Gravity vs Mass

[Thief]

I have a question of which I will not post
I already know.....no one can answer it

but it does relate to this topic and so.....a redirect and a blindside
right up front

do you THINK you understand gravity?
and WHAT has mass got to do with it?

and if the Creator gets a mention
don't be surprised

 

[Subduction Zone]

I have more than a sneaking suspicion that the OP does not understand either.

 

[Darkforbid]

Yep, fully

 

[McBell]

What do I need to know beyond "you drop something it falls"?

 

[Subduction Zone]

What do I need to know beyond "you drop something it falls"?

Don't stand underneath people dropping things.

 

[McBell]

Don't stand underneath people dropping things.

I will have to try and remember that...
Though with all the bumps to the head, I would forget my head were it not attached.

 

[Terry Sampson]

do you THINK you understand gravity? and WHAT has mass got to do with it?

Can I ask "rational experiences"?

 

[exchemist]

I have a question of which I will not post
I already know.....no one can answer it

but it does relate to this topic and so.....a redirect and a blindside
right up front

do you THINK you understand gravity?
and WHAT has mass got to do with it?

and if the Creator gets a mention
don't be surprised

Depends what you mean by "understand".

As with everything, there are levels of understanding. If one goes deep enough on any subject there always comes a point at which one has to say, "I don't know the answer to that".

I understand the Newtonian model of gravity , and I know in outline how General Relativity models it. According to both, gravitation arises from mass. Why it does so is not known. But then we do not know why electric charges attract and repel either: they just do. It is just how we observe nature to behave.

 

[Native]

do you THINK you understand gravity?
and WHAT has mass got to do with it?

Well, even Newton admitted that he couldn´t explain the dynamic force of gravity . . . he just assumed it from watching an apple fall to the ground and also assumed the planets to be held in orbits by the Sun.

If something cannot be dynamically explained, it of course cannot be fully understood.

The Standard Cosmology idea of "mass" and "gravity" is completely out of order, right from the ideas of formation of stars and up to the strange and very speculative idea that a "Higgs Boson particle" is assumed to "give mass" to everything.

All atoms and particles have electromagnetic properties which either attracts or repels each other, all depending of the overall existence of diverse elements and effects from cosmological sources and movements.

Mass isn´t a question of "gravitational binding atoms and particles together". It is generally a question of electromagnetic binding of atoms and molecules - right from the microcosmic and up to the macrocosmic scale.​

 

[blü 2]

I have a question of which I will not post
I already know.....no one can answer it

but it does relate to this topic and so.....a redirect and a blindside
right up front

do you THINK you understand gravity?
and WHAT has mass got to do with it?

and if the Creator gets a mention
don't be surprised

It's a force that only acts between objects that have mass.

So the way to be gravity-free is to have a rest mass of zero, and never to move.

In a relativistic world, that last requirement is even harder than it first seems.

 

[Polymath257]

I have a question of which I will not post
I already know.....no one can answer it

but it does relate to this topic and so.....a redirect and a blindside
right up front

do you THINK you understand gravity?
and WHAT has mass got to do with it?

and if the Creator gets a mention
don't be surprised

Gravity is the curvature of spacetime that is produced when there is energy and momentum in a region. Mass tends to be the largest concentration of energy in many situations simply because in E=mc^2, the c is so large.

But all types of energy enter into the equation for gravity.

The basic equation is
G_{\mu\nu} =(8G\pi/c^2) T_{\mu\nu}

Where the left hand side is a tensor describing the curvature geometrically and the right hand side is the stress-energy tensor. The T_{00} component of this tensor is the energy (and mass contributes to this) and is, by far, the largest contribution in most cases. But the other diagonal elements are related to pressure and the off-diagonal elements are related to momentum density.

This equation is slightly modified in the presence of a cosmological constant, which can either be treated as an additional term on the left (representing a curvature present even when there is no stress-energy) or on the right side where it represents an energy density of the vacuum.

Next.

 

[`mud]

Such a waste of chalk on those blackboards !

Why do hydrogen and helium rise ?

What else does ?

Does the earth ?

 

[Native]

Gravity is the curvature of spacetime that is produced when there is energy and momentum in a region. Mass tends to be the largest concentration of energy in many situations simply because in E=mc^2, the c is so large.

You most certainly have your equations written right - but what about the cosmological explanations and it´s correctness? Are you sure you really have understood it?

Watch this: "Why E=mc^2 is wrong" -

 

[HonestJoe]

I have a question of which I will not post
I already know.....no one can answer it

Then I won’t give the correct answer the question you’ve not asked as I already know you’ll refuse to accept it.

do you THINK you understand gravity?

At a very basic level, much like I understand how a car works well enough to drive one and carry out basic wear-and-tear maintenance but I wouldn’t know where to start if I was asked to build one from scratch.

and WHAT has mass got to do with it?

The gravitational force an object exerts is a function of its mass.

and if the Creator gets a mention
don't be surprised

And if mention of "the Creator" gets strongly challenged as entirely off-topic, don’t be resentful.

 

[Polymath257]

You most certainly have your equations written right - but what about the cosmological explanations and it´s correctness? Are you sure you really have understood it?

Watch this: "Why E=mc^2 is wrong" -

*sigh*. Yes, that is the equation for a mass that is not moving. The more general equation that even works for massless particles is

E^2 =m^2 c^4 +p^2 c^2

where E is the energy, m is the (rest) mass, and p is the momentum.

So, for photons, m=0, giving E=pc.

For a particle with mass m and velocity v, the momentum is given by

p=(mv)/sqrt(1-(v/c)^2 )

As for 'cosmological explanations' and 'correctness', the correctness is determined via observation. The phrase 'cosmological explanation' is likely to be philosophical rubbish.

 

[Thief]

Mass isn´t a question of "gravitational binding atoms and particles together". It is generally a question of electromagnetic binding of atoms and molecules - right from the microcosmic and up to the macrocosmic scale.​

in eighth grade......sooooooooooo long ago

two classmates were given the assignment.....What if gravity failed
and they assumed all of the large objects....and us.....
would float off into space

at the time I was naïve enough to ask.....
would not the atomic structures fail?
and we simply pop into the nothing from which reality came forth?

kinda dropped a bomb on their science report

but neither did I think I was right
I was just asking

 

[Thief]

At a very basic level, much like I understand how a car works well enough to drive one and carry out basic wear-and-tear maintenance but I wouldn’t know where to start if I was asked to build one from scratch.

well....I guess I am two up on you
as a body repair man...….I can take your vehicle apart and put it back together

as a toolmaker......I can make any of the hard items
but that would take sooooooooo much longer

a new car would be cheaper

 

[Thief]

*sigh*. Yes, that is the equation for a mass that is not moving. The more general equation that even works for massless particles is

E^2 =m^2 c^4 +p^2 c^2

where E is the energy, m is the (rest) mass, and p is the momentum.

So, for photons, m=0, giving E=pc.

For a particle with mass m and velocity v, the momentum is given by

p=(mv)/sqrt(1-(v/c)^2 )

As for 'cosmological explanations' and 'correctness', the correctness is determined via observation. The phrase 'cosmological explanation' is likely to be philosophical rubbish.

so.....you discount observation?

I do find your post interesting

particles …...of no mass

like a ghost having form
but no substance

 

[Heyo]

Such a waste of chalk on those blackboards !

Why do hydrogen and helium rise ?

What else does ?

Does the earth ?

Hydrogen and helium don't rise. They get pushed up by other molecules falling.

 

[Twilight Hue]

I have a question of which I will not post
I already know.....no one can answer it

but it does relate to this topic and so.....a redirect and a blindside
right up front

do you THINK you understand gravity?
and WHAT has mass got to do with it?

and if the Creator gets a mention
don't be surprised

I understand it based on actual experience as with everybody else.

I think energy has a lot to do with gravity involving the characteristics and properties of atoms.

It seems denser material has more gravity than that of less dense material and is interesting in terms of how electromagnetism works as it relates with gravity. Now with research suggesting gravitational waves now, the whole topic has gotten so much more interesting.