going back to point A. Point B is erased; it never happened in the first place. Thus, you wouldn’t be conscious of it ever existing.
Now, if you are aware and everything goes backwards, would you be aware in the same way. What I mean is, if your thinking is also reversed, would you still think of the past as your past and the future as your future. Though I don’t really think this comes into play. If everything is moving in reverse, the tea cup is reassembled, then wouldn’t your thoughts also be in reverse? Your thoughts are impulses, chemicals working together or what have you, so your thoughts would never have existed as well. The chemical reactions in your brain would have undone, and you’d never have thought that certain thought.
Also, scr4, I’m a little confused. Isn’t the contraction theory (called the Oscillating Universe theory, I think) still around? So all evidence against the theory points to it expanding forever, right? Anyway, I was just wondering about this. Matter has gravity that pulls objects towards it (like forming a fruit bowl in space) and thus it’s like a dip in space. If the universe’s speed approached zero, then wouldn’t it eventually reach zero? If something is slowing down, won’t it eventually stop? I’m not sure if this applies to objects in space, but isn’t gravity helping the slowing anyway? So if they finally stop and the combined gravity pulls, won’t the universe eventually start moving inwards? Again, I’m not sure of this, so please forgive me if I have made incorrect assumptions.
I think the point S.H. was making about the Teacup was that the laws of thermodynamics would have to be reversed in irrational ways for it to be put back together.
I did find this paper, by Hector C. Parr. He seems to say that we’ll be looking back at the future. Right now I’m looking for more on what Hawkings was to say on the subject.
http://www.c-parr.freeserve.co.uk/hcp/collapse.htm
Peace,
mangeorge
Expanding Universe: If there’s no cosmological constant (counter to the evidence, but simpler to consider), then a flat Universe will eventually reach zero speed, but only after an infinite amount of time. If there is a cosmological constant, then that will provide a “force” to counteract normal gravity, ad the Universe will eventually go into an exponential expansion, never to slow down. Further, the current evidence seems to be indicating that this process has already begun.
Relativity and different observers: As silent_rob says, no matter what gravitational field an observer is in, or at what speed they’re travelling, local time (and all the rest of physics) always seems normal to a given observer.
Memory and entropy: The two definitions of “past” and “future” provided by Smeghead actually work out to be the same: The time that we remember is the time of lower entropy. This can actually be proven via statistical mechanics, and I believe that Hawking addresses it in A Brief History of Time. The relevant question, is does the thermodynamic arrow of time (past is when entropy was lower) necessarily always agree with the cosmological arrow of time (past is when the Universe was smaller). There’s absolutely no scientific evidence to suggest that this would be the case, and the simplest answer is “no, of course not”, but if it did, then we would perceive the time proceeding as normal until the midpoint of the Universe, and then nothing: There would be no point futureward of the midpoint.
I’ve gone round and round on this with my physicist friends. The way we know the direction of the arrow of time right now is that we know the universe is expanding. But Percival Lowell might just as easily have discovered that the universe is contracting. We are still bound by the physical laws in effect. The questions are ‘Does the time line reverse direction if the universe starts to contract’, and ‘if it does, do all of the physical laws under which we live start running backward’?
Before the universe starts to contract, it will have to stop. It doesn’t look like that’s going to happen but, if it did, there would be a substantial (to us a million years or a billion?) time lag between the sloooooooow stop and the slooooooow beginnings of contraction.
So then, we live in a state of NO physical laws while the universe is resting? I don’t think we, here on earth, will ever see a difference (except right near the end). I don’t think the time line will change no matter whether the universe in expanding or contracting. Because I don’t think OUR universe controls the time line. I think the laws of physics are dictated to us by whatever OUR universe lives in.
Call me crazy…what the heck, I still don’t understand how we get space probes through the concentric crystal rings that hold the planets in place.
So let’s assume the universe stops expanding and starts contracting, and time goes in reverse…
If two cars uncollide at -35 MPH, is it the same as one car uncolliding into a brick wall at -70? 
oh, no…not this again