Therefore time travel is not possible.

---

Added on November 2, 2010, 12:11 amEntropy always increases no matter what you do. The reason for entropy to "decrease" is because you are only looking at a local system. The entropy decreases from clay to a ceramic cup is less than the work (that is lost as a result) that requires to form it. Hence when you sum the total entropy of the total system, entropy increases.

This post has been edited by SpikeMarlene: Nov 2 2010, 12:11 AM

correct, hence the phrasing of the question from the perspective of the "cup". given that time travel ideas almost always involve extra dimensions. our 3/4 dimensions can be considered a "local system"?

what is this??somebody invent delorean time machine?

What is then hidden within our normal 4 dimensional space-time? What is outside our universe that interacts with it thermodynamically to decrease entropy? We may have a lot of ideas but these to me are just speculative. I am an old fashioned guy and have yet to see evidence for multi dimensional theories ...

its a thought exercise that's nothing more than an idea. currently explored in super string, m-theory etc by various top minds such as michio and hawking.

hawking and other top quantum physicist did suggest that there is nothing wrong with traveling opposite of the thermodynamic arrow. just that we cant do it

i hope you didnt get the idea that i meant time traveling is possible now. it's at about the same region at traveling at light speed, wormholes, hyperspace, etc. science fiction fodder (for now)

Of course not. I find some of your thoughts mirror my own, and I am always excited for any lively rational discussion on ideas, after all these are the seeds that may lead to something useful.

There is 1 great book on string theory and science, if you have not read it yet, I highly recommend it -> Lee Smolin "Trouble with Physics"

Some astronaut traveled in the future, he is 0.02 seconds faster than us. Lul

I remembered reading another possible theory about time travelling, which mentioned that we can "travel" to the past only as an observer. In another word, we can't actually do anything, we just see the image of the past because we simply go back to the time when the light is still there (which in turn, allow us to "see")
However, even if it's possible, it may not qualify as time travelling.

hum... yep.. I guess it won't be time travel, I guess it's like how scientist are tracing the history of the universe from radiation let off from the pass.

We are definately just an observer.

Yes. But still, it's also similar to time travel. However, this theory won't work for travelling to the future.
And I believe this theory is more feasible than travelling to the past through the timeline. I honestly doubt it's possible to travel time and alter the past. There's just too many paradoxes. And if there's already a written future infront, then it will only mean that our lives are predestined.

Hmm, i never thought of it this way. Perhaps if we can create a machine to view a certain event, certainly much more feasible than a machine to take us physically there. This could find good use in forensics

What you would do is to tunnel across the universe through some wormholes, arrive at a location and wait for the lights of the events to arrive from earth, use you ultra sensitive image correction super device and view the events in the past ....

a concept explored in the movie "deja vu" (ignore the ending)

if you are referring to traveling into the past,
I would say impossible.
think of this situation,
you are traveling into the past, in order to kill your father.
and then you see him, you're gonna shoot him with a gun,
but you succeed? okay let say you miss him for the first time,
then you travel back to that moment to do it once again,
but will you be able to kill him?
if so, then how are you born in the future?
if you are not born, how do you even exist in the first place to travel back in time and kill you father?
and what is preventing you from killing your father when you traveled back in time?
where's your free will?
as a human with free will, you should be able to commit your act independent of these 'destiny' of the time travel paradox.

traveling to the future is of course possible, as claim by special theory of relativity.

another issue, the arrow of time.
law of physics treat the flow of time equally, forward or backward.
the only physical law that seems to provide an arrow of time would be entropy, or second law of thermodynamics, it USUALLY increases with time.
however there will be rare statistical fluctuation in which the total entropy of the universe decreases, because there's a non-zero probability for entropy to decrease. for further reference read from The Fabric of the Cosmos by Briane Green, page 167

The machine is called video camera with added functions.

Attempting to answer this question with science is not as interesting as exploring why must there be life in the first place and why only human are unique who creates than live like animals. What is the purpose to go backward or forward? Looking for the beginning or the end?

sorry to barge in. hot topic in /kopitiam got close and mod directed to here.

can i say my opinion on ur view? i think that if a person was to kill his father in past, then the future will reset?
there will be no trace of u in the future/present like the theory in back 2 the future where marty disappearing. for that world or dimension, u will cease to exist at all. the question of how u exist and kill ur father is irrelevant bcoz the important matter of fact is ur father is killed. what happen before the incident and beyond isn't counted anymore.

however, i'm of the view that, even if u can go to past, u can't change anything. u will only delayed it. this is the theory in The Time Machine film.whatever u do, u can only change ur future, and not the past.

This post has been edited by fix24311: Nov 7 2010, 12:47 AM

I see, this topic isn't about science of time travel but the urge of fantasy mind that want to travel through time. Like chasing ghost or define spirit kind of thing, at least come up with better story to narrate through the process than try to ration with it.

Then this is the predestine idea.

Yep, I've touched on this, if we are predestined, does that mean that if we know what happens in our future, and our future actually comes, does that mean, that we cannot do anything that we already knew we'd do?

For example, we knew we'd reply "Yes" to an answer instead we want to reply "No" this round.

Will our bodies be out of our control for that moment and force us to say "yes" nonetheless?

Your welcome to share your thoughts.

Imagine the urine from the toilet went back to your genital and came out from your mouth, also the feces that turn back into food and backward all the way to the farm, body parts of animals and the grass they eat, the vegetable grow backward to form the past that you visit all the way to the beginning of life.

Then fast forward the same and see where the urine and feces become part of someone's body and turn into some thing else and so on, if there is a beginning, there is an end and when you come back to present time, what do you think will change? I don't think you want to live.

There is theory, however. That even if you killed whoever conceived you, you will still exist.

The theory suggests that time does not really move in a straight line like an arrow. It moves likes a river, in different sets of streams. At times, the river can split into different directions, resulting in different timelines, or else known as the explaination for parallel universes. This theory is probably oming from an everyday human experiences. Have you remebered how certain minutes actually "felt" as if it is longer than other days? Theory suggests that the river sometimes forms a small vortex, trapping any matter into a temporary time stop, hence you hear things like, "That is the longest ONE minute I ever have".

Theories, anyways. But it sure gave a way out for time paradoxes.