Dividing by zero

Originally posted by ImaFungi
reply to post by yampa

 

If not a black hole, what exists at the center of the galaxy?

What is your understanding of the term black hole and what it physically means?

I'm arguing with the initial justification for black holes via mathematical results obtained by Hilbert, Schwarzschild, Chandrasekhar etc -the mainstream, standard model picture of a what a black hole is proposed to be. I'm disagreeing with the theoretical postulates, any data collected which happens to fit those models is irrelevant if the original justification is false.

Stephen Crothers makes many compelling arguments against the justification for black holes here:

reply to post by yampa


I have just spent time in another thread arguing someone who posted the same videos...


www.abovetopsecret.com...

I explained why I thought crothers was misinterpreting and misunderstanding the meaning of terms and concepts, and was bothered that he failed to present his hypothesis or theory on what exists at the center of a spiral galaxy and what interactions might take place there.

He isn't attempting to prove anything physical about the universe. He's pointing out how the original justification for the theory is self-contradictory and hacked. What actually is at the centre of galaxies is irrelevant to this.

reply to post by yampa


But the original theories arent hacked, they make sense. To point out and say,' This cant be right, because a, b,c'. He must have some idea about is going on, even hypothetically or theoretically, just an idea of what is going on.

If not, ok. But he didnt explain what about his reasoning and thinking disagreed with the status quo of physics and black holes, and yes I did watch the videos. Does he not agree that space is 'something'? Does he not agree that a significant amount of energy can be trapped in the center of spiral galaxies? Thats all a black hole is. If there is a concentration of energy at the center of spiral galaxies, black holes exist, because most simply, thats what a black hole is, this is why I need to know what he thinks is otherwise, what are the other options? A large area of no energy and matter at the center? Is that what he believes? That could actually be true, but might mean the same thing.

its not contradictory.




1:38:00 is stress energy tensor

K so I think Eisenstein stress energy tensor equations = 0, is because the total space or gravity field has 0 energy. It only has potential energy when a mass is introduced, and a single mass in space is in free fall, the masses existence gives the gravity field the potential to be energetic, I think...

Black holes were produced as a theoretical speculation *first* - they were not trying to explain unexplained data. If the original speculation is false, and you can point out mathematically why it is false then why would you return to a broken theory?

Crothers is making serious specific technical charges against the mathematical basis of the models - it is not easy understand his objections without quite a lot of experience around mathematical modelling (same reason many people never challenge the original theory).

I watched that video last year and I couldn't quite grasp the objections because I hadn't studied enough of the math. I've done a lot more study and practice since, and for what it's worth, it now seems to me that he really knows his subject and is pretty much smashing it out the park.

It's not like we have all this crazy blackholeish data pouring down on us which is begging to be explained. What we have is a completely fictional model, that science has spent fortunes and countless careers on trying to fit data to.

reply to post by yampa


I have watched 3 videos of his, I understand his objections but he also lacks in understanding.

Is the milky way a spiral galaxy?

Is there a relative center of the geometric shape of a spiral, (a center which the 'stuff' is spiraling around)?

Does energy/matter that is more near that centers edge, then not, enter into the center?

If yes, that is the concept of a black hole.

If no, what is another possibility?

Does gravities strength increase as mass increases?

If the center of a spiral galaxy was not massive, would the bulk of stars near the center remain in an orbit around the center?

reply to post by mbkennel

The number line is a totally abstract mathematical construction.

Correct me if I am wrong, but that number line sure looks to be a concrete construction.

reply to post by totallackey


Its abstract in that it needed the human mind to become manifest. Though it is an interesting argument about the absolute nature of math, I think related to Platonism of mathematics or something like that.

reply to post by ImaFungi

Thanks for the reply. So, the number line is a visual representation of "IF a tree falls in a forest?"

Anything divided by zero is undefined simply because we cannot plot it on a graph. Other values may be irrational, but they can still be plotted: e, π, and even i can be envisioned, located on a graph, and plotted. Infinity (∞) cannot; it is a totally abstract concept.

Now, if we take the limit of division as the divisor approaches zero, then we get infinity as an answer. That does not mean x/0=∞, it means the limit(y→0) x/y=∞. Those are different statements.

Khan Academy offers great free tutorials on mathematics that explain much better than I can in a forum post. Remember that math is a language like any other: if you come across a word you don't understand, you look it up; you don't make up your own definition based on limited context and declare you know the full definition. Works the same way with math.

TheRedneck

reply to post by totallackey


I guess. If man writes 1+1=2 it exists and is true. If man never existed and never wrote that...would 1+1=2 exist and be true, without ever being manifested or realized?

When man discovered that 1+1=2... before he realized that 2+1 = 3.... did it?

reply to post by yampa


What is your personal understanding of how gravity may occur? This is certainly important when discussing black holes because they are mainly a phenomenon of mass and gravity.

reply to post by yampa


So I think the only problem you really have is the syntaxical name 'Black hole' which appears mysterious and scary to you. You can call it 'Area in the middle of spiral galaxies that contains a massive amount of energy which is very dense in relation to its volume' if it makes you feel better. Why doesnt ^that, exist?

I agree there may be things about the concept that are wrong and unknown, like the assumption light cant escape, I can possibly for fun assume that its not that light cant escape, its the light cant enter, and/or the photon field becomes completely broken and dismantled at the event horizon and inward because of the tremendous torque and density of energy.

Anyone interested in what an actual, real-life expert has to say on the matter? What's that? No? You'd rather stick to only uninformed opinions by people who haven't ever done any real physics?

Originally posted by yampa
Black holes were produced as a theoretical speculation *first* - they were not trying to explain unexplained data. If the original speculation is false, and you can point out mathematically why it is false then why would you return to a broken theory?

Except that no one has given any remotely reasonable explanation for why GR does not work. Not just on this thread--ever.

Crothers is making serious specific technical charges against the mathematical basis of the models - it is not easy understand his objections without quite a lot of experience around mathematical modelling (same reason many people never challenge the original theory).

No, the reason no one questions the theory is that anyone who has the foggiest understanding of it knows it is completely correct for literally hundreds of independent reasons.

I watched that video last year and I couldn't quite grasp the objections because I hadn't studied enough of the math. I've done a lot more study and practice since, and for what it's worth, it now seems to me that he really knows his subject and is pretty much smashing it out the park.

I can absolutely 100% guarantee you that if you could not understand gravity last year, you absolutely did not learn enough this year to even come close to giving an informed opinion or understanding of a criticism of it.

It's not like we have all this crazy blackholeish data pouring down on us which is begging to be explained. What we have is a completely fictional model, that science has spent fortunes and countless careers on trying to fit data to.

Right, because it not like bat Nobel prizes have been given out for anything related to general relativity or anything. Especially for analyzing data. And no other prizes either.

reply to post by Moduli


Purely out of interest, in your understanding, what is a black hole? Is it purely energy, like a quark-gluon soup? Or is it more plasmic and primal then that? Im talking about the super massive black hole at the center of the galaxy. Im wondering if it is rotating so unbelievably fast, how can it grow in density, when matter goes near it (as data shows it appears to be shredded), how is it thought that the matter gets sucked in? Wouldnt that be like saying if there was a playground merry go round with solid walls spinning 100000 mph and we throw some watermelons at it the watermelons will enter and 'stick' to this? Or is the idea of gravity that this is more of a whirlpool toilet bowl affect, and the watermelon analogy is wrong (for a number of reasons, but mainly) because the gravity and air surrounding the merry go round is not in affect in space, in a galaxy, near the center black hole, that center point is the strongest source of gravity locally (/closest to the drain of a toilet bowl) and so if matter gets near there, its path of least resistance is to continue being sucked tighter and tighter towards the center, like how planets and stars form?

Originally posted by ImaFungi
Purely out of interest, in your understanding, what is a black hole?

There's no "in my (or anyone else's) understanding" about it. It's a very precisely defined, well-understood thing. In simple terms, it's a region of space where the escape velocity is larger than the speed of light.

Is it purely energy, like a quark-gluon soup? Or is it more plasmic and primal then that?

It's not any of those things, because all of those things are technobabble and don't have any meaning.

Im talking about the super massive black hole at the center of the galaxy. Im wondering if it is rotating so unbelievably fast, how can it grow in density, when matter goes near it (as data shows it appears to be shredded), how is it thought that the matter gets sucked in?

If the escape velocity of it is, at some location, faster than light, then it doesn't matter how fast it--or any matter around it--is rotating or anything else. If anything enters that region, it doesn't get out. Though the spiraling-in of particles around black holes does cause the emission of synchrotron radiation, which is one way we can directly detect the matter falling into a black hole and understand properties of black holes.

Originally posted by wildespace

For me, the two examples are quite enough to conclude that dividing by zero results in infinity.

The problem of dividing by zero reminds me of the impossibility of having square root of -1. Yet we have found a way to deal with it by using imaginary numbers. Perhaps dividing by zero is not as scary as the academia makes it to be.

The reason maths has such trouble with division by zero is because a) the result of a calculation is expected to be a number (and infinity is not a number), and b) because in algebra, division is the inverse of multiplication, and multiplying any number by zero results in zero.

So sometimes it's good to think outside the box.

This appears to contain a contradiction. If "dividing by zero results in infinity," then infinity IS a number.

The truth is that infinity is a math concept and not a point on the real line. So your feeling about infinity should be expressed as

a/0 -> ∞

rather than

a/0 = ∞

There is a difference between dividing a number different than zero by 0 and the case when that number equals to zero. a/0 fails the multiplication check, but 0/0 does not: 0/0 = k, where k can be any real number. That means there are infinitely many solutions to the equation 0/0 =x.

It all depends on the type of axiomatic framework a particular branch of math stands on. There is a fancy branch of projective geometry where you can divide by zero, because one of the axioms permits it.

If you investigate a real physical system and encounter a/0 in your computation, then one or more of your assumptions about that system are more than likely incorrect.

X/0 is undefined, as has already been mentioned (X being any real number). It's just nothing.

X/Y can have many outcomes. If X goes towards a definite number, different from 0, as Y goes to zero, there can be two cases: if Y keeps fluctuating between a positive and negative value (fig. 1), then you could say it's a sort of infinity, one that isn't either negative or positive (it's best described as nothing, though). If instead Y settles on a particular sign, then the result is either positive or negative infinity (fig. 2):

If X goes towards 0, and Y goes towards 0, it can be literally any real number or extended real number: 6, -7829, infinity, or even nothing. See fig. 3, fig. 4, fig. 5 and fig. 6 for respective examples.

0/Y represents 0 for all real values of Y, even Y = 0 (it's not defined at Y = 0 but can be extended) See fig. 7.

Figures:
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7

Note: An extended real number can be any real number or either positive or negative infinity.

It's actually quite simple. You cannot divide by something that doesn't exist. It doesn't produce infinity, it doesn't produce anything because it cannot be done.

You can look at what happens as the divisor approaches zero and it would give you the false assumption that infinity would be approached, but it's false because the function cannot be completed since there is no value.

Originally posted by Moduli


It's not any of those things, because all of those things are technobabble and don't have any meaning.

Ah yea, I assumed wrongly about the big bang. I thought it was thought that the earliest form of energy was quark-gluon plasma, so I was wondering if black holes break matter down to an energetic state similar. Or if they are so violent and dense and energetic they create an even more simpler and primal form of energy. But after looking at the theory I see the theorized most primal form of universal energy is 'inflation'.