How do planets get gravity

Same way as all gravity, it is generally lost kinetic energy from atoms that is transferred via the magnetic lines of force to a low level of quantized phase.  Electrons in motion in a planet cause magnetic lines of force, which will not stabilized because magnetism does not pack nulls at quant levels near the atom. So, when magnetic lines of force become extreme, either atoms causing it are slowly replaced by atoms with smaller dipoles, the atom gains thermal energy, or the magnetic lines dissipate outward until they can be stabilized by null packing by gravity.

There is an assumption in physics that particles can be detected.  But think about it for a moment, how do we detect particles? By manipulating other particles.  Gravity has such a low level of quantization that we assume it is a property of 'space'.  Nope, gravity is stabilized wave, held in place by packed nulls, like any other particle. The closest particle we have seen at that size is the neutrino, but that is still way too large.

What makes the difference is there are no null packing quants left for magnetism, but the electron and gravity both pack nulls. Protons do not cause gravity except when they have kinetic energy or help cause magnetic lines.  Protons are targets of phase gradients because protons are full of packed nulls which offer a minimum phase path.

Is there an infinitely stretchable medium over which we can assign dimensions and then take the limit to zero?  No.

If we want to find the missing magnetic null quant, look at neutrinos.

Most neutrinos passing through the Earth emanate from the Sun. About 6.5×10¹⁰ solar neutrinos per second pass through every square centimeter perpendicular to the direction of the Sun in the region of the Earth.^[2]

They emanate from the Sun which has a strong magnetic field, but they are not stabilized by any standing wave. That they travel at light speed is a good indication that the wave number is not quite large enough to contain the null number. So the thing will be wave when in motion.

They have no charge, but charge is a unit of phase relative to the electron. Until we get out of the habit of thinking there is one unit of phase, we will never work these issues.  Flavor is certainly a form of phase. Neutrinos come from the compaction of the electon and positron, they do not mix and when their packed nulls dissipate, we are likely to get the next null quant available, the magnetron.

They have tiny mass, thus long wavelength and couple to gravity phase gradient. If they went at the speed of light, their quant would double and they end up in electron space. But thats not happening, more likely they swirl increasingly outward from the Sun and eventually become fractional components of gravity.