Could the Casimir effect possibly be an explanation for gravity?

"Could the Casimir effect possibly be an explanation for gravity?"

No, of course not. Casimir effect falls off by 1/r^4, and gravity by 1/r^2. Casimir effect is strongest between two conductors, and weakest between non-conductors... gravity does not care.

"If two plates can be pushed together in a vaccum because there are more particles outside of than between them then why couldn't the same effect apply to all particles not just the particles that make up the plates in the test?"

LeSage gravitation is what you are describing, and it fails experimental test. Read up on it:

http://en.wikipedia.org/wiki/Le_Sage%27s_theory_of...

"Wouldn't that mean that there would be a threshold in space where once two objects got close enough that basically the Casimir effect would take effect and force them together but if far away enough like galaxies it would force them apart(cosmological constant right?)"

Nope.

"I'm not a genius physicist I just read about this stuff and the casimir effect sparks my interest and seems like a good explanation for the effects of gravity. Why isn't it I guess is my question basically?"

See above.

Consider that mass is a constant times magnetic moment. Magnetic moment is the ability to store energy in a changing magnetic field. Propagating photons *everywhere*, produce changing magnetic fields *here*. So maybe gravitation (and expansion) is just games that light plays with us.

But Casimir effect is just "work function" effects of solids.

The Casimir effect is only apparent when two flat plates are extremely close together and falls off very rapidly to zero as the plates are moved apart a very small distance. In other words the effect falls off far more rapidly, as the plates move apart, than by the square of the distance between two masses that gravity does. Also, the Casimir effect is not a function of the mass of two bodies; it has much more to do with the geometry of the two objects. The Casimir effect also doesn't explain gravitational lensing. The link is to an alternative theory of gravity that may unite both gravity and dark energy.

I do believe that it could be the case, yes. The Casimir effect might even explain Dark Matter and Dark Energy! At certain scales, gravity seems to be either stronger than it should be, or much weaker than it should be.