Gravity vs Mass

[exchemist]

so.....you discount observation?

I do find your post interesting

particles …...of no mass

like a ghost having form
but no substance

Nobody is "discounting observation". That's just silly.

General Relativity, like any other well-established theory of science, has been amply corroborated by observation, for example:-

- precession of the perihelion of Mercury
- bending of light from stars, as it passes the Sun
- the fact that GPS only works because a GR correction is applied to the clocks: GPS and Relativity

And the general formula E² = (mc²)² + p²c⁴ , which comes from Special Relativity, is also well observed to apply:-

i) For massless entities like photons, m = 0 and you can see it reduces to E = pc. If you then apply de Broglie's relation to that, from quantum mechanics, you will find you get Planck's Relation E=hν, which is what we observe in a huge range of physical phenomena.

ii) For massive particles, when momentum p = 0, it reduces to E=mc². We observe this in the "mass defect" measured in atomic masses of the elements and the energy release in nuclear reactions.

So it is all well checked by observation and it works out.

 

[halbhh]

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

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

I think: "What good would it be to talk about General Relativity?" Usually a person would be better off today watching an introductory video. What can we add that is useful?

Well, here's one thing that might be good to know: General Relativity has been very extensively tested by a lot of physicists trying very hard to find a point of failure, like prospectors searching for gold.

And it's stood up great, without any point of failure, so far. Which isn't even slightly the same as saying it's the final version of the best theory that integrates gravity with all other things. ;-)

But --
"You drop something and it falls" is a pretty good understanding of gravity for daily use.

The moon falls in a stable orbit around the Earth, or two balls fall at the same rate -- those are a nice connecting step to a beginning of physics.

But the common sense understanding is useful, and we all got it.

But mebbe you want to tease us with a metaphysical or new physics hypothesis? I never mind considering either.

 

[Skwim]

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

A simple musing.

The gravity of my understanding is massive, of a physical force far from passive.

Though fodder for the debater, it brooks no creator, a claim writ in confusion: the result of illusion.

'Tis no creator behind this odd reaction, but simply the nature of physical attraction.

How then to stand
....................under the gravity of gravity, this invisible tugging to be more than mutual hugging?

A simple "don't know" is far more in keeping than a divine cause at the end of our seeking.

So that's where we stand, our minds in despair, to most of those who simply don't care.

Gravity be dammed

​

I'm leaving this land

.






​

 

[A Vestigial Mote]

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

I figure you're getting at the "why" question - as in why is mass attracted to mass, or why does mass cause a curvature to spacetime, right? We can understand the mechanics and develop equations and functions that describe it so that we can predict the behavior of massive bodies, but that doesn't get at the "why?" these things are as they are.

I get it.

However - for there to be anything... anything at all that can be observed, there simply has to be a fundamental level at which things "just are." As in, there is no getting an answer to the question "why?" when you reach a certain level of base functionality or behavior. You can ask the question all day long, but there may not be any answer to be found, and indeed that makes the question nonsensical in a way. "Why?" Because that is the way it is. It doesn't work any other way. We can't know that it could have. We certainly can't know that something "selected" the attributes of our universe. It makes no sense to position a "creator" when, at a certain point, EVEN IN A UNIVERSE THAT WAS CREATED, things just are the way they are with no reason or "why?" to be had. In your case, you would probably point to "God" as this base level. Asking "why?" about God's existence probably seems nonsensical to you. It is very possibly the same with asking "why?" about gravity. There probably isn't an answer. It just is the way it is. Depending on your actual beliefs in this vein, perhaps ask yourself: Why can you grasp the nonsensical nature of the question "why?" when it comes to God's existence, but you can't extend that to anything at all that actually appears/functions in the universe as we know it?

 

[Polymath257]

so.....you discount observation?

I do find your post interesting

particles …...of no mass

like a ghost having form
but no substance

Like photons? Yes. We know light comes in particles (and waves) and that those particles move at the speed of light, which forces them to be massless.

 

[Polymath257]

so.....you discount observation?

Not at all. What I have written is supported by observation.

 

[Polymath257]

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

Yes and no. In a gravitational field any gas will have essentially an exponential drop in concentration as you move up. The coefficient on that exponential is linear in the molecular weight of the molecules in that gas. So small molecules will naturally be distributed higher whether or not there are heavier ones around. And, in fact, each type of molecule finds its distribution independently of the others (well, very close to independently).

Of course, this is focusing only on the thermodynamics and ignoring the fluid flow aspects of the situation.

 

[Subduction Zone]

Like photons? Yes. We know light comes in particles (and waves) and that those particles move at the speed of light, which forces them to be massless.

Well yeah If you cheat and use math

 

[Terrywoodenpic]

Gravity is a function of time.

 

[halbhh]

I figure you're getting at the "why" question - as in why is mass attracted to mass, or why does mass cause a curvature to spacetime, right? We can understand the mechanics and develop equations and functions that describe it so that we can predict the behavior of massive bodies, but that doesn't get at the "why?" these things are as they are.

I get it.

However - for there to be anything... anything at all that can be observed, there simply has to be a fundamental level at which things "just are." As in, there is no getting an answer to the question "why?" when you reach a certain level of base functionality or behavior. You can ask the question all day long, but there may not be any answer to be found, and indeed that makes the question nonsensical in a way. "Why?" Because that is the way it is. It doesn't work any other way. We can't know that it could have. We certainly can't know that something "selected" the attributes of our universe. It makes no sense to position a "creator" when, at a certain point, EVEN IN A UNIVERSE THAT WAS CREATED, things just are the way they are with no reason or "why?" to be had. In your case, you would probably point to "God" as this base level. Asking "why?" about God's existence probably seems nonsensical to you. It is very possibly the same with asking "why?" about gravity. There probably isn't an answer. It just is the way it is. Depending on your actual beliefs in this vein, perhaps ask yourself: Why can you grasp the nonsensical nature of the question "why?" when it comes to God's existence, but you can't extend that to anything at all that actually appears/functions in the universe as we know it?

Funny, before I saw this thread I made up a poem this morning that fits what you are saying in a way.

One Higgs particle to rule them all, one particle to mass them,
One particle to bring them all, and in the universe bind them.

Just an amusement, and not necessarily meaning anything special.

 

[Polymath257]

Well yeah If you cheat and use math

Or, for that matter, any other language.

 

[Subduction Zone]

Or, for that matter, any other language.

Gravity can be a very confusing topic. Not that long back Edward Current, known for his satirical "checkmate atheist!" videos made a serious one where he tried to explain how gravity is not a force in General Relativity. He tried to do so without math and it was not well received by another well known YouTuber, Desertphile (the man behind the Gravity Rant). It was not well received:

 

[Polymath257]

Gravity can be a very confusing topic. Not that long back Edward Current, known for his satirical "checkmate atheist!" videos made a serious one where he tried to explain how gravity is not a force in General Relativity. He tried to do so without math and it was not well received by another well known YouTuber, Desertphile (the man behind the Gravity Rant). It was not well received:

Yikes. This guy definitely does NOT understand GR.

Although, truthfully, the other does also.

 

[Subduction Zone]

Yikes. This guy definitely does NOT understand GR.

Or even orbits. He conflated centripetal force with centrifugal force in one part of the video. But otherwise he is fairly sensible. I enjoyed Edward Current's attempt to explain GR without using math. But on some it falls on deaf ears.

 

[MJ Bailey]

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

Maybe there is a relevancy to the coexistence of both

 

[MJ Bailey]

If Matter did not exist what would be the relevance of gravity?

 

[Heyo]

Gravity is a function of time.

I'd like to see the maths on that.

 

[Valjean]

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

Mass creates gravity wells by warping spacetime.
What's your question?

 

[MJ Bailey]

I'd like to see the maths on that.

Lol/ a bit more complicated than simple math; logic applies though

 

[Polymath257]

I'd like to see the maths on that.

For example, a gravitational wave varies in time.