posted
Siminon, you can't calculate future events with complete certainty, according to the uncertainty principal, an event cannot be counted on until it has been observed, and since you can't observe future events, you can't exactly predict them. There are quantum events which have unpredictable outcomes, therefore the positions of future objects have not been determined at the present time. In a way the future your headed for does not exist, and even if it did, things wouldn't be the way you expected.
Posts: 9912 | Registered: Nov 2005
| IP: Logged |
The equation means that mass and energy are one and the same. Matter is just a way of storing energy. The two are related through the constant speed of light. This has been thoroughly tested. So technically... *shrug* energy is mass. Where the problem comes in is the absolutely COLLOSSAL amount of energy needed to create a little mass. M = e/c^2. c being the speed of light (roughly: 3x10^8 m/s) you're looking at a whole ton of energy needed just to create a kilogram of mass.
Also, I'm not entirely sure that light counts as pure energy. I haven't taken modern yet, so while I learned the significance of the energy/mass relationship, I'm not quite sure where light fits in (being made up of massless photons). Its a form of energy to be sure (or contains it anyway), but is it pure energy?
Either way, it would take a whole shitload more light than we are capable of firing through a lazer to even produce the equivelent of some sort of nominal mass. Forget one large enough to warp space time.
To give you an idea how much:
1 kg equivelent in energy is: 9x10^16 J
Robert Zubrin estimated in his book Entering Space That humanity used about 29 TWh (terra-watt hours) in the years 1998 to 2000. By my calculations (feel free to check em) thats about 1.044x10^17 J. In otherwords, we'd need about as much energy as we used in two years to create the equivelent of 1 kg worth of light.
Yeah... its not gonna work. But let him try it, some of the most significant discoveries in science came from people experiementing on seriously crackpot theories hoping for completely different results.
Posts: 3295 | Registered: Jun 2004
| IP: Logged |
posted
Orincoro, that's a rather large misstatement of the uncertainty principle. The uncertainty principle "merely" has to do with the simultaneous measurement of certain pairs of variables. It doesn't have anything to do with events, per se. You seem to be thinking of the uncertainty of unobserved events due to the action of probabilistic quantum phenomena, leading to a quantum wavefunction that hasn't collapsed yet, such as in the Schrodinger's Cat paradox.
Posts: 15770 | Registered: Dec 2001
| IP: Logged |
posted
Alcon: once you get small enough, it becomes almost useless to talk about a difference between mass and energy; its just convenient to use one in some contexts, and the other in others. In a limited sense, photons are pure energy, because they have no rest mass, but because they're always moving, they have mass (or energy, from another perspective).
Posts: 15770 | Registered: Dec 2001
| IP: Logged |
quote:Originally posted by fugu13: Orincoro, that's a rather large misstatement of the uncertainty principle. The uncertainty principle "merely" has to do with the simultaneous measurement of certain pairs of variables. It doesn't have anything to do with events, per se. You seem to be thinking of the uncertainty of unobserved events due to the action of probabilistic quantum phenomena, leading to a quantum wavefunction that hasn't collapsed yet, such as in the Schrodinger's Cat paradox.
Your right, I just conflated two ideas into one argument, the uncertainty principal AND the cat.
I was thinking of schrodinger's Cat, the idea that future events exist as a waveform that doesn't collapse until you open the box. This is in the same vain. I am also aware that you can't measure position without effecting speed, speed without changing position etc. This too would not allow for a person to predict future events from the information they could gather at present, since the information will always be either incomplete or innacurate.
Posts: 9912 | Registered: Nov 2005
| IP: Logged |
posted
Orinoco, the movement of the planets is not an "event" at all. If you know what Schrödinger's Cat experiment is about, then you shouldn’t confuse things. It's one thing to "predict" an event based on a quantum wave function, and quite another to apply the laws of Mechanics.
True, the EXACT (as in 100% accurate) position AND speed cannot be calculated simultaneously, not for an electron and not even for an elephant.[The magnitude of mass IS relevant.] The incertitude/error for the electron is important, but the incertitude/error for an elephant is so small that it is null for any practical purpose.
So, the position of the other end of the space-time distortion is subject to such an "imprecision". But an irrelevant one. Assuming that the distortion can be “cleanly localised” (as opposed to a worm-hole the size of a planet), the incertitude in the prediction of its position is the least of the problems.
quote:Originally posted by Alcon: Also, I'm not entirely sure that light counts as pure energy.
posted
Suminon, your saying that in a billion years the uncertainty will STILL be negligable? a BILLION years?
For every event there is an effect bubble which moves away from that event at the speed of light in all directions. In traveling to the future, there would be a reverse bubble effect, so that the farther you travel, the larger the bubble of events that will effect the world you arrive in, will be. If you travelled a billion years in the future, then the future you arive in will be affected in some way by every event which has occured over a billion light years since you left. That's too much uncertainty in combination.
Besides all that, since the speed of light is finite, you couldn't predict a future any more lightyears away than you could actually see, or else unseen events which are in your reverse effect bubble will change the future before you get there, and things will be different.
Posts: 9912 | Registered: Nov 2005
| IP: Logged |
quote:Originally posted by Orincoro: Suminon, your saying that in a billion years the uncertainty will STILL be negligable? a BILLION years?
No, that’s not what I‘m saying.
quote:For every event there is an effect bubble which moves away from that event at the speed of light in all directions. In traveling to the future, there would be a reverse bubble effect, so that the farther you travel, the larger the bubble of events that will effect the world you arrive in, will be. If you travelled a billion years in the future, then the future you arive in will be affected in some way by every event which has occured over a billion light years since you left. That's too much uncertainty in combination.
Besides all that, since the speed of light is finite, you couldn't predict a future any more lightyears away than you could actually see, or else unseen events which are in your reverse effect bubble will change the future before you get there, and things will be different.
I agree with the “effect bubble” description. As long as we don’t completely know “the present”, we won’t be able to perfectly predict the future. In a billion years it might be that our entire Solar System wouldn’t exist at all anymore. Or at least our frail blue marble that we call Earth. The laws of Mechanics allow us to calculate the position of Earth with respect to the Sun at ANY point in time. For the past (but obviously not past the birth of the Solar System) we are sure the Earth “was there”. For the future, the further we go, the less chances we have to find the Earth (existing) there. So in a billion years, the “certainty” of finding the Earth in the expected spot is quite small.
But the incertitude on its position it is not the sum of “combined uncertainty” for every particle in the Universe evolving “second by second” until then. The presence of an asteroid that we presently ignore, which could intersect Earth’s trajectory and deviate/destroy it is a totally uncontrollable incertitude. And it has nothing to do with Heisenberg’s Incertitude Principle.
The Solar System is a stable enough mechanical system to be predictable. That’s what I was saying.
Not sure as in: "I don't know" Anything measured in joules maybe?
Light probably does count, still with the needing more of it than we're capable of producing to do anything along these lines.
Posts: 3295 | Registered: Jun 2004
| IP: Logged |
quote:Originally posted by suminonA: The Solar System is a stable enough mechanical system to be predictable. That’s what I was saying.
A.
Works for me! As long as your not thinking you could actually predict the future PRACTICALLY. Since this might would building a computer so big that generated its own gravity well, thus the act of calculating future events might also alter them. Now we really are in insano physics territory.
Posts: 9912 | Registered: Nov 2005
| IP: Logged |
Printer-friendly view of this topic
![[Razz]](tongue.gif)
Anything measured in joules maybe? ![[Wink]](wink.gif)
![[Smile]](smile.gif)
As long as your not thinking you could actually predict the future PRACTICALLY. Since this might would building a computer so big that generated its own gravity well, thus the act of calculating future events might also alter them. Now we really are in insano physics territory.
