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Dave W.
Info Junkie
USA
26022 Posts |
 Posted - 08/15/2004 : 19:53:21 [Permalink]
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Hippy wrote:quote:
I had a feeling you were going to say something like that. As I've read books on Relativity, the authors have often said that we can't really know what something is, we just percieve it as thus-and-so. Then they go on to talk like our perceptions are reality.
Without knowing to which authors and books you are referring, they probably go on to talk as if our perceptions are, for all intents and purposes, all we can make of reality.
Have you ever played a game called "Black Box?" It was popular with the crowd I ran with back in elementary school. One player would set up a few marbles on a 5-by-5 grid, and then hide them. The other player would "shoot" virtual "light beams" into the grid from the side, and - following a simple set of rules of reflection - the first player would show where the beams came out of the grid. From that data (the starting and ending points of each beam), the second player would have to deduce the positions of the hidden marbles.
The tricky part of the game was that the second player couldn't shoot beams in from every possible position. He/she was limited to something like five or six beams, total (out of twenty possible starting locations). But, if the player were sharp, just that small fraction of all possible data could lead to an accurate description of the position of all the hidden marbles. A "win."
This game is a very good analogy to how science is conducted in general. But scientists have the luxury of testing for the position of one marble, getting feedback as to their prediction, and then going onto the second. They're not limited to just a handful of guesses, unless their funding runs out.quote:
That being the case, if you're only using "space distortion" as a description, then why do you think that space will actually change it's properties under gravitational forces as are found in black holes?
I don't think that. I think that space is undergoing a massive amount of distortion inside black holes, not that the distortion is fundamentally "different" somehow.quote:
Why is the Big Bang a barrier to knowledge if you're not claiming that space actually will fold in on itself and change matter into something unrecognizable?
[Skip for continuity]
Just what is it that actually makes the Big Bang a barrier to science and logic?
The Big Bang was quite a bit different from your average, run-of-the-mill black hole. The Big Bang's singularity was the singularity, containing everything. As far as we know, it marked the beginning of time itself. How can one probe beyond such an event? It is entirely unprecedented, by its very nature.
I'm trying to think of a decent analogy for this amongst everyday situations, and am failing. That's how different the Big Bang was.
But to answer your question: how can we measure anything before there was anything? Science is about measurement. The Big Bang is the hypothetical creation of everything. If there was nothing to measure before then (and we've got no evidence there was), we can't do science on it. Plus, we can only see back to about 300,000 years after the Big Bang. The cosmic microwave background (CMB) radiation is that old. Before that time, the entire universe was - theoretically - so hot that it would have been opaque. Everywhere. That the CMB exists confirms that idea, but the CMB also represents a barrier to our telescopes' ability to "look back in time."
For these reasons, and more, the Big Bang is a barrier to science.quote:
[Snip Back]
You say that the Theory correctly predicts one set of natural phenomena (the bending of light). Are you then going to say that it must be right in predicting another set of natural phenomenoa (space folding in on itself)?
No, I'm saying that General Relativity correctly predicts a large set of natural phenomena. Not only can we see the bending of starlight around our Sun when the conditions are right, but we can see the bending of light from distant galaxies around closer galaxies. Not only that, but Newtonian physics wasn't up to the task of correctly predicting Mercury's orbit around the Sun, which is so fast one needs to take Relativistic effects into account. Not only that, but we can synchronize two precise clocks on Earth, shoot one up in a rocket for 1,000 miles or so, and when it gets back to Earth, it is running a predictable amount of time behind the one left on the Planet. Not only that, but the GPS system depends on Relativistic corrections to accurately pinpont a location on the planet.
There have been hundreds, if not thousands, of tests of various aspects of General Relativity, and it has remained unscathed from all of them. Another test - this one of a peculiar phenomenon called "frame dragging" - will be launched within the next year or so. If General Relativity is correct, the highly-precise gryoscopes riding in this satellite will be off by the angle subtended by a human hair seen from a quarter mile after a year orbiting the Earth.
That's what we're down to. All the experiments which could quickly demonstrate large errors are done. They were done decades ago. General Relativity is still around. We're now down to "nit-picking," or testing whether or not Einstein might have been wrong by a few millimicroseconds of arc after some 365 days have gone by. This is how sensitive one needs to be if one thinks one can make a dent in Relativity's evidenciary armor.
And so no. I'm not saying that because Relativity correctly predicts the bending of light, all its other predictions will be true, also (why bother testing them, then?). What I'm saying is that the theory had been so thoroughly tested in so many ways, it is reasonable - though not required - to give it the benefit of a doubt with regard to aspects of the theory which haven't yet been tested. But, the testing continues.
You picked the right time for these questions, Hippy. The current issues of both Discover and Scientific American are devoted to the 100th anniversary of Einstein's "miracle year." In 1905, Einstein published four incredible papers, one of which - the one describing Special Relativity - laid the groundwork for General Relativity just a few years later. Look for these issues in your library. |
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hippy4christ
Skeptic Friend
193 Posts |
Posted - 08/18/2004 : 14:22:49 [Permalink]
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Astropin: I wasn't talking about the Big Bang theory itself, I was talking about the idea that you can't specualte what happened before the Big Bang. This whole thread is really an offshoot of another thread I was doing.
Dave: quote:
The Big Bang's singularity was the singularity, containing everything. As far as we know it marked the beginning of time itself.
This is what I really want to know: why do you think that time has a beginning? Have we ever experienced anything that appeared out of nowhere, that it could be said that that was the beginning of time for it? I understand that right now you can't scientifically probe past the Big Bang. But how can you say that the universe just started to exist? What reasons, what evidence do you bring forth to say that time has a beginning?
If you want to say that it's only hypothetical that time has a beginning, fine. Logic can go where science cannot. I've heard you say before that logic is only applicable to something that can or soon can be determined. An ancient Greek philosopher once reasoned that sound worked by an object disturbing the air until the disturbance reached the ear. Hence, he thought, sound could not exist in a vacuum. It wasn't until thousands of years later that we developed vacuums and proved his hypothesis.
Therefore, I once again use logic to say that either:
1) Something existed before the Big Bang.
or
2) Nothing existed before the Big Bang. (or the Big Bang was the beginning of time, either way you say the same thing.)
If something existed before the Bang then either:
1a) It consisted of the same material and followed the same rules as that which came after the Big Bang.
or
1b) It did not consist of the same material and/or did not follow the same rules as that which came after the Big Bang.
If nothing existed before the Big Bang then please explain how:
2a) Something can come out of nothing.
or how
2b) Time can have a beginning.
If 1a is most logical to you then how do you account for the entropy effect? If 1b is most logical to you please explain how the substance and/or rules of the universe could possibly change.
Hippy
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Faith is believing what you are told, whether it's by a priest or a scientist. A person's scientific beliefs are ones based on personal observation and experimentation.
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furshur
SFN Regular
USA
1536 Posts |
Posted - 08/19/2004 : 06:10:13 [Permalink]
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Hippy, we do not know what was before the big bang. There is no way to use logic to determine what was before the big bang. Look at this quote from http://www.ncsu.edu/felder-public/kenny/papers/inflation.html:
quote:
When we talk about extrapolating backwards in the big bang model we are referring to running the equations of general relativity backwards to earlier times and higher densities. We know, however, that general relativity ceases to be valid when we try to describe a region of spacetime whose density exceeds a certain value known as the Planck density, roughly 1093 g/cm3. If we try to consistently apply quantum mechanics and general relativity at such a density we find that quantum fluctuations of spacetime become important, and we have no theory that describes such a situation.
The bottom line is how can you speculate on something if the physics are on longer applicable.
Science says, "We do not know".
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If I knew then what I know now then I would know more now than I know. |
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Dr. Mabuse
Septic Fiend
Sweden
9688 Posts |
Posted - 08/21/2004 : 06:42:20 [Permalink]
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quote:
><font size="1" face="Verdana,Arial,Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by furshur
Hippy, we do not know what was before the big bang. There is no way to use logic to determine what was before the big bang. Look at this quote from http://www.ncsu.edu/felder-public/kenny/papers/inflation.html:
quote:
<font size="1" face="Verdana,Arial,Helvetica" id="quote">quote:<hr height="1" noshade id="quote">When we talk about extrapolating backwards in the big bang model we are referring to running the equations of general relativity backwards to earlier times and higher densities. We know, however, that general relativity ceases to be valid when we try to describe a region of spacetime whose density exceeds a certain value known as the Planck density, roughly 1093 g/cm3. If we try to consistently apply quantum mechanics and general relativity at such a density we find that quantum fluctuations of spacetime become important, and we have no theory that describes such a situation.
The bottom line is how can you speculate on something if the physics are on longer applicable.
Science says, "We do not know".
Planck density, roughly 1093 g/cm3... that can't be right, seems like way too light...
Let's make a google...
http://www.fact-index.com/n/na/natural_units.html
says: ~ 5.1 x 10^96 kilograms/meters³
I can see where the numbers came from...
Edit: What the **** is wrong with the code? I get stuff like : ]><font size="1" face="Verdana,Arial,Helvetica" id="quote">quote:<hr height="1" noshade id="quote"> instead of the usual forum code... |
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| Edited by - Dr. Mabuse on 08/21/2004 06:46:35 |
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H. Humbert
SFN Die Hard
USA
4574 Posts |
Posted - 08/21/2004 : 08:36:09 [Permalink]
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quote:
Have you ever played a game called "Black Box?" It was popular with the crowd I ran with back in elementary school. One player would set up a few marbles on a 5-by-5 grid, and then hide them. The other player would "shoot" virtual "light beams" into the grid from the side, and - following a simple set of rules of reflection - the first player would show where the beams came out of the grid.
What elementary school was that, Harvard? Sheesh.  We played dodgeball. |
"A man is his own easiest dupe, for what he wishes to be true he generally believes to be true." --Demosthenes
"The first principle is that you must not fool yourself - and you are the easiest person to fool." --Richard P. Feynman
"Face facts with dignity." --found inside a fortune cookie |
| Edited by - H. Humbert on 08/21/2004 08:41:31 |
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Dave W.
Info Junkie
USA
26022 Posts |
Posted - 08/22/2004 : 01:16:53 [Permalink]
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Dr. Mabuse wrote:quote:
Planck density, roughly 1093 g/cm3... that can't be right, seems like way too light...
A lot of copy-and-paste jobs don't handle formating like "1093 g/cm3" correctly. I bet that was the problem there.
H. Humbert wrote:quote:
What elementary school was that, Harvard? Sheesh. We played dodgeball.
We played dodgeball, also. "Black Box" was a rainy-day activity.
To be perfectly honest, I was in a superior-learners program from third grade through eighth. Got bussed to different schools than the "normal" kids in my neighborhood because of that. I'm sure I would have stayed in it past then, had the program been available in high-school in my county, but no, they just started in with the "Advanced Placement" crappola then.
But, along with "Black Box," there was this kick-ass board game about the human circulatory system that I enjoyed, and another board game about the solar system that was good, also. At home, I could never get enough Monopoly. |
- Dave W. (Private Msg, EMail)
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furshur
SFN Regular
USA
1536 Posts |
Posted - 08/23/2004 : 13:36:56 [Permalink]
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You are absolutley right Dave, the cut and paste gave a low number of 1093 gms/cm3 for planks density when it should have been 10^93 gms/cm3. Just a tad more dense.
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If I knew then what I know now then I would know more now than I know. |
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hippy4christ
Skeptic Friend
193 Posts |
Posted - 08/23/2004 : 16:19:33 [Permalink]
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Furshur:
Let me see if I have this right:
General Relativity states that matter bends space-time, therefore, if given enough matter, space-time will (fold in on itself?) and the laws of physics will change. Or are you simply saying that you don't know if the laws of physics will be applicable in a singularity? Or are you saying that General Relativity is no longer applicable in a singularity? When I talk about the laws of physics, I don't mean anything Newtonian or Einsteinian, I'm simply talking about the way things work.
Hippy
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Faith is believing what you are told, whether it's by a priest or a scientist. A person's scientific beliefs are ones based on personal observation and experimentation.
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Dr. Mabuse
Septic Fiend
Sweden
9688 Posts |
Posted - 08/23/2004 : 17:44:35 [Permalink]
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It's something like this...
Newtonian physics is an approximation of the Real Laws of Physics.
It works well in the normal conditions we meet in most cases on the face of the earth.
However, in more extreme cases the Newtonian approximation gets inadequate to describe the situation. Too many variables are approximated to not have an impact, and thus throw the calculations off.
Relativistic physics as described by Einstein is a much more advanced description of the Real Laws of Physics. Yet, even Einsteins formulae are approximations. In the extreme event of a black hole, even relativistic calculations become inadequate to describe it.
What scientists are looking for is the Grand Unifying Theory (GUT) which is/are the ultimate formulas describing the Real Laws of Physics.
Some say even the GUT will actually be an approximation.
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Dr. Mabuse - "When the going gets tough, the tough get Duct-tape..."
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"Equivocation is not just a job, for a creationist it's a way of life..." Dr. Mabuse
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Skyhawk
New Member
33 Posts |
Posted - 08/23/2004 : 18:21:09 [Permalink]
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Funny, that's what i was just about to say. hippy4christ, all your questions dwell into the world of Unified Field Theory, the Theory of Everything. In a singularity, space-time doesn't really 'fold' onto itself but its just one helluva deep dent. Now the problem is, that Relativity can explain everything in the macroscopic world beautifully. But, in a sub-atomic level it breaks down. Quantum Mechanics answers that. So you have relativity that says "Everything is predictable under a set of equations." and another theory that says "Everything is PROBABLE given certain circumstances." Now here is the bad thing, they both explain the same Universe.
The reason Black Holes are so interesting is because at the singularity, space-time is so warped that you cannot explain it unless both Quantum and Relativity are used (as said before). But these two don't agree. That's where UFT comes in to solve this. Einstein spent 30 of his remaining years trying to solve UFT just with Relativity in mind. However, he wasn't successful. The best we have is M-theory (which I hate) that tries to solve UFT.
As for the Big Bang, we don't know what happened before. In fact, we can't really explain what happened during Big Bang either. What makes the beginning so special is because the rules that govern space-time were different, because the actual RULES were being made! To make things more clear, we have 4 forces that gives these rules. Strong, Weak, EM, and Gravity. During the early stages, these forces was one single force that split apart. Now, if Relativity gives a strong explaination of Graity and Quantum explains the other 3...and in the beginning these forces were together...we cannot solve the Big Bang until UFT comes around.
As to if time existed before Big Bang. The reason we predict it IMO, is because according to Relativity space and time are linked. So if there was no space in the beginning how can there be time? Remember whatever the 'thing' was at time zero, was a single mathematical point. It wasn't in space nor does it have time. Its hard to picture and thats why to really understand it you need to know the math behind it. Just like thinking what is 'outside' the Universe. Well, space-time doesn't exist outside it. Hard to picture something inside of literally nothing. But, I was talking to a Math prof, and he put it to me this way. Why not? Why CAN'T space-time be round? Why can't space exist in nothing? Technically we have equal proof for both something in nothing and something in something (zero).
So to answer all of your questions, we can get back to you with nice answers once UFT is solved. Gwarg, so why did I post something this long? :P |
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hippy4christ
Skeptic Friend
193 Posts |
Posted - 08/24/2004 : 14:21:53 [Permalink]
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Skyhawk:
You seem to be contradicting yourself. At one point you say that you can't know what happened during the Big Bang, at another point you say that at the moment of the Big Bang there was no space or time. If you can't know what happened during the Big Bang, then how can you know that there was no time or space at the moment of the Big Bang? And if you don't know what was going on during the Big Bang then how do you know that the Real Laws of physics were "being formed" then?
Again, you (all) are equating your perceptions with reality. I can believe that you will be able to better predict the effects of gravity if you treat gravity like it "bends space" rather than treating it like it exerts a force over distance. But then you go and say that there once wasn't any space. You still have yet to prove that space is a quantifiable substance. How does one create space? By the way, you never explained why you said that space didn't exist at the moment of the Big Bang.
Same thing with time. I understand that as you approach the speed of light atoms don't vibrate as fast as they normally do. And from that you say that there was a point at which there was no time?
As I understand it, you can't measure what goes on in a black hole because a black hole sucks everything into it and therefore any light or EM wave or whatever you would use to study would also be sucked in. So answer me this: is this idea that you have about there being no space-time at the point of the Big Bang based on any actual evidence, or is it based on equations that some mathmeticians wrote up?
Hippy |
Faith is believing what you are told, whether it's by a priest or a scientist. A person's scientific beliefs are ones based on personal observation and experimentation.
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Ricky
SFN Die Hard
USA
4907 Posts |
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Skyhawk
New Member
33 Posts |
Posted - 08/24/2004 : 15:38:44 [Permalink]
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Sorry if I contradicted myself. My bad. We don't know what happened. But the reason I gave an explanation is that I'm trying to explain what physicist try to explain from the mathematics they have. In other words, it's a prediction with an explanation not proved concepts. Truthfully, the only evidence we have of these predictions are explained in the mathematics of it all. Thats why it's so hard to explain it unless you go through the equations. The reason I said that space nor time existed at the single point right at the Big Bang is because mathematically, thats what the Big Bang was. A single mathematical point. It wasn't a point in space nor time. It was just some mathematical reference point so we can develop the math to it (the point doesn;t reeally exist anywhere...kind of hard to understand). At the instant after, this point space-time 'just happened' though there are math behind this to say that it did happen. We know that the laws of physics are formed at the moment of the Big Bang because of the mathematics from studying astronomical objects such as black holes. Using the ground work on these astronomical objects and seeing its relation to our Universe we can predict mathematically the timeline of our Universe. Using this we can get a theory going on when atoms, etc were formed and the four fundamental forces.
Is space quantifiable? Well, IMO the way we define space is with 3 co-ordinates (x,y,z). I think thats the best way to define it. Space is something that can be given these co-ordinates to define dimensions. Now with M-theory you get to 11 co-ordiantes describing space. Giving four co-ordinates given time gives you an event (which is space-time).
Now about our perception. You are right. It is a perception. We first percieved gravity as a force, and then Einstein came along and said it's a warp in space-time. Both can explain our reality to a certain degree. Einstein's perception and explanation works out mathematically/experimentally the best. That's why we use it. On another note, scientists do predict that there will be other explanations/perceptions of gravity in the future that will be better than Einstein's. History predicts this will happen. If you do some further reading you will find out thats how science is. Each age in our history has a "view." One of the first views of science was Galilean view. Then the Newtonian view. Then the Einsteinian(?) view. Our view today of the phsyical view is called Modern Physics view (to include Quantum Mechanics) or the formal name is the Standard Model. This model is incomplete and needs UFT to complete it.
As for going about creating it. Well you create space-time through the Big Bang. Thats how. This is question can be taken philosophically or scientifically. If you are M-theory phanatic, then the creation of space was done by 2 M-branes colliding and causing a shockwave that is the Big Bang to create space. But, all of these are still theories and lack real hard evidence that you ask for.
I hope I answered some of your questions. Thanks for the feedback hippy. If you have more I'll take it. I argue like a teenager (cuz I am one) so it's nice to learn how to argue/post from you guys. |
| Edited by - Skyhawk on 08/24/2004 20:55:07 |
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astropin
SFN Regular
USA
970 Posts |
Posted - 08/24/2004 : 21:37:56 [Permalink]
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How about the "White Hole" theory? I kind of like it.
http://www.space.com/scienceastronomy/white_hole_030917.html |
I would rather face a cold reality than delude myself with comforting fantasies.
You are free to believe what you want to believe and I am free to ridicule you for it.
Atheism:
The result of an unbiased and rational search for the truth.
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astropin
SFN Regular
USA
970 Posts |
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