Mathematicians are idiots.
I seriously hope that you are joking.
Posted 14 February 2012 - 09:44 AM
Mathematicians are idiots.
Posted 14 February 2012 - 11:22 AM
Posted 14 February 2012 - 06:04 PM
The functionality of calculus is not dependent upon the existence of black holes. They may very well be real things, but if there are not any then calculus will still work.You didn't. Come on, the prediction of Black Holes through math is about 90 years old! This got predicted around WWI with math. We have now confirmed objects that actually fullfill these predictions. What's so weird about it?
Posted 15 February 2012 - 04:25 AM
The functionality of calculus is not dependent upon the existence of black holes. They may very well be real things, but if there are not any then calculus will still work.
It is over-reaching the scope of mathematics to name parameters or results from calculations as real objects. Maths is just a model of reality - not reality itself.
Hence my little dig.
Posted 15 February 2012 - 08:54 AM
Had you said, "If this model is correct, there must be black holes", I wouldn't have an issue.... if calculus is correct, there must be black holes....
Posted 03 May 2012 - 09:12 PM
I've got a question that perhaps someone can explain to someone like me who is no good at physics or astronomy. I heard somewhere that according to the Big Bang theory, the universe doesn't have a center. But wouldn't it have a center if everything was supposed to blow up out of that little dot somewhere.
Now, I don't believe in the BBT but I just wanted to understand it a little better.
Posted 04 May 2012 - 09:09 AM
In quantised fashion? Redshifts of stars group into certain ranges dependent upon their distance. This is best explained if the Earth is near the center of the universe and at the center of the expansion (though there are attempts at ad hoc fixes to protect the big bang theory).You misunderstood, the universe certainly has a center, as any volume does. What you heard was that the expansion that we observe does not seem to be centered on a point. From our perspective, the vast majority of heavenly bodies are moving away from us, so it appears that we are the center... but this is also true from any other point in the universe. No matter where you are you would observe everything moving away from you.
These explanations assume the truth of the cosmological theory of homogeneity and isotropy. The simple model of the 3D observation of matter being the only one easily accepts the observations we see.Now, this seems counter-intuitive at first thought, but you have to realize that this is exactly what we would observe if all of the space in the universe was expanding equally. The classic example is to explain this is to attach things to a length of rubber band and then stretch that rubber band apart. As you stretch it it expands across it's entire length, so everything attached to it moves away from everything else. If you consider the perspective of any of those things then it would appear that everything else is moving away from that point, so there is no center of expansion.Another classic example is that of raisins all moving apart from each other in a loaf of raisin bread that is rising in the oven. All of the material throughout the entire loaf of bread expands, the expansion is not centered on any point in the bread, but the bread of course still has a center.
Posted 04 May 2012 - 09:35 AM
In quantised fashion? Redshifts of stars group into certain ranges dependent upon their distance.
This is best explained if the Earth is near the center of the universe and at the center of the expansion
These explanations assume the truth of the cosmological theory of homogeneity and isotropy.
Posted 04 May 2012 - 09:37 AM
Posted 04 May 2012 - 10:49 AM
It defies the simple 3D physics we understand. Much easier to not have to imagine extra dimensions to explain what we see.Yes you are correct. In fact what we observe is that stars that are farther away from us are receding faster than stars that are nearer to us, on average. This makes perfect sense if you consider either of the two analogies I presented. From any point on the expanding rubber band the outer edges would appear to recede faster than any other point in the middle closer to your perspective, try it, it's true. This is actually great evidence in favor of a center-less expansion, an expansion of all points in space not centered on a given point.
Depends on the reason for the quantisation. And it wouldn't take much to explain what we see with the assumption of the simple model.Actually, it's evidence against that... if there were a center of expansion and if we were close to it we would not expect to observe a correlation between the distance of other heavenly bodies and their rate of recession from us.
I've no problem with you making an explanation. But the observations do not belong to your explanation. The observations can be explained by other models in different ways. You may not coopt an explanation as if it were evidence.Well, I don't think that's true, but even if it were what is your point? I am explaining a position, why wouldn't I assume that position to explain it? How else could I explain it?
I don't challenge the measurements made. I just have alternative explanations based on a simple 3D model.Further, the degree of homogeneity and isotropy of the observable universe has been measured extremely accurately by the WMAP satellite based instrument... are you challenging these measurements and if so on what authority?
Posted 04 May 2012 - 12:05 PM
I've no problem with you making an explanation. But the observations do not belong to your explanation. The observations can be explained by other models in different ways. You may not coopt an explanation as if it were evidence.
Posted 05 May 2012 - 05:07 AM
Posted 03 June 2012 - 02:04 AM
That isn't true. A finite Euclidean volume has a center, but we don't know that the Universe is either of those things. Consider the analogy with surfaces : any flat, finite surface (like a piece of paper) has a center. But an infinite surface wouldn't have a center, and neither does a finite but unbounded curved surface like the surface of the Earth.You misunderstood, the universe certainly has a center, as any volume does.
That isn't true either. You described the expansion well, and correctly pointed out that any point in the expanding space would see the same thing (everything moving away from them, and moving away faster the further away they were), but that would be as true of the center as it is of any other point.Actually, it's evidence against that... if there were a center of expansion and if we were close to it we would not expect to observe a correlation between the distance of other heavenly bodies and their rate of recession from us.
The expansion of the Universe doesn't require extra dimensions beyond the 3 space dimensions we have and time, and those are the dimensions we observe every day.It defies the simple 3D physics we understand. Much easier to not have to imagine extra dimensions to explain what we see.
Posted 03 June 2012 - 02:37 AM
The universe is three dimensional. Every three dimensional object has a center (disregarding the different definitions of the word). If you want to assume the universe is fundamentally not as it plainly appears, you're going to have to provide very compelling evidence.That isn't true. A finite Euclidean volume has a center, but we don't know that the Universe is either of those things. Consider the analogy with surfaces : any flat, finite surface (like a piece of paper) has a center. But an infinite surface wouldn't have a center, and neither does a finite but unbounded curved surface like the surface of the Earth.
Sure, we can... we can't say it has a center...
Maybe general relativity isn't necessary.The expansion of the Universe doesn't require extra dimensions beyond the 3 space dimensions we have and time, and those are the dimensions we observe every day.It does require that space be non-Euclidean, but the whole of General Relativity requires this, and that theory's predictions related to the curving of spacetime (such as time moving more slowly the faster one goes) have been verified experimentally to high levels of numerical accuracy.
Posted 03 June 2012 - 03:00 AM
It's just maths. A center is defined with respect to bounds, an unbounded space cannot have a center. Every three dimensional object we encounter is bounded; we can see their edges. We do not see any hint of the Universe's edges and have no reason to think it's bounded. Or, AFAIK, that it's not.The universe is three dimensional. Every three dimensional object has a center (disregarding the different definitions of the word). If you want to assume the universe is fundamentally not as it plainly appears, you're going to have to provide very compelling evidence.
It is necessary to the GPS.Maybe general relativity isn't necessary.
Posted 03 June 2012 - 03:29 AM
It's maths under the assumptions you bring. What I propose is maths based as well.It's just maths.
The universe is the sum total of the matter created. The area that matter stretches to defines the shape of the universe. Finding its center, given knowledge of the distribution of its matter, would be a simple exercise.A center is defined with respect to bounds, an unbounded space cannot have a center. Every three dimensional object we encounter is bounded; we can see their edges. We do not see any hint of the Universe's edges and have no reason to think it's bounded. Or, AFAIK, that it's not.
No, it's not. A GPS system could be built and work just as effectively with a different mathematical model that compensates for gravity's effect on light.It is necessary to the GPS.
Posted 03 June 2012 - 03:58 AM
Posted 03 June 2012 - 04:50 AM
Space and time are also part of the Universe, as the word is understood in physics.It's maths under the assumptions you bring. What I propose is maths based as well.The universe is the sum total of the matter created.
If that distribution is bounded and finite, yes. But we don't know the distribution of its matter.The area that matter stretches to defines the shape of the universe. Finding its center, given knowledge of the distribution of its matter, would be a simple exercise.
No, given it's not gravity's effect on light that needs to be compensated for, it's its effect (and the effect of velocity) on time. How would you calculate the effect of gravity on light by the way ?No, it's not. A GPS system could be built and work just as effectively with a different mathematical model that compensates for gravity's effect on light.
I assume no such thing. I say we don't know.That would be incorrect… It could be described using mathematical terms, BUT since we are discussing a physical phenomenon (the universe), it is illogical to ASSUME that it has no center or edges.
But many of its properties can be described using maths. The very concept of "three dimensional" is a mathematical concept. That happens to apply to an aspect of our Universe.Premises 1 - The universe is PHYSICAL (therefore it is NOT just “maths”)
Premises 4 - We have absolutely NO evidence of ANYTHING that is physical, three dimensional and had an origin that is unbounded. Indeed. But nor do we have evidence that the Universe isn't such a thing. We do have evidence that the Universe is very unlike the objects it contains in a few ways. For one, it's so much bigger that the largest object in it is a mere speck compared to the whole thing. Also, it isn't euclidean. So we can't just assume that because everything in it is bounded, the Universe itself is bounded too. Nor can we assume the opposite.
Not necessary… But if you can empirically prove your assertion, please do so.
Posted 03 June 2012 - 06:48 AM
Space and time are not physical entities. Matter is. Space and time are just descriptions of our observations of matter.Space and time are also part of the Universe, as the word is understood in physics.
We know it cannot be infinite. That we do not know the distribution and that we know it is not infinite necessitates a center and a boundary.If that distribution is bounded and finite, yes. But we don't know the distribution of its matter.
Gravity affects light is the assumption I would use in order to produce a mathematical model that could be used to deploy a GPS system. And it would work too.No, given it's not gravity's effect on light that needs to be compensated for, it's its effect (and the effect of velocity) on time. How would you calculate the effect of gravity on light by the way ?
Uh .. you're completely incorrect.The calculations that allow GPS to determine a location down to a few meters are extremely precise. You won't get a correct value with qualitative concepts like "the effect of gravity on light" or "time moves more slowly in a strong gravitational field". You need to know exactly how slowly time moves in how strong a gravitational field. The equations that allow those calculations are the equations of general relativity.
I assume no such thing. I say we don't know.
the Universe ... isn't euclidean.
Posted 03 June 2012 - 08:47 AM
Just out of curiosity, what do you think of energy ? And would you say space and time don't exist independently of matter ?Space and time are not physical entities. Matter is. Space and time are just descriptions of our observations of matter.
How do we know it cannot be infinite ?We know it cannot be infinite. That we do not know the distribution and that we know it is not infinite necessitates a center and a boundary.
But how does it affect light ? What does gravity make light do, to what degree ? And if you did produce such a mathematical model, how would you use it to deploy a GPS when what the satellites need to correct for is the dilation and contraction of time under the effect of gravity and velocity ?Gravity affects light is the assumption I would use in order to produce a mathematical model that could be used to deploy a GPS system. And it would work too.
You might be confusing "evidence" with "proof". It isn't proof in the mathematical sense, which is why science doesn't deal with that kind of proof, but it is a piece of evidence. Applying models to reality and seeing if they match is what empirical experimentation is all about.The application of a model is not evidence that the model is representative of reality.
What am I incorrect about ? That GPS involves calculations to determine something's location ? That they're very precise ? That calculations require quantitative, not qualitative concepts ? That the GPS accounts for the effects of gravity and velocity on time ? That it uses the equations of general relativity to do so ?Uh .. you're completely incorrect.
That's weird given when Einstein developed his model there were no direct observations of gravity affecting light. And how about the direct observation that velocity and gravity affect time ? And there's nothing "overly complicated" about general relativity - quite the opposite, explaining such disparate observations with a single concept and an elegant equation is as simple as theories go. It's Kepler's heliocentric ellipses to Ptolemy's geocentric epicycles.General relativity is just an overly complicated, and subtly flawed, way of describing the direct observation that gravity affects light.
No model "becomes reality", and general relativity in particular is almost certainly wrong given it's incompatible with quantum mechanics. But when a model matches reality as closely as general relativity does there's usually a reason. And how you propose to do "much of the same calculations" without using the same equations?All the same precision can be achieved with much of the same calculations. But the model, regardless of how useful it is, does not automatically become reality.
Just because the Universe isn't Euclidean doesn't mean it has no center. Non-Euclidean spaces can be finite and bounded too.
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