Meteors
In every culture in the world, throughout all ages in history, there is a pervading myth that stars are spirits, which fall to earth so that children may be born.
Many variations exist, e.g. stars rise when men die and fall when they reincarnate, stars are gods that take mortal shape on occasion, it was punishment for breaking the natural order, and so on, but one fact can be confirmed: meteor strikes happen near gatherings of living creatures, and happen more frequently the larger the gathering gets, but rapidly taper off if the creatures leave or die.
While the mechanism for this is still unknown, the reasoning has likely been discovered: starsteel forms the core of all known cell types, and is therefore the primary bottleneck for true population growth. This may help explain the prevalence of mutations in high-starsteel areas, the general increases in both healing and body coordination in the past several centuries, and indeed form the core of modern medicine.
Starsteel
It has long been known that meteors do not always burn up in their descent. The resulting substance has had many names, but in this age, the common one is Starsteel.
(This is actually a misnomer brought about by several factors, but no one's managed to get it fixed.)
Historically, no force was known that could shape the metal once it fell to earth and cooled - even when more Starsteel was used for tools. With no way to work them, however, meteors were mostly prestige objects, often sacred.
What few tools it was used for sometimes had strange effects, but they weren't well recorded. They're mostly believed to be real, though, thanks to the discovery of Isolation.
Isolation
Isolation is a phenomenon seemingly unique to Starsteel, that happens as it cools.
When Starsteel is affected by two stimuli at once, it appears to link them somehow, accepting the one stimulus as a trigger for the other effect - even if the response is vastly disproportionate to the energy supplied. Sufficient heat will deactivate these links, and allow new ones to be formed. The modern word for this is Programming.
There are a few limits on Programs. The first, and most obvious, is initial stimulus - if you can't produce an effect in the first place, it's very hard to make Starsteel reproduce it.
The second is the number of Programs. A Program can be made very complex indeed, having almost completely unrelated effects at different levels of stimulus - a change in average surface pressure, for example, may determine whether a device glows in response to vibration or vibrates in response to electrical current, as in a common radio - but to produce truly different effects with the same, limited number of stimuli, another device must be made.
The third is a secondary phenomena, that occurs when two Programmed pieces of Starsteel make contact. When they do so, their Programs begin to integrate, producing a new one with attributes of both. This process is known as Program Corruption, and is the only known way to work around the first limit.
Interlude: Time
The planet on which our heroes live spins on two major axes. The first, used to measure days, spins perpendicular to the magnetic poles, at a rate of one full rotation per twenty hours. The second, slower rotation goes perpendicular to the planet's orbit, and runs in the opposite direction, at roughly the same speed of revolution. This means that a magnetic pole faces the sun at four points during a full solar orbit, twice for each, and that each orbit is equivalent to two crop years, which are naturally the most widespread form of time measurement.
By comparison, the moons' orbit isn't nearly so tidy (25 times for every three and a half crop years) and is rarely used.