time and space

[RandomNPC]

So, here you are sitting in front of your computer reading this. I bet in five minuets, you will still be in the same place, in front of your computer.

So we have established you can be in two different times at the same place. Why can't you be in two different places at the same time?

why does this not work?

[Sneak]

So, here you are sitting in front of your computer reading this. I bet in five minuets, you will still be in the same place, in front of your computer.

So we have established you can be in two different times at the same place. Why can't you be in two different places at the same time?

why does this not work?

Because the converse of a true statement isn't necessarily true?

To use the classical example: all squares are rectangles, but not all rectangles are squares.

Also, it just doesn't make any damn sense.

[PersonMan]

Because there is only one "you", but there are multiple times. You have seven days to be somewhere, for example, but there are not seven of you to be there, so you may be at the same place multiple times.

[Copacetic]

Because we are constantly in motion when it comes to time. I.E., we are moving toward the future. If you could stop time, however, that's a different story.

[RandomNPC]

wow, i wasn't expecting that serious of a reaction. I'd really like some kind of way to pull it off. Even if it just a theory.

good job physics experts though.

[Ichneumon]

You can, it's called time travel.

[PirateMonk]

So, here you are sitting in front of your computer reading this. I bet in five minuets, you will still be in the same place, in front of your computer.

So we have established you can be in two different times at the same place. Why can't you be in two different places at the same time?

why does this not work?

Make a graph, with time on the x-axis and space on the y-axis. If two points are at the same location on the y-axis but different places on the x-axis, this is fine, but if two different points are on the same location on the x-axis, it ceases to be a function, which is bad.

Of course, the only reason why graphs with time on the x-axis must be functions is because time travel doesn't exist, so this is really just a needlessly complicated way of explaining.

[xPANCAKEx]

actually in 5 minutes time i wouldn't be in the same place, not even the exact same geographic location even if sat in the same chair in the same spot

you have:
the earths rotation
the movement of the earth around the sun
microscopic levels of tectonic plate shift

if i time travelled back to same co-ordinates in space i occupied 5 minutes ago i'd either be underground or floating in space

[RandomNPC]

actually in 5 minutes time i wouldn't be in the same place, not even the exact same geographic location even if sat in the same chair in the same spot

you have:
the earths rotation
the movement of the earth around the sun
microscopic levels of tectonic plate shift

if i time travelled back to same co-ordinates in space i occupied 5 minutes ago i'd either be underground or floating in space

You are the first person i've ever seen state why back to the future doesn't work. You win.

[Generic Archer]

Actually you can.
If we take position to be a vector of 4 parts, time and 3 spatial dimensions
(ct,x,y,z)

The the distance between two of these will be
Sqrt[(ct1-ct2)^2 - (x1-x2)^2 -(y1-y2)^2 - (z1-z2)^2]

If this distance is 0 then they are "light like" ie. a photon can be present at both events
if it is >0 they are "time like" ie. an observer can see both events
if it is <0 they are "space like" ie. they are further apart in space than light can travel in the time allowed.

so if we take (0,0,0,0) and (0,1,0,0) then the distance is -1, <0 therefore not possible to be in both places.

But, the distance in these 4 vectors is distance in space-time, so = 0 means that you are at the same time relative to location 1.

From this (1,1,0,0) and the origin are actually one and the same. ie. if you travel at the speed of light you can be in two places at once.


tl:dr. If you can travel at the speed of light then you can be in multiple places at once. This of course causes other problems.


Dane
(This is kind of like revision for the exam tomorrow right?)

[Yarram]

I think the reason, is because a duck is a bird, but a bird is not necessarily a duck.

[Dr. Bath]

You can. It's called Time Dilation, and it's happening right now. Admittedly it's the same time in different inertial frames, but now you're just nitpicking. Why would you do such a thing to me, RandomNPC? :smallfrown:

p.s. Pfft. Back to the Future totally works, the Delorean is rather obviously a time and space machine. It's a car! Moving through space is what cars do. :P

[Telonius]

So, here you are sitting in front of your computer reading this. I bet in five minuets, you will still be in the same place, in front of your computer.

In five minutes, I'll be some distance away from where I am now, relative to the center of the universe.

EDIT: Okay, clearly some kind of time loop just happened now.

[Telonius]

So, here you are sitting in front of your computer reading this. I bet in five minuets, you will still be in the same place, in front of your computer.

In five minutes, I'll be some distance away from where I am now, relative to the center of the universe.

EDIT: Didn't see Pancake's post above. Time Bandits Ninjas!

[Mr. Mud]

Back to the Future Totally works. Don't think into it. Save the catgirls, dear god, SAVE THE CATGIRLS :smallfurious:!

[Kcalehc]

tl:dr. If you can travel at the speed of light then you can be in multiple places at once. This of course causes other problems.


Dane
(This is kind of like revision for the exam tomorrow right?)

So how come light can't be in multiple places at once? It still takes it millions of years to get here, from a star millions of light years away...

You cannot be in the same place at two different times either, simply because its impossible to know where there was, and when then was exactly. You can get close, but Heisenbergs uncertainty principle will get you before you can know if you're right or not. (and as we're constantly moving through space and time at indeterminable rates, it's pretty tricky to measure either way).

[Dallas-Dakota]

[QUOTE=RandomNPC;7276821]wow, i wasn't expecting that serious of a reaction./QUOTE]
You're on a forum full of (physics) nerds, did you really expect a not-serious reaction?

Except maybe some silly ones full of memes and funny. >.>

[Generic Archer]

So how come light can't be in multiple places at once? It still takes it millions of years to get here, from a star millions of light years away...

You cannot be in the same place at two different times either, simply because its impossible to know where there was, and when then was exactly. You can get close, but Heisenbergs uncertainty principle will get you before you can know if you're right or not. (and as we're constantly moving through space and time at indeterminable rates, it's pretty tricky to measure either way).

Relative to us, certainly. But relative to the star, time propagates at the speed of light, therefore you are in multiple places at the same time.
Think of Einstein's clocks

of course if we take a frame that is moving at C - your velocity, then you can always be in two places at once, but that's just silly

Dane

[Volos]

I depends on who you ask.

Quantum Physics Dude: We are nowhere and everwhere! So you can be in every and no place at the same time!

Real Scientist: Because you are a singular event, we cannot have you be in two places at the same time, it would destroy the universe.

[Yora]

I probably did not get the stuff about 4th dimension right, but I think it means that you actually can't be at the same place at different times. As the point in time is a part of the location.

[The Extinguisher]

Basic logic says we should be. If A --> B is true, Not B ---> Not A must be true.

A: Different times
B: Same place
Not A: Same time
Not B: Different places.

At different times we can be in the same place

Thus,

When were are in different places, we can be there at the same time.

Yay logic!

[Devils_Advocate]

LOGICAL IMPLICATION DOES NOT WORK THAT WAY!

The correct logic is: If at different times something must be in the same place, then when in different places it must be at the same time.

Which makes perfect sense. If something always stays in one location, then in order to also be at a different location, it must occupy both locations at once. Otherwise it wouldn't always stay in one location!


Because there is only one "you", but there are multiple times. You have seven days to be somewhere, for example, but there are not seven of you to be there, so you may be at the same place multiple times.
I remember once seeing a discussion on identity in which the following exchange took place:

"It's common sense that while an object can be in two different locations at two different times, it can't be in two different locations at the same time."
"How can that possibly be? You're WEAKENING the criteria!"

That is to say, it's counterintuitive for object A and object B to potentially be "the same" if they have different spacial and temporal coordinates, but not potentially "the same" if they have they have different spacial coordinates but identical temporal coordinates -- because "sameness" normally implies shared properties, not different properties!

The idea being that if a "duplicate" of you is more similar to how you are now than than "you" will be in the future, then it's silly to say that your future copy is you and your present one isn't. Being in the future instead of the present just gives your future "self" less in common with you.


Make a graph, with time on the x-axis and space on the y-axis. If two points are at the same location on the y-axis but different places on the x-axis, this is fine, but if two different points are on the same location on the x-axis, it ceases to be a function, which is bad.

Of course, the only reason why graphs with time on the x-axis must be functions is because time travel doesn't exist, so this is really just a needlessly complicated way of explaining.
... That doesn't explain anything. Saying that time travel doesn't exist because position is a function of time and position is a function of time because time travel doesn't exist is circular logic. Rephrasing a phenomenon and throwing in the word "because" does not account for it. Saying e.g. "This man is a bachelor because he's unmarried" can actually be sort of misleading, because the phrasing implies that you're linking two facts together.

[Partof1]

Because time doesn't actually exist. The idea that everything that has happened is embedded there is an idea of man. Yes, things have happened, but they aren't happening again on a different plane. Time isn't aomething that can be manipulated, or even observed, forward and back, it is just a simple way of knowing when things will, and for some important reason, have happened. What happens now unravels as you go, it does affect what will be, but what is, in and of itself, is gone.

This means, finding a specific point in time in which to be multiple places is impossible, as time is imagined.

[littlebottom]

ok, normally i would say something like many people above have said, but to break the mold im gonna go bat for the other team.

theres theorys upon different dimensions, which, if true, you occupy a near infinate amount of spaces at the same time, as long as its a possible outcome of some event within your life, theres a dimension that holds that result, every decision you make makes more dimensions, for example, if some one said "your name is [insert name here] correct?" your answers could be "yes" or "no" (or "whos asking" or "maybe?" or "i have amnesia, i dont know who i am" etc etc) if you choose "yes" then you live out that result, while annother dimension is created in which another you in another world, lives out the result of you saying "no" (or any other possible reply) and they in turn create more and more and more dimensions, so that to date, there literally is a near infinite number of dimensions, if this is to be believed. of course, its only a theory as is time travel, but so was "electricity" and "radios with pictures!" yet they are now real.

and yes, if that theory IS to be believed, then ive created several billion more just by typing this:smalltongue: LITTLEBOTTOM, CREATOR OF UNIVERSES!