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ElectricalEngg.

Tue Jun 30 2009, 09:05PM

Registered Member #1946 Joined: Sat Jan 31 2009, 11:37AM
Location: India
Posts: 43

Post removed temporarily due to personal reasons!! Kindly forgive me. Will put it back up soon. Thank You for understanding.

Proud Mary

Tue Jun 30 2009, 10:05PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

I'll just say that Albert Einstein did not have a knighthood, and leave it at that.

Do such entities as "wormholes" actually exist, or are they no more than post-doctoral dreams and mathematical artifice?

The great wave of enthusiasm for Higgs' boson does not mean to say that the elusive particle actually exists, or ever will do so, but press your ear to any laboratory door and you will hear people talking as though its existence was already a certainty.

Thus we cobble together a narrative where authentic observations are linked together by theoretical speculation and wishful thinking, somewhat after the manner of the conspiracy theorist.

This is not to say that your ideas are either of wrong or right, but to avoid the kind of speculative narrative that may be fun to think about, but is at present not amenable to the scientific method, to deductive reasoning, and so is a mere article of faith, like the existence or non-existence of God.

Steve Conner

Tue Jun 30 2009, 10:24PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

I've come from the year 30019 to warn you that time travel is impossible. How do you like that?

Seriously though, I believe what the laws of physics say is that causality must always hold. Effects aren't allowed to happen before their causes, and that's what the grandfather paradox illustrates.

Proud Mary

Tue Jun 30 2009, 10:53PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

And what of the laws of entropy? It is hard to imagine the glass smashed into a thousand pieces reassembling itself.

Zum Beispiel

Wed Jul 01 2009, 01:24AM

Registered Member #514 Joined: Sun Feb 11 2007, 12:27AM
Location: Somewhere in Pirkanmaa, Finland
Posts: 295

I've traveled through time many a time. This has usually happened after I've gone to a bar. I remember going in and then waking up 12-24 hours later. The splitting headache must have been just a side effect of time travel...

I find consepts such as entropy and causality confusing, however:

If causality always holds, then what or who is the unmoved mover? Whether or not there is an entity that we'd call 'god', what made the universe happen? There must have been a cause for the big bang, if things always happen for a reason and there has to be a cause for an effect, that is.

In the Newtonian model causality is absolute. Everything happens for a reason and if we could know the position and direction of every particle in the universe, we could then predict the future. We could do this, because causality determines that when object A interacts with object B at velocity Ã„, object B will move in direction Z with velocity Ã–... and so on. This seems to be the case with all physical interactions in the universe.

But why is it then, that when we do a double-slit experiment, we can never say where an individual photon is going to go? We can only make predictions, but we can never be quite sure where it'll strike. When firing a single photon into the slit, it can land freely where ever it 'wants' to go on the screen. Only when firing a group of photons, do we see a pattern, an interference pattern, with maximums and minimums.

Now let's think about this: the smallest of particles don't always seem to conform to absolute causality, instead they seem to follow a statistical form of causality. There is an infinite number of possible outcomes for when a particle interacts with another, some are much more likely than others (the photon in a double-slit experiment is much more likely to strike the first interference maximum than the fourth, for example). But nevertheless, there is a possibility. This seems strange, but then again, we are talking about a world where the very act of observing an event changes the outcome.

But why should we care what happens at such a small level, when all the things and matter big enough to be of any importance seem to follow absolute causality? In our world, the macro world, there's a cause and an effect.

But aren't all physical objects made of these tiny particles, the things on the micro level, where causality doesn't seem to hold? Even our thoughts are just chemical reactions happening in our very physical brains. Now, let's think of all matter in a physical object as not as a single entity, but as a group of about a bajillion different particles. When a physical object interacts with something, it's basically those bajillion particles interacting. If those interactions are governed by this statistical causality, then there are also a bajillion different possible outcomes for the interaction. Some particles will 'want' to do outcome C, some will 'want' to do B, but most will do A, as that is the most likely outcome. Thusly, the most likely outcome will happen, as it outweights the less likely. So to us it seems as if the physical object behaved like it was under absolute causality.

In short, anything is possible, but the most likely will happen almost always. You break a glass, and it will never reassemble itself, but in theory that could happen, if one of the more unlikely interactions were to happen. If this is the case, absolute causality doesn't hold as the probabilities are, that sometimes, the more unlikely interactions are going to happen.

A physicist named K.V Laurikainen wrote a good book called 'Todellisuus ja ElÃ¤mÃ¤' (I don't think there's an English translation), where he talked about the relationship between absolute and statistical causality and how they effect the micro and macro world. He was talking more about how physics could give answers to methaphysical questions, such as the existance of a god, saying something about how one could find god in entropy, how you could see 'his will' in, for example, the double slit experiment. Because, hey, 'god works in mysterious ways' and whether you believe in the absolute or statistical version of causality, you never have free will, therefore there has to be a unmoved mover of some kind. I'm not sure if I'm willing to believe that, but then again, I'm an agnostic.

But what does this have to do with the topic at hand? Very little, just that: if the future isn't yet determined (regardless of free will), how could one possibly go there?

The more important questions are, however:
Do I know what I'm talking about? No.
Should I click 'reply to thread'? Probably not. (I will, though.)

Hon1nbo

Wed Jul 01 2009, 02:12AM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: North Texas
Posts: 1040

(note: I am not an expert, but this is what I can deduct from logic and some knowledge I do have in Physics)

The main issue I can't seem to get around is the interaction of particles that is the foundation of pretty much everything.

for the sake of my argument (and to make explanation easier) assume you could attempt time travel somehow. Say you are in the process of traveling, the particles of either you or whatever capsule you might be in have to interact with their surroundings, which are allegedly moving faster than you are. Therefore, you would simply be interacting with them as normal as there is not way you could cause the particles to not interact. If you could make the outer layer of your capsule or whatnot avoid interaction with the space around the capsule, why would they be able to interact with the particles inside the capsule? - if you could make only interactions with the inner particles, then the energy absorbed by the capsule outer layer would suddenly disappear or be converted into mass - either way, you would end up losing all of the energy being transferred amongst particles and end up with no particle motion, a.k.a: Absolute Zero Temperature, from which no human could survive, nor likely any type of man-made machine (of, course I refer to the functions ability to perform of that machine, not it physically)

this would occur assuming you could stop the capsule or whatnot from interacting with its surroundings...

if the capsule did interact with its surroundings, then it would be affected by whatever events in time it is trying to travel past, or it is itself altering the behavior of the space around it, i.e. not leading to "the future" but leading to a different present

again, I am no expert but this is what seems logical

Frosty90

Wed Jul 01 2009, 03:21AM

Registered Member #1617 Joined: Fri Aug 01 2008, 07:31AM
Location: Adelaide, South Australia
Posts: 139

I was actually think to myself about time travel the other day. Wouldn't time travel violate mass-energy conservation? Say you sent an atom into the future. Wouldn't your universe then be one atom short until you arived at the time to which your atom was 'sent'? Or maybe the universe is happy if the average mass over all time is constant.

Time travel into the future is actually quite easy, I'm doing it now.

Turkey9

Wed Jul 01 2009, 04:33AM

Registered Member #1451 Joined: Wed Apr 23 2008, 03:48AM
Location: Boulder, Co
Posts: 661

Time "travel" into the future is definitely possible. Astronauts traveling at tens of thousands of miles an hour experience time slower than the rest of us on earth. Thus, everyone on earth has traveled a couple thousanths of a second into the future with respect to the astronaut.

Something else interesting, according to Einstein and his special theory of relativity... Traveling at extreme speeds compared to another object will make the space time flows of the objects different. Think the thought experiment about the two twins, one traveling around the universe at near the speed of light and the other staying on earth... Well because the motion is relative to each other, if you fly away from the earth in that spaceship, there is no way to tell if it is in fact the earth moving away from you. But as soon as you change your direction and hence your velocity to return to earth, you are now the one that was moving away from the earth. Thus, the acceleration (change in velocity) is what really determines the flow of time.

Carbon_Rod

Wed Jul 01 2009, 06:42AM

Registered Member #65 Joined: Thu Feb 09 2006, 06:43AM
Location:
Posts: 1155

We all generally travel through time at 1 second per second under the assumption space time is locally flat.

This clearly notes why primates will never achieve space or time travel:

mikeselectricstuff

Wed Jul 01 2009, 07:18AM

Registered Member #311 Joined: Sun Mar 12 2006, 08:28PM
Location:
Posts: 253

Time is just Nature's way of stopping everything happenning at once

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