Developing the technology is of utmost importance. Without this, you will never be able to dominate the galaxy. New inventions will reinforce your ships - making them much more powerful with new modules. Your planets will have better income and the citizens will be happier, regardless of conditions. Some technologies will allow erecting new buildings and structures; others will allow unique improvements and wonders. Sometimes their effects are immediate - you just need to develop them. When you open the technology tree, you will see it's divided into four categories. A sum of science points coming from your whole empire counts for technological development - planets, systems, events and other bonuses all contribute to this. Remember that you need to unlock technologies closer to the center if you want to discover more advanced things that await at the rims of this diagram.
What do the specific categories mean?
- At the top, there's everything you need about the Military, that is new weapon modules, structures and tactics, as well as ground units. Note that the entries on the left have new modules that don't require strategic resources. The downside is that these are inferior to those that do require such resources, which are on the right.
- Economy and Trading are on the right. Here are trade and industry projects, as well as improvements in Dust output in systems. You unlock here access to the Marketplace and the ability to colonize some of the inhabitable planets. Each new project here allows developing your systems further, as well as to extract new resources.
- On the bottom, we have Science and Exploration. As the name suggests, you can obtain new ways of traveling and of discovering the mysteries of the anomalies (curiosity). Here also are the technologies that allow terraforming and adding more population slots on planets.
- The ones on the right, are Empire Development tech. System improvements concerning the food output and the levels of happiness and influence are all here. You can unlock new diplomatic actions and forms of government. Some of the technologies will ensure new projects of better and bigger ships, which can be useful if you're planning to expand the fleet.
Unlocking subsequent "rings" (Stages). Every new stage requires a few technologies from the latest stage. The number of lock icons indicates how many technologies you need to be able to research the next stage. The Stages themselves don't necessarily have to be developed, but they often yield some interesting inventions. Besides, every stage usually offers some additional challenges (such as "develop 40 technologies"). This may yield some awards and adds to your score. Some stages are more critical than others: Economy and Trading will unlock system improvements at some point. That's not only very profitable, but allows interplanetary migration. Both of these are extremely useful. In the Empire Development, on the other hand, add new slots for Laws in the government. In subsequent stages of Exploration and Science, you will gain access to new modules, hence improving your military.