Ichus' upper atmosphere is capped off with a very thick, durable, transparent barrier made of a substance that is still being studied today that has temporarily been dubbed Skyshell. It is nearly invisible to the naked eye, does not obscure our view of the cosmos, and creatures of flight seem to have an innate sense of where it is, with the higher-altitude flyers often veering away from it seconds before impact.

Celestial visitors such as meteors and angels do not have this sense; collisions with Skyshell eventually create Skypearls, large, warped inclusions of alien matter that are very slowly brought into the barrier. Particularly large pearls are visible with the naked eye from the surface of Ichus, causing oblong refractions of light that almost resemble the prismatic eye of a fish, or a ripple of water frozen in time. Large skypearls cast colorful shadows onto the surface. It is advised to avoid looking at the sky when a shadow passes over you due to the intensifying effect of the sun around the warped edge of the Skypearl.

[ Image here of a skypearl as seen from the ground, then another next to it of a person lying in a field with a skypearl's shadow cast over them with figure 01 and figure 02 ]

Skypearls can take years to fully descend through the barrier, often moving a few centimeters per year. Once half of the pearl is exposed to the inner atmosphere of Ichus, it will "pop" -- the material making up the pearl abruptly disappearing to drop the contained inclusion to the surface. The resulting pockmark will rapidly heal over once all foreign material has been removed.

Theories on the purpose of the shell range from physical protection from the bombardments of space to it being Ichus' own psychic barrier. Skyshell will be breached in order to attain travel to the stars beyond, though this project has sparked intense debates on whether doing so would be a self-destructive move.

Ichus does not appear to be the only body that possesses a skyshell -- using a telescope can reveal that there are several satellites orbiting Ichus that appear to be much smaller hollow spheres with unique environments within them. The existence of their shells is proven by the visible evidence of other skypearls around their atmosphere. Skyshells rotate independently of their contained core, so that pearls can appear to move against the rotation of stars and the sun.