michel123456

Doesn't this fact create a "special" (preferred) Frame Of reference, the FOR that is at rest ? The only one FOR in which one can measure invariant mass.

Fair. Things are not relative, observations are relative. To me Has 2 meanings. 1. It may say that there is a reality and that is what you measure. I agree with this interpretation. 3. It may say that there is an equal sign between reality and measurement. I disagree. Measurement is different from reality. Measurement is a tiny tiny little part of reality. And if many measurements from many observers are different but describe the same tiny little part of reality, it is sure that measurement is different from reality.

That is an axiomatic statement. There is no way to prove that. -------------------------- (edit) What do you say about "reality" when multiple observers moving with respect to each other observe different things? For example the rocket becoming shorter and the astronaut in the rocket observing nothing unusual.

The first painting in the O.P. post #1 represents a PhD from above.

An image is worth a thousand words and a thousand five hundred years. That's what Leonardo achieved when representing something described with words by someone else 1500 years before him. The drawing is dated circa 1490 while Vitruvius description is circa 15 B.C. So, the use of images can boost a scientific idea, be it right or wrong. It could be interesting to make a research on how scientific data has been represented in imagery through centuries. Reminding me ancient geographic maps with illustrations and planispheres. Aso, an influence of art is that scientific laws are supposed to be "beautiful". A concept that made irrational numbers not so acceptable in the beginning. A same concept that imposed circles instead of ellipses for planetary motion. A same concept that says that life (ie ourselves) must be beautiful. That the entire universe must be beautiful (although what we observe are burning furnaces, freezing void and chaos). And so on. And nobody dare to say the contrary. --------------------- Also, the PhD couvre-chef is ART.

There you have mixed gravitation. and gravitation puts back the pieces in a spherical shape when the object is large enough. which is not the case (if i understand clearly) with a drop of water in zero g. As if there were 2 kind of forces both regulated by geometry. Gravity through the curvature of spacetime and atomic/molecular bonds (is that E.M. interaction?) through the curvature of the surface of material objects. Or have I missed something?

The bonds between molecules are the same that bonds between atoms? And the bonds inside molecules are the same too?

So what?

I have absolutely no idea since it is not my field at all. But If there is a drop, IMHO it must mean that what you describe as a white noise is not a white noise, it is a noise. ------------------------ There is a radio signal at 60 Khz for time & frequency standards. http://www.armms.org/media/uploads/s_day_implementation_of_a_software_defined_radio_for_the_60khz_msf_time_signal.pdf

Let's say yes. But then, following the same logic, when you put the debris together you should have a release of energy. Which is not the case. Right. But i had the (false) impression that the sphere was caused by gravity, not by molecular or atomic interactions. Anyway "zero g" is a situation where acceleration from Earth is not felt (free fall), not a situation where objects have no mass. I mean, a drop of water still has its own mass even under zero g. And also i had the impression that gravity is invoked for the formation of planets in spherical shape. Not molecular or atomic forces. That is soo interesting. It is like saying that geometry is the cause.

Oh, that's not gravity's job?

Yes i understand. But still it is counter-intuitive in terms of energy. It is bizarre to think that the ocean for example has less energy as a whole than if it was entirely spread in droplets. That a statue has less energy than a sandbox. I'll read more. Well, I was thinking that when you break something, you do not deal with atomic forces but with molecular forces.

That is totally new to me. And counter-intuitive. i would have thought that many parts have less energy than a solid block. I would have thought that you need energy to construct a rock, more than you need to have sand.

That's about atoms. I thought it should have something to do with molecular bonds. --------------------- (edit) thanks for the article anyway. It does not explain why the process is not reversed when putting back the broken parts though. Thanks. Ignorant as I am, I looked at this wikipedia article which is not so clear as your answer is. Do you mean that it is a same force that changes sign as the distance decreases?

Question Why, when I break a glass for example and then assembling the pieces that fit perfectly together, why do the pieces not stick together just like that and reform the glass solid as it was without glue? Has the structure been modified so that the pieces correspond perfectly but the structural bonds are gone? I hope my question is clear.

I remember Swansont having stated somewhere that "the curvature of spacetime is not the cause of gravity, the curvature of spacetime is gravity". Hoping to remember correctly.

I am thinking about a mechanical bond based on the concept of dovetail joint. Something like this Where both materials could be cut microscopically. It depends on the dimensions of the finished product. ------------------- (edit) That could be curved as well. Like a zipper.

O.K. based on the laws of planetary motion, you get a speed decreasing with distance. I don't understand why does that give you "how much mass is actually inside the orbit of each star". Do you mean as if the "how-much-mass' was concentrated in the centre? I really don't understand. If the law predicts that speed must decrease with distance, and we are observing that it is not the case, how is it possible to correct the situation by increasing the mass inside the orbit?

Oh, I see. But in this case, dark matter should be "in" the objects. I mean, the observed objects should be more massive than expected. Not that there should exist dark matter around them.

I thought it was established that in a spiral galaxy, the objects do not go towards the center but simply orbit the galaxy round and round. Just like objects in the solar system orbit the Sun, objects in a galaxy orbit the center of the galaxy.

A common factor of large disasters is that there is not a single cause but an accumulation of causes. Sometimes human error combined with faulty equipment and wathever. I find no reason to kill that many people without any claim. If it was a hijack, it is a failure. Anyway I don't see anyone having won anything from this event. It is lose-lose situation.

But the spiral shape corresponds to the predictions of laws of motion without dark matter. No?

My thoughts go towards the 20 passengers who were employees of Freescale Semiconductor, a company based in Austin, Texas see http://en.wikipedia.org/wiki/Malaysia_Airlines_Flight_370#Passengers and http://en.wikipedia.org/wiki/Freescale_Semiconductor A company that produces technology for transponders. Can that be a coincidence? As I go deeper, I am afraid many conspiracy theories will rise from this tragic incident. For example: One of the passenger was a China telecom executive who returned from Kuala Lumpur after signing the construction and maintenance agreement for future Sea-Me-We-5. Knowing that there are accusations from French operator Orange against NSA having tapped the Sea-Me-We-4, we have all the ingredients for a new James-Bond-Spying-Game-like story. Sources http://www.fiercetelecom.com/story/freescale-huawei-zte-employees-among-malaysia-airlines-flight-370-passenger/2014-03-10 http://www.fiercetelecom.com/story/nsa-taps-seamewe-4-cable-system-orange-threatens-suit/2014-01-02 Nevertheless, i don't think it was intended for the plane to crash. You don't kill hundred of people just like that. I am more tented to believe it is a failure of some sort. An accident.

IIRC orbital speed goes less and less as the distance from the center increases. Laws of planetary motion do not give a same orbital speed for all objects. from http://en.wikipedia.org/wiki/Orbital_speed#Transverse_orbital_speed

Is it possible that the airplane remained flying without any pilot alive?