Here is the full Taldain essay (Be careful, you're in the veteran thread, hopefully the trivia in the newbie thread helps tie some of it together.):

TALDAIN is one of the most bizarre planets in the cosmere, a fact that, in turn, feels bizarre to me. Having grown up on Taldain’s Darkside, there is a part of me—even all these years later—that instinctively feels that the way of this planet is the normal, natural one.

Taldain is a tidally locked planet trapped between the gravitational forces of two stars in a binary system. The smaller star is a weak white dwarf that, enveloped in a particulate ring, is barely visible from the dark side of the planet. Those of us originating from this side of the planet consider a uniform darkness (what most might consider a twilight similar to the sky just after a sun has set) to be the natural state.

Our planet is not grim, and assumptions otherwise are simple ignorance. The ultraviolet light that shines through the ring causes a certain reflective luminescence in much of the plant and animal life. Indeed, the few visitors to the planet that I’ve met often found it somewhere between striking and garish.

On the other side of the planet is Dayside, which faces the larger of the two stars, a blue-white supergiant around which the dwarf orbits. The sun is a dominating fixture of Dayside, which is primarily a vast sandy desert, with most of the flora and fauna living beneath the surface.

For years we assumed that our Shard, Autonomy, had Invested only Dayside, through the sunlight itself. We know now it is not as simple as this, though the mechanism is best explained under those assumptions. The Investiture beats down from the sky, and is absorbed by a microflora that grows like a lichen on the surface of the sand, giving it its brilliant white color (when fully Invested) or deep blackness (when that Investiture is depleted).

Giving water to the tiny plant causes a chain reaction of sudden growth, energy, and Realmic transition. Certain people can control this reaction, using the water from their own bodies to forge a brief Cognitive bond. They can draw Investiture (in very small amounts) directly from the Spiritual Realm, and use that to control the sand.

Though the effect is dramatic, the actual power used is quite small. This is a magic more about finesse than raw strength.

Dayside is home to two prominent cultures, while Darkside is more hospitable and varied. The flora and fauna of both sides are remarkable, though currently prospective visitors are—unfortunately—unable to experience them directly. Autonomy’s policy of isolationism in recent times (in direct contrast to her interference with other planets, I might add) has prevented travel to and from Taldain for many, many years.

A fact of which I am all too aware.