The Missing Matter Conundrum
It's estimated that about 85% of the matter in the universe is missing as the gravitational effects (observed by the rotational velocity or rate of spin of galaxies) point to a discrepancy between the amount of visible matter and the the rotational acceleration of the galaxies. Instead of questioning the underlying concept and assumptions of gravity, scientists go to the other extreme and postulate that the matter must instead be "invisible" to normal methods of observation (i.e. dark matter). To begin with, much of our assumptions about gravity have to do with the amount of matter that we postulate must exist within the earth, where the deeper you go into the earth's center, purportedly the more dense, and hence the more matter that must necessarily exist. What if, instead we core out 85% of the earth's matter (make it hollow) and then attribute the observable gravitational effects to this less dense earth model? Would this newly calculated mass model have a ripple effect throughout astro-physics which would then correct the offset of gravitational pull with the amount of visible matter? I postulate that it would certainly go a long way in explaining one of the biggest scientific conundrums of our time.
radial density profile that is a commonly held scientific postulation, results in a hollow shell that is on average approximately 340 miles thick.]
Most spinning systems in nature (tornados, hurricanes, cyclones, water vortices, atoms, etc.) are all naturally occurring hollow phenomena. Just try holding onto the center of a merry-go-round. In a spinning system, matter cannot cling to the center of rotation but is spun out to the edge and would continue to fling outward if it weren't for a force to counteract this outward tug. The balancing force, in the planetary scenario, is gravity. Proto-planetary systems all begin their formation having a substantial rotational velocity or angular momentum. Thus, the matter in a spinning system accretes at the boundary where the centrifugal force (due to angular momentum or spinning energy) and gravity cancel out at the point (radius) of null-force or equilibrium. This fact is evidenced by the larger planets in our solar system (Jupiter, Saturn, Uranus & Neptune) having a shorter rotational period (9.9 hrs., 10.8 hrs., 17.3 hrs., 16.1 hrs. respectively) or greater rotational velocity than earth. Effectively, it can be said that these planets are larger because they possessed more angular momentum during their formation.
This effect can be observed experimentally by taking a weight on a string and slowly spinning around while standing and holding the end of the string and observing how far from your body the weight flings outward from the center of rotation. With a slower rate of spin, the weight will only move several inches until gravity equals the centrifugal acceleration generated by the system's rotational inertia. As you spin faster, observe what happens to the distance of the weight relative to your body. As you move with a greater rate of spin, the weight finds a new equilibrium point between gravity and the new centrifugal acceleration with a radius or point which is further from your body (the axis of rotation). This illustrates the same manner in which planetary diameters and orbits settle out during planetary formation.
As the matter in a proto-planetary body coalesces along the equilibrium point between gravity and the centrifugal force due to rotational inertia, it slowly cools and hardens to form a planetary shell. Effectively, planets are bubbles. The sphere is the strongest naturally occurring physical form (not the triangle, sorry). This is why the earth and the moon ring like bells after quakes or some event which effectively strikes them like a hammer to a bell.
It's a rather interesting paradigm shift to explore the option that all planets are merely cosmic bubbles floating through space. As such, there is the potential that they can harbor life within the protective confines of their shell. There is estimated to be nearly twice as many jupiter size rogue planets (planets not tethered to a star) wandering through the galaxy than there are visible stars. This greatly multiplies the possibility of life in the universe as we have, literally, only begun scratching the surface in our search for extra-terrestrial life. No more is it necessary for planets to exist in the fabled goldilocks zone but now all celestial spheres can potentially harbor life regardless of their distance from a star. Effectively, planetary objects are spaceships hurling through space. We just happen to live on the outside of our spaceship which is a bit of a mathematical improbability in cosmic terms due to our unlikely fortuitous position or distance away from our central star.