This layer gives you a view of the solar system you inhabit. You can see other planets, the star(s) that provide your planet(s) with energy and asteroid fields you some day might be able to harvest for resources.
Remember to explore your surroundings. Hidden inside asteroid fields you may find another player's listening post, eavesdropping on your communication. Possible just a 'curious George', but might also be the initial information gathering stage of war.
Hidden among the gigatonnes of rocks could also be entire asteroids of gold, silver and other valuable metals or resources.
Build a sensor network to discover interlopers and manage communication in your system.
Explore your neighbouring planets and set up outposts to start colonization. You decide if the indigenous species (possibly other players) deserves any mercy. Just remember that trade might be easier than conquest. Your species may be able to breathe in an atmosphere with only 6% oxygen, but other species might not be able to survive with that little amount of oxygen, or they might not even need oxygen at all.