Question about gravity

[Southwind17]

I think there are a number of posters here that understand those quite well, but I for one am not willing to spend more time trying to determine what you are after. Do you want one of us to write a book on GR in a series of forum posts?

Understanding those things requires learning some background, just as understanding rain at the same level of detail would (particularly if you started off not knowing what evaporation was).

Look - everybody knows water evaporates and condenses because everybody's seen it happen for themselves. So they feel they "understand" rain. Most people have not noticed two objects attracting each other due to gravity in any way that made it obvious what was happening, so they don't feel they "understand" gravity. But fortunately the human mind is capable of going beyond what we can see easily with our eyes, and that allows us to observe and understand gravity just as well as - actually better than - rain. But you have to do a little work if you want to get there.

I don't think you understand the meaning of "understand" as well as you think you do. I also don't think you appreciate the difference between "theory" and "scientific proof". The fact that you seem incapable of explaining gravity even at a rudimentary level seems to support my views.

 

[Southwind17]

Ah I see your problem, you don't understand it, so that means it is not understood. This is not really true you know.

We'll take it you can't demonstrate such understanding, then, shall we, electing, instead, to side-step the issue?

 

[ponderingturtle]

We'll take it you can't demonstrate such understanding, then, shall we, electing, instead, to side-step the issue?

Ah but I am not making claims about how well understood it is. And at my school there was not any GR courses, and as I am moving from physics to engineering I see no strong reason to learn it.

 

[Southwind17]

Ah but I am not making claims about how well understood it is. And at my school there was not any GR courses, and as I am moving from physics to engineering I see no strong reason to learn it.

Your admitted lack of understanding suggests you're not qualified to comment about levels of understanding.

 

[ponderingturtle]

Your admitted lack of understanding suggests you're not qualified to comment about levels of understanding.

And if you believed that you would not be argueing here, with people who do understand telling them that they are wrong.

 

[sol invictus]

You see, this doesn't qualify as an explanation to any meaningful extent.

I don't think you understand the meaning of "understand" as well as you think you do.

Your admitted lack of understanding suggests you're not qualified to comment about levels of understanding.

'Nuff said.

 

[Southwind17]

And if you believed that you would not be argueing here, with people who do understand telling them that they are wrong.

You presume too much!

 

[Southwind17]

'Nuff said.

I understand.

 

[Southwind17]

Can we look forward to seeing a meaningful, albeit abridged, if necessary, explanation of gravity posted here any time soon by somebody who understands gravity, i.e. an explanation that does not purport to be so simply by reference to theories and associated formulae, neither of which demonstrates understanding? Anybody?

 

[Fredrik]

Can we look forward to seeing a meaningful, albeit abridged, if necessary, explanation of gravity posted here any time soon by somebody who understands gravity, i.e. an explanation that does not purport to be so simply by reference to theories and associated formulae, neither of which demonstrates understanding? Anybody?

You want an explanation of gravity that doesn't mention the theory that describes it!? You obviously have no idea how absurd that is. It is absolutely ridiculous.

It is also absurd that you keep going on about this nonsense without explaining what it is you want to see. We have asked you repeatedly to explain something (anything) that you think you can explain, so that we can see what you would consider an explanation, but you keep ignoring it. This discussion can't possibly go anywhere until you've done that.

I'm also getting the impression that you haven't even read most of the answers we've given you. There are several good ones above, and they explain a lot of things that you need to learn, but you obviously haven't learned anything in this thread.

 

[Southwind17]

You want an explanation of gravity that doesn't mention the theory that describes it!?

So, gravity is only capable of explanation by reference to a theory. You do realize, don't you, that theories are essentially abstract thoughts, some of which become replaced by scientific proof, at which point understanding pervades? I take it you have no explanation, other than theories?

 

[Southwind17]

We have asked you repeatedly to explain something (anything) that you think you can explain, so that we can see what you would consider an explanation, but you keep ignoring it. This discussion can't possibly go anywhere until you've done that.

How about photosynthesis?

 

[Fredrik]

So, gravity is only capable of explanation by reference to a theory. You do realize, don't you, that theories are essentially abstract thoughts, some of which become replaced by scientific proof, at which point understanding pervades? I take it you have no explanation, other than theories?

You are very wrong about this. There is nothing than can give us a better understanding than a theory, and theories are never replaced by "scientific proof". There's is no such thing as a "scientific proof" of a theory.

Why do you keep ignoring the questions? Edit: OK, I see you have given us a partial answer.

 

[Fredrik]

How about photosynthesis?

Can you explain photosynthesis without mentioning light, or chemical reactions? (The answer is no). So how do you explain light? How do you explain chemistry?

 

[Irony]

How about photosynthesis?

Given the level of "understanding" you expect with gravity, that simply won't cut it. To say you "understand" photosynthesis you also need to explain how photons exist, how carbon exists, how oxygen exists, how hydrogen exists, how the spacetime that photon must travel through to to reach the matter exists, how a photon can travel through spacetime, how it is possible for matter to absorb a photon, how that absorption can result in a chemical reaction, and you must explain all similar questions which will undoubtedly arise from your explanations.

 

[sol invictus]

So, gravity is only capable of explanation by reference to a theory. You do realize, don't you, that theories are essentially abstract thoughts, some of which become replaced by scientific proof, at which point understanding pervades? I take it you have no explanation, other than theories?

As Fredrik has pointed out, the phrase "scientific proof" is an oxymoron. All we have, and all we will ever have, are theories.

It appears from the examples you've given that what you want is a mechanism - an explanation for gravity in terms of some process involving other ingredients of some kind. Is that correct?

If so, general relativity provides such a mechanism. Gravity is understood as the curvature of spacetime. The presence of energy in a spacetime bends it in a particular way (given by the equation that was posted above). As in Newtonian mechanics, particles follow "straight" lines at constant velocity unless acted on by some external force (which in this case does not include gravity). However straight lines on a curved space look curved - for example if you plot the flightpath of transatlantic flights on a flat map, they look curved (but are actually the shortest paths). At this point you should picture the sun as a bowling ball deforming a taught rubber sheet, and the earth as a marble rolling around and around in circles in the well created by the sun (like one of those coin donation things you see sometimes at airports).

OK?

 

[robinson]

As Fredrik has pointed out, the phrase "scientific proof" is an oxymoron. All we have, and all we will ever have, are theories.

Somebody should tell Randi.

1.1 How long has this Challenge been open?

The Challenge was first introduced in 1964 when James Randi offered $1,000 of his own money to the first person who could offer proof of the paranormal.

http://www.randi.org/joom/content/view/47/37/

 

[robinson]

You are very wrong about this. There is nothing than can give us a better understanding than a theory, ...

That isn't true. It isn't even close.

 

[Skeptic Guy]

Can we look forward to seeing a meaningful, albeit abridged, if necessary, explanation of gravity posted here any time soon by somebody who understands gravity, i.e. an explanation that does not purport to be so simply by reference to theories and associated formulae, neither of which demonstrates understanding? Anybody?

Do you understand what a scientific theory^WP is?

In science, a theory is a mathematical or logical explanation, or a testable model of the manner of interaction of a set of natural phenomena, capable of predicting future occurrences or observations of the same kind, and capable of being tested through experiment or otherwise falsified through empirical observation. It follows from this that for scientists "theory" and "fact" do not necessarily stand in opposition. For example, it is a fact that an apple dropped on earth has been observed to fall towards the center of the planet, and the theories commonly used to describe and explain this behaviour are Newton's theory of universal gravitation (see also gravitation), and general relativity.

At the risk of using Wikipedia, I think it is interesting that they used gravity as an example.

How about photosynthesis?

Ok, if that works for you then gravity^WP.

That isn't true. It isn't even close.

How so?

 

[robinson]

Have you ever heard of the "inverse square law"? It isn't considered "the inverse square theory", and if you were to talk about it like that, you would be considered uneducated.

Same for many other laws. Here is a list
http://en.wikipedia.org/wiki/Scientific_laws_named_after_people

sometimes they are called "equations", "principles", or "functions". But nobody who is educated in science would try to tell you that they are only theories, and we can never get any closer than a theory, in regard to understanding the real world, and the forces in it.

The naive belief that we are never certain about anything, is sometimes trotted out to make some kind of bizarre point, usually that we can never know anything, we only have theories and stuff. It just isn't true.

The most important part of science is the experiment, not the theory.

I've had this discussion before, and if you want to argue that there are no laws, only theories, go right ahead. But after this attempt to enlighten you, I'm only going to mock you, not try and educate you.