So, why is gravity weaker than the other forces? Could it be that the power of a force is inversely proportional to the range that it must act across? Of the three forces mentioned, in order of power they go gravity, electromagnetic, nuclear. In order of range they decay over, they go nuclear, electromagnetic, gravity.
So is it something like k/(Force of the force when two objects are touching)=(distance where force is half as much as when the two objects are touching)?
>>7736742
>Could it be that the power of a force is inversely proportional to the range that it must act across?
No.
https://en.wikipedia.org/wiki/General_relativity
>>7736742
>k/(Force of the force when two objects are touching)=(distance where force is half as much as when the two objects are touching)?
No. For instance, that is actually the same distance for gravity and electromagnetism! Both follow an inverse-square law where the force at a distance d is half the force at d/sqrt2.
>>7738995
The only reason it seems like gravity has a longer range than electromagnetism is just that matter in general is composed of equal numbers of positive and negative charges, so large bodies have almost zero net charge*. Gravity, however, attracts everything, so large bodies build up a truly enormous gravitational "charge". This is why gravity dominates the universe, despite seeming so weak.
*the same goes for magnetism: Since every magnetic dipole has a North and South pole right next to one another, over long distances they cancel out.
>>7736742
>So, why is gravity weaker than the other forces?
If I knew I would be writing a paper not posting on /sci/.
>>7736742
>"weak"
>"strong"
>not just realizing that they're governed by different potential functions
"dark energy" is really just a fifth, as of yet unidentified fundamental force. It's like an even weaker, repulsive version of gravity. It's so weak that we haven't noticed it on earth yet.
>>7738949
>>7738995
I don't understand why physicists assume gravity is just an inverse square law when it obviously has a flaw (hence the addition of dark matter).
Actually found something related to my idea and OP's idea:
https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics
http://arxiv.org/pdf/astro-ph/0606197v1.pdf
in development, but this makes more sense to me.
>>7739070
http://arxiv.org/pdf/astro-ph/0104435v1.pdf
>>7739093
To summarize:
If you try to make MOND work, it does indeed approximately explain the rotation curve of galaxies, but every single other thing in physics and cosmology completely breaks. It's not even obvious that MOND is self-consistent.
And it doesn't even explain the rotation curve of galaxies very well.
>>7739115
really nigger?
GR doesn't even explain the shape of galaxies.
>>7739115
Because GR is incredibly hard to do calculations with.
Also, trying to extend GR in a MONDy way is really awkward. To quote the posted paper:
Zhitnikov & Nester (1994) presented a very elegant
argument about the form of reasonable extensions to GR
which might explain flat rotation curves. They assumed that
such modifications are in the framework of metric theories
which also conform to several other rather weak assumptions.
The most general metric that they found is more general
than the usual Parameterized Post-Newtonian formalism
(see e.g. Will 1993). They found that constraints on the
terms and symmetries within such a metric (coming from the
necessity to fit with solar system experiments, gravitational
deflection of light, etc.) make it seem rather improbable that
flat rotation curves can be explained away without the need
for dark matter.
>>7739111
Also, there's the problem of colliding galaxy clusters. Because gravity bends light, we can measure the density of apparent mass by looking at the pattern of bending. By examining colliding clusters like the Bullet Cluster and comparing their visible matter distributions and apparent gravitational density, the mass distribution appears to be the same shape, but somewhat offset from the actual distribution of visible matter - as though when the two galaxies collided, most of their mass had just kept going without slowing down.
This is a perfect fit for some kind of dark matter, but virtually impossible to explain with modified gravity.
>>7739070
Except physicists don't assume gravity is an inverse square law because it isn't exactly. The inverse square law is a good approximation in weak gravitational fields, which can be experimentally verified. The approximation involves the use of a linearized curvature perturbation applied to the spacetime metric when solving Einstein's field equations in addition to assuming negligible effects arising from Special Relativity. But without using approximations, in General Relativity, gravity certainly does not obey an inverse square law.
>>7739132
>The approximation involves the use of a linearized curvature perturbation applied to the spacetime metric when solving Einstein's field equations in addition to assuming negligible effects arising from Special Relativity.
Yeah this^
