Science education - How much of the theory is true enough?

In science class, we were taught that atom is the smallest particle available in the universe. Everything around us is made up from combinations of these atoms.Earth studies told us that our living continents are moving slowly around the Earth's crust like floated platforms moving on water. The constant friction between the giant plates creates earthquakes. What if, one day we found out that the contemporary teachings and theories were not complete enough? That means everything we have learnt and known need to be redefined. 

It was recently found by scientists that the atom is able to be divided into smaller components, which they named as sub-atom. This sub-atomic theory was then realized to be able to describe the birth of universe. Although this theory contradicts the well-known theory of general relativity by Einstein, both theories describe our universe fitly in their own respective way. 

I have read of some articles saying that our Earth is actually growing and expanding throughout these years since its birth. The expansion of Earth's diameter has caused the continents that we are living in to crack and become sub-divided into several smaller tectonic plates. If this theory happened to be true, it means that the tectonic studies and plate movement mechanism used for earthquake studies need to be redefined.

I slowly become aware that nothing is perfect as I grow up. In fact, things become even clearer when I entered the world of industry. Most theories, or products were being commercialized even before they are fully tested. Most system providers will tend to do R&D of their product alongside the implementation. 

Therefore, we are living in a contemporary world - that the world is everyday improving and changing. What we know today might become wrong the next day.