Why is gravity a force and dark energy is energy?

[Steve3007]

Which is why Feynman made the point that you can't really understand this stuff without the math...

Or perhaps it should be "you can't describe this stuff without the maths?"

I think one interesting thing is why we ever feel that we need to describe these things using anything other than the maths; why we ever feel the need to do more than shut up and calculate. The mathematical descriptions of such things are the most effecient and accurate descriptions that we know. But we still have this hangover (if that's what it is) from what are sometimes called classical times that there is something called an intuitive, gut feeling about the way the world works, that is supposedly helped if we use analogies from our everyday experiences. Hence balls, and boomerangs and rubber membranes with objects rolling around on them.

[Mgrinder]

Which is why Feynman made the point that you can't really understand this stuff without the math...

Or perhaps it should be "you can't describe this stuff without the maths?"

I think one interesting thing is why we ever feel that we need to describe these things using anything other than the maths; why we ever feel the need to do more than shut up and calculate. The mathematical descriptions of such things are the most effecient and accurate descriptions that we know. But we still have this hangover (if that's what it is) from what are sometimes called classical times that there is something called an intuitive, gut feeling about the way the world works, that is supposedly helped if we use analogies from our everyday experiences. Hence balls, and boomerangs and rubber membranes with objects rolling around on them.

Math is hard, I think. Words are easy.

[Steve3007]

Yes, but perhaps one of the reasons why maths is hard is because it crams a lot of content into a small space. Words involve a lot of fluffy polystyrene packaging and relatively sparse content.

-- Updated Wed Jun 15, 2016 10:05 pm to add the following --

One trouble with the wordy analogies, I think, is that it's sometimes forgotten how metaphorical they are. The good thing about purely mathematical descriptions is that they don't have that baggage of metaphorical connection to the world we think we experience directly. They simply say "if you can quantitatively measure this thing that you're observing then you will find that it has this numerical relationship with this other thing that you're observing". It doesn't have to pretend that an electron, say, is some kind of fuzzy ball, or whatever. It can simply be a collection of measurable quantities.

[Mgrinder]

Yes, but perhaps one of the reasons why maths is hard is because it crams a lot of content into a small space. Words involve a lot of fluffy polystyrene packaging and relatively sparse content.

-- Updated Wed Jun 15, 2016 10:05 pm to add the following --

One trouble with the wordy analogies, I think, is that it's sometimes forgotten how metaphorical they are. The good thing about purely mathematical descriptions is that they don't have that baggage of metaphorical connection to the world we think we experience directly. They simply say "if you can quantitatively measure this thing that you're observing then you will find that it has this numerical relationship with this other thing that you're observing". It doesn't have to pretend that an electron, say, is some kind of fuzzy ball, or whatever. It can simply be a collection of measurable quantities.

Not a bad thought there. I like it.

[Steve3007]

Thanks. I was particularly proud of the "fluffy polystyrene packaging" part. Although I did worry that people might take it literally.

[Mgrinder]

Thanks. I was particularly proud of the "fluffy polystyrene packaging" part. Although I did worry that people might take it literally.

You should know that I think this is the first time I ever praised anyone on this forum. Don't let it go to your head though...

[Raymond]

It would seem that dark energy is the opposite of gravity where gravity pulls and dark energy pushes. Yet gravity is described as a force while dark energy is described as...well, energy.

Also with dark energy, within our solar system, it doesn't seem to operate while gravity does and gravity helps to keep our planets in orbit about our Sun.

Can anybody add to this?

PhilX

Dark energy is the effect of a negatively curved 4D space (5D spacetime) underlying the 3D space we observe. It is the virtual particle field that gives this space a default structure of two 4D infinite spaces connected by a thin wormhole. All real particles are confined to two 3D structures, universes, inflating into existence, then decelerating, and then accelerating again. Then the stage is set at the wormhole singularity to let two new 3D universes inflate into existence on the 4D substrate. Gravity is not confined to the three dimensions. The contribution of the matter to the curvature is positive but as space expands the contribution of the negative curvature grows and the matter ends up accelerating away to infinity and the whole process repeats from the start.