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Just because you can write down something on a piece of paper that doesn't mean it has no time in it.

Where is the time in

[math]ax^2 + bx + c =0[/math]

Mathematics are a language. Or like music if you prefer.

More than a language I think ... but anyway what has this to do with the physical notion of time?

you write mathematics, you read mathematics.

And what has this to do with time?

What do you really mean by static? I think we are missing each other here.

Mathematicans are not static. Mathematics is not static in the sense that we do develop/discover new things as time goes on. But still, mathematics as mathematics need not say anything about time.

Mathematic is static in the sense that once a proof of a statement is given that statement is considered true for ever and was always true.

It is how we apply mathematics that may or may not say something about time.

Oh you think mathematics are static?

This depends on what you mean... so what do you mean?

If mathematics are static, then it is also evident that you will never find emergent time from it.

If mathematics have already time in it then you can use time in physics without second thought.

What do you mean by static? I think we have some crossed wires here.

My point is that you cannot have the slightest notion of mathematics without time.

I cannot because I exist in a Universe that has time... but that does not mean that mathematics itself has time written into it.

My opinion is that time is inherent in mathematics and thus you must consider time as already existing when using mathematics in physics. I thought it was an evidence but now I realize it is an opinion...

But time is not inherent in mathematics. We can disucss mathematical theoerms that do not used the notion of time. For example, the quadratic formula itself says nothing about time - though that formula maybe useful in phsyics.

????? Isn't that all mathematics?

The universal truths of mathematics are independent of the notation used.

Let me be wrong but I know no static language. (maybe it is worth another thread)

You seem to have missed what one means in mathematics by 'dynamics'. We are not talking about how mathemaics is written. You were talking about how space and time could arise as non-fundamental features of a theory in some kind of limit - right?

I remember Dio more for his later stuff, but of course including Black Sabbath. I really like is live works including in London 2005 \m/

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Maybe is is worth saying 1978 was the year Judas Priest released the album Stained Class.

Fat Bottom girls was released in 1978 - the same year DIO left Rainbow... a little fun fact for you there.

Dio then joined Black Sabbath in 1979 -- that lead to this beast of a tune

I never really got into queen ... still a good band.

as to the nature of " quantum gravity "

 

But obviously , like everybody else , people are trying to reconcile this with Geneal Relativities role in Gravity .

However, the vast majority of people working in physics are not looking into quantum gravity.

Anyway, Rovelli is know for loop quantum gravity. This approach interests you?

Elvin Bishop had a degree in physics... so we approve his music!

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Together we are stronger... fu*king leave voters.

Rovelli is well known - but he is in France at the moment?

Another well known Italian here is Giovanni Landi.

Any equation is dynamical. You read it from left to right, or from right to left.

 

Like any written language.

You are mixing mathematics, the notation of mathematics, the writing and reading of mathematics.

Mathematics are conceptually dynamical.

Dynamical means that 'something changes' with respect to some paramaters - sometimes this can mean just 'time'. For example, just think about how to describe the position of a particle moving in 1d.

If you use mathematics you must take time as already there.

Why?

If you think it differently what you are asking is to make time emerging from a static model (a model in which nothing happens).

Like I said, no one is sure how to do physics without time. Doing so will require some new mathematical notions.

I think one can prove that it is an impossible task.

You maybe able to prove that it is impossible within a given framework - but for in total generality.

The thing is to make space-time emergent.

Meaning you want to see space and time as not being fundamental in a theory, but rather coming as a macrosopic limit and/or a classical limit or something similar. The point is that you do not want to start with space or time.

So while nothing in law has changed - and it may be two or more years until it does - practice has changed. It is the just not knowing what will replace the existing systems that is the problem.

But it is not all doom and gloom. The UKs participation in large projects like CERN are not through the EU. ESA works with the EU, but again it is not part of the EU.

However ITER is funded by the UK through the EU. This will need looking at.

As for the Horizons 2020 and so on, it is possible for the UK to pay into that pot and take money out. However, no one in governmant has actually said that we will contuine to pay into the EU science pot.

My definition is as follows:

Dimensions are the pathways used and travelled by energy that combine to create reality.

What?

Looking back on what I have written using your definition.. yes I agree, that makes no sense.

Try re-reading it using my definition

But what you said makes no sense. It is just nonsense.

I am not sure what a particle is without space-time, I am not sure what gravitational collapse of a particle means - with or without space-time.

The general accepted idea is as follows....

String theory, loop quantum gravity and so on all suggest that space-time at some level should be 'fuzzy' - that is described by a noncommutative geometry.

Keeping time as classical , it may be possible that the dynamics of some theory involving a noncommutative geometry - our quantum space - in some macroscopic classical limit give us space as we know it. This is plausable, but no theory has really been given yet.

However, this is would not be enough. If space comes as some classical limit then so should time - we like to treat space and time on equal footing. Now we are in trouble. We would like some theory on or of a noncommutative geometry to be such that the dynamics in some limit gives us space-time + general relativity (+ maybe small corrections). But we have to do this without time from the start. This is a big problem - we don't know how to do physics (so dynamics) without time!

To be a bit nit-picky, that would give you good approximations, but not exact solutions.

Of course. I had in mind physical situations where these non-linear effects are too small to be detected.

I am only "fishing" but (perhaps I am asking the same question) is there ever a physical situation where the same circumstance can be exactly described by either a linear or a non-linear equation?

Only if the non-linear effects are small. I am sure there are such examples, but I can't think of anything off the top of my head.

Is that a principle that stretches right across mathematics?

If the equations are non-linear then you cannot usually add solutions to get another solution.

Is there ever a situation where non-linear equations can ever be translated into linear equations? (if I am making sense)

It depends what you mean - for sure there are some equations that a change of variables can make them linear. But more generally, we can always (or just about always?) linearise a differnetial equation. This gives us an approximation to the original equation, which more or may not be a reliable thing to do.

I have already made sense of this. A long time ago. But who listens?

I mean you will need a mathematical theory that show that we really can think of matter (or fields) as being the source of space-time.

Outside yes, like in Set Theory.

General relativity and field theory are based on space-time already 'existing'. A theory that has space-time as something emerging is going to be different to these existing theories - or mathematical frameworks.

I am not saying that it is impossible to create some theory - it is an interesting question and I think linked to some things in NCG and so on.

Is it possible (in theory) to "subtract" one geometry from another (the changed from the pre-existing) and arrive at those diagrams that showed the signature of the BH merger that we all saw recently?

In general no - you cannot add or subtarct solutions to the field equations and get another solution. What is often done is add this small linear correction and in an approximate sense the sum of the background and the correction satisfy the field equations

But what is being said is that people, specifically black youths, "may need to be more careful when".

And you disagree?

But ultimately there are expectations people in society should have and not having to fear being killed in one of them.

Which is what I have said in this thread earlier. Nobody should be in fear for their lives when dealing with an officer of the law - but it seems that some people are and maybe for good reason.

If I do not need to be "more careful" than I will not ask, recommend, suggest, imply, or etc that other may need to.

I don't understand what you are really arguing here. I understand that in principle all peoples should be treated the same - but that is not what we are seeing.

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There is a BBC report on 'Why do US police keep killing unarmed black men'. That report presents he finding from the study that I spoke of way back in this thread. It is interesting reading.

http://www.bbc.com/news/world-us-canada-32740523

A more effective way to save lives would be to adjust the way we training police officers and the degree to which we hold them accountable.

Agreed... nobody has said it is all one sided or that the police do not need to look at themselves.

More people like her, willing to stand against what is wrong, is superior to asking a generation of young people to accomodate the fears and biases of an overly aggressive police force.

You are missunderstanding. Nobody has said that nothing needs to be done. Nobody had said that people should accomodate fears and biases. Nobody has has said that people should tolerate police killings and so on.

She was arrested.

Which she knew full well would happen. She took the risk for a greater good.

She also became the face of a movement that saw many of it participants killed.

We all know this... but it is besides the point.

All that some of us have said is that a measure that individuals can take today is to be extra careful when dealing with the police. Not that they should have to do that, but it could save their lives. If they want to risk getting shot for some higher goal then so be it. Only they can make that choice.