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anteck7
2002-Dec-05, 12:51 AM
Me and a friend were talking and i though you guys might have some insignt as to if this was possible or not.

you link two quantum particles so a change in one changes the other like Bell.

Anyway, you send one particle off at close to the speed of light (yea not possible...yet) anyway, a computer onboard changes the spin of the particle on board, the changes would occour back on earth... instantly, because of the difference in speeds, there would be a time difference between the ship and earth. Could we use this to see into the future?

GrapesOfWrath
2002-Dec-05, 01:25 AM
No (http://eve.physics.ox.ac.uk/NewWeb/Research/communication/communication.html). Welcome to the board. Keep thinking.

Dunash
2002-Dec-05, 02:07 AM
The interesting crime film "Frequency" (2000) depicts this very possibility.
http://us.imdb.com/Title?0186151

JS Princeton
2002-Dec-05, 03:24 PM
You will never be able to accelerate a massive particle to the speed of light with physics as we currently know it. Any new physics that allows something like that will have drastic implications to our current theory, so it's difficult for us to speculate about this possibility.

However, you can accelerate a particle arbitrarily close to the speed of light. Maybe that's what you want to do?

Zathras
2002-Dec-05, 03:27 PM
On 2002-12-05 10:24, JS Princeton wrote:
You will never be able to accelerate a massive particle to the speed of light with physics as we currently know it. Any new physics that allows something like that will have drastic implications to our current theory, so it's difficult for us to speculate about this possibility.

However, you can accelerate a particle arbitrarily close to the speed of light. Maybe that's what you want to do?


It doesn't matter whether the particle is massive or not. The same quantum coupling can occur with photons as well, so the speculation is legitimate.

JS Princeton
2002-Dec-05, 03:54 PM
Well, I think it's rather hard to build a computer out of nothing but photons, zathras. But, who knows? maybe someday we'll build spaceships out of photons: I guess I hadn't thought of that.

traztx
2002-Dec-05, 04:04 PM
Could quantum coupling of photons allow someone to peer into a black hole? Seems like cheating to me /phpBB/images/smiles/icon_razz.gif

2002-Dec-05, 05:04 PM
<a name="2-12-05.TC"> page 2-12-05.TC aka Two Commmpputers
ONE A pc THE OTHER A mac
start them together in 1980
and meassure the time interval untill
the Operating System changes from $ denominated
to .edu nominated { from ? to UNex }
note carefull it takes Mac a couple of years
longer to make the flip {but it does so instantly}
(yes the part that does} while the pc changes Gradually
(1980 : 1990 {pcU5%} 2003 Mac!: 2020 pc 98%} 2025} Loss of power

DJ
2002-Dec-05, 06:17 PM
On 2002-12-05 10:24, JS Princeton wrote:
You will never be able to accelerate a massive particle to the speed of light with physics as we currently know it. Any new physics that allows something like that will have drastic implications to our current theory, so it's difficult for us to speculate about this possibility.

<snip>

Wow, this statement left me really wondering.

So how does this affect your understanding of the Big Bang? Didn't that accelerate out a bunch of particles at light speed?

DJ

Wiley
2002-Dec-05, 06:22 PM
On 2002-12-05 13:17, DJ wrote:


On 2002-12-05 10:24, JS Princeton wrote:
You will never be able to accelerate a massive particle to the speed of light with physics as we currently know it. Any new physics that allows something like that will have drastic implications to our current theory, so it's difficult for us to speculate about this possibility.

<snip>

Wow, this statement left me really wondering.

So how does this affect your understanding of the Big Bang? Didn't that accelerate out a bunch of particles at light speed?

DJ


No, the BB accelerated particles very, very close to light speed, but not at light speed. And this does not say anything about how fast space itself expanded.

Wally
2002-Dec-05, 06:42 PM
On 2002-12-05 13:22, Wiley wrote:


On 2002-12-05 13:17, DJ wrote:


On 2002-12-05 10:24, JS Princeton wrote:
You will never be able to accelerate a massive particle to the speed of light with physics as we currently know it. Any new physics that allows something like that will have drastic implications to our current theory, so it's difficult for us to speculate about this possibility.

<snip>

Wow, this statement left me really wondering.

So how does this affect your understanding of the Big Bang? Didn't that accelerate out a bunch of particles at light speed?

DJ


No, the BB accelerated particles very, very close to light speed, but not at light speed. And this does not say anything about how fast space itself expanded.


Just read about this very thing in Dec. issue of Astronomy (I think). the writer there stated expansion did in fact happen at faster than light speeds, but since it was space itself that was expanding, no rules of physics were broken. Keep in mind I'm paraphrasing here. Wally

JS Princeton
2002-Dec-05, 06:53 PM
Indeed, superluminal expansion of spacetime is perfectly well allowed by GR which is utterly consistent with the local phenomenon of massive objects not being able to go faster than the speed of light. The expansion of the space in between two objects faster than the speed of light just means, unless the expansion deccelerates sufficiently, that you will not see the other object. There is an effective event horizon between one part of spacetime and another.

GrapesOfWrath
2002-Dec-07, 12:39 PM
On 2002-12-05 10:54, JS Princeton wrote:
Well, I think it's rather hard to build a computer out of nothing but photons, zathras. But, who knows? maybe someday we'll build spaceships out of photons: I guess I hadn't thought of that.

But why would you have to do that? The computer could have parts that are not made of photons, but used photons to communicate. Don't we have some of that going on already?

JS Princeton
2002-Dec-07, 06:43 PM
Grapes, I was simply trying to answer the question posed by the OP which was putting an entangled particle on a ship that could travel at the speed of light. In order to do that, your whole ship including the computer would have to be made out of photons. Just seems a bit outlandish to me...

xriso
2002-Dec-08, 12:39 AM
According to special relativity, any kind of superluminal signalling device can be used to transmit information into the past. So, if you ever find a way to do such a signal, let spacetime brace itself for temporal paradoxes.

(Paired particles are not a useful signalling device)

GrapesOfWrath
2002-Dec-08, 01:12 AM
On 2002-12-07 13:43, JS Princeton wrote:
I was simply trying to answer the question posed by the OP which was putting an entangled particle on a ship that could travel at the speed of light. In order to do that, your whole ship including the computer would have to be made out of photons.

Ah. But the OP said "close to the speed of light"

JS Princeton
2002-Dec-08, 01:40 AM
So it does, Grapes... must be a cognitive disonance thing I have going here. Hey, you can send anything off at close to the speed of light.

GrapesOfWrath
2002-Dec-08, 10:34 AM
LOL. When I really get going, my pedometer gets stuck at c--must be because of the up and down jouncing.

The reason I mentioned it, I'm looking forward (with some trepidation) to computers computing with light.