michel123456

As to the Universe, there are oscillations from some maximum matter density to some minimum. Pleas read the book; I cannot retype it here.

I will.

As to ignoring, ask yourself if you want to read the Logunov's book and papers. Nobody cares, everybody is busy with his own things.

I can't believe that.

The cube/square law has been discovered & explained by Galileo 500 years ago. IMO the most important galileo's discovery. It is a law of nature related to the (Euclidian) space we are living in, it cannot be overcome. This law applies for animals & for human constructions in general, buildings, naval constructions, aeronautics, etc.

A generalization of this law consists on saying that the scale factor is not applicable in nature: you cannot double the scale of something without having to change its structure. Galileo's conclusion was that if you wanted to double a horse you have to increase the proportion of his legs so that he would look like ...an elephant. You can make a model of the Eiffel Tower with chop sticks in your kitchen, but you cannot make the real Eiffel tower with the same material. You can make a little ship with a piece of paper in your bath tub but you cannot build a real tanker with paper. a.s.o.

That is the reason why there are no ants big like houses, and there are no elephants small like ants.

The world we are living in is structurated.

I suppose that is the reason why quarks are different from electrons, atoms are different from molecules, and molecules are different from rocks, rocks from planets, and planets from galaxies, a.s.o.

And every time someone explains you the structure of something small like it was something big (the structure of the atom like the structure of the solar system) you can be sure at 99% it is wrong.

I repeat myself: there must be something wrong in this theory.

i cannot believe that the west is simply ignoring something so big. that is too sad.

As AJB asked, no singularities? That mean no Big Bang either. So what?

Welcome joe.

You have chosen one of the most difficult subject.

I am on a quest to get a complete understanding of gravity

So do I. And not only.

Your questions make me think you have your own ideas.

Shoot.

Thus by Occam's Razor general relativity is chosen.

Occam's razor is obviously not enough to cut off singularities. Alexander's sword is best (to cut the gordian knot).

Seriously, what is the problem with Logunov's theory?

A theory without singularities (no black holes) is quite remarkable, especially when hundred of astronomers are observing in their telescopes manifestations of BH that respectable professors like Hawking have spend a lifetime on studying their properties.

There must be something wrong in it.

The theory was developed not so long ago

1986? 24 years ago? I never heard from this theory. Thank you for the information.

Here is my point.

In GR and SR, we have matter, mass, energy. We have space, we have time. And we are working with all these. WE KNOW that matter, mass & energy exist. As about space & time, the question is still open.

So, my point is: how are we so sure that space & time are curving, expanding, accelerating, a.s.o.?

Why do we give properties to entities we don't even know if they exist?

Shouldn't it be more sensible to suppose that things that WE KNOW exist are curving, expanding, accelerating, a.s.o.?

The principle of mathematics (the = sign) is symmetric. This wonderful feature allows us to flip the elements of equations at will.

That make me think that we can turn some sentences upside-down without having to change anything in the theory. For example, instead of saying that matter & energy tell space-time how to curve, we could say that matter & energy inversely curve into space-time.

The only difference between the 2 statements is the equation of the curve must be the inverse. To pose it otherwise: the equation we know is exactly the inverse of what is actually happening because we are observing all phenomenas from the inside.

That is my point of vue.

Gravity is the "thing" that makes apples fall from trees and the planets orbit the Sun.

Hi AJB. Apples fall from trees hand hit the ground. Planets orbiting the sun is the consequence of gravity & something else, "initial velocity", as mentioned in another thread on this forum. Gravity all alone is not enough for orbiting. Right?

Let us consider a 3D Euclidean space.

 

Nothing exist in the whole universe.

 

Now we introduce one thing into this universe that has no moving parts, but is some homogenous thing fundamentally different in some way from its surroundings.

 

Time does not pass in this universe.

 

I know that your presentation is the regular common and accepted one.

I think it is wrong.

What I believe is you can't have Euclidian space without time.

For me (I am trying to spread my thoughts here), time is sooooo fundamental that you can't have a single line (a 1d space) without time.

The fine structure constant has the square of the fundamental charge

 

The Bohr radius has e^2 and h^2

 

The Stefan-Boltzmann constant has k^4 and h^3

Hm. Right. I still find it intriguing to square a constant. Is that so natural?

When Insane-A says

besides, its better to have the one constant with an operator instead of making up a second constant so it doesn't require an operator.

C has unities meter/sec. When you square C, you square the unities as well. Csquared are m^2 / sec^2 which is physically representing something (what is it ?) that is not a speed any more.

I am always confused with those kind of questions.

I suppose the result must be symmetric. Gravitation must be the same as measured from the FOR of the observator A at rest & for an observator B upon the rotating object.

yes B/E=c2 where B is magnetic & E electric field.

Hm. I mean it is unusual to square a constant. Usually, the squared values are variables, like in [math]\pi r^2[/math].

In reality in [math]e=m c^2[/math], [math]c^2[/math] is the constant, not c.

The fact that energy cannot vanish (conservation of energy) should show us that energy cannot be created from nothing either. The question is not the cause of creation, the question is about the concept of creation itself. If you suppose that creation is a wrong concept, admitting that actual observations are about transformation (opposed to creation), than there is no mystery.

"E=mc2"

is there another equation in physics where the constant is squared?

Good.

What a relief.

T symmetry is related to that weird thing that happen in physical real life, this arrow represented by the blue arrow on the diagram. The blue arrow of time is introduced arbitrarily, i.e. because we know that's the way things happen, and not because it comes from some physical law.

But instead of looking at T symmetry, I'd like to look at space.

We know that time is always positive, but we can have positive & negative coordinates for time.

Regarding space, positive & negative coordinates are of common usage too.

But there is something that is always positive in space.

Distance.

Negative distance does not exist, as negative time does not exist.

And you know that distance can be expressed as time, and vice-versa.

Correct?

Yes.

 

You should think about things in terms of a Minkowski diagram. (Even better in in general relativity is a Penrose diagram).

Ha.

So, in a Minkowski diagram, I can put a + sign in the low part (the past) and a minus sign in the upper part (the future).

I was asking about initial velocity of an orbiting body like Earth or Moon. I don't think the creation of the Moon has anything to do with my question. The material of the accretion disk was orbiting before the Earth was created.

I was just interested to hear someone say that gravity is not enough to make bodies orbit. You need something else, like "initial velocity". And I am still asking, where does this "initial velocity" come from?

For example, the solar system is orbiting the galaxy: where does its initial velocity come from?

It is not necessarily positive.

So [math]\{t\}[/math] considered as a coordinate can be positive or negative.

I suppose the physical interpretation is:

positive = past

negative = future.

Correct?

The moon is constantly falling towards the Earth, but because of its initial velocity it continues to miss us. That's what an orbit is.

What is the "initial velocity"? The one we got from the Big Bang?

Speaking technically, in the set of inertial coordinates [math]\{t,x,y,z\}[/math] only [math]\{t\}[/math] is always positive, negative time does not exist.

By opposition [math]\{x,y,z\}[/math] can be both positive or negative.

How come that something always positive by definition can be transformed in something that can change sign?

In other words, if time can be changed in space and vice-versa, what about the arrow of time?

You all should agree that if the arrow exist in time, it must also exist in space, don't you?

Where is it?

Indeed, this should be the first thing one learns in relativity 101.

 

As we have transformations that mix space and time it is not clear in general how to make a distinction between space and time.

"Space=Time"

I am glad to see that writed down by someone (Galindo) and supported by AJB. Usually when i go on such an assertion I am treated like a troll and being presented a list of major differences between space & time.

For example, when discussing the concept of "the arrow of time", people use to oppose that there is no such a concept applying to space. In space, they say, there is no "arrow", you can go everywhere.

And like a troll, I begin into disagreeing with this "fact".

And try to explain that there is an "arrow" in space too.

Usually I am ejected at once.

Now that AJB seems to back up the space=time equation, can I try again explaining my ideas?

They bump, after falling for many many times the age of the universe. The set up is they have an initial relative velocity of zero. An orbit requires a sideways component to velocity.

In the case of the Earth-Moon system, what is the "sideways component to velocity"?

As a purely classical physics question, then yes, they fall towards one another.

Would they bump, or orbit one another?

God is not of a good advice, we need Prometheus.

Any scientific theory is based on the scientific method:

"Four essential elements of a scientific method are iterations, recursions, interleavings, and orderings of the following:

Characterizations (observations, definitions, and measurements of the subject of inquiry)

Hypotheses (theoretical, hypothetical explanations of observations and measurements of the subject)

Predictions (reasoning including logical deduction from the hypothesis or theory)

Experiments (tests of all of the above). from http://en.wikipedia.org/wiki/Scientific_method#Elements_of_scientific_method

We begin with observation, we end with observation. The circle must be closed. If something escapes from observation, the scientific method cannot apply and there is no proper theory.

Relativity is based upon observation: C the speed of light is both a measurement and an axiom. And Relativity is supported by observational experiment. The circle is closed, everything goes well, Relativity is a Theory.

But if Mother Nature was more tricky than we thought, and if something bizarre happened in what we call "observation", the tricky part would be hidden both in the axiom and in the experiment. Even in this case, the theory could work, the circle would still be closed, the "tricky error" would be "outside" the theory, and we would never be able to notice anything of it. Everything would be explained perfectly, mathematically, but not necessary the way it really works.