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Posted: Sat Sep 08, 2007 3:57 pm
by Axel
SmartAZ wrote:I guess I understand the 4D universe concept as well as anybody, which is to say zero equals zero.
When I asked him about higher dimensions in his last year at Princeton, Emil Artin told me that visualizing space up to six dimensions was "Easy! After that it is difficult."
Posted: Sat Sep 08, 2007 4:06 pm
by Axel
Chris Peterson wrote:I guess it depends on what you mean by "observable". By your definition, perhaps you don't believe in electrons, quarks, or even other galaxies. These are all observed indirectly. Likewise for the geometry of the Universe.
That, in a nutshell, is the problem of the 21st century. How do we know to "believe" in quarks but not in the secret military programs of small dictatorial regimes? In brief, how do we handle the verb "believe"?
Posted: Sat Sep 08, 2007 5:47 pm
by Chris Peterson
Axel wrote:That, in a nutshell, is the problem of the 21st century. How do we know to "believe" in quarks but not in the secret military programs of small dictatorial regimes? In brief, how do we handle the verb "believe"?
Like many other words, it has different meanings in different contexts. I don't see it as a problem, except that the lay public doesn't usually understand what it means in the context of science.
Scientists "believe" something when good theories support it. This belief isn't absolute: a scientist recognizes that beliefs are subject to change, and may have differing degrees of faith (another tricky word) in different theories explaining the same thing.
I "believe" in the Big Bang, and I "believe" that the Universe has a four-dimensional structure. I "believe" these things because they provide (by far) the best explanations for what we actually observe. I also "believe" that we will continue to refine these theories, but probably not radically invalidate them, much the way that GR has refined, but not invalidated Newtonian mechanics. I also "believe" that there is a small, but non-zero possibility that the current cosmological theories are completely wrong. (Note that I didn't use "believe" the same way in each statement above.)
Posted: Sat Sep 08, 2007 6:54 pm
by Axel
Chris Peterson wrote:Like many other words, it ["believe"] has different meanings in different contexts. I don't see it as a problem, except that the lay public doesn't usually understand what it means in the context of science.
Scientists "believe" something when good theories support it. This belief isn't absolute [ ... ]
I "believe" in the Big Bang, and I "believe" that the Universe has a four-dimensional structure. I "believe" these things because they provide (by far) the best explanations for what we actually observe. [ ... ] I also "believe" that there is a small, but non-zero possibility that the current cosmological theories are completely wrong. (Note that I didn't use "believe" the same way in each statement above.)
I cannot disagree with you: having been a translator for over fifty years I'm well aware that context is everything. Still, the problem remains of how we can expect people to "believe" statements, in whatever way and to whatever degree, that they have no means of validating themselves. It's all very well for you to say you "believe" (provisionally) in current cosmological theory if you have the mathematical knowledge to read its essential statements; but I don't, and until I do I can't honestly "believe" it, unless I agree to "believe" because you and a lot of very intelligent people "believe". (Of course I don't disbelieve, which would be as silly as believing.) That's why I called this the problem of the 21st century - it's the condition of citizens in a complex world full of experts telling them what's what.
Posted: Sun Sep 09, 2007 5:38 pm
by Dr. Skeptic
SmartAZ wrote:I guess I understand the 4D universe concept as well as anybody, which is to say zero equals zero. I am very suspicious of any concept not based on observation, and this one is by definition not observable.
And the Big Bang is based on the assumption that only gravity powers the universe. As soon as you consider any other force that might be in operation the Big Bang concept no longer applies.
The number Zero is a cognitive concept only- a mathematical representation for a NULL set. It does not exist in the physical universe, quantum mechanics does not allow for it.
Posted: Tue Sep 11, 2007 1:45 am
by Astronomy teen
I have read countless times that the Big Bang did not happen in one fixed point, but rather everywhere at once. Every point of whatever was there before the Big Bang simualtaneously "exploded", making it not a sphere, but rather an irregular shape. This void now I believe could possibly but not likely be a "ripple" on the edge of the observable universe, such as a divet shown below by this crude representation:
~~~~~~~~~
or
(
)
(
) etc...
Posted: Wed Sep 12, 2007 1:32 am
by Dr. Skeptic
I have read countless times that the Big Bang did not happen in one fixed point, but rather everywhere at once.
Good try but your summation doesn't account for and in a way misleads the moments leading up to the Big Bang, there was no space or time - the BB created space/time. But, you are also right in that the expansion did/does not need to be uniform and that the "everywhere at once" could have been as small as a single point.
Posted: Thu Sep 13, 2007 2:30 am
by Astronomy teen
What, though, would be existing before the bb? Remember, nothing is still something. It's just a vacuum. I have yet to understand, though, how time ceased to exist before the bb. Is it trying to say that, before the bb, there was no such thing as 1 hour?
Time
Posted: Thu Sep 13, 2007 11:54 am
by Case
Astronomy teen wrote:Is it trying to say that, before the bb, there was no such thing as 1 hour?
In out day-to-day lives, 1 hour could be measured as 1/24 of the rotation of the earth around its axis. But what if there is no earth yet? One second could be measured as 9,192,631,770 periodic changes in energy levels of a cesium-133 atom (atomic clock). But what if there is no cesium atom yet?
The concept of time implies change of some sort (megastructure, atomic scale, anything). If nothing changes, or no change can be observed, then time can't be measured.
The beginning of the universe is a singularity: a point in space-time at which gravitational forces cause matter to have infinite density and infinitesimal volume, and space and time to become infinitely distorted. If, by a wild stretch of imagination, anything happened 'before' that, there is no way of information about that being measurable after the BB. Not only is the question unanswerable, but it is also meaningless: The singularity itself created a starting point for time as we know it.
Posted: Thu Sep 13, 2007 12:26 pm
by Dr. Skeptic
Note: All concepts are theoretic involving the creation of the universe.
To start, an event occurred (Big Bang?). Not from nothing but from a different type of universe where the four dimensions we can touch measure did not exist. No space/time or gravity. One theory is two other universe types violently collided creating new dimensions - including the four we have (the 4 of 11 that are thought to exist).
If quantum mechanics is true, time cannot be infinite ruling out the possibility of a Steady-State Universe. let me know if I need to elaborate on time and QM.
Posted: Fri Sep 14, 2007 2:13 am
by SmartAZ
Ok, let's say we had a big bang when time and matter came into existence. What was before that? The question is meaningless, because no time means no "before". Ok, so what caused the big bang? I don't think anybody is ready to give up cause and effect, because that would mean magic was involved. But wait, the principle of cause and effect implies time, since that is the dimension in which cause and effect operate.
Conclusion: The big bang implies that there are at least two dimensions of time!
Posted: Fri Sep 14, 2007 3:21 am
by Chris Peterson
SmartAZ wrote:Ok, let's say we had a big bang when time and matter came into existence. What was before that? The question is meaningless, because no time means no "before". Ok, so what caused the big bang? I don't think anybody is ready to give up cause and effect, because that would mean magic was involved. But wait, the principle of cause and effect implies time, since that is the dimension in which cause and effect operate.
Sorry, there's no more reason to believe that cause and effect has a meaning without a Universe than time does. The fact that these things are wired so deeply into our internal models of the world that we can't imagine how they can't exist doesn't mean that they must exist. The Big Bang didn't need a cause. There didn't need to be a before. And for the most part, "before" and "cause" are meaningless in this context.
There's no reason that the workings of the Universe have to make sense to us on some intuitive level.
Posted: Fri Sep 14, 2007 11:51 am
by Dr. Skeptic
SmartAZ wrote:Ok, let's say we had a big bang when time and matter came into existence. What was before that? The question is meaningless, because no time means no "before". Ok, so what caused the big bang? I don't think anybody is ready to give up cause and effect, because that would mean magic was involved. But wait, the principle of cause and effect implies time, since that is the dimension in which cause and effect operate.
Conclusion: The big bang implies that there are at least two dimensions of time!
What existed before the Big Bang was a universe without space/time, or at least without the space/time we know.
Because science hasn't evolved far enough to answer all the questions, there is no need to inject "Magic" into the equation.
Except, of course, the magic of wonder!
Posted: Fri Sep 14, 2007 5:27 pm
by inertnet
If all matter was created during the big bang, it means that there was not a single particle in existence at the "time". To me, without particles there also couldn't have been space, nor time, as we know it. I believe (meaning I cannot prove) that space and time are impossible without any particles to "shape" them.
Posted: Sat Sep 15, 2007 12:47 am
by Dr. Skeptic
You are correct, Space/Time cannot exist without Mass/Gravity in our four dimensions.
Can Dark Matter/Dark Energy exist in the absents of Space/Time, is Dark Matter an integral part in the creation of normal matter? (rhetorical questions for pondering) The oldest galaxies seen to have formed on filaments of dark matter, or is Dark Matter/Dark Energy an incorrect assessment of unknown physics.
Posted: Sat Sep 15, 2007 11:06 am
by SmartAZ
There's no reason that the workings of the Universe have to make sense to us on some intuitive level.
One of the axioms of science is that if the axioms are not true we can't know anything. You may be correct, but if you are then the universe runs on magic and/or religion and there is no point in pursuing science.
Posted: Sat Sep 15, 2007 1:23 pm
by Chris Peterson
SmartAZ wrote:There's no reason that the workings of the Universe have to make sense to us on some intuitive level.
One of the axioms of science is that if the axioms are not true we can't know anything. You may be correct, but if you are then the universe runs on magic and/or religion and there is no point in pursuing science.
I didn't say anything about magic or religion. And I didn't say we couldn't understand how the Universe works. I only said those workings don't need to be intuitive. Many people feel the need to make analogies between how things work on a very small or very large scale to how they work on the scale we see. There's absolutely no reason to think those analogies have to hold. Thus we have quantum mechanics and cosmology, neither of which are naturally intuitive, and neither of which can really be compared with the behavior of things as we naturally see them.
The fact that we can't really picture the absence of time, or the idea of something coming from nothing, without cause, doesn't mean these things aren't real. And it doesn't mean that we can't understand them deeply using math and the other tools of science.
Posted: Sun Sep 16, 2007 3:26 am
by Martin
The BB was neither big nor was there a bang according to the theory. So lets give it another name ="The creation of all observable mass -origin and cause unkown". The BB is speculation based on observations and workable calculations. Though it is clearly a step in the right direction. and of course there was something before the BB or it could not have (in theory) occured.
It's amusing yet distirbing to see people assume space did not exist prior to the BB event. Despite the fact that all current theories to support a simutaneous creation of space/time with the BB is based on mass and energy. So... many people just "safely" assume that (space) which we cannot "observe" as having any mass or energy is only along for the ride -sort of speak.
There is no direct evidence that shows space was less then than it is now. The BB can still hold water without including space in it. The mass in our observable/theoretical universe can still be expanding without including space in the expansion. Furthermore, there is no direct evidence that shows space was and is not infinate (not that it has to be). I strongly think that thru our failures to explain everthing we are inventing explinations. The creation of observable mass is not tied to the creation of space or the expansion of it. When more people realize this we may get closer to explaining the "dark"matter and energy we observe.
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Posted: Sun Sep 16, 2007 4:24 pm
by Dr. Skeptic
Mathematically your hypothesis is flawed. In our four dimensional universe Space/time and Gravity/Mass must exist in a symbiotic relationship. That is not to suggest the universe did not exist, only our Space/Time did not exist before the BB event.
Once again, here is the reason Space/Time (and its relationship to Mass/Gravity) cannot be infinite:
Take the unit of one second and divide in in half, now take the 1/2 second and divide it again and so on until the smallest unit of time is reached. If the second could be divided ∞ times the smallest unit would be 1/∞ seconds.
Now take the value of 1 billion years and repeat the process and again the result is 1/∞. A non-value in mathematical terms suggesting that both 1 second and 1 billion years are equal.
If the science of quantum mechanics is true, time must move in finite increments with a finite value assigned concluding that Space/Time must have a beginning point, and eventually, have an end point.
This is a very simple exercise in math and logic, refuting the conclusion would be refuting the validity of all mathematical representations.
Posted: Mon Sep 17, 2007 12:05 am
by Martin
Must exist in a symbiotic relationship-hmmm really?
I believe QM shows us less of a symbiotic anything as we approach it's smallest scales. You assume space co-exists with time because why?
Can the measurement of time solve or dismiss this "hypothesis". There may be no relationship hence no symbiotic relationship. Space may not be bound by the same principles and mathematical representations as time. Our theories assume the relationship -that does not really make it a truth. However, it does make it easier.
Perhaps on the largest or smallest scales space has properties unknown to us in our observable bubble of relevant time and matter.
Posted: Mon Sep 17, 2007 2:26 am
by Qev
Dr. Skeptic wrote:Take the unit of one second and divide in in half, now take the 1/2 second and divide it again and so on until the smallest unit of time is reached. If the second could be divided ∞ times the smallest unit would be 1/∞ seconds.
Now take the value of 1 billion years and repeat the process and again the result is 1/∞. A non-value in mathematical terms suggesting that both 1 second and 1 billion years are equal.
How do you figure that? All you've basically pointed out is that n/x -> 0 as x-> infinity. It doesn't say anything at all about n itself.
Posted: Mon Sep 17, 2007 2:50 am
by goredsox
Hey, Dr. Skep, I am intrigued and skeptical about time proceeding in quantum bits that cannot be subdivided.
If that were true, then photons moving at the the speed of light (300 million meters per second) would not move smoothly through space, but would jump a small distance during each minimual time quantum.
And if that were true, then light detectors placed in space closer together than that small distance would detect the photon passing by at the same time, even though they are not at the same place. That would seem to be inconsistent with General Relativity because information would be shared at two locations simultaneously.
Posted: Mon Sep 17, 2007 4:49 am
by Qev
Quantum mechanics is funny that way. Under that model, -everything- is quantized, including time and space. I -think- the Planck time and Planck length are the smallest units of either (I'm not completely clear on all the Planck units).
Your scenario is an interesting thought experiment, except that you could never make a pair of detectors small enough, nor get them close enough. The minimum separation between them would always be at least the Planck length.
Posted: Mon Sep 17, 2007 11:51 am
by Dr. Skeptic
goredsox wrote:Hey, Dr. Skep, I am intrigued and skeptical about time proceeding in quantum bits that cannot be subdivided.
If that were true, then photons moving at the the speed of light (300 million meters per second) would not move smoothly through space, but would jump a small distance during each minimual time quantum.
And if that were true, then light detectors placed in space closer together than that small distance would detect the photon passing by at the same time, even though they are not at the same place. That would seem to be inconsistent with General Relativity because information would be shared at two locations simultaneously.
To quote Bystander:
Planck Time (the time reqired for one photon to cross a Planck Length) is defined as 5.3912×10-44 seconds
Quantum Mechanics states that if one could observe a photon crossing one planck distance it would disappear from one side and reappear on the other side 5.3912×10-44 seconds later. By definition quantum mechanics means all things move in measurable quantum units (not allowing for fractions of units). As an electron moving from one energy state to another, it is in one state or the other and never somewhere in between.
Posted: Tue Sep 18, 2007 9:24 pm
by NoelC
All I can say is that they've set the simulation cycle time pretty small in the Matrix.
And regarding things happening "instantaneously", don't tunneling particles at the quantum level appear at the far side of an obstruction without the passage of time?
I guess they simplified the programming of this grand simulation a bit and hoped no one would notice. Or maybe there are a few bugs in the code.
-Noel